SatNOGS Wiki - User contributions [en]

SatNOGS Rotator v3

2019-01-28T13:12:51Z

Azisi:

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tags/v3.1-pre-release
|latest-release-name= v3.1
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ v3.0.1] [https://wiki.satnogs.org/SatNOGS_Rotator_v3#Build_Sequence v3.1]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || ?, ~30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -5 and -6, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
File:C1084-1.png|C1084-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

{{Message|
Prior to Step 8, the rotary encoders must be ready and prior to Step 11 the motor must be mounted in A1070-1. For the rotary encoder assembly look at the next section [https://wiki.satnogs.org/SatNOGS_Rotator_v3#Rotator_Controller Rotator_Controller].}}

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].
Also construct [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Encoders the rotary encoders] for DC motor set up.

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

<gallery widths=200 heights=200 perrow=4>
File:Cover_box_1.JPG| Put the C1080-3 with screws M4 L10 DIN912, C1084-1 and washers M4 DIN125 to the azimuth module. The screw with the Phillips Rounded Head Screws For Sheet Metal, M3,5 X 6,5, DIN 7981,INOX A2, C1082-5 to the C1080-3 and put the C1083-1. Note screw only the middle screw.
File:Power_cable_1.JPG| The power - data cable must be passed inside the azimuth axis. This solution is tested [https://network.satnogs.org/stations/200/ in station 200] without problem.
File:Power_cable_2.JPG| In the other side of power cable must be installed a connector with 4 terminals and waterproof like [https://grobotronics.com/connector-sp-4-pin-male.html Weipu - SP1310/P4I]. Also it is needed to have the female connector for cable that connected to the client. For cheaper solution use a bigger cable to connect the rotator with client and power source.
File:Other_cables_2.JPG|The 3 CAT5e UTP cables are 2x sensors (encoders - end stops) 1x power and data (RS-485). For color code use [https://en.wikipedia.org/wiki/Power_over_Ethernet#Pinouts 802.3af Standards A and B] from the power sourcing equipment perspective.
File:Other_cables_3.JPG|The other cables are for DC motor or stepper motors. In each side of the CAT5e UTP cables must be put a Heat-shrinkable asreferred in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM]. Also a Heat-shrinkable must be putin the cable gland in rotator controller for motor cables.
File:Other_cables_1.JPG|Pass all the cables though the hole in the bottom of C1080-3
File:Motor_ferrite_bead.JPG|Add ferrite beads for motor cables, dimensions L25mm and OD 13mm
File:Velcro_for_controller_1.JPG|Add velcro to mount the rotator controller outside the box. Velcro tape specifications: Heavy duty, stick on, max 7Kg, 50mm x 100mm. The tape might be used to mount [https://wiki.satnogs.org/No_rotator client box] in the rotator.
File:Rotator_controller_1.JPG| Cabling management inside the rotator controller. The controller is mounted to the rotator by using a tape as mentioned previously.
File:Rotator controller 2.JPG| Cabling management outside the rotator controller
File:Testing_1.JPG| The rotator is ready for testing, before the final step do not put the C1081-3, in order to most of components must be accessible
File:Testing 2.JPG| The final step. If everything is working properly, must be put the C1081-3 by using sheet metal screws as mentioned previously. In this step if the holes of C1081-3 are not aligned with the holes of the other two parts, C1082-5 and C1080-3, drill new holes and screw them, take a look in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/issues/73 issue 73]. Put stickers!!!!!!

</gallery>

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator v3

2019-01-28T13:11:46Z

Azisi:

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tags/v3.1-pre-release
|latest-release-name= v3.1
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ v3.0.1] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || ?, ~30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -5 and -6, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
File:C1084-1.png|C1084-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

{{Message|
Prior to Step 8, the rotary encoders must be ready and prior to Step 11 the motor must be mounted in A1070-1. For the rotary encoder assembly look at the next section [https://wiki.satnogs.org/SatNOGS_Rotator_v3#Rotator_Controller Rotator_Controller].}}

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].
Also construct [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Encoders the rotary encoders] for DC motor set up.

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

<gallery widths=200 heights=200 perrow=4>
File:Cover_box_1.JPG| Put the C1080-3 with screws M4 L10 DIN912, C1084-1 and washers M4 DIN125 to the azimuth module. The screw with the Phillips Rounded Head Screws For Sheet Metal, M3,5 X 6,5, DIN 7981,INOX A2, C1082-5 to the C1080-3 and put the C1083-1. Note screw only the middle screw.
File:Power_cable_1.JPG| The power - data cable must be passed inside the azimuth axis. This solution is tested [https://network.satnogs.org/stations/200/ in station 200] without problem.
File:Power_cable_2.JPG| In the other side of power cable must be installed a connector with 4 terminals and waterproof like [https://grobotronics.com/connector-sp-4-pin-male.html Weipu - SP1310/P4I]. Also it is needed to have the female connector for cable that connected to the client. For cheaper solution use a bigger cable to connect the rotator with client and power source.
File:Other_cables_2.JPG|The 3 CAT5e UTP cables are 2x sensors (encoders - end stops) 1x power and data (RS-485). For color code use [https://en.wikipedia.org/wiki/Power_over_Ethernet#Pinouts 802.3af Standards A and B] from the power sourcing equipment perspective.
File:Other_cables_3.JPG|The other cables are for DC motor or stepper motors. In each side of the CAT5e UTP cables must be put a Heat-shrinkable asreferred in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM]. Also a Heat-shrinkable must be putin the cable gland in rotator controller for motor cables.
File:Other_cables_1.JPG|Pass all the cables though the hole in the bottom of C1080-3
File:Motor_ferrite_bead.JPG|Add ferrite beads for motor cables, dimensions L25mm and OD 13mm
File:Velcro_for_controller_1.JPG|Add velcro to mount the rotator controller outside the box. Velcro tape specifications: Heavy duty, stick on, max 7Kg, 50mm x 100mm. The tape might be used to mount [https://wiki.satnogs.org/No_rotator client box] in the rotator.
File:Rotator_controller_1.JPG| Cabling management inside the rotator controller. The controller is mounted to the rotator by using a tape as mentioned previously.
File:Rotator controller 2.JPG| Cabling management outside the rotator controller
File:Testing_1.JPG| The rotator is ready for testing, before the final step do not put the C1081-3, in order to most of components must be accessible
File:Testing 2.JPG| The final step. If everything is working properly, must be put the C1081-3 by using sheet metal screws as mentioned previously. In this step if the holes of C1081-3 are not aligned with the holes of the other two parts, C1082-5 and C1080-3, drill new holes and screw them, take a look in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/issues/73 issue 73]. Put stickers!!!!!!

</gallery>

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator v2

2019-01-24T14:32:21Z

Azisi: Add more info about the v2 rotator

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v2
|image= 29854586940 d47e229453 k.jpg
|type= Az/El
|cost= ~200 (with electronics)
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tags/v2.0
|latest-release-name= v2
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/ gitlab
|documentation= https://satnogs.dozuki.com/c/SatNOGS_Hardware dozuki
}}

== Intro ==

v2 is the first attempt to build a rotator for SatNOGS project.

[[File:30033213301 ef78e64120 k.jpg|thumb|center|800x420px|alt=|Inside the v2 rotator]]

== Assembly ==

Assembly instructions can be found [https://satnogs.dozuki.com/Guide/SatNOGS+Ground+Station+v2+Electronics+Assembly/2 here].

All the parts are placed [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tags/v2.0 here].
The electronics and firmware to control the motors are placed [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags/v1 here].
The v2 rotator could be also controlled by the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags/v2.2 v2.2]
controller. The [https://wiki.satnogs.org/SatNOGS_Rotator_Controller v2.2 rotator controller wiki].

In the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags/v1 v1] board the new [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware firmware] hasn't been tested. At first changes in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/libraries/rotator_pins.h rotator_pins.h] header file must be done to match with v1 board pins. But the different mcu Atmega32u4, optiboot bootloader and WDT peripheral may create problems to nominal operation of the rotator.

Related posts in [https://community.libre.space/ libre space community]:

* [https://community.libre.space/t/design-files-for-satnogs-v2-box/468 Design files for SatNOGS v2 box]
* [https://community.libre.space/t/iz5rzr-satnogs-v-2-from-italy/1001 IZ5RZR Satnogs V.2 from Italy]
* [https://community.libre.space/t/newbie-wants-to-build-a-v2-ground-station/3189 Newbie wants to build a V2 ground station]

File:29854586940 d47e229453 k.jpg

2019-01-24T14:27:01Z

Azisi: satnogs rotator v2

satnogs rotator v2

File:30033213301 ef78e64120 k.jpg

2019-01-24T14:21:32Z

Azisi: satnogs rotator v2

satnogs rotator v2

SatNOGS Rotator v3

2019-01-24T13:37:04Z

Azisi: Update the latest release

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tags/v3.1-pre-release
|latest-release-name= v3.1
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || ?, ~30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -5 and -6, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
File:C1084-1.png|C1084-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

{{Message|
Prior to Step 8, the rotary encoders must be ready and prior to Step 11 the motor must be mounted in A1070-1. For the rotary encoder assembly look at the next section [https://wiki.satnogs.org/SatNOGS_Rotator_v3#Rotator_Controller Rotator_Controller].}}

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].
Also construct [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Encoders the rotary encoders] for DC motor set up.

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

<gallery widths=200 heights=200 perrow=4>
File:Cover_box_1.JPG| Put the C1080-3 with screws M4 L10 DIN912, C1084-1 and washers M4 DIN125 to the azimuth module. The screw with the Phillips Rounded Head Screws For Sheet Metal, M3,5 X 6,5, DIN 7981,INOX A2, C1082-5 to the C1080-3 and put the C1083-1. Note screw only the middle screw.
File:Power_cable_1.JPG| The power - data cable must be passed inside the azimuth axis. This solution is tested [https://network.satnogs.org/stations/200/ in station 200] without problem.
File:Power_cable_2.JPG| In the other side of power cable must be installed a connector with 4 terminals and waterproof like [https://grobotronics.com/connector-sp-4-pin-male.html Weipu - SP1310/P4I]. Also it is needed to have the female connector for cable that connected to the client. For cheaper solution use a bigger cable to connect the rotator with client and power source.
File:Other_cables_2.JPG|The 3 CAT5e UTP cables are 2x sensors (encoders - end stops) 1x power and data (RS-485). For color code use [https://en.wikipedia.org/wiki/Power_over_Ethernet#Pinouts 802.3af Standards A and B] from the power sourcing equipment perspective.
File:Other_cables_3.JPG|The other cables are for DC motor or stepper motors. In each side of the CAT5e UTP cables must be put a Heat-shrinkable asreferred in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM]. Also a Heat-shrinkable must be putin the cable gland in rotator controller for motor cables.
File:Other_cables_1.JPG|Pass all the cables though the hole in the bottom of C1080-3
File:Motor_ferrite_bead.JPG|Add ferrite beads for motor cables, dimensions L25mm and OD 13mm
File:Velcro_for_controller_1.JPG|Add velcro to mount the rotator controller outside the box. Velcro tape specifications: Heavy duty, stick on, max 7Kg, 50mm x 100mm. The tape might be used to mount [https://wiki.satnogs.org/No_rotator client box] in the rotator.
File:Rotator_controller_1.JPG| Cabling management inside the rotator controller. The controller is mounted to the rotator by using a tape as mentioned previously.
File:Rotator controller 2.JPG| Cabling management outside the rotator controller
File:Testing_1.JPG| The rotator is ready for testing, before the final step do not put the C1081-3, in order to most of components must be accessible
File:Testing 2.JPG| The final step. If everything is working properly, must be put the C1081-3 by using sheet metal screws as mentioned previously. In this step if the holes of C1081-3 are not aligned with the holes of the other two parts, C1082-5 and C1080-3, drill new holes and screw them, take a look in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/issues/73 issue 73]. Put stickers!!!!!!

</gallery>

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator v3

2019-01-23T15:05:29Z

Azisi: Update Cover Box - Cabling, with photos and descriptions

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || ?, ~30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -5 and -6, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
File:C1084-1.png|C1084-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

{{Message|
Prior to Step 8, the rotary encoders must be ready and prior to Step 11 the motor must be mounted in A1070-1. For the rotary encoder assembly look at the next section [https://wiki.satnogs.org/SatNOGS_Rotator_v3#Rotator_Controller Rotator_Controller].}}

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].
Also construct [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Encoders the rotary encoders] for DC motor set up.

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

<gallery widths=200 heights=200 perrow=4>
File:Cover_box_1.JPG| Put the C1080-3 with screws M4 L10 DIN912, C1084-1 and washers M4 DIN125 to the azimuth module. The screw with the Phillips Rounded Head Screws For Sheet Metal, M3,5 X 6,5, DIN 7981,INOX A2, C1082-5 to the C1080-3 and put the C1083-1. Note screw only the middle screw.
File:Power_cable_1.JPG| The power - data cable must be passed inside the azimuth axis. This solution is tested [https://network.satnogs.org/stations/200/ in station 200] without problem.
File:Power_cable_2.JPG| In the other side of power cable must be installed a connector with 4 terminals and waterproof like [https://grobotronics.com/connector-sp-4-pin-male.html Weipu - SP1310/P4I]. Also it is needed to have the female connector for cable that connected to the client. For cheaper solution use a bigger cable to connect the rotator with client and power source.
File:Other_cables_2.JPG|The 3 CAT5e UTP cables are 2x sensors (encoders - end stops) 1x power and data (RS-485). For color code use [https://en.wikipedia.org/wiki/Power_over_Ethernet#Pinouts 802.3af Standards A and B] from the power sourcing equipment perspective.
File:Other_cables_3.JPG|The other cables are for DC motor or stepper motors. In each side of the CAT5e UTP cables must be put a Heat-shrinkable asreferred in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM]. Also a Heat-shrinkable must be putin the cable gland in rotator controller for motor cables.
File:Other_cables_1.JPG|Pass all the cables though the hole in the bottom of C1080-3
File:Motor_ferrite_bead.JPG|Add ferrite beads for motor cables, dimensions L25mm and OD 13mm
File:Velcro_for_controller_1.JPG|Add velcro to mount the rotator controller outside the box. Velcro tape specifications: Heavy duty, stick on, max 7Kg, 50mm x 100mm. The tape might be used to mount [https://wiki.satnogs.org/No_rotator client box] in the rotator.
File:Rotator_controller_1.JPG| Cabling management inside the rotator controller. The controller is mounted to the rotator by using a tape as mentioned previously.
File:Rotator controller 2.JPG| Cabling management outside the rotator controller
File:Testing_1.JPG| The rotator is ready for testing, before the final step do not put the C1081-3, in order to most of components must be accessible
File:Testing 2.JPG| The final step. If everything is working properly, must be put the C1081-3 by using sheet metal screws as mentioned previously. In this step if the holes of C1081-3 are not aligned with the holes of the other two parts, C1082-5 and C1080-3, drill new holes and screw them, take a look in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/issues/73 issue 73]. Put stickers!!!!!!

