Sunday, September 03, 2006

Wired News: Ecobot Eats Dead Flies for Fuel

Wired News: Ecobot Eats Dead Flies for Fuel

Robots walk, robots talk and, soon, robots will eat, too.

Researchers at the University of the West of England, Bristol, are working on creating autonomous robots that power themselves using substances found in the environment. Professors Chris Melhuish and John Greenman plan to give robots their very own guts -- artificial digestive systems and the corresponding metabolisms that will allow robots to digest food.

Doing away with solar cells and batteries, their robot Ecobot II has a stomach consisting of eight microbial fuel cells, or MFCs, that contain bacteria harvested from sewage sludge. The microbes break down the food into sugars, converting biochemical energy into electricity that powers the robot. With bacteria breaking the food down and a type of robotic "respiration" in which air provides oxygen to the fuel cells to create useful energy, the whole system mimics real digestion as closely as possible.

Currently being fed a diet of dead flies and rotten apples, the robot isn't one for speed, though. Ecobot II can crawl along at a top speed of about 2 to 4 centimeters every 15 minutes, fueled by eight flies that are fed directly into the MFCs.

"People have built these things before but this is the first robot that actually uses unrefined food," said Melhuish.

Earlier efforts at creating robots that could ingest food included the Gastrobot developed by Stuart Wilkinson at the University of Florida. Dubbed Chew Chew, the train-like bot was hand-fed a diet of pure sugar cubes. An earlier version of Ecobot was also powered by sugar but the team developed the fly-eating version to simulate conditions found in nature.

"If you put unrefined sugars in there like a fly, then it has to do work on the fly to generate sugar," said Melhuish. "If you put sugar in there in the first place, then it doesn't have to do any work in doing the conversion, and with a special cathode in the fuel cell you can make it 90 times faster. But then you are giving it stuff which it wouldn't find out in the wild."

Right now, though, any robot powered by MFCs can work only in short spurts, powering up in the intervals. While MFCs, with their capacity to provide a continuous power supply, seem to be the best bet to create such bots, the technology is still in its infancy, and a single fuel cell is no match for a standard alkaline battery. The cells are only capable of giving out a very low trickle of power, which must be accumulated until it reaches a level high enough to power the robot.

Wow. Imagine creating a robot army that eats the enemy dead for fuel. Why couldn't they put THAT in the Terminator movies?

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