SatNOGS Rotator Controller

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Revision as of 12:38, 30 August 2017 by Zisi (talk | contribs) (Motor Drivers)
SatNOGS Rotator Controller
SatNOGS Rotator Controller
Type: Rotator Controller for SatNOGS rotator.
Release Information
Status: Working
Latest Release: [ ]
Repository: []
Documentation: []


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

The PCB are tested in this ground station.


  • It is designed to fit the entire electronics needed to control rotator in Euroboard 80x50 mm.
  • Main micro-controller is Arduino pro-mini dev-board with ATmega328p.
  • The modular design includes plug-in either stepper drivers (DRV8825) or DC motor drivers (MC33926).
  • The power supply in embed in the same board in contrast with previous version.
  • Filter in power supply of micro controller.
  • It has an I2C multiplexer 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-temperature.
  • More dev-pins to connect other peripherals like IMU, LCD display.
  • Pins with RC-Low Pass filter for end-stops.
  • Default communication interface is RS-485 (WIP) but it can be also used UART.
  • Avoid connection with GNDD directly with motor GND use keep out area.
  • Electrolytic capacitor and TVS-diode in PSU input

Build sequence

  • Make sure you have a mechanical assembly of the rotator constructed and ready
  • Buy the PCB
  • 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

Motor Drivers

  • Stepper motor driver
JP3/JP6 JP2/JP5 JP1/JP4 Microstep Resolution
Low Low Low Full step
Low Low Low Full step
Low Low Low Full step
Low Low Low Full step
Low Low Low Full step
Low Low Low Full step
Low Low Low Full step
Low Low Low Full step
Stepper 2.png
Stepper 1.png
  • DC motor driver


  • UART
  • RS-485

Power Supply


  • Mechanical Endstops


For stepper motor setup is optional.

  • AS5601 encoder


Temporary wiring

Rotator Controller enclosure - Placement

Firmware and Pin Assignments

Pre-Flight Check

Need to add testing procedure here.

Rotator Controller v1