The premise of any science fiction movie worth its salt is robots operating without human supervision for long stretches of time. (Those pesky robots do get into trouble, don’t they?) Researchers at the UK’s Bristol Robotics Laboratory have brought us a step closer to that prospect with the Ecobot III, the first robot capable of powering itself by consuming and excreting biomass that can run unsupervised for a full week. The bot uses a set of 48 microbial fuel cells to break down its food, extracting electrons from the metabolic process to run ultra low-power circuitry.
So what exactly does it eat? Why, partially processed sewage of course! It navigates toward a trough and “eats” what it needs, generating electricity by metabolizing its, err, meal with bacteria in the fuel cells. Any undigested matter gets pumped back up into the bot’s gut to maximize its energy use. The waste is, shall we say, “purged” every 24 hours with a colon-like pump that uses pressure waves to expel it into a litter tray.
Chris Melhuish, director of the lab, said the robot was called Ecobot III, but admitted “diarrhea-bot would be more appropriate, as it’s not exactly knocking out rabbit pellets.” Well, as they say: garbage in, garbage out.
This tasty little system is C02-neutral, but, as it stands now, the bot gets just 1 percent of the energy available from its “food.” Its efficiency will likely improve with new iterations, though, and the Bristol team sees value in powering such release-and-forget robots with a wider range of — again the scare quotes — “foodstuffs” than would work in robots that burn, rather than digest, biomass. But you might want to bring a match along just in case if you’ll be spending any time with this R2D2.