</gallery>

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

File:Testing 2.JPG

2019-01-23T15:00:35Z

Azisi: Final step and testing

Final step and testing

File:Testing 1.JPG

2019-01-23T14:58:19Z

Azisi: The rotator is ready for testing

The rotator is ready for testing

File:Rotator controller 2.JPG

2019-01-23T14:55:06Z

Azisi: Cabling management

Cabling management

File:Rotator controller 1.JPG

2019-01-23T14:53:22Z

Azisi: Rotator controller set up

Rotator controller set up

File:Velcro for controller 1.JPG

2019-01-23T14:50:13Z

Azisi: Velcro to mount the rotator controller

Velcro to mount the rotator controller

File:Motor ferrite bead.JPG

2019-01-23T14:48:09Z

Azisi: Ferrite beads for motor cables

Ferrite beads for motor cables

File:Cover box 1.JPG

2019-01-23T14:39:57Z

Azisi: Cover box assembly

Cover box assembly

File:Power cable 2.JPG

2019-01-23T14:36:34Z

Azisi: Power cable connector

Power cable connector

File:Power cable 1.JPG

2019-01-23T14:33:41Z

Azisi: Power cable

Power cable

File:Other cables 3.JPG

2019-01-23T14:27:01Z

Azisi: Cabling management

Cabling management

File:Other cables 2.JPG

2019-01-23T14:21:01Z

Azisi: Cabling management inside the rotator

Cabling management inside the rotator

File:Other cables 1.JPG

2019-01-23T14:16:01Z

Azisi: Showing how to pass cables in rotator

Showing how to pass cables in rotator

SatNOGS Rotator v3

2019-01-23T14:03:37Z

Azisi: /* Assembly */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || ?, ~30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -5 and -6, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
File:C1084-1.png|C1084-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

{{Message|
Prior to Step 8, the rotary encoders must be ready and prior to Step 11 the motor must be mounted in A1070-1. For the rotary encoder assembly look at the next section [https://wiki.satnogs.org/SatNOGS_Rotator_v3#Rotator_Controller Rotator_Controller].}}

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].
Also construct [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Encoders the rotary encoders] for DC motor set up.

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator v3

2019-01-23T13:49:49Z

Azisi: /* Assembly */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || ?, ~30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -5 and -6, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
File:C1084-1.png|C1084-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

{{Message|
Prior to final step, Step 12, the encoders and motors must be installed to each axis module, in Step 11. For the rotary encoder assembly look at the next section [https://wiki.satnogs.org/SatNOGS_Rotator_v3#Rotator_Controller Rotator_Controller].}}

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].
Also construct [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Encoders the rotary encoders] for DC motor set up.

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator v3

2019-01-23T13:45:25Z

Azisi: /* Rotator Controller */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || ?, ~30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -5 and -6, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
File:C1084-1.png|C1084-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].
Also construct [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Encoders the rotary encoders] for DC motor set up.

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator Controller

2019-01-23T13:40:38Z

Azisi:

{{Template:Development
|Name= SatNOGS Rotator Controller
|image= Rotator controller v2.jpg
|type= Rotator Controller for SatNOGS rotator.
|cost= 60-80€
|status= Working
|latest-release-name= -
|latest-release= v2.2
|source-repo= [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller satnogs-rotator-controller - GitLab]
[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller-encoder satnogs-rotator-controller-encoder - GitLab]
|documentation= https://wiki.satnogs.org/index.php?title=SatNOGS_Rotator_Controller SatNOGS wiki
}}

== Intro ==
SatNOGS Rotator Controller refers to the set of electronics designed to operate a SatNOGS Rotator. There have been multiple iterations of the rotator controller design, but the modularity of the approach enables operations between different versions of the controller and the rotator.
Since the start of 2016, the rotator controller design is able to facilitate a DC-motors or stepper-motors rotator design. We intend to keep this modularity for the electronics and firmware design to facilitate the variety of build by our community.

== Rotator Controller v2 ==
<gallery>
Pcb_schema_v2_revC.png
Pcb_board_v2_revC.png
</gallery>

The PCB are tested in this [https://network.satnogs.org/stations/9/ ground station].

=== Features ===
* It is designed to fit the entire electronics needed to control rotator in Euroboard 80x50 mm.
* Main micro-controller is [https://store.arduino.cc/arduino-pro-mini Arduino pro-mini], [https://github.com/sparkfun/Arduino_Pro_Mini_328 SparkFun's Arduino Pro Mini 328] dev-board with ATmega328p.
* The modular design includes plug-in either [https://www.pololu.com/product/2133 DRV8825]/[https://www.pololu.com/product/1182 A4988] or [https://www.pololu.com/product/1213/resources DC motor drivers] (MC33926).
* The power supply in embed in the same board in contrast with previous version.
* Filtered power supply of micro controller.
* An I2C multiplexer is used to connect I2C encoders AS5601 (same ID) to get position feedback for each axis.
* A temperature sensor TC-74 monitoring the temperature inside the controller box in order to protect them from over-heating.
* There are some spare dev-pins in order to connect other peripherals like IMU or an LCD display.
* Pins with integrated RC-Low Pass filter for end-stops connection.
* Default communication interface is RS-485 but it can also be used as a UART.
* Using different paths for digital and power (motors) GND.
* Electrolytic capacitor and TVS-diode in PSU input
* Flashed either by using UART or ISP header

=== Build sequence ===
* Make sure you have a [[SatNOGS Rotator v3|mechanical assembly]] of the rotator constructed and ready
* Buy the PCB. [https://oshpark.com OshPark],[https://www.seeedstudio.com/fusion_pcb.html Seeed Fusion][https://www.pcbway.com PCBWay.com], [http://dirtypcbs.com DirtyPCBs.com], [https://www.elecrow.com/ Elecrow] have been used in the past with good results.
** You can order the v2.2 of the board directly using [https://oshpark.com/shared_projects/w0s8d4OJ this OSHPark link] or [https://dirtypcbs.com/store/designer/details/6933/5904/satnogs-v3-motor-controller-zip this DirtyPCBs link].
** You can order the v1.0 of the rotary encoder board using [https://oshpark.com/shared_projects/I3b8SCci this OSHPark link]
** You can order PCB as well as [https://www.seeedstudio.com/prototype-pcb-assembly.html PCB Assembly service] from Seeed Studio
* Get all the necessary components according to BOM from latest tag (or the version that you want to build), [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags Gitlab Tags]
* Assemble the PCB, by soldering the components
* Burn the firmware
* Using the wiring diagram, connect the controller to the Rotator
* You are ready! Proceed with testing

==== Assembly Guide ====

[[File:H1000_aluminium_enclosure.png|thumb|center|800x420px|alt=|Rotator Controller - Drill holes]]
[[File:Rotator_controller_sheet1.png|thumb|center|800x420px|alt=|Rotator Controller sheet 1/2]]
[[File:Rotator_controller_sheet2.png|thumb|center|800x420px|alt=|Rotator Controller sheet 2/2]]

==== Microcontroller ====
<gallery mode=packed heights="250px">
Uc.png|Microcontroller
Uc_orientation.png|Microcontroller Orientation
I2c_pullup.png|I2C pull-up resistors
</gallery>


The main micro-controller of the board is arduino pro-mini 5V@16MHz, ATmega328P.
The +5V of the controller are produced from arduino pro-mini.
Some clones do not use correct parts in LDO, like the original one, with
result, when it powers up with +12V, burned.

Some examples,
* [https://community.libre.space/t/v2-controller-board-magic-smoke/1878 SatNOGS Community]
* [http://westsideelectronics.com/blew-up-a-cheap-arduino-pro-mini-clone/ West Side Electronics]

One Solution is not use clones, use [https://www.sparkfun.com/products/11113# Sparkfun's arduiuno pro-mini 5V@16MHz, ATmega328P].
The second solution is to add a LDO, like [https://gr.mouser.com/datasheet/2/268/mic5205-778789.pdf MIC5205] (maybe in a new revision of v2).

The power consumption in +5V is:

{| class="wikitable"
|-
! -
! QTY.
! VCC(V)
! IDD(mA)
! Total(mA)
|-
| AS5601
| 2
| 5
| 6.5
| 13
|-
| PCA9540B
| 1
| 5
| 0.1
| 0.1
|-
| SN65HVD485E
| 1
| 5
| 2
| 2
|-
| TC74
| 1
| 5
| 0.35
| 0.35
|-
| arduino pro mini
| 1
| 5
| 20
| 20
|-
| MC33926
| 2
| 5
| 0.2
| 0.4
|-
| DRV8825
| 2
| 5
| 0.1
| 0.2
|}

The LDO MIC5205 guaranteed 150mA output, for Stepper motors ~35-40mA, for DC motors ~35-40mA.

==== Motor Drivers ====
===== Stepper motor driver =====
[[File:Stepper_2.png|thumb|320x240px|Stepper motor driver]]
[[File:Stepper_1.png|thumb|320x240px|Jumpers]]
[[File:Stepper_orientation.jpg|thumb|320x240px|Orientation]]

For the stepper motor driver 2 options have been tested, [https://www.pololu.com/product/2133 DRV8825] and [https://www.pololu.com/product/1182 A4988].
For both options it is necessary to solder:
* 2 electrolytic capacitors C3, C4 100uF
* 4 single 0.1" male connectors for U3, U4
* 2 fixed terminal blocks P7, P8, Amphenol-VI0421550000G
* 6 jumpers to adjust the micro-step, '''default option is Full Step'''
Note: [https://hackaday.com/2016/08/29/how-accurate-is-microstepping-really/ Guide for microstepping selection]
{| {{table}}
| align="center" style="background:#f0f0f0;"|'''JP3/JP6'''
| align="center" style="background:#f0f0f0;"|'''JP2/JP5'''
| align="center" style="background:#f0f0f0;"|'''JP1/JP4'''
| align="center" style="background:#f0f0f0;"|'''Microstep Resolution'''
|-
| align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Full step'''
|-
| align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''Low''' || align="center"|'''Half step'''
|-
| align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''1/4 step'''
|-
| align="center"|'''High''' || align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''1/8 step'''
|-
| align="center"|'''Low''' || align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''1/16 step'''
|-
| align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
| align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
| align="center"|'''High''' || align="center"|'''High''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
|}

* Do'''NOT''' solder 2 resistors 100k, R4, R7 in default configuration (full step)
* If you have A4988 for stepper motor drive and you want to use micro stepping, when the MS1 is HIGH
it is necessary to solder R4, R7 according to [https://www.pololu.com/product/1201 A4983 Stepper Motor Driver Carrier, Step (and microstep) size].

In case of DRV8825, all pins MS1, MS2, MS3 have internal pull-up resistor.

Also it is necessary to update the definitions in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/stepper_motor_controller/stepper_motor_controller.ino firmware], according to microstepping selection.
Example:
* Step Angle: 1.8 deg
* Microstep: 1/8 step
* Steps per Revolution: (360/1.8)*8 = 1600

That means:

#define MICROSTEP 8 ///< Set Microstep
#define MAX_SPEED 6400 ///< In steps/s, consider the microstep
#define MAX_ACCELERATION 1600 ///< In steps/s^2, consider the microstep
#define SPR 1600L ///< Step Per Revolution, consider the microstep

It is necessary to change the maximum speed and acceleration according to new SPR.

Be careful:
* [http://reprap.org/wiki/Pololu_stepper_driver_board adjust the current (current limiting) for stepper motors]
* add a heat-sink.
* plug the stepper motor drivers

The stepper motor that is used, is [https://www.omc-stepperonline.com/hybrid-stepper-motor/nema-17-bipolar-59ncm-84ozin-2a-42x48mm-4wires-w-1m-cable-and-connector-17hs19-2004s1.html Nema 17 Bipolar 59Ncm],
* Size: ▱42 x 48 mm
* Weight: 390 g
* Shaft diameter: 5 mm
* Step Angle: 1.8 deg
* Nominal speed @ 12V: 720deg/s
* Rated Current/phase: 2.0A
* Stall torque @ 12V: 0.59Nm

===== DC motor driver =====
[[File:Dc_motor_driver.png|thumb|320x240px|DC motor driver]]

It is necessary to solder:
* Solder U6 with 0.1" female connectors as shown in picture
* Solder 2 pads in yellow circle by using ~1mm diameter wire
* Solder 2 2-pin 3.5mm terminal blocks for 2 DC motors

The DC motor controller is [https://www.pololu.com/product/1213 Dual MC33926 Motor Driver Carrier ]

* Motor driver: MC33926
* Motor channels: 2
* Minimum operating voltage: 5V
* Maximum operating voltage: 28V
* Operating voltage: 12V
* Continuous output current per channel: 2.5A
* Current sense: 0.525 V/A
* Maximum PWM frequency: 20 kHz
* Operating PWM frequency: 3921.5Hz (~4kHz)
* Minimum logic voltage: 2.5V
* Operating logic voltage: 5V
* Maximum logic voltage: 5.5V

The DC motor that we use is [https://www.pololu.com/product/1104 50:1 Metal Gearmotor 37Dx54L mm],
* Size: 37D x 54L mm
* Weight: 195 g
* Shaft diameter: 6 mm
* Free-run speed @ 12V: 200 rpm
* Free-run current @ 12V: 300 mA
* Stall current @ 12V: 5000 mA
* Stall torque @ 12V: 1.2Nm

 

==== Communication ====
Note: For both options the firmware is the same.
===== ''UART'' =====
[[File:Jumper.png|thumb|320x240px|UART Jumpers]]
[[File:Rs 485.png|thumb|320x240px|Pin Header]]

To use UART:
* solder JP7 and JP8
* solder pin header 0.1" female connector
* not solder C1, U2, R18, R19 R9, R8, R1, D3
* A is TX and B is RX

===== ''RS-485'' =====
[[File:RS485_solder.png|thumb|320x240px|RS485]]
[[File:Missing_rs485_r19.png|thumb|320x240px|RS485]]

To use RS485:
* solder pin header 0.1" female connector
* solder C1, U2, R18, R19 R9, R8, R1, D3
* not solder JP7 and JP8

If you use PCB without R19 footprint, you can add it in arduino pro-mini UART header.

