Additionally, monitors the flight mode for changes and sets the parking brake servo accordingly (on when HOLD mode is selected). Controls a relay (lawnmower blade PTO) based on an RC channel's PWM ...

Please visit ardupilot.org for more information on Ardupilot, Ardurover, and Mission Planner. Connect the other board to a Pixhawk compatible flight controller. I only used three wires: Transmit, ...