Autonomous lawnmowers have been around for several years, but after improving through hard knocks (some of them into trees), the newest generation is gaining popularity.

Of course, a human must set the stage, by outlining a yard with a dirt-level guide wire and by programming the robot with dates and times for cutting. After that, though, the electric mowers will start themselves, cut and return to base for recharging as needed, all on their own. Contrary to myth, they do not store maps of the territory or consult the Global Positioning System; they simply track where they are in relation to the guide wire.

Of course, a human must set the stage, by outlining a yard with a dirt-level guide wire and by programming the robot with dates and times for cutting. After that, though, the electric mowers will start themselves, cut and return to base for recharging as needed, all on their own. Contrary to myth, they do not store maps of the territory or consult the Global Positioning System; they simply track where they are in relation to the guide wire.