The project started out with an old electric wheelchair from Craigslist - not a bad find for $75! The batteries and motor controller were shot, so the first version of it used an old gutted toy RC truck with no speed control that activated some relays. Full throttle or nothing, boy was that fun to drive indoors!
After some painful run ins with shins, a cardboard boat (plus the guy working on it), and managing to knock over a table with a 3D printer going, it was upgraded with a Dimension Engineering Sabertooth 2x25 and an RC receiver.
At that point, it was time to strap a lawn mower behind it and pull it through the yard.
The next upgrade came from the addition of two more motors and an additional speed controller. After adding the additional drive motors, it was time for some modification to the lawn mower for more precise mowing capabilities. I welded a pneumatic swiveling caster to the front and redid the mounting bracket so the mower gets pushed now instead of pulled.
Next attachment will be a snow blower, hopefully before winter.