Mower of Doom

Gulf Racing Livery!

Originally it was just a Remote Control Mower project but the thought of an autonomous lawn mower jokingly became the Mower of Doooom.

In the Houston summer, grass grows nearly fast enough to watch. If you are not mowing at least once a week, it gets to be a jungle. A few years ago, I lost my lawn guys several times in a Summer so I started cutting it myself and remembered why I hired a service in the first place. I was between car projects and saw an RC Mower article somewhere so I decided to give it a shot. Really, how hard could it be?

I purchased some powered wheelchair motors, some cheap Chinese motor controllers and an RC radio from Ebay and proceeded to weld up a frame and give it some racy paint!

Fun up until now, the real pain began as I tried to get an Arduino to talk to the RC receiver and motor controllers. Some begging ensued and my Brother came to the rescue.

Eventually, we got it assembled but the cheap drivers just wouldn’t move the big mower properly. Either too slow, popping fuses or both. We tried a different brand but they are all the same. Finally, I broke down and spent the money for a proper Sabertooth dual channel motor driver. I highly recommend this route as it is a brilliant piece of kit; basically plug and play!

Note the relay so all the power doesn’t go through the E-Stop.

Originally, I used two 12V batteries which give the mower impressive speed wired in series (24V!!!) but I have found that a single battery provides adequate (and controllable) speed and allows me to charge one while using the other.

Lastly, note the Emergency Stop button on the post. This kills power to the electronics and, more importantly, grounds the spark plug which turns off the mower. I cannot stress enough the value of this feature. It is critical to have an easy and quick way to turn off the mower, especially if it loses radio sync and starts doing it’s own thing…

It’s been three years now and the MoD is still going strong. I finally got around to making a video of the operation (coming soon).