Sunday, September 12, 2004

On the fly

Self-sustaining killer robot creates a stink

New Scientist, 15:13 09 September 04, by Duncan Graham-Rowe

It may eat flies and stink to high heaven, but if this robot works, it will be an important step towards making robots fully autonomous.

To survive without human help, a robot needs to be able to generate its own energy. So Chris Melhuish and his team of robotics experts at the University of the West of England in Bristol are developing a robot that catches flies and digests them in a special reactor cell that generates electricity. ...

Called EcoBot II, the robot is part of a drive to make "release and forget" robots that can be sent into dangerous or inhospitable areas to carry out remote industrial or military monitoring of, say, temperature or toxic gas concentrations. ...

The robot's energy source is the sugar in the polysaccharide called chitin that makes up a fly's exoskeleton. EcoBot II digests the flies in an array of eight microbial fuel cells (MFCs), which use bacteria from sewage to break down the sugars, releasing electrons that drive an electric current (see graphic). ...

Each MFC comprises an anaerobic chamber filled with raw sewage slurry - donated by UWE's local utility, Wessex Water. The flies become food for the bacteria that thrive in the slurry.

Enzymes produced by the bacteria break down the chitin to release sugar molecules. These are then absorbed and metabolised by the bacteria. In the process, the bacteria release electrons that are harnessed to create an electric current.

My suggestion: add a holding chamber for some flies and then harvest their maggot larvae for fuel. Reprocess some of the digested flies and maggots into a food for future flies to make more maggots. Pete and repeat. Pretty unappetizing, but, if a smart person spent time on this, it could be a virtually self-sustaining symbiotic ecosystem.

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