 

==== Power Supply ====
[[File:Psu.png|thumb|320x240px|Power Supply]]

Recommended power supply for rotator controller is: 48V @ 1A DC.
A good choice is the [https://gr.mouser.com/ProductDetail/709-LRS50-48 MEAN WELL LRS-50-48]

The switching power supply could get as input voltage, 19-60V DC. 
In different input voltages, must be change the components like D4 and F1. 
Default PCB components works at 48VDC.

 

==== Endstops ====
[[File:Endstop_part.png|thumb|320x240px|Endstop Specification]]
[[File:Endstop.jpg|thumb|320x240px|Endstop]]

In reference design, mechanical endstops (the [https://www.aliexpress.com/item/10PCS-MICROSWITCH-LIMIT-SWITCH-3pin-N-O-N-C-MICRO-SWITCH-free-shipping/32692144896.html?spm=2114.search0104.8.13.2f3c2457pmCyFH&transAbTest=ae803_5&priceBeautifyAB=0 P/N SS0505] of endstop is specified in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator satnogs rotator BOM]) , are used.

The controller has the capability to accommodate optical or magnetic endstop which connected to
P2 header with silkscreen, SW1, SW2, +5V and GND.

Mechanical endstops are connected to
* SW1 and GND for azimuth axis
* SW2 and GND for elevation axis

 

==== Encoders ====
Source files: [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller-encoder satnogs-rotator-controller-encoder - GitLab]
Firmware: [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/libraries/as5601.h satnogs-rotator-firmware - GitLab]

For stepper motor setup is optional (AS5601 encoder).

For DC motor setup is necessary.

[[File:Encoder_sheet1.png|thumb|center|800x420px|alt=|Rotary Encoder sheet 1/2]]
[[File:Encoder_sheet2.png|thumb|center|800x420px|alt=|Rotary Encoder sheet 2/2]]

 

=== Firmware and Pin Assignments ===

===== Firmware =====

[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware For stepper motors] 
[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware For DC motors, thanks to ] [https://github.com/ph4as ph4as]

===== Pins Configuration =====
This configuration is from the latest release in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags Rotator Controller repository]

* M1IN1 10, Step or PWM1
* M1IN2 9, Direction or PWM2
* M1SF 7, Status flag
* M1FB A1, Load measurment

* M2IN1 11, Step or PWM1
* M2IN2 3, Direction or PWM2
* M2SF 6, Status flag
* M2FB A0, Load measurment

* MOTOR_EN 8, Enable/Disable motors

* SW1 5, Endstop for axis 1
* SW2 4, Endstop for axis 2

* RS485_DIR 2, RS485 Half Duplex direction pin

* SDA_PIN 3, Data I2C pin
* SCL_PIN 4, Clock I2C pin

* PIN12 12, Digital output pin
* PIN13 13, Digital output pin
* A2 A2, Analog input pin
* A3 A3, Analog input pin

 

=== Pre-Flight Check ===

[[File:Pcb_testing_points.png|thumb|center|800x420px|alt=|Testing Points]]

* Power your PCB with 48VDC, without plug-in arduino pro-mini and motor drivers, measure with multimeter the voltage in point 1. Expected voltage +12V (reference to GND).
* Plug arduino pro-mini and measure with multimeter the voltage in point 2. Expected voltage +5V (reference to GND).
* Plug motor drivers (for steppermotors ensure the current is adjusted properly)
* Connect all peripheral devices like motors, sensors, endstops

If the two first steps fail, something is wrong (maybe there is a short circuit) in PCB. Check the connections with a multimeter.

Then the board is ready to run the firmware, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/README.md satnogs-rotator-firmware].

 

=== Troubleshooting hints ===

As soon as the board is powered up or reset, it will auto-home, on first build you can trigger a reset multiple time or move the homing ring to get it "home".

[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/README.md Connecting directly to the Arduino pro-mini] you will need to use 19200 bauds and "newline" line ending.

Here is some commands (took from [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware#easycomm-implemantation]) you can issue in the terminal emulator of your choice to test things:

* '''VE''', it will returns something like "SatNOGS-v2.0"
* '''RESET''', move to home position
* '''AZxx''', '''ELxx''', move to specified position (number)

Nothing moves ? Look at the status and error register :

* '''GS''', status register : 1 idle, 2 moving, 4 pointing, 8 error
* '''GE''', error register : 1 no error, 2 sensor, 4 homing, 8 motor, 12 over temperature, 16 watch dog timer interrupt

By example, at first start, you might be in '''GS8''' and '''GE4''' until you get a good homing position for the rotator to start working.

If you using an unreleased version of the board (the board that has fuse holder), in [https://community.libre.space/t/stepper-motor-issue/2438/2 community post] you can find pin configuration file.

 

== Rotator Controller v1 ==

SatNOGS Rotator v3

2018-12-29T12:17:36Z

Azisi: /* Specifications */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || ?, ~30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -5 and -6, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
File:C1084-1.png|C1084-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

File:A1050-1.png

2018-11-27T16:43:20Z

Azisi: Azisi uploaded a new version of File:A1050-1.png

File:A1040.png

2018-11-27T16:40:10Z

Azisi: Azisi uploaded a new version of File:A1040.png

File:A1001-3.png

2018-11-27T16:32:27Z

Azisi: Azisi uploaded a new version of File:A1001-3.png

File:A1011.png

2018-11-27T16:30:13Z

Azisi: Azisi uploaded a new version of File:A1011.png

SatNOGS Rotator v3

2018-11-27T16:28:30Z

Azisi: /* Parts */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -5 and -6, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
File:C1084-1.png|C1084-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

File:C1061.png

2018-11-27T16:27:29Z

Azisi: Azisi uploaded a new version of File:C1061.png

File:A1050-1.png

2018-11-26T15:36:50Z

Azisi: Azisi uploaded a new version of File:A1050-1.png

SatNOGS Rotator v3

2018-11-26T15:33:24Z

Azisi: /* Parts */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -3 and -4, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
File:C1084-1.png|C1084-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

File:C1084-1.png

2018-11-26T15:33:04Z

Azisi:

SatNOGS Rotator v3

2018-11-21T13:51:22Z

Azisi: Update C1001 part

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -3 and -4, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

File:C1001.png

2018-11-21T13:50:33Z

Azisi: Azisi uploaded a new version of File:C1001.png

SatNOGS Rotator v3

2018-11-15T16:45:26Z

Azisi: /* Parts */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3, Note with part C1001-3 it exists [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/issues/65 an open issue]
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -3 and -4, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1083-1.png|C1083-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1080-3 2.png|C1080-3, Cover Box bottom part, galvanized steel sheet, thickness 0.5mm
File:C1081-3 2.png|C1081-3, Cover Box top part, galvanized steel sheet, thickness 0.5mm
File:C1082-5.png|C1082-5, Cover Box side part, galvanized steel sheet, thickness 0.5mm
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

File:C1082-5.png

2018-11-15T16:44:54Z

Azisi:

File:C1081-3 2.png

2018-11-15T16:43:15Z

Azisi:

File:C1080-3 2.png

2018-11-15T16:40:49Z

Azisi:

File:C1083-1.png

2018-11-15T16:37:34Z

Azisi:

SatNOGS Rotator v3

2018-09-06T10:49:32Z

Azisi: /* Parts */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3, Note with part C1001-3 it exists [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/issues/65 an open issue]
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -3 and -4, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator v3

2018-08-30T16:21:00Z

Azisi:

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/] [https://wiki.satnogs.org/SatNOGS_Rotator_v3]
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -3 and -4, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator Controller

2018-08-29T16:34:20Z

Azisi: /* Troubleshooting hints */

{{Template:Development
|Name= SatNOGS Rotator Controller
|image= Rotator controller v2.jpg
|type= Rotator Controller for SatNOGS rotator.
|cost= 60-80€
|status= Working
|latest-release-name= -
|latest-release= v2.2
|source-repo= [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller satnogs-rotator-controller - GitLab]
[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller-encoder satnogs-rotator-controller-encoder - GitLab]
|documentation= https://wiki.satnogs.org/index.php?title=SatNOGS_Rotator_Controller SatNOGS wiki
}}

== Intro ==
SatNOGS Rotator Controller refers to the set of electronics designed to operate a SatNOGS Rotator. There have been multiple iterations of the rotator controller design, but the modularity of the approach enables operations between different versions of the controller and the rotator.
Since the start of 2016, the rotator controller design is able to facilitate a DC-motors or stepper-motors rotator design. We intend to keep this modularity for the electronics and firmware design to facilitate the variety of build by our community.

== Rotator Controller v2 ==
<gallery>
Pcb_schema_v2_revC.png
Pcb_board_v2_revC.png
</gallery>

The PCB are tested in this [https://network.satnogs.org/stations/9/ ground station].

=== Features ===
* It is designed to fit the entire electronics needed to control rotator in Euroboard 80x50 mm.
* Main micro-controller is [https://store.arduino.cc/arduino-pro-mini Arduino pro-mini], [https://github.com/sparkfun/Arduino_Pro_Mini_328 SparkFun's Arduino Pro Mini 328] dev-board with ATmega328p.
* The modular design includes plug-in either [https://www.pololu.com/product/2133 DRV8825]/[https://www.pololu.com/product/1182 A4988] or [https://www.pololu.com/product/1213/resources DC motor drivers] (MC33926).
* The power supply in embed in the same board in contrast with previous version.
* Filtered power supply of micro controller.
* An I2C multiplexer is used to connect I2C encoders AS5601 (same ID) to get position feedback for each axis.
* A temperature sensor TC-74 monitoring the temperature inside the controller box in order to protect them from over-heating.
* There are some spare dev-pins in order to connect other peripherals like IMU or an LCD display.
* Pins with integrated RC-Low Pass filter for end-stops connection.
* Default communication interface is RS-485 but it can also be used as a UART.
* Using different paths for digital and power (motors) GND.
* Electrolytic capacitor and TVS-diode in PSU input
* Flashed either by using UART or ISP header

=== Build sequence ===
* Make sure you have a [[SatNOGS Rotator v3|mechanical assembly]] of the rotator constructed and ready
* Buy the PCB. [https://oshpark.com OshPark],[https://www.pcbway.com PCBWay.com], [http://dirtypcbs.com DirtyPCBs.com], [https://www.elecrow.com/ Elecrow] have been used in the past with good results.
** You can order the v2.2 of the board directly using [https://oshpark.com/shared_projects/w0s8d4OJ this OSHPark link] or [https://dirtypcbs.com/store/designer/details/6933/5904/satnogs-v3-motor-controller-zip this DirtyPCBs link].
** You can order the v1.0 of the rotary encoder board using [https://oshpark.com/shared_projects/I3b8SCci this OSHPark link]
* Get all the necessary components according to BOM from latest tag (or the version that you want to build), [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags Gitlab Tags]
* Assemble the PCB, by soldering the components
* Burn the firmware
* Using the wiring diagram, connect the controller to the Rotator
* You are ready! Proceed with testing

==== Assembly Guide ====

[[File:H1000_aluminium_enclosure.png|thumb|center|800x420px|alt=|Rotator Controller - Drill holes]]
[[File:Rotator_controller_sheet1.png|thumb|center|800x420px|alt=|Rotator Controller sheet 1/2]]
[[File:Rotator_controller_sheet2.png|thumb|center|800x420px|alt=|Rotator Controller sheet 2/2]]

==== Microcontroller ====
<gallery mode=packed heights="250px">
Uc.png|Microcontroller
Uc_orientation.png|Microcontroller Orientation
I2c_pullup.png|I2C pull-up resistors
</gallery>


The main micro-controller of the board is arduino pro-mini 5V@16MHz, ATmega328P.
The +5V of the controller are produced from arduino pro-mini.
Some clones do not use correct parts in LDO, like the original one, with
result, when it powers up with +12V, burned.

Some examples,
* [https://community.libre.space/t/v2-controller-board-magic-smoke/1878 SatNOGS Community]
* [http://westsideelectronics.com/blew-up-a-cheap-arduino-pro-mini-clone/ West Side Electronics]

One Solution is not use clones, use [https://www.sparkfun.com/products/11113# Sparkfun's arduiuno pro-mini 5V@16MHz, ATmega328P].
The second solution is to add a LDO, like [https://gr.mouser.com/datasheet/2/268/mic5205-778789.pdf MIC5205] (maybe in a new revision of v2).

