Comment by defanor

That's my concern about their home vacuum cleaners as well: if a battery runs out, it would hit my computer. There are some programmable models though (were not available here at the time), and various certainly programmable DIY ones (may be a fun project, but would take some time); that seems like a much better solution -- both for efficiency and predictability (as opposed to random walk), and for this particular case with paths/boundaries (define them once in the robot's memory, maybe even just by moving it manually or otherwise showing it the path/boundaries, and don't rely on batteries in external devices).