Scientists at the University of the West of England have designed a potentially autonomous robot which feeds on flies attracted by human excrement and uses them to generate electricity, the New Scientist reports.
EcoBot II is reckoned to be a real step towards "release and forget" autonomous robots - albeit it a small one. At present, EcoBot II has to be fed bluebottles manually by its creators and can generate enough juice to travel at about 10 centimetres an hour.
The device uses the chitin in the fly's exoskeleton for fuel. The six-legged snacks are digested by bacteria in eight "microbial fuel cells" (anaerobic chambers filled with raw sewage slurry). The bacteria produce enzymes which break down the fly chitin, releasing sugars which the bacteria then absorb and metabolise. This latter process produces electrons which EcoBot II captures to generate electricity.
So far, so good. But the next challenge for the team is to enable its roving robotic insectivore to acquire its own lunch. While lead boffin Chris Melhuish admits that "one of the great things about flies is that you can get them to come to you", the sticky problem of how to capture them is yet to be resolved. The scientists say that a solution would perhaps "involve using a bottleneck-style flytrap with some form of pump to suck the flies into the digestion chambers".
EcoBot II is intended for use in inhospitable environments where humans might fear to tread - which is just as well. As the New Scientist notes, any fly-noshing autobot which deploys human excrement as a means to get its neck in the trough is going to "stink to high heaven". ®