The power consumption in +5V is:

{| class="wikitable"
|-
! -
! QTY.
! VCC(V)
! IDD(mA)
! Total(mA)
|-
| AS5601
| 2
| 5
| 6.5
| 13
|-
| PCA9540B
| 1
| 5
| 0.1
| 0.1
|-
| SN65HVD485E
| 1
| 5
| 2
| 2
|-
| TC74
| 1
| 5
| 0.35
| 0.35
|-
| arduino pro mini
| 1
| 5
| 20
| 20
|-
| MC33926
| 2
| 5
| 0.2
| 0.4
|-
| DRV8825
| 2
| 5
| 0.1
| 0.2
|}

The LDO MIC5205 guaranteed 150mA output, for Stepper motors ~35-40mA, for DC motors ~35-40mA.

==== Motor Drivers ====
===== Stepper motor driver =====
[[File:Stepper_2.png|thumb|320x240px|Stepper motor driver]]
[[File:Stepper_1.png|thumb|320x240px|Jumpers]]
[[File:Stepper_orientation.jpg|thumb|320x240px|Orientation]]

For the stepper motor driver 2 options have been tested, [https://www.pololu.com/product/2133 DRV8825] and [https://www.pololu.com/product/1182 A4988].
For both options it is necessary to solder:
* 2 electrolytic capacitors C3, C4 100uF
* 4 single 0.1" male connectors for U3, U4
* 2 fixed terminal blocks P7, P8, Amphenol-VI0421550000G
* 6 jumpers to adjust the micro-step, '''default option is Full Step'''
Note: [https://hackaday.com/2016/08/29/how-accurate-is-microstepping-really/ Guide for microstepping selection]
{| {{table}}
| align="center" style="background:#f0f0f0;"|'''JP3/JP6'''
| align="center" style="background:#f0f0f0;"|'''JP2/JP5'''
| align="center" style="background:#f0f0f0;"|'''JP1/JP4'''
| align="center" style="background:#f0f0f0;"|'''Microstep Resolution'''
|-
| align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Full step'''
|-
| align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''Low''' || align="center"|'''Half step'''
|-
| align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''1/4 step'''
|-
| align="center"|'''High''' || align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''1/8 step'''
|-
| align="center"|'''Low''' || align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''1/16 step'''
|-
| align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
| align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
| align="center"|'''High''' || align="center"|'''High''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
|}

* Do'''NOT''' solder 2 resistors 100k, R4, R7 in default configuration (full step)
* If you have A4988 for stepper motor drive and you want to use micro stepping, when the MS1 is HIGH
it is necessary to solder R4, R7 according to [https://www.pololu.com/product/1201 A4983 Stepper Motor Driver Carrier, Step (and microstep) size].

In case of DRV8825, all pins MS1, MS2, MS3 have internal pull-up resistor.

Also it is necessary to update the definitions in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/stepper_motor_controller/stepper_motor_controller.ino firmware], according to microstepping selection.
Example:
* Step Angle: 1.8 deg
* Microstep: 1/8 step
* Steps per Revolution: (360/1.8)*8 = 1600

That means:

#define MICROSTEP 8 ///< Set Microstep
#define MAX_SPEED 6400 ///< In steps/s, consider the microstep
#define MAX_ACCELERATION 1600 ///< In steps/s^2, consider the microstep
#define SPR 1600L ///< Step Per Revolution, consider the microstep

It is necessary to change the maximum speed and acceleration according to new SPR.

Be careful:
* [http://reprap.org/wiki/Pololu_stepper_driver_board adjust the current (current limiting) for stepper motors]
* add a heat-sink.
* plug the stepper motor drivers

The stepper motor that is used, is [https://www.omc-stepperonline.com/hybrid-stepper-motor/nema-17-bipolar-59ncm-84ozin-2a-42x48mm-4wires-w-1m-cable-and-connector-17hs19-2004s1.html Nema 17 Bipolar 59Ncm],
* Size: ▱42 x 48 mm
* Weight: 390 g
* Shaft diameter: 5 mm
* Step Angle: 1.8 deg
* Nominal speed @ 12V: 720deg/s
* Rated Current/phase: 2.0A
* Stall torque @ 12V: 0.59Nm

===== DC motor driver =====
[[File:Dc_motor_driver.png|thumb|320x240px|DC motor driver]]

It is necessary to solder:
* Solder U6 with 0.1" female connectors as shown in picture
* Solder 2 pads in yellow circle by using ~1mm diameter wire
* Solder 2 2-pin 3.5mm terminal blocks for 2 DC motors

The DC motor controller is [https://www.pololu.com/product/1213 Dual MC33926 Motor Driver Carrier ]

* Motor driver: MC33926
* Motor channels: 2
* Minimum operating voltage: 5V
* Maximum operating voltage: 28V
* Operating voltage: 12V
* Continuous output current per channel: 2.5A
* Current sense: 0.525 V/A
* Maximum PWM frequency: 20 kHz
* Operating PWM frequency: 3921.5Hz (~4kHz)
* Minimum logic voltage: 2.5V
* Operating logic voltage: 5V
* Maximum logic voltage: 5.5V

The DC motor that we use is [https://www.pololu.com/product/1104 50:1 Metal Gearmotor 37Dx54L mm],
* Size: 37D x 54L mm
* Weight: 195 g
* Shaft diameter: 6 mm
* Free-run speed @ 12V: 200 rpm
* Free-run current @ 12V: 300 mA
* Stall current @ 12V: 5000 mA
* Stall torque @ 12V: 1.2Nm

 

==== Communication ====
Note: For both options the firmware is the same.
===== ''UART'' =====
[[File:Jumper.png|thumb|320x240px|UART Jumpers]]
[[File:Rs 485.png|thumb|320x240px|Pin Header]]

To use UART:
* solder JP7 and JP8
* solder pin header 0.1" female connector
* not solder C1, U2, R18, R19 R9, R8, R1, D3
* A is TX and B is RX

===== ''RS-485'' =====
[[File:RS485_solder.png|thumb|320x240px|RS485]]
[[File:Missing_rs485_r19.png|thumb|320x240px|RS485]]

To use RS485:
* solder pin header 0.1" female connector
* solder C1, U2, R18, R19 R9, R8, R1, D3
* not solder JP7 and JP8

If you use PCB without R19 footprint, you can add it in arduino pro-mini UART header.

 

==== Power Supply ====
[[File:Psu.png|thumb|320x240px|Power Supply]]

Recommended power supply for rotator controller is: 48V @ 1A DC.
A good choice is the [https://gr.mouser.com/ProductDetail/709-LRS50-48 MEAN WELL LRS-50-48]

The switching power supply could get as input voltage, 19-60V DC. 
In different input voltages, must be change the components like D4 and F1. 
Default PCB components works at 48VDC.

 

==== Endstops ====
[[File:Endstop_part.png|thumb|320x240px|Endstop Specification]]
[[File:Endstop.jpg|thumb|320x240px|Endstop]]

In reference design, mechanical endstops (the [https://www.aliexpress.com/item/10PCS-MICROSWITCH-LIMIT-SWITCH-3pin-N-O-N-C-MICRO-SWITCH-free-shipping/32692144896.html?spm=2114.search0104.8.13.2f3c2457pmCyFH&transAbTest=ae803_5&priceBeautifyAB=0 P/N SS0505] of endstop is specified in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator satnogs rotator BOM]) , are used.

The controller has the capability to accommodate optical or magnetic endstop which connected to
P2 header with silkscreen, SW1, SW2, +5V and GND.

Mechanical endstops are connected to
* SW1 and GND for azimuth axis
* SW2 and GND for elevation axis

 

==== Encoders ====
Source files: [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller-encoder satnogs-rotator-controller-encoder - GitLab]
Firmware: [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/libraries/as5601.h satnogs-rotator-firmware - GitLab]

For stepper motor setup is optional (AS5601 encoder).

For DC motor setup is necessary.

[[File:Encoder_sheet1.png|thumb|center|800x420px|alt=|Rotary Encoder sheet 1/2]]
[[File:Encoder_sheet2.png|thumb|center|800x420px|alt=|Rotary Encoder sheet 2/2]]

 

==== Wiring ====

[[File:Wiring_diagram.png|thumb|center|800x420px|alt=|Wiring Diagram]]

 

==== Rotator Controller enclosure - Placement ====
Mount the rotator controller enclosure by using two sides adhesive tape (as mentioned in BOM)

[[File:Box_placement.png|thumb|center|800x420px|alt=|Rotator Controller enclosure - Placement]]

 

=== Firmware and Pin Assignments ===

===== Firmware =====

[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware For stepper motors] 
[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware For DC motors, thanks to ] [https://github.com/ph4as ph4as]

===== Pins Configuration =====
This configuration is from the latest release in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags Rotator Controller repository]

* M1IN1 10, Step or PWM1
* M1IN2 9, Direction or PWM2
* M1SF 7, Status flag
* M1FB A1, Load measurment

* M2IN1 11, Step or PWM1
* M2IN2 3, Direction or PWM2
* M2SF 6, Status flag
* M2FB A0, Load measurment

* MOTOR_EN 8, Enable/Disable motors

* SW1 5, Endstop for axis 1
* SW2 4, Endstop for axis 2

* RS485_DIR 2, RS485 Half Duplex direction pin

* SDA_PIN 3, Data I2C pin
* SCL_PIN 4, Clock I2C pin

* PIN12 12, Digital output pin
* PIN13 13, Digital output pin
* A2 A2, Analog input pin
* A3 A3, Analog input pin

 

=== Pre-Flight Check ===

[[File:Pcb_testing_points.png|thumb|center|800x420px|alt=|Testing Points]]

* Power your PCB with 48VDC, without plug-in arduino pro-mini and motor drivers, measure with multimeter the voltage in point 1. Expected voltage +12V (reference to GND).
* Plug arduino pro-mini and measure with multimeter the voltage in point 2. Expected voltage +5V (reference to GND).
* Plug motor drivers (for steppermotors ensure the current is adjusted properly)
* Connect all peripheral devices like motors, sensors, endstops

If the two first steps fail, something is wrong (maybe there is a short circuit) in PCB. Check the connections with a multimeter.

Then the board is ready to run the firmware, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/README.md satnogs-rotator-firmware].

 

=== Troubleshooting hints ===

As soon as the board is powered up or reset, it will auto-home, on first build you can trigger a reset multiple time or move the homing ring to get it "home".

[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/README.md Connecting directly to the Arduino pro-mini] you will need to use 19200 bauds and "newline" line ending.

Here is some commands (took from [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware#easycomm-implemantation]) you can issue in the terminal emulator of your choice to test things:

* '''VE''', it will returns something like "SatNOGS-v2.0"
* '''RESET''', move to home position
* '''AZxx''', '''ELxx''', move to specified position (number)

Nothing moves ? Look at the status and error register :

* '''GS''', status register : 1 idle, 2 moving, 4 pointing, 8 error
* '''GE''', error register : 1 no error, 2 sensor, 4 homing, 8 motor, 12 over temperature, 16 watch dog timer interrupt

By example, at first start, you might be in '''GS8''' and '''GE4''' until you get a good homing position for the rotator to start working.

If you using an unreleased version of the board (the board that has fuse holder), in [https://community.libre.space/t/stepper-motor-issue/2438/2 community post] you can find pin configuration file.

 

== Rotator Controller v1 ==

SatNOGS Rotator v3

2018-08-27T20:00:51Z

Azisi: /* Build Sequence */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -3 and -4, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

==== Heading Calibration ====
The heading calibration is a manual process:

* Power the rotator, it starts moving in order to find the home position, to find the end-stops
* Remove the power from the rotator, the rotator is in home position
* Install the rotator to vertical axis by using U-Bolt clamps
* The azimuth axis it must be heading to the North, this is achieved by using a compass (e.g. from smart phone)
* Secure the rotator in the vertical axis
* Install the elevation axis with the same process, now the zero elevation is achieved by using a pocket level
* Secure the elevation axis
* In the case of wrong rotation:
** For stepper motors swap a pair of two stepper motor cables ([https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 it exists an open issue to be done by a command])
** For DC motors, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/commit/961fb696536e35642f2b7064cc3c64676ebebb17 change the sign of encoder reading], it is a hacky method but it would be resolved by [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/issues/15 this issue]

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator Controller

2018-08-27T11:44:49Z

Azisi: /* Troubleshooting hints */

{{Template:Development
|Name= SatNOGS Rotator Controller
|image= Rotator controller v2.jpg
|type= Rotator Controller for SatNOGS rotator.
|cost= 60-80€
|status= Working
|latest-release-name= -
|latest-release= v2.2
|source-repo= [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller satnogs-rotator-controller - GitLab]
[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller-encoder satnogs-rotator-controller-encoder - GitLab]
|documentation= https://wiki.satnogs.org/index.php?title=SatNOGS_Rotator_Controller SatNOGS wiki
}}

== Intro ==
SatNOGS Rotator Controller refers to the set of electronics designed to operate a SatNOGS Rotator. There have been multiple iterations of the rotator controller design, but the modularity of the approach enables operations between different versions of the controller and the rotator.
Since the start of 2016, the rotator controller design is able to facilitate a DC-motors or stepper-motors rotator design. We intend to keep this modularity for the electronics and firmware design to facilitate the variety of build by our community.

== Rotator Controller v2 ==
<gallery>
Pcb_schema_v2_revC.png
Pcb_board_v2_revC.png
</gallery>

The PCB are tested in this [https://network.satnogs.org/stations/9/ ground station].

