Many people take great satisfaction in a beautifully manicured lawn, and some even enjoy mowing, trimming hedges, spreading mulch, and so on. This project isn’t for those kinds of people. This project is for those of us who would rather sit on the porch drinking sweet tea than be out in the sun sweating behind a lawn mower. The agriculture industry has had semi-autonomous tractors for a while now, and you can even purchase robotic lawnmowers for your residential lawn. YouTuber Michael Rechtin took an approach somewhere in the middle and added remote control capability to a heavy duty riding lawnmower.
So why not just purchase a robotic lawnmower? They’re essentially Roombas with lawnmower blades attached, and that’s not a good thing. They’re virtually all battery powered, which limits the size of the lawn they can cut in one go and the power available to mow through dense grass. But, aside from the relatively high prices, most people probably aren’t willing to trust a robot to mow their lawn safely. If you’ve ever seen a Roomba collide with a sleeping dog or tumble down a flight of stairs, you know autonomous navigation systems are not foolproof. Add sharp whirling blades, and you’re asking for trouble.
Rechtin’s solution is safer and also capable of plowing through much larger yards. It’s essentially just an old gas powered riding lawnmower that has been retrofitted with a remote control receiver. That receiver connects to an Arduino Mega 2560 board, which controls the steering motor and gear actuator through motor drivers. Those receive power from a large LiPo battery to avoid taxing the lawnmower’s battery. The steering motor is actually a car windshield wiper that turns the steering wheel via a sprocket and chain. A linear actuator is used to move the pedal that selects the forward or reverse gear. Two servo motors are used to adjust the throttle and choke. There is also a relay board, which is used to connect power to headlights and starter motor.
That all works with a standard RC transmitter so that Rechtin can drive the lawnmower from very far away. One stick is used to operate the steering motor, and a potentiometer provides position feedback. Another potentiometer gives feedback on the gear pedal position. Knobs at the top of the transmitter are used to adjust the throttle and choke. We can’t think of a better lawn care solution for those of us who dread mowing the lawn.