Hey Jason, I was viewing this more as an aid for those of us that keep up our families yards.  If I dont have to mow, I just saved at least 2 hours that can be used for the trimming and little details instead.  Where I live, we usually have to mow once a week, but the trimming can be done a little less often when it hasnt been raining a lot.

This is also an (extremely slow) work in progress. If I can get it to mow on its own at all, I will be happy.  From there I will try to make it more precise and able to follow walls and fences to trim as it mows, etc.  Unfortunately this has been put on the backburner for way too long.  I need to get back to work on it.  Thanks for the feedback!

Hi Thomas, I have been pondering the building of one of these for years but I am always stymied by the cost. At least where I live, the cost of a thing like this (even if I build it myself) exceeds the cost of hiring someone to mow the yard for at least a couple of years by a substantial margin. And it doesn't eliminate the garden work entirely because the yard still needs to be edged and the clippings blown off the walks and such. For an able bodied person that might be OK but for your granddad, probably not.

However, recently a development has been made that might reduce the cost substantially (though probably not enough for commercialization). At U.T. Austin, researchers have been able to achieve centimeter precision positioning with commercial-grade GPS. ( http://spectrum.ieee.org/tech-talk/transportation/self-driving/cheap-centimeterprecision-gps-for-cars-and-drones ) That ought to be sufficient for safety concerns and avoiding obstacles without having to use beacons and perimeter wires and the like.

Good luck!