=== Features ===
* It is designed to fit the entire electronics needed to control rotator in Euroboard 80x50 mm.
* Main micro-controller is [https://store.arduino.cc/arduino-pro-mini Arduino pro-mini], [https://github.com/sparkfun/Arduino_Pro_Mini_328 SparkFun's Arduino Pro Mini 328] dev-board with ATmega328p.
* The modular design includes plug-in either [https://www.pololu.com/product/2133 DRV8825]/[https://www.pololu.com/product/1182 A4988] or [https://www.pololu.com/product/1213/resources DC motor drivers] (MC33926).
* The power supply in embed in the same board in contrast with previous version.
* Filtered power supply of micro controller.
* An I2C multiplexer is used to connect I2C encoders AS5601 (same ID) to get position feedback for each axis.
* A temperature sensor TC-74 monitoring the temperature inside the controller box in order to protect them from over-heating.
* There are some spare dev-pins in order to connect other peripherals like IMU or an LCD display.
* Pins with integrated RC-Low Pass filter for end-stops connection.
* Default communication interface is RS-485 but it can also be used as a UART.
* Using different paths for digital and power (motors) GND.
* Electrolytic capacitor and TVS-diode in PSU input
* Flashed either by using UART or ISP header

=== Build sequence ===
* Make sure you have a [[SatNOGS Rotator v3|mechanical assembly]] of the rotator constructed and ready
* Buy the PCB. [https://oshpark.com OshPark],[https://www.pcbway.com PCBWay.com], [http://dirtypcbs.com DirtyPCBs.com], [https://www.elecrow.com/ Elecrow] have been used in the past with good results.
** You can order the v2.2 of the board directly using [https://oshpark.com/shared_projects/w0s8d4OJ this OSHPark link] or [https://dirtypcbs.com/store/designer/details/6933/5904/satnogs-v3-motor-controller-zip this DirtyPCBs link].
** You can order the v1.0 of the rotary encoder board using [https://oshpark.com/shared_projects/I3b8SCci this OSHPark link]
* Get all the necessary components according to BOM from latest tag (or the version that you want to build), [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags Gitlab Tags]
* Assemble the PCB, by soldering the components
* Burn the firmware
* Using the wiring diagram, connect the controller to the Rotator
* You are ready! Proceed with testing

==== Assembly Guide ====

[[File:H1000_aluminium_enclosure.png|thumb|center|800x420px|alt=|Rotator Controller - Drill holes]]
[[File:Rotator_controller_sheet1.png|thumb|center|800x420px|alt=|Rotator Controller sheet 1/2]]
[[File:Rotator_controller_sheet2.png|thumb|center|800x420px|alt=|Rotator Controller sheet 2/2]]

==== Microcontroller ====
<gallery mode=packed heights="250px">
Uc.png|Microcontroller
Uc_orientation.png|Microcontroller Orientation
I2c_pullup.png|I2C pull-up resistors
</gallery>


The main micro-controller of the board is arduino pro-mini 5V@16MHz, ATmega328P.
The +5V of the controller are produced from arduino pro-mini.
Some clones do not use correct parts in LDO, like the original one, with
result, when it powers up with +12V, burned.

Some examples,
* [https://community.libre.space/t/v2-controller-board-magic-smoke/1878 SatNOGS Community]
* [http://westsideelectronics.com/blew-up-a-cheap-arduino-pro-mini-clone/ West Side Electronics]

One Solution is not use clones, use [https://www.sparkfun.com/products/11113# Sparkfun's arduiuno pro-mini 5V@16MHz, ATmega328P].
The second solution is to add a LDO, like [https://gr.mouser.com/datasheet/2/268/mic5205-778789.pdf MIC5205] (maybe in a new revision of v2).

The power consumption in +5V is:

{| class="wikitable"
|-
! -
! QTY.
! VCC(V)
! IDD(mA)
! Total(mA)
|-
| AS5601
| 2
| 5
| 6.5
| 13
|-
| PCA9540B
| 1
| 5
| 0.1
| 0.1
|-
| SN65HVD485E
| 1
| 5
| 2
| 2
|-
| TC74
| 1
| 5
| 0.35
| 0.35
|-
| arduino pro mini
| 1
| 5
| 20
| 20
|-
| MC33926
| 2
| 5
| 0.2
| 0.4
|-
| DRV8825
| 2
| 5
| 0.1
| 0.2
|}

The LDO MIC5205 guaranteed 150mA output, for Stepper motors ~35-40mA, for DC motors ~35-40mA.

==== Motor Drivers ====
===== Stepper motor driver =====
[[File:Stepper_2.png|thumb|320x240px|Stepper motor driver]]
[[File:Stepper_1.png|thumb|320x240px|Jumpers]]
[[File:Stepper_orientation.jpg|thumb|320x240px|Orientation]]

For the stepper motor driver 2 options have been tested, [https://www.pololu.com/product/2133 DRV8825] and [https://www.pololu.com/product/1182 A4988].
For both options it is necessary to solder:
* 2 electrolytic capacitors C3, C4 100uF
* 4 single 0.1" male connectors for U3, U4
* 2 fixed terminal blocks P7, P8, Amphenol-VI0421550000G
* 6 jumpers to adjust the micro-step, '''default option is Full Step'''
Note: [https://hackaday.com/2016/08/29/how-accurate-is-microstepping-really/ Guide for microstepping selection]
{| {{table}}
| align="center" style="background:#f0f0f0;"|'''JP3/JP6'''
| align="center" style="background:#f0f0f0;"|'''JP2/JP5'''
| align="center" style="background:#f0f0f0;"|'''JP1/JP4'''
| align="center" style="background:#f0f0f0;"|'''Microstep Resolution'''
|-
| align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Full step'''
|-
| align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''Low''' || align="center"|'''Half step'''
|-
| align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''1/4 step'''
|-
| align="center"|'''High''' || align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''1/8 step'''
|-
| align="center"|'''Low''' || align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''1/16 step'''
|-
| align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
| align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
| align="center"|'''High''' || align="center"|'''High''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
|}

* Do'''NOT''' solder 2 resistors 100k, R4, R7 in default configuration (full step)
* If you have A4988 for stepper motor drive and you want to use micro stepping, when the MS1 is HIGH
it is necessary to solder R4, R7 according to [https://www.pololu.com/product/1201 A4983 Stepper Motor Driver Carrier, Step (and microstep) size].

In case of DRV8825, all pins MS1, MS2, MS3 have internal pull-up resistor.

Also it is necessary to update the definitions in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/stepper_motor_controller/stepper_motor_controller.ino firmware], according to microstepping selection.
Example:
* Step Angle: 1.8 deg
* Microstep: 1/8 step
* Steps per Revolution: (360/1.8)*8 = 1600

That means:

#define MICROSTEP 8 ///< Set Microstep
#define MAX_SPEED 6400 ///< In steps/s, consider the microstep
#define MAX_ACCELERATION 1600 ///< In steps/s^2, consider the microstep
#define SPR 1600L ///< Step Per Revolution, consider the microstep

It is necessary to change the maximum speed and acceleration according to new SPR.

Be careful:
* [http://reprap.org/wiki/Pololu_stepper_driver_board adjust the current (current limiting) for stepper motors]
* add a heat-sink.
* plug the stepper motor drivers

The stepper motor that is used, is [https://www.omc-stepperonline.com/hybrid-stepper-motor/nema-17-bipolar-59ncm-84ozin-2a-42x48mm-4wires-w-1m-cable-and-connector-17hs19-2004s1.html Nema 17 Bipolar 59Ncm],
* Size: ▱42 x 48 mm
* Weight: 390 g
* Shaft diameter: 5 mm
* Step Angle: 1.8 deg
* Nominal speed @ 12V: 720deg/s
* Rated Current/phase: 2.0A
* Stall torque @ 12V: 0.59Nm

===== DC motor driver =====
[[File:Dc_motor_driver.png|thumb|320x240px|DC motor driver]]

It is necessary to solder:
* Solder U6 with 0.1" female connectors as shown in picture
* Solder 2 pads in yellow circle by using ~1mm diameter wire
* Solder 2 2-pin 3.5mm terminal blocks for 2 DC motors

The DC motor controller is [https://www.pololu.com/product/1213 Dual MC33926 Motor Driver Carrier ]

* Motor driver: MC33926
* Motor channels: 2
* Minimum operating voltage: 5V
* Maximum operating voltage: 28V
* Operating voltage: 12V
* Continuous output current per channel: 2.5A
* Current sense: 0.525 V/A
* Maximum PWM frequency: 20 kHz
* Operating PWM frequency: 3921.5Hz (~4kHz)
* Minimum logic voltage: 2.5V
* Operating logic voltage: 5V
* Maximum logic voltage: 5.5V

The DC motor that we use is [https://www.pololu.com/product/1104 50:1 Metal Gearmotor 37Dx54L mm],
* Size: 37D x 54L mm
* Weight: 195 g
* Shaft diameter: 6 mm
* Free-run speed @ 12V: 200 rpm
* Free-run current @ 12V: 300 mA
* Stall current @ 12V: 5000 mA
* Stall torque @ 12V: 1.2Nm

 

==== Communication ====
Note: For both options the firmware is the same.
===== ''UART'' =====
[[File:Jumper.png|thumb|320x240px|UART Jumpers]]
[[File:Rs 485.png|thumb|320x240px|Pin Header]]

To use UART:
* solder JP7 and JP8
* solder pin header 0.1" female connector
* not solder C1, U2, R18, R19 R9, R8, R1, D3
* A is TX and B is RX

===== ''RS-485'' =====
[[File:RS485_solder.png|thumb|320x240px|RS485]]
[[File:Missing_rs485_r19.png|thumb|320x240px|RS485]]

To use RS485:
* solder pin header 0.1" female connector
* solder C1, U2, R18, R19 R9, R8, R1, D3
* not solder JP7 and JP8

If you use PCB without R19 footprint, you can add it in arduino pro-mini UART header.

 

==== Power Supply ====
[[File:Psu.png|thumb|320x240px|Power Supply]]

Recommended power supply for rotator controller is: 48V @ 1A DC.
A good choice is the [https://gr.mouser.com/ProductDetail/709-LRS50-48 MEAN WELL LRS-50-48]

The switching power supply could get as input voltage, 19-60V DC. 
In different input voltages, must be change the components like D4 and F1. 
Default PCB components works at 48VDC.

 

==== Endstops ====
[[File:Endstop_part.png|thumb|320x240px|Endstop Specification]]
[[File:Endstop.jpg|thumb|320x240px|Endstop]]

In reference design, mechanical endstops (the [https://www.aliexpress.com/item/10PCS-MICROSWITCH-LIMIT-SWITCH-3pin-N-O-N-C-MICRO-SWITCH-free-shipping/32692144896.html?spm=2114.search0104.8.13.2f3c2457pmCyFH&transAbTest=ae803_5&priceBeautifyAB=0 P/N SS0505] of endstop is specified in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator satnogs rotator BOM]) , are used.

The controller has the capability to accommodate optical or magnetic endstop which connected to
P2 header with silkscreen, SW1, SW2, +5V and GND.

Mechanical endstops are connected to
* SW1 and GND for azimuth axis
* SW2 and GND for elevation axis

 

==== Encoders ====
Source files: [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller-encoder satnogs-rotator-controller-encoder - GitLab]
Firmware: [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/libraries/as5601.h satnogs-rotator-firmware - GitLab]

For stepper motor setup is optional (AS5601 encoder).

For DC motor setup is necessary.

[[File:Encoder_sheet1.png|thumb|center|800x420px|alt=|Rotary Encoder sheet 1/2]]
[[File:Encoder_sheet2.png|thumb|center|800x420px|alt=|Rotary Encoder sheet 2/2]]

 

==== Wiring ====

[[File:Wiring_diagram.png|thumb|center|800x420px|alt=|Wiring Diagram]]

 

==== Rotator Controller enclosure - Placement ====
Mount the rotator controller enclosure by using two sides adhesive tape (as mentioned in BOM)

[[File:Box_placement.png|thumb|center|800x420px|alt=|Rotator Controller enclosure - Placement]]

 

=== Firmware and Pin Assignments ===

===== Firmware =====

[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware For stepper motors] 
[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware For DC motors, thanks to ] [https://github.com/ph4as ph4as]

===== Pins Configuration =====
This configuration is from the latest release in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags Rotator Controller repository]

* M1IN1 10, Step or PWM1
* M1IN2 9, Direction or PWM2
* M1SF 7, Status flag
* M1FB A1, Load measurment

* M2IN1 11, Step or PWM1
* M2IN2 3, Direction or PWM2
* M2SF 6, Status flag
* M2FB A0, Load measurment

* MOTOR_EN 8, Enable/Disable motors

* SW1 5, Endstop for axis 1
* SW2 4, Endstop for axis 2

* RS485_DIR 2, RS485 Half Duplex direction pin

* SDA_PIN 3, Data I2C pin
* SCL_PIN 4, Clock I2C pin

* PIN12 12, Digital output pin
* PIN13 13, Digital output pin
* A2 A2, Analog input pin
* A3 A3, Analog input pin

 

=== Pre-Flight Check ===

[[File:Pcb_testing_points.png|thumb|center|800x420px|alt=|Testing Points]]

* Power your PCB with 48VDC, without plug-in arduino pro-mini and motor drivers, measure with multimeter the voltage in point 1. Expected voltage +12V (reference to GND).
* Plug arduino pro-mini and measure with multimeter the voltage in point 2. Expected voltage +5V (reference to GND).
* Plug motor drivers (for steppermotors ensure the current is adjusted properly)
* Connect all peripheral devices like motors, sensors, endstops

If the two first steps fail, something is wrong (maybe there is a short circuit) in PCB. Check the connections with a multimeter.

Then the board is ready to run the firmware, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/README.md satnogs-rotator-firmware].

 

=== Troubleshooting hints ===

As soon as the board is powered up or reset, it will auto-home, on first build you can trigger a reset multiple time or move the homing ring to get it "home".

[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/README.md Connecting directly to the Arduino pro-mini] you will need to use 19200 bauds and "newline" line ending.

Here is some commands (took from [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware#easycomm-implemantation]) you can issue in the terminal emulator of your choice to test things:

* '''VE''', it will returns something like "SatNOGS-v2.0"
* '''RESET''', move to home position
* '''AZxx''', '''ELxx''', move to specified position (number)

Nothing moves ? Look at the status and error register :

* '''GS''', status register : 1 idle, 2 moving, 4 pointing, 8 error
* '''GE''', error register : 1 no error, 2 sensor, 4 homing, 8 motor, 12 over temperature, 16 wdt

By example, at first start, you might be in '''GS8''' and '''GE4''' until you get a good homing position for the rotator to start working.

