A device that mimics the squeezing action of the human heart has been used to pump urine into a microbial fuel cell, which could power robots that convert the waste into electricity.

"In the future, we hope the robots might be used in city environments for remote sensing," where they could help to monitor pollution, said study researcher Peter Walters, an industrial designer at the University of the West of England. "It could refuel from public lavatories, or urinals, " Walters said.