London: Scientists have invented a pair of high-tech socks which, when filled with urine, and activated by the wearer’s footsteps, can produce enough power to send a message.

Researchers at the University of the West of England (UWE) in Bristol created the socks which are embedded with miniaturised microbial fuel cells (MFCs) and can wirelessly transmit a signal to a computer.

This is the first self-sufficient system powered by a wearable energy generator based on MFC technology, researchers said.

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 manual pump was based on a simple fish circulatory system and the action of walking caused the urine to pass over the MFCs and generate energy.

Soft tubes, placed under the heels, ensure frequent fluid push-pull by walking. The wearable MFC system successfully run a wireless transmission board, which is able to send a message every two minutes to the computer-controlled receiver module.

“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. 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,” said Ioannis Ieropoulos, a professor at UWE.

“This work opens up possibilities of using waste for powering portable and wearable electronics,” Ioannis said. “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,”
said Ioannis.

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 findings were published in the journal Bioinspiration and Biomimetics.

(This appeared in PTI on Dec. 15, 2015)