 

== Rotator Controller v1 ==

SatNOGS Rotator Controller

2018-08-27T11:42:19Z

Azisi: /* Pre-Flight Check */

{{Template:Development
|Name= SatNOGS Rotator Controller
|image= Rotator controller v2.jpg
|type= Rotator Controller for SatNOGS rotator.
|cost= 60-80€
|status= Working
|latest-release-name= -
|latest-release= v2.2
|source-repo= [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller satnogs-rotator-controller - GitLab]
[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller-encoder satnogs-rotator-controller-encoder - GitLab]
|documentation= https://wiki.satnogs.org/index.php?title=SatNOGS_Rotator_Controller SatNOGS wiki
}}

== Intro ==
SatNOGS Rotator Controller refers to the set of electronics designed to operate a SatNOGS Rotator. There have been multiple iterations of the rotator controller design, but the modularity of the approach enables operations between different versions of the controller and the rotator.
Since the start of 2016, the rotator controller design is able to facilitate a DC-motors or stepper-motors rotator design. We intend to keep this modularity for the electronics and firmware design to facilitate the variety of build by our community.

== Rotator Controller v2 ==
<gallery>
Pcb_schema_v2_revC.png
Pcb_board_v2_revC.png
</gallery>

The PCB are tested in this [https://network.satnogs.org/stations/9/ ground station].

=== Features ===
* It is designed to fit the entire electronics needed to control rotator in Euroboard 80x50 mm.
* Main micro-controller is [https://store.arduino.cc/arduino-pro-mini Arduino pro-mini], [https://github.com/sparkfun/Arduino_Pro_Mini_328 SparkFun's Arduino Pro Mini 328] dev-board with ATmega328p.
* The modular design includes plug-in either [https://www.pololu.com/product/2133 DRV8825]/[https://www.pololu.com/product/1182 A4988] or [https://www.pololu.com/product/1213/resources DC motor drivers] (MC33926).
* The power supply in embed in the same board in contrast with previous version.
* Filtered power supply of micro controller.
* An I2C multiplexer is used to connect I2C encoders AS5601 (same ID) to get position feedback for each axis.
* A temperature sensor TC-74 monitoring the temperature inside the controller box in order to protect them from over-heating.
* There are some spare dev-pins in order to connect other peripherals like IMU or an LCD display.
* Pins with integrated RC-Low Pass filter for end-stops connection.
* Default communication interface is RS-485 but it can also be used as a UART.
* Using different paths for digital and power (motors) GND.
* Electrolytic capacitor and TVS-diode in PSU input
* Flashed either by using UART or ISP header

=== Build sequence ===
* Make sure you have a [[SatNOGS Rotator v3|mechanical assembly]] of the rotator constructed and ready
* Buy the PCB. [https://oshpark.com OshPark],[https://www.pcbway.com PCBWay.com], [http://dirtypcbs.com DirtyPCBs.com], [https://www.elecrow.com/ Elecrow] have been used in the past with good results.
** You can order the v2.2 of the board directly using [https://oshpark.com/shared_projects/w0s8d4OJ this OSHPark link] or [https://dirtypcbs.com/store/designer/details/6933/5904/satnogs-v3-motor-controller-zip this DirtyPCBs link].
** You can order the v1.0 of the rotary encoder board using [https://oshpark.com/shared_projects/I3b8SCci this OSHPark link]
* Get all the necessary components according to BOM from latest tag (or the version that you want to build), [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags Gitlab Tags]
* Assemble the PCB, by soldering the components
* Burn the firmware
* Using the wiring diagram, connect the controller to the Rotator
* You are ready! Proceed with testing

==== Assembly Guide ====

[[File:H1000_aluminium_enclosure.png|thumb|center|800x420px|alt=|Rotator Controller - Drill holes]]
[[File:Rotator_controller_sheet1.png|thumb|center|800x420px|alt=|Rotator Controller sheet 1/2]]
[[File:Rotator_controller_sheet2.png|thumb|center|800x420px|alt=|Rotator Controller sheet 2/2]]

==== Microcontroller ====
<gallery mode=packed heights="250px">
Uc.png|Microcontroller
Uc_orientation.png|Microcontroller Orientation
I2c_pullup.png|I2C pull-up resistors
</gallery>


The main micro-controller of the board is arduino pro-mini 5V@16MHz, ATmega328P.
The +5V of the controller are produced from arduino pro-mini.
Some clones do not use correct parts in LDO, like the original one, with
result, when it powers up with +12V, burned.

Some examples,
* [https://community.libre.space/t/v2-controller-board-magic-smoke/1878 SatNOGS Community]
* [http://westsideelectronics.com/blew-up-a-cheap-arduino-pro-mini-clone/ West Side Electronics]

One Solution is not use clones, use [https://www.sparkfun.com/products/11113# Sparkfun's arduiuno pro-mini 5V@16MHz, ATmega328P].
The second solution is to add a LDO, like [https://gr.mouser.com/datasheet/2/268/mic5205-778789.pdf MIC5205] (maybe in a new revision of v2).

The power consumption in +5V is:

{| class="wikitable"
|-
! -
! QTY.
! VCC(V)
! IDD(mA)
! Total(mA)
|-
| AS5601
| 2
| 5
| 6.5
| 13
|-
| PCA9540B
| 1
| 5
| 0.1
| 0.1
|-
| SN65HVD485E
| 1
| 5
| 2
| 2
|-
| TC74
| 1
| 5
| 0.35
| 0.35
|-
| arduino pro mini
| 1
| 5
| 20
| 20
|-
| MC33926
| 2
| 5
| 0.2
| 0.4
|-
| DRV8825
| 2
| 5
| 0.1
| 0.2
|}

The LDO MIC5205 guaranteed 150mA output, for Stepper motors ~35-40mA, for DC motors ~35-40mA.

==== Motor Drivers ====
===== Stepper motor driver =====
[[File:Stepper_2.png|thumb|320x240px|Stepper motor driver]]
[[File:Stepper_1.png|thumb|320x240px|Jumpers]]
[[File:Stepper_orientation.jpg|thumb|320x240px|Orientation]]

For the stepper motor driver 2 options have been tested, [https://www.pololu.com/product/2133 DRV8825] and [https://www.pololu.com/product/1182 A4988].
For both options it is necessary to solder:
* 2 electrolytic capacitors C3, C4 100uF
* 4 single 0.1" male connectors for U3, U4
* 2 fixed terminal blocks P7, P8, Amphenol-VI0421550000G
* 6 jumpers to adjust the micro-step, '''default option is Full Step'''
Note: [https://hackaday.com/2016/08/29/how-accurate-is-microstepping-really/ Guide for microstepping selection]
{| {{table}}
| align="center" style="background:#f0f0f0;"|'''JP3/JP6'''
| align="center" style="background:#f0f0f0;"|'''JP2/JP5'''
| align="center" style="background:#f0f0f0;"|'''JP1/JP4'''
| align="center" style="background:#f0f0f0;"|'''Microstep Resolution'''
|-
| align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Low''' || align="center" style="background:#f0f000;"|'''Full step'''
|-
| align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''Low''' || align="center"|'''Half step'''
|-
| align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''1/4 step'''
|-
| align="center"|'''High''' || align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''1/8 step'''
|-
| align="center"|'''Low''' || align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''1/16 step'''
|-
| align="center"|'''High''' || align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
| align="center"|'''Low''' || align="center"|'''High''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
| align="center"|'''High''' || align="center"|'''High''' || align="center"|'''High''' || align="center"|'''1/32 step'''
|-
|}

* Do'''NOT''' solder 2 resistors 100k, R4, R7 in default configuration (full step)
* If you have A4988 for stepper motor drive and you want to use micro stepping, when the MS1 is HIGH
it is necessary to solder R4, R7 according to [https://www.pololu.com/product/1201 A4983 Stepper Motor Driver Carrier, Step (and microstep) size].

In case of DRV8825, all pins MS1, MS2, MS3 have internal pull-up resistor.

Also it is necessary to update the definitions in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/stepper_motor_controller/stepper_motor_controller.ino firmware], according to microstepping selection.
Example:
* Step Angle: 1.8 deg
* Microstep: 1/8 step
* Steps per Revolution: (360/1.8)*8 = 1600

That means:

#define MICROSTEP 8 ///< Set Microstep
#define MAX_SPEED 6400 ///< In steps/s, consider the microstep
#define MAX_ACCELERATION 1600 ///< In steps/s^2, consider the microstep
#define SPR 1600L ///< Step Per Revolution, consider the microstep

It is necessary to change the maximum speed and acceleration according to new SPR.

Be careful:
* [http://reprap.org/wiki/Pololu_stepper_driver_board adjust the current (current limiting) for stepper motors]
* add a heat-sink.
* plug the stepper motor drivers

The stepper motor that is used, is [https://www.omc-stepperonline.com/hybrid-stepper-motor/nema-17-bipolar-59ncm-84ozin-2a-42x48mm-4wires-w-1m-cable-and-connector-17hs19-2004s1.html Nema 17 Bipolar 59Ncm],
* Size: ▱42 x 48 mm
* Weight: 390 g
* Shaft diameter: 5 mm
* Step Angle: 1.8 deg
* Nominal speed @ 12V: 720deg/s
* Rated Current/phase: 2.0A
* Stall torque @ 12V: 0.59Nm

===== DC motor driver =====
[[File:Dc_motor_driver.png|thumb|320x240px|DC motor driver]]

It is necessary to solder:
* Solder U6 with 0.1" female connectors as shown in picture
* Solder 2 pads in yellow circle by using ~1mm diameter wire
* Solder 2 2-pin 3.5mm terminal blocks for 2 DC motors

The DC motor controller is [https://www.pololu.com/product/1213 Dual MC33926 Motor Driver Carrier ]

* Motor driver: MC33926
* Motor channels: 2
* Minimum operating voltage: 5V
* Maximum operating voltage: 28V
* Operating voltage: 12V
* Continuous output current per channel: 2.5A
* Current sense: 0.525 V/A
* Maximum PWM frequency: 20 kHz
* Operating PWM frequency: 3921.5Hz (~4kHz)
* Minimum logic voltage: 2.5V
* Operating logic voltage: 5V
* Maximum logic voltage: 5.5V

The DC motor that we use is [https://www.pololu.com/product/1104 50:1 Metal Gearmotor 37Dx54L mm],
* Size: 37D x 54L mm
* Weight: 195 g
* Shaft diameter: 6 mm
* Free-run speed @ 12V: 200 rpm
* Free-run current @ 12V: 300 mA
* Stall current @ 12V: 5000 mA
* Stall torque @ 12V: 1.2Nm

 

==== Communication ====
Note: For both options the firmware is the same.
===== ''UART'' =====
[[File:Jumper.png|thumb|320x240px|UART Jumpers]]
[[File:Rs 485.png|thumb|320x240px|Pin Header]]

To use UART:
* solder JP7 and JP8
* solder pin header 0.1" female connector
* not solder C1, U2, R18, R19 R9, R8, R1, D3
* A is TX and B is RX

===== ''RS-485'' =====
[[File:RS485_solder.png|thumb|320x240px|RS485]]
[[File:Missing_rs485_r19.png|thumb|320x240px|RS485]]

To use RS485:
* solder pin header 0.1" female connector
* solder C1, U2, R18, R19 R9, R8, R1, D3
* not solder JP7 and JP8

If you use PCB without R19 footprint, you can add it in arduino pro-mini UART header.

 

==== Power Supply ====
[[File:Psu.png|thumb|320x240px|Power Supply]]

Recommended power supply for rotator controller is: 48V @ 1A DC.
A good choice is the [https://gr.mouser.com/ProductDetail/709-LRS50-48 MEAN WELL LRS-50-48]

The switching power supply could get as input voltage, 19-60V DC. 
In different input voltages, must be change the components like D4 and F1. 
Default PCB components works at 48VDC.

 

==== Endstops ====
[[File:Endstop_part.png|thumb|320x240px|Endstop Specification]]
[[File:Endstop.jpg|thumb|320x240px|Endstop]]

In reference design, mechanical endstops (the [https://www.aliexpress.com/item/10PCS-MICROSWITCH-LIMIT-SWITCH-3pin-N-O-N-C-MICRO-SWITCH-free-shipping/32692144896.html?spm=2114.search0104.8.13.2f3c2457pmCyFH&transAbTest=ae803_5&priceBeautifyAB=0 P/N SS0505] of endstop is specified in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator satnogs rotator BOM]) , are used.

The controller has the capability to accommodate optical or magnetic endstop which connected to
P2 header with silkscreen, SW1, SW2, +5V and GND.

Mechanical endstops are connected to
* SW1 and GND for azimuth axis
* SW2 and GND for elevation axis

 

==== Encoders ====
Source files: [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller-encoder satnogs-rotator-controller-encoder - GitLab]
Firmware: [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/libraries/as5601.h satnogs-rotator-firmware - GitLab]

For stepper motor setup is optional (AS5601 encoder).

For DC motor setup is necessary.

