Pee-Powered Wearable Generates Electricity

Wearable tech seems to be all the rage these days. From fitness trackers, to smart contact lenses, to wearable drones—yeah, that’s a thing—the relationship between our bodies and personalized technology is becoming increasingly intimate.

Now, in what may be a case of taking it a bit too far, researchers at the University of West England, Bristol, have invented a wearable energy generation system powered solely by human urine.

The paper, headed by Associate Professor Ioannis Ieropoulos and temptingly titled ‘Self-sufficient Wireless Transmitter Powered by Foot-pumped Urine Operating Wearable MFC,’ appears in the science journal Bioinspiration & Biomimetics.

The mechanism essentially consists of a sock lined with tubes of microbial fuel cells (MFCs) into which urine is systematically pumped and then removed. In order to generate power, all you need to do is rely on the pressure of your foot on the ground to pulse the liquid throughout the tubes as you walk.

Urine itself is abundant in nitrogen and phosphorous, key nutrients on which the microbes feed. Other, less mentionable human waste is also rich in these nutrients, so if you were worried about sticking your foot into a urine-lined sock, don’t worry; these other wastes could be substituted to achieve the same results.

As the microbes devour these nutrients, they release electrons, which are then taken up by the fuel cells to produce electricity.

In a previous study, the team effectively powered a mobile phone using only urine, but they wanted to replicate their results in the form of a wearable device.

“We also wanted the system to be entirely self-sufficient,” Ieropoulos said, “running only on human power—using urine as fuel and the action of the foot as the pump.”

Admittedly, none of this sounds particularly appealing as a marketable product, and with a maximum achievable power of only 110 microwatts, the system itself does not even generate a significant amount of electricity. So why subject yourself to the potential gross-factor?

For one, it would work anywhere, any time, in any weather, when other energy sources like solar may fail, making it a viable option for hikers and mountaineers.

“This work opens up possibilities of using waste for powering portable and wearable electronics,” said Ieropoulos. “For example, recent research shows it should be possible to develop a system based on wearable MFC technology to transmit a person’s coordinates in an emergency situation. At the same time this would indicate proof of life since the device will only work if the operator’s urine fuels the MFCs.”

Feature photo courtesy of Wikimedia Commons.