Yada, yada, we know how it goes: Scarecrow gets a brain, the lion musters up some courage, and a microbial-fuel-cell-powered EcoBot gets a heart.
Ten years ago, researchers at the Bristol Robotics Laboratory (a collaboration between the University of the West of England and the University of Bristol) first dreamed up the EcoBot, a robot that ran on E. coli bacteria and would scour the landscape for dangerous levels of pollution and predators. The engineers figured that in the near future, the self-sustaining EcoBot could travel with astronauts to scope out unknown terrains, search for resources amid disaster scenes, or clean up wastewater and produce electricity.
Three EcoBots later, the researchers proved that their robot could feed on rotten fruit and dead flies and survive on its own for a week. But the EcoBot III was also still severely limited. If it wanted to do anything, it would have to hang out and wait for its microbial fuel cells to charge before performing short activities and recharging again.
In the interest of keeping EcoBot's groove going, the University of West of England's Peter Walters and a team of researchers decided to give the robot a heart. But in keeping with the bot's microbial fuel cell and waste-conscious mission, it runs on urine.
"We speculate that in [the] future, a urine-powered EcoBot could be employed as an environmental sensing platform within an urban setting. The EcoBot could harvest energy from waste collected from urinals at public lavatories," researchers wrote in the journal Bioinspiration and Biomimetics, which published the heart plans last week. "The energy harvested could be used by the EcoBot to perform sensing tasks such as monitoring air quality and pollution levels, and a number of such EcoBots could form a distributed mobile sensor network within a future city environment."
The urine-heart actually does function like a human one to some degree. Containing 24.5 ml of fluid, the heart employs "artificial muscles," or smart materials called shape-memory alloys, to compress the pump and send urine to the EcoBot's 24 microbial fuel cells.
Researchers still have to assess how the heart will hold up in the long run and whether it's scalable. But now that they've got a prototype, they are hopeful that "the artificial heartbeat actuator" could function as part of a larger bio-robotic art project—a "cyborg-like machine with a biologically driven artificial heartbeat." Forget golems made of clay. This one runs on pee.