[[File:Encoder_sheet1.png|thumb|center|800x420px|alt=|Rotary Encoder sheet 1/2]]
[[File:Encoder_sheet2.png|thumb|center|800x420px|alt=|Rotary Encoder sheet 2/2]]

 

==== Wiring ====

[[File:Wiring_diagram.png|thumb|center|800x420px|alt=|Wiring Diagram]]

 

==== Rotator Controller enclosure - Placement ====
Mount the rotator controller enclosure by using two sides adhesive tape (as mentioned in BOM)

[[File:Box_placement.png|thumb|center|800x420px|alt=|Rotator Controller enclosure - Placement]]

 

=== Firmware and Pin Assignments ===

===== Firmware =====

[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware For stepper motors] 
[https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware For DC motors, thanks to ] [https://github.com/ph4as ph4as]

===== Pins Configuration =====
This configuration is from the latest release in [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-controller/tags Rotator Controller repository]

* M1IN1 10, Step or PWM1
* M1IN2 9, Direction or PWM2
* M1SF 7, Status flag
* M1FB A1, Load measurment

* M2IN1 11, Step or PWM1
* M2IN2 3, Direction or PWM2
* M2SF 6, Status flag
* M2FB A0, Load measurment

* MOTOR_EN 8, Enable/Disable motors

* SW1 5, Endstop for axis 1
* SW2 4, Endstop for axis 2

* RS485_DIR 2, RS485 Half Duplex direction pin

* SDA_PIN 3, Data I2C pin
* SCL_PIN 4, Clock I2C pin

* PIN12 12, Digital output pin
* PIN13 13, Digital output pin
* A2 A2, Analog input pin
* A3 A3, Analog input pin

 

=== Pre-Flight Check ===

[[File:Pcb_testing_points.png|thumb|center|800x420px|alt=|Testing Points]]

* Power your PCB with 48VDC, without plug-in arduino pro-mini and motor drivers, measure with multimeter the voltage in point 1. Expected voltage +12V (reference to GND).
* Plug arduino pro-mini and measure with multimeter the voltage in point 2. Expected voltage +5V (reference to GND).
* Plug motor drivers (for steppermotors ensure the current is adjusted properly)
* Connect all peripheral devices like motors, sensors, endstops

If the two first steps fail, something is wrong (maybe there is a short circuit) in PCB. Check the connections with a multimeter.

Then the board is ready to run the firmware, [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware/blob/master/README.md satnogs-rotator-firmware].

 

=== Troubleshooting hints ===

As soon as the board is powered up or reset, it will auto-home, on first build you can trigger a reset multiple time or move the homing ring to get it "home".

Connecting directly to the Arduino pro-mini you will need to use 19200 bauds and "newline" line ending.

Here is some commands (took from [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator-firmware#easycomm-implemantation]) you can issue in the terminal emulator of your choice to test things:

* '''VE''', it will returns something like "SatNOGS-v2.0"
* '''RESET''', move to home position
* '''AZxx''', '''ELxx''', move to specified position (number)

Nothing moves ? Look at the status and error register :

* '''GS''', status register : 1 idle, 2 moving, 4 pointing, 8 error
* '''GE''', error register : 1 no error, 2 sensor, 4 homing, 8 motor, 12 over temperature, 16 wdt

By example, at first start, you might be in '''GS8''' and '''GE4''' until you get a good homing position for the rotator to start working.

 

== Rotator Controller v1 ==

SatNOGS Rotator v3

2018-08-24T15:16:16Z

Azisi: /* Parts */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant], [https://community.libre.space/t/help-to-buy-metric-tubing-for-v3-rotator/784/6 tool that helps to build imperial part]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -3 and -4, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator v3

2018-08-24T15:12:33Z

Azisi: /* Parts */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath], [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant]
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [https://community.libre.space/t/version-3-1-stepper-varient-with-v2-controller/1430/5 Imperial variant]
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -3 and -4, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator v3

2018-08-24T15:03:25Z

Azisi: /* Vendors Table */

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
| -
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
| -
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
| -
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
| -
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
| -
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
| -
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
| -
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
| -
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
| -
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
| -
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
| -
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
| -
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors, T-slots, fasteners
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -3 and -4, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]

SatNOGS Rotator v3

2018-08-24T15:01:52Z

Azisi:

{{Template:Rotator
|Rotator-Name=SatNOGS Rotator v3
|image=V3.jpg
|type= Az/El
|cost=~220 USD
|status= Beta
|latest-release= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/tree/v3.0.1
|latest-release-name= Torx Flathead (v3.0.1)
|source-repo= https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/
|documentation= https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/
}}

== Intro ==

v3 marks a major re-haul of the SatNOGS Rotator design, with learnings from [[SatNOGS Rotator v2|v2]] applied. You can see a lot of the thinking and background research that was conducted prior to v3 development in this [https://community.satnogs.org/t/satnogs-rotator-version-3/226 thread]. Also in this wiki page you can also find a "How to build the rotator", mechanical analysis and all documentation about the [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator SatNOGS rotator].

Also in this [https://www.ethercalc.org/v3specs list] is presented different rotators, either commercial or DIY builds.

==Specifications==

{| {{table}}
| align="center" style="background:#f0f0f0;"|'''''
| align="center" style="background:#f0f0f0;"|'''SatNOGS v3 Rotator'''
|-
| Plastic Parts || 15
|-
| Non Printed Parts || 38
|-
| Cost||~ $220
|-
| Controller Electronics|| [[SatNOGS Rotator Controller]]
|-
| Type||AZ/EL (possible X/Y)
|-
| Motors||2x NEMA 17 Stepper or 2x DC Motors
|-
| Frame Material|| Aluminum T-slot 20x20
|-
| Speed (deg/sec) || 7
|-
| Torque (Nm) || 30
|-
| Brake Torque (Nm) || ?
|-
| Dimensions (mm) || 280x140x140 (AZ/EL)
|-
| Weight (kg) || ~5
|
|}

==== Brake Torque ====
The greatest force the tracker needs to withstand is the force created by strong wind. The worst case is when one antenna is elevated at 90 degs, facing the direction of the wind. We based our calculations on an [http://k7nv.com/notebook/topics/windload.html article] found online after comparing it to others. We “translated” the second table in metric (because we don’t understand imperial and because we needed same units system in our calculations)

{| class="wikitable"
|-
! Method
! Wind Zone(km/h)
! Height (m)
! Pressure(N/m^2)
|-
| EIA-222-C
| 160
| N/A
| 1280

|-
| EIA-222-F
| 128
| 14
| 1260

|-
| EIA-222-F
| 128
| 21
| 1390

|-
| EIA-222-F
| 128
| 30
| 1500

|-
| UBC'97
| 128
| 14
| 1290

|-
| UBC'97
| 128
| 21
| 1160

|-
| UBC'97
| 128
| 21
| 1390

|-
| UBC'97
| 128
| 30
| 1260

|-
| UBC'97
| 128
| 42
| 990

|-
| UBC'97
| 128
| 42
| 1360

|-
| Generic Formula
| 150
| N/A
| 1270

|}

and we applied the worst case model (EIA-222-F) in 3 different antennas: in the biggest one of our designs, and in two others, for which we obtained data from [http://download.qrz.ru/pub/hamradio/antenna/rotators/G-800SA_1000SA.pdf yaesu G800 rotator manual at page 3]. We assumed that antennas are mounted in 1m away from the azimuth axis. For our antenna with 2m length (actual, not wavelength), made by 2cm square tube, the generated torque was ≈600Kg*cm. For the 144MHz 10-elements Yagi from the article is ≈6000Kg*cm and for the third 430MHz, 12-elements Yagi is ≈1800Kg*cm

==== Moment of inertia ====
Now for the moment of inertia: (for all installation methods we assumed that antennas are counterbalanced in the elevation axis) the worst case scenario here is to use two 3kg (our designs are less than 1kg) back mounted yagis with 3kg counterbalances both mounted in 0.75m away from azimuth axis. The torque you need in order to accelerate this system from ω=0deg/s angular velocity to ω=5deg/s (the math about angular velocity is below) in one second is about 60kg*cm.

Note: we suppose that the mass of antennas is near to the altitude axis, so the torque of this axis that is needed to accelerate is approximately 0.

* M1: torque of Azimuth axis
* L: length of center of mass of antennas from azimuth axis (0.75m)
* m: mass of antennas and of counterweight (3kg + 3kg = 6kg)
* I: moment inertia
* a: angular acceleration of azimuth axis 5deg/s^2
* I = I1 + I2 = m*L^2 + m*L^2 = 2*m*L^2 = 6.75 kg*m^2
* M1 = I*a = 6.75kgm^2 * 0.087rad/s^2 = 0.58 Nm = 5.8 kgm = 58 kgcm

==== Angular velocity ====
(How well do you remember trigonometry?)For the angular velocity max needed in altitude axis the things are straightforward. The closer is the satellite the larger the velocity. According to the wikipedia article about LEO, the lowest height limit is 160 km and the speed unit to orbit earth in this altitude is 7,8 km/s. As a result, maximum velocity in ALT axis is 2,8 deg/s. In ALT AZ rotator design there is a well known limitation: the closer something passes near zenith the biggest gets the velocity of the AZ axis. Therefore, we have analyzed this problem to figure out the optimal velocity and how high we are allowed to track a target in relation to AZ velocity. The picture below illustrates a ground station B which tracks a satellite Γ in X degrees altitude. The satellite velocity at this point is vertical to the screen (page) plane.

[[File:Anglular_velocity.png|thumb|center|800x420px|alt=|Angular Velocity]]

The equations that lead to maximum altitude at which we can track in relation to AZ angular velocity are
* ω : angular velocity of AZ DOF in rad/s
* H = ΑΕ + ΕΓ : Minimum Height of LEO, 160 km
* R = ΑΕ : Radius of Earth, 6500 km
* u : linear velocity of satellite that rotates in 160km height is 7.8 km/s
* ΒΔ = u / ω : ΒΔ in km
* α = atan(ΒΔ / R)
* δ = π - α
* γ = asin( sqrt(R^2+ΒΔ^2) * sin(δ) / (H+R) )
* ά = π - δ - γ
* ΓΔ = (H+R) * sin(ά) / sin(δ)
* χ = atan(ΓΔ / ΒΔ)

Below you can see the plot of the equations mentioned above, where horizontal axis represents angular velocity (ω) in deg/s and vertical axis shows the max track altitude (χ) for lower bound of LEO.

[[File:Anglular_velocity_plot.png|thumb|center|800x420px|alt=|Angular Velocity Plot]]

After studying this diagram, we came up to the conclusion that an angular velocity of 5 deg/s is adequate. For this decision, we took into consideration the main lobe of antenna (Δ3db) which in most situations is about 20 deg.

==== General Specifications ====
Together with the above mentioned specifications, we would also like for the 3rd version of SatNOGS rotator to be:

* inexpensive (less than €300, if possible)
* lightweight and portable (~6Kg, size:~300x~150x~150mm)
* rigid and durable
* easy to build and fix (try to use easily available materials)
* weatherproof
* electromagnetically shielded, so that noise in reception is reduced
* accurate (<1deg, backslash reduction and use of encoders at the axis)

== Sourcing ==

'''3d Printing at a Fab Lab or your local hackerspace:''' If you don't have your own 3d printer, then a local Fab Lab or hackerspace may be able to do it for you. Fab Labs and hackerspaces are places that have invested in the machinery and you can take the designs to them. Generally they need .stl files to import into the software that runs the machines, but this should be discussed with the Fab Lab or hackerspace. You then pay for the material, time or a combination of the two for each of the parts or any other agreement in place.

* [http://www.fabfoundation.org/fab-labs/ FabLabs]
* [https://wiki.hackerspaces.org/List_of_Hacker_Spaces List of hacker spaces]

Most people building the rotator have had success builds with simple ABS material for the 3D printing parts.

'''T Slot''' - If you don't want to cut the pieces yourself, then you may be able to find a supplier that will do this for you. ([http://www.kjnltd.co.uk/ Here's one in the United Kingdom].)

Hidden corner connectors - AliExpress gave the cheapest supplier

A good US source is [http://us.misumi-ec.com/ MISUMI-USA]; they will also cut to length. MISUMI has several other global locations [https://www.misumi-ec.com].

Beware, the 20-series T-slot from [https://8020.net/ 80/20 Inc.] in the US has slots that are only 5.2mm wide. The hidden corner connectors from e.g. AliExpress '''will not fit'''.

'''Stepper Motors''' - eBay

'''Belts''' - eBay

'''Fixings / Pipe''' - eBay

==== Vendors Table ====

Like the [https://reprap.org/wiki/RepRap_Buyers%27_Guide RepRap Buyers' Guide wiki], feel free to populate the table.

{| class="wikitable"
|-
! Vendor
! Location
! Parts
! Notes
|-
| [https://www.pololu.com/ pololu]
| USA, Worldwide
| Motors, electronics
|
|-
| [http://mouser.com/ mouser]
| Worldwide
| Motors, electronics
|
|-
| [https://www.ebay.com/ ebay]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
|
|-
| [https://www.aliexpress.com/ aliexpress]
| Worldwide
| Motors, electronics, Fasteners, T-Slots, pulleys, Tubes
|
|-
| [https://grobotronics.com/ grobotronics]
| GR, EU
| Motors, electronics, Fasteners, T-Slots, pulleys
|
|-
| [https://www.motedis.com/shop/index.php motedis]
| DE, EU
| T-Slots, Tubes
|
|-
| [https://uk.misumi-ec.com/ Misumi]
| Worldwide
| T-Slots, Tubes, Fasteners, Pulleys
|
|-
| [https://www.omc-stepperonline.com/ omc-stepperonline]
| Worldwide
| Stepper motors
|
|-
| [https://www.fastenal.ca/ fastenal]
| USA
| Fasteners
|
|-
| [https://www.mcmaster.com/ mcmaster]
| USA
| Fasteners
|
|-
| [http://www.rs-online.com/ rs]
| Worldwide
| Electronics, fasteners, motors
|
|-
| [https://8020.net/ 80/20]
| USA
| T-Slots
|
|-
| [https://www.pcbway.com/ pcbway]
| CN
| PCB fabrication
|
|-
| [https://www.servocity.com/ servocity]
| USA
| Motors
| Most of parts are not metric
|-

|}

== Build Sequence ==

==== Tools & Consumables ====
Here are presented tools and consumables about part fabrication, port-processing and assembly process.
Most of the tools are available in every hackerspace, makerspaces, FabLabs etc.

