German researchers have built shoe-sized devices that harvest power from the act of walking.
The technology could be used to power wearable electronic sensors without the need for batteries.
There are two separate devices: a “shock harvester” that generates power when the heel strikes the ground and a “swing harvester” that produces power when the foot is swinging.
They could also form the basis of a self-lacing shoe for the elderly.
Details of the advance are outlined in the journal Smart Materials and Structures.
“We have tried to power a wireless transmitter and to power a simple sensor,” said Klevis Ylli from HSG-IMIT, a research centre in Villingen-Schwenningen, Germany.
“One application we are working on is indoor navigation which means we have sensors within the shoe that measure the acceleration of the foot, the angular velocity – whether you’re turning the foot or not – and the magnetic field.
“From the data from these sensors, you could calculate how far you have travelled and in which direction. So imagine a rescue unit walking into a building they don’t know. They could then track which way they went on their handheld device.”