"Cyborg insects" (using remote-controlled or chip-based neural stimulators to control movements) could be powered by piezoelectric strips attached to their backs (generating 10 millivolts per fiber in in a proof-of-concept experiment), Tokyo University of Agriculture and Technology researchers have found.
Powering these "stimulator chips" is a big limitation. "Wires from an external power source restrict their motion, and most battery cells are too heavy and wouldn't fit on the insect," says Keisuke Morishima from the Tokyo University of Agriculture and Technology in Japan. Smaller batteries have been used, but run down in as little as a few minutes.
Instead, Morishima suggests that the insects themselves could power the slave-driving chips. As a proof of concept, he glued a piezoelectric fibre - 4 centimetres in length but just 200 micrometres across - to the back of a Madagascar hissing cockroach. As the cockroach walked, each step stretched and squeezed the piezoelectric fibre, generating electricity via mechanical stress.
His experiments show that the cockroach's movement can generate more than 10 millivolts in a single fibre. About 100 of these fibres would be enough to power the stimulators, he says (Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, DOI: 10.1016/j.cbpb.2008.09.055).
Kevin Warwick, a cybernetics expert at the University of Reading in the UK, thinks it may be difficult to store the generated energy in order to provide a steady supply throughout a cyborg insect's mission. He also thinks this number of fibres may be too heavy for the insect to carry. "I'm quite sceptical of the leap to using this as a power supply," he says.
However, Warwick says the method may be more easily applied to larger animals like rats, which could generate greater power when controlled using a similar system.
