4tronix M.A.R.S. Rover Robot remote control using the PiHut Wireless USB Game Controller

Sources, references, dependencies

• The Pi Zero variant of 4tronix M.A.R.S. Rover Robot
• The original code from 4tronix M.A.R.S. Rover, installed as explained in Programming M.A.R.S. Rover on Raspberry Pi Zero (inc v2)
• The PiHut Wireless USB Game Controller [WUGC]
• Dependencies: rover.py and pca9685.py, RPi.GPIO, aproxeng.input, rpi_ws281x, python3-systemd, dataclasses, PyYAML, python3-smbus
  • The rpi_ws281x module is the official Python binding for the userspace Raspberry Pi library for controlling WS281X LEDs, and uses /dev/mem for DMA/PWM/PCM and /dev/gpiomem for GPIO access (see ws2811.c). Therefore, the LED control on the Rover works only with root access!

Version history

V1.0, February 2023

• Joysticks:
  • Use left stick to set speed (forward or reverse) and right stick to set direction (left or right).
• Buttons:
  • Analog for 3 sec to exit program (and stop the service unit).
  • Circle+Square for 3 sec to initiate system shutdown with ./scripts/sd.sh.
  • Triangle+Cross for 3 sec to initiate system reboot with ./scripts/rb.sh.
• LEDs (must be run with root access):
  • Initialisation LED sequence.
  • White color in the front; red color in back; etc.
  • Program termination LED sequence.
• Simple driving mode: all (6) DC motors are driven with the same speed. Direction is set only by the servo motors.
• Logging to (rotating) log file driverover.log and console.
• Use systemd service unit to start, monitor (watchdog) and re-start the driverRover_wugc.py on missed watchdog; has to be installed as system-wide unit (root access) when LEDs are used!
• Use YAML configuration file driveconfig.yaml for most common custom parameters; other parameters are configured in driveconfig.py.

V1.1, March 2023

• Implement Ackermann steering driving mode (with hwd limitations). Can be set in driverconfg.yaml with mode: 'ackermann'.

V1.2, March 2023

• Scale direction angle in the function mixer_dir() in drivefunc.py.
• Code clean-up. Fix most of the pylint errors and warnings (except in the orginal code rover.py, etc.)

V1.3, September 2023

• Support power management hardware for clean shutdown/poweroff: push button activated or low battery triggered. Prototype circuit diagram provided.
• Systemd services to handle power management hardware and clean shutdown/poweroff. See scripts for details.

TODOs:

• Add support for customized 2-axis camera mount
• Add support for sensors (motion, proximity, light)
• Design custom 3-D printed enclosure