Robots are great and all, but they do have a tendency to ratchet up the old electricity bills. But hey, never fear, because soon they might be powered by... pee.
A team of researchers from the University of the West of England, UK, have latched onto the idea that urine can make electricity, but taken the idea a step further -- to make a dynamic system that could keep powering a robot for a long ol' time. Using a device that mimics the pumping action of the human heart, the researchers are able to provide a microbial fuel cell with all the urine it needs to convert waste into electricity.
The fuel cells themselves contain microorganisms -- like those in the human gut or sewage treatment plants -- which digest waste (in this case urine) and produce electrons along the way. Those electrons are harvested as electrical current.
But it's the pumping system that's really neat. Constructed from smart materials which remember their shape after being deformed, the pump cab be pinged with an electric current to compress the centre and force urine to the fuel cell. Then the pump relaxes, before the same thing happens again -- providing a steady supply of, err, fuel.
You'll be pleased to hear that the pump just about uses less electricity than it helps provide, according to a report in Bioinspiration and Biomimetics, but it's still fairly inefficient. Not that inefficiency matters too much when you just to drink a glass of water to get things started again. [Bioinspiration and Biomimetics via Live Science]