{| class="wikitable"
|-
! Tool/Consumable
! Description
|-
| Drill bits
| 2mm for aluminum, 3mm, 4mm and 5mm for plastic
|-
| Drill driver
| For aluminum tube drill hole, 3D printed part
|-
| Sandpaper
| 80(dry), 120(dry), 240(dry) and 1000(wet) grit
|-
| Acetone
| For acetone vapor bath
|-
| Hacksaw
| For aluminum Tube
|-
| Square File
| For worm axis, for use on steel
|-
| Precision Knife
| For general use, especially in 3d-Printed parts
|-
| Caliper
| Measuring Range 0-150mm
|-
| Combination Wrenches
| 5.5mm, 7mm and 8mm
|-
| Thread-locker
| Like Loctite 271
|-
| Cyano acrylic glue
| Like Loctite 401
|-
| Screw driver
| Number 1 Phillips
|-
| Heat Gun
| For Heat-shrinkables or use a lighter
|-
| Ball-End L-Keys
| Hex 1.5mm, 2mm, 2.5mm, and 3mm
|-
| Soldering iron and consumables
| For cables
|-
| Wire Cutter
| For cables
|-
| Long-Nose Plier
| General purpose
|-
|}

==== Parts ====
Make sure you have all parts, according to [https://gitlab.com/librespacefoundation/satnogs/satnogs-rotator/blob/master/rotator-bom.ods BOM].

Most of the parts could be fabricated by a FDM 3D-printer. Some parts have only 2D geometry so could be
fabricated by a laser cutter. Other parts have modifications of common(hardware) parts like threaded rods or
aluminum pipes. Also you could find a lot of guides for [https://www.3dhubs.com/knowledge-base/post-processing-fdm-printed-parts post processing for FDM printed parts].

<gallery widths=200 heights=200 perrow=4>
File:C1001.png|C1001, Aluminum Tube 6063 OD40mm TH1.5mm L240mm, 2 variants -1 and -3
File:C1010-3.png|C1010-3, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1011-3.png|C1011-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1020-1.png|C1020-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1021-1.png|C1021-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material, [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1022-3.png|C1022-3, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1030-1.png|C1030-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1040-1.png|C1040-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1041-1.png|C1041-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1042-1.png|C1042-1, laser cut in 3mm Acrylic Sheet or in FDM-3Dprinter with same fabrication parameters as C1010-3
File:C1043-1.png|C1043-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], Support material, Brim Width: 2 mm
File:C1050.png|C1050, Aluminum Profile 20x20 B-type slot 6, 2 variants -1 and -5
File:C1060-1.png|C1060-1, M5 Threaded rod A2 stainless steel(304)
File:C1061.png|C1061, 2 variants -3 and -4, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1062-1.png|C1062-1, It is recommended to build in laser sintering like Shapeways with White Versatile Plastic (cost ~10€) or like C1030-1 and [http://sinkhacks.com/building-acetone-vapor-bath-smoothing-3d-printed-parts/ Smoothing the part with acetone vapor bath]
File:C1070-1.png|C1070-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1071-1.png|C1071-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
File:C1072-1.png|C1072-1, FDM-3Dprinted, Material: ABS, Layer height: 0.4 mm, Perimeters: 2, Top/bottom solid layers: 3, Fill density: 20%, Fill pattern: Honeycomb, Fan speed: [35, 100], No support material
</gallery>

==== Assembly ====
Follow the [https://ohai.satnogs.org/project/satnogs-rotator-v3-mechanical-assembly/hardware/ instructions for mechanical assembly] and also you can [https://www.youtube.com/watch?v=D6P9HK23Gmo watch timelapse]
Also, exploded views and instructions are present here.

<gallery widths=180 heights=180 perrow=4>
File:A1010-1.png|Step 1, Prepare the assembly of worm gear
File:A1011.png|Step 2, Prepare the assembly of worm gear mount, 2 variants -1 and -2 (mirror)
File:A1020-1.png|Step 3, Prepare the assembly of shaft collar for worm wheel
File:A1033-1.png|Step 4, Prepare the encoder gear
File:A1070-1.png|Step 5, Prepare the Motor mount
File:A1060-1.png|Step 6, In case of DC motor configuration
File:A1031-1.png|Step 7, Bearing side without encoder and end-stop mounts
File:A1032-1.png|Step 8, Bearing side with encoder and end-stop mounts
File:A1030.png|Step 9, Prepare symmetric and asymmetric axis, 2 variants -1 and -3
File:A1001-3.png|Step 10, Frame with worm gear mount and A1001-1 assembly
File:A1040.png|Step 11, Rotator module 2 Variants -1 and -3, symmetric and asymetric
File:A1050-1.png|Step 12, Final step of Antenna Rotator
</gallery>

==== Rotator Controller ====
Once mechanical assembly is ready, construct the [[SatNOGS Rotator Controller]].

==== Cover Box - Cabling ====
Prepare the cover box and install it to antenna rotator with rotator controller and cables.

==== Testing ====
You are ready! Proceed with [https://wiki.satnogs.org/SatNOGS_Rotator_Controller#Troubleshooting_hints testing].

== Mechanical Analysis [WIP] ==

Horizontal distance between pulleys (P1, P2) is 58mm.
Vertical distance between pulleys (P1, P2) is w = 9.5mm.

Pulleys and Belt are GT2, 2mm pitch.
Belt width, 6mm.
Belt thickness, 1.38mm (0.76 tooth).

Wrap angle in both pulleys is larger than 60deg.
At least 6 teeth in contact with the pulley at any given time.
In practice that means you want a minimum of a 12 tooth pulley, and usually try to get at least 18 teeth.

Outer Diameter of pulleys:

P(T) | OD(mm) 
16 | 10.2 
20 | 12.7 
36 | 22.9 
40 | 25.5 

Belt calculation (according to calculator):

Ratio | P1(T) | P2(T) | Belt(T) | L(mm) 
2.25|16|36|85/86|58.65/59.66 
1.8|20|36|86/87/88|57.78/58.78/59.78 
2.5|16|40|87/88|58.5/59.5 
2|20|40|89/90|58.65/59.66 

Motor Maximun no-load speed, 200RPM = 1200deg/s
Motor Maximum stall-torue, 1.2Nm

[[File:Motor_perfomance_graph.png|thumb|center|800x420px|alt=|Angular Velocity]]

Position of idler do not care, or min 1.3*P1, max 1.5*P1 (for 20T, ~16mm/~20mm).

Belt gear selection:
* 20/36 with 1.8 ratio and 86T/172mm belt without idler
* 20/40 with 2 ratio and 90T/190mm belt with idler

To calculate Deflection force, (page T-31, sdp - design-guidelines)
* Y = 2.05, Tst = 1.3kg
* span length, t = 57.64mm
* Belt pitch length, L = 180mm
* Fd,min =
* Fd,max =
* 2.8kg Working Tension [shapeoko - Belts and Pulleys](https://www.shapeoko.com/wiki/index.php/Belts_and_Pulleys#Tensile_Cord_Materials)

P3 
/ \ 
P1 P2 
| 
P4-P5 

* Determination of design load
According to perfomance graph of DC motor, the optimal output power is Tm = 0.6Nm with efficiency of 0.2 and 100RPM = 600deg/s.
Select a service factor of 1.5 (service factors between 1.5 and 2.0 are generally recommended when
designing small pitch synchronous drives).
Tpeak = SF*Tm = 1.5*0.6 = 0.9Nm

* Choice of belt pitch
Due to backslash and accuracy in both directions of movements and volume constrains, we choose GT2, pitch 2mm.

* Check belt pitch selection based on individual graphs
Due to Tpeak = 0.9Nm No-load speed,(Speed of fastest shaft) = 100RPM = 600deg/s
GT2 pitch 2mm belt is the better solution for our application.

* Determine speed ratio
Speed ratio 1.8-2.25 according to specification of output rotation speed of 5deg/s.

* Check belt speed
V(m/s) = 0.0000524 x pulley PD (mm) x pulley rpm = 0.066548m/s
Belt speeds up to 6,500 fpm (33.02 m/s) do not require special pulleys.

* Determine belt length
Table 'Belt calculation (according to calculator)'
Teeth in mesh: 9

* Determine the belt width
From Table 43
torque = 0.17Nm
Length Correction Factor = 0.9
width multiplier = 1.00
torque*Length Correction Factor*width multiplier = 0.17*0.9*1.00 = 0.153Nm
Teeth in mesh: 9
Tpeak = 0.9Nm, so belt width is nice for our application

* Check the number of teeth in mesh
Teeth in mesh: 9 according to calculator

* Determine proper belt installation tension
SECTION 10, on page T50, look at 'To calculate Deflection force, (page T-31, sdp - design-guidelines)'
* Y = 2.05, Tst = 0.812*DQ/d + mS^2 = 12.8lb + 0 = 5.8kg
* DQ = Tpeak = 0.9Nm = 7.9lb-in
* d = 12.7mm = 0.5in
* S = (0.5*100/3.82)/1000 = 0.0131ft/min
* m = 0.039
* span length, t = sqrt(CD^2 - (PD-pd/2)^2) = 57.64mm
* Belt pitch length, L = 180mm
* t/L = 0.32
* Fd,min = 0.8lb = 0.36kg
* Fd,max = 0.9lb = 0.41kg

* Safety factor 1.5

* P2 timing pulley torque - Maximum radial load of timing belt ball bearing 625zz
Tpeak = 0.9Nm
TorqueP2 = 2*0.9Nm = 1.8Nm, PDp2 = 25.5mm
Radial static load of 625ZZ is 0.38kN
T-39

* Maximum thrust load of timing belt ball bearing 625zz

* Maximum radial and thrust load of output ball bearings 6008zz
Calculate or evaluate correct loads for deep groove ball bearings
radial static load = 11.6kN
thrust static load = 0.7*11.6kN = 8.12kN
This type of construction permits the bearings to support relatively high thrust load in either direction.
In fact the thrust load capacity is about 70% of the radial load capacity. A ball bearing primarily designed
to support radial load can also support high thrust load; because only few balls carry the radial load,
whereas all the balls can withstand the thrust load.

* Maximum self-locking or back-drivable torque of gear box (according to more weak component)
It necessary to achieve [specs](https://community.libre.space/t/satnogs-rotator-version-3/226), 60Nm (6Kg in 1 meter)

* Nominal torque of drivable torque of gear box (according to more weak component) and maximum rotational speed of gear box

Notes:
* [https://sdp-si.com/eStore/CenterDistanceDesigner sdp distance calculator]
* [http://www.ebay.com/itm/2GT-Timing-Belt-L-172-232-240-244-640-810-GT2-Belts-closed-loop-5pcs-lot-/221977955532?var=&hash=item33aeeacccc:m:me5GvSt_amrm6RWT03Ut4JA belt GT2-6mm wide, 172mm]
* [https://www.ebay.com/itm/2GT-GT2-synchronous-Timing-belt-Perimeter-98-194mm-width-6-9mm-Cogged-close-loop/222574382655?ssPageName=STRK%3AMEBIDX%3AIT&var=521434616407&_trksid=p2060353.m2749.l2649 belt GT2-6mm wide, 180mm]
* [http://www.ebay.com/itm/5pcs-Timing-Pulley-GT2-Idler-16-20T-gear-Bearing-Reprap-6mm-Belt-3-5mm-Bore-3D-/132195520937?var=&hash=item1ec77791a9:m:mljSYBViBlKOgXr3Gy-u0Tg idler pulley, no-teeth-ID3mm-OD18mm]
* [http://www.brecoflex.com/products/pulleys/design-guidelines/ brecoflex - design-guidelines]
* [http://www.shreegeeimpex.com/TECH_DATA_PAG/idlers_ten.htm shreegeeimpex - design-guidelines]
* [http://www.sdp-si.com/PDFS/Technical-Section-Timing.pdf sdp - design-guidelines]

==== Motor Specification ====

General Specification about motors. The voltage and current consumption also it depends from the motor controller which is (maybe) different
from [https://wiki.satnogs.org/SatNOGS_Rotator_Controller SatNOGS Rotator Controller].

{| class="wikitable"
|-
! Specification
! Value
|-
| Min-Max Stall Torque (Nm)
| 0.4 - 1.5
|-
| Min-Max Speed (RPM)
| 100 - 200
|-
| Size (mm) (LxWxH)
| 47x42x64
|-
|}

<gallery widths=200 heights=200 perrow=4>
File:Motor mount dimensions.png|Motor mount dimensions
File:Max motor height.png|Maximum Motor Height
</gallery>

==== Worm Gear Box Calculations ====

* Gear ratio: i12 = 30
* Angle between axis of gears: δ = 90 deg
* Number of threads in worm: If i12 >= 30 then z1 = 1
* Number of teeth in worm wheel: z2 = i12*z1 = 30
* Center distance: initial case a = 45.5 mm
* Worm reference diameter: AGMA d01>= 11.5*(a/25.4)^0.875 = 19.15 mm, so d01 = 19.5mm
* Worm wheel reference: d02 = 2*a - d01 = 71.5 mm
* Axial module: ms = d02/z2 = 2.38 , so ms = 2.5
Recalculate d02, a with new axial module
* d02 = z2*ms = 75mm, a = (d02+d01)/2 = 47.25mm
* Axial pitch: ts = π*ms = 7.854mm
* Reference lead angle: γ0 = atan(d02/(i12*d01)) = 7.3 deg
* Worm tip diameter: dk1 = d01 + 2*hk = 24.5mm
** Worm teeth reference addendum in axial section: hk = hk* *ms = 2.5mm
** Worm tooth reference addendum coefficient: hk* = 1
* Worm root diameter: df1 = d01 - 2*hf = 13.5mm
** Worm tooth reference dedendum: hf = hf* _ms = 1.2_ms = 3mm
** Dedendum coefficient: hf* = 1.2
* Worm length: L = 2.5_ms_sqrt(z2+2) = 35.36mm
* Worm tooth thickness: smx1 = smx1* * ts = 3.927mm
** Tooth thickness coefficient: smx1* = 0.5
* Normal pressure angle: aon = 20 deg
* Worm wheel throat diameter: dk2 = d02+2*hk = 80mm
* Worm wheel root diameter: df2 = d02 - 2*hf = 69mm
* Worm wheel outside diameter: de2 = dk2 + 2*mx = 83.5mm
** Worm wheel tooth external addendum: mx = n*ms, 0.4<=n<=1.5
* Effective worm wheel face width: b2H,max = sqrt((2_a - df2)^2 - (2_a - de2)^2) = 23mm

[[Category:Rotator]]