Robots of the Future Could Run on Human Urine

Robots of the future may be fueled by pee. Yes, pee.

Robotics engineers have constructed a new device that can pump human waste into the "engine room" of a self-sustaining mechanical system, which employs a team of live microorganisms to digest the organic matter, in the process generating electricity to power the machine.

A recent test of the system used microbial fuel cells, powered by urine, to charge a mobile phone. (See video below.)

Future applications of the system, the researchers contend, could be used in the new generations of more advanced "EcoBots."

"We speculate that in the future, urine-powered EcoBots could perform environmental monitoring tasks such as measuring temperature, humidity and air quality. A number of EcoBots could also function as a mobile, distributed sensor network," said lead study author Peter Walters, of the University of the West of England.

"In the city environment, they could re-charge using urine from urinals in public lavatories. In rural environments, liquid waste effluent could be collected from farms."

The urine-powered mobile phone charging system is modeled after the human heart. The system compresses a pump to force liquid into the designated space. The system also uses shape memory alloys, a group of smart materials that are able to "remember" their original shape, as the artificial "muscles" in the heart-like system.

"When heated with an electric current, the artificial muscles compressed a soft region in the center of the heart-pump causing the fluid to be ejected through an outlet and pumped to a height that would be sufficient to deliver fluid to an EcoBot's fuel cells," the researchers explained in a statement. "The artificial muscles then cooled and returned to their original shape when the electric current was removed, causing the heart-pump to relax and prompting fluid from a reservoir to be drawn in for the next cycle."

The fuel cells were able to generate enough electricity to charge a capacitor, and the energy stored in the capacitor was enough start another cycle of pumping from the artificial heart.

"The artificial heartbeat is mechanically simpler than a conventional electric motor-driven pump by virtue of the fact that it employs artificial muscle fibers to create the pumping action, rather than an electric motor, which is by comparison a more complex mechanical assembly," Walters said.