robo sprinkler

yes, yes... i 'stole' this from the intelligent sprinkler but my idea is better (so there!). Okay, how about a small robot device that has a hose attatched to it. the robot learns the geography of your particular lawn by a remote or something (like one of those r/c toys), or you could use gps or have magnets in the ground. the robot runs around (using something like a tank tread system to get over uneven areas). the water sprays from the bottom so that it doesn't overspray onto the sidewalk. the water pressure might even be able to re-charge the batteries using some sort of water wheel principle. it could also monitor the amount of water used. i think the only real drawback is the hose... it's heavy and it could get in the way... hmmmm.. . still on the drawing board.