This Raspberry Pi Lawnmower caught my eye this week. Three brother from Salt Lake City created this ingenious device while at a 24 hour StarFEST hackathon. Dan, Doug and David Leonard decided they wanted to use off the shelf devices to make the lawnmower autonomous.
They ended up removing the back axel and replacing it with two electric drills that were in turn connected to the wheels. This allowed individual control over each wheel, meaning the lawnmower could be steered.
They created an instructable on how they did it that can be viewed here. Their invention was also picked up by Fox News!