Wearable device uses urine to power wireless transmitter

Scientists have developed a first self-sufficient system powered by a wearable energy generator that uses urine to power wireless transmitter.

This is the first self-sufficient system powered by a wearable energy generator based on microbial fuel cell (MFC) technology.

"Having already powered a mobile phone with MFCs using urine as fuel, we wanted to see if we could replicate this success in wearable technology," said professor Ioannis Ieropoulos from Bristol BioEnergy Centre at the University of the West of England (UWE Bristol).

"We also wanted the system to be entirely self-sufficient, running only on human power -- using urine as fuel and the action of the foot as the pump," he added.

A pair of socks embedded with miniaturised microbial fuel cells (MFCs) and fuelled with urine pumped by the wearer's footsteps powered a wireless transmitter to send a signal to a personal computer.

Soft MFCs embedded within a pair of socks was supplied with fresh urine, circulated by the human operator walking.

Normally, continuous-flow MFCs would rely on a mains powered pump to circulate the urine over the microbial fuel cells, but this experiment relied solely on human activity.

The wearable MFC system successfully ran a wireless transmission board, which was able to send a message every two minutes to the PC-controlled receiver module.

This work opens up possibilities of using waste for powering portable and wearable electronics.

"For example, it should be possible to develop a system based on wearable MFC technology to transmit a person's coordinates in an emergency situation," Ieropoulos noted.

At the same time, this would indicate proof of life since the device will only work if the operator's urine fuels the MFCs.

Microbial fuel cells (MFCs) use bacteria to generate electricity from waste fluids.

They tap into the biochemical energy used for microbial growth and convert it directly into electricity.

This technology can use any form of organic waste and turn it into useful energy without relying on fossil fuels, making this a valuable green technology.

The paper was published in the journal Bioinspiration and Biomimetics.