A significant challenge for researchers has been trying to harvest enough energy to power these tiny wearable circuits.
“The issue has been powering the wearable. Capturing just ambient light, for example, requires photo voltaic technology, but obviously you can’t have rigid solar panels on your clothes so we are trying to make the textile itself photo voltaic,” says Steve.
“We have managed to reach up to two per cent efficiency and, although that doesn’t sound much, scientifically it is quite a step forward.”
Cutting edge research into harvesting kinetic energy is also taking place in our industry-standard cleanroom laboratories.
Mobile phone companies have been investing in research to see whether a device could be charged from a person’s own movement and have tested the idea at festivals where movement is increased.
Steve says: “Harvesting energy from human movement relies on people dancing around and being active. In reality we aren’t all dancing all the time, we are mostly sat or still. Mobile phones are very, very thirsty devices and are, at times, consuming watts of power. Realistically, that comes back to the amount of energy that can potentially be harvested.”
Harvesting mechanical energy from the movement of the textile is even more challenging because the fabric by its very nature is designed to be compliant. Its ability to bend and move with the person wearing it means it is not ideal for capturing the energy needed.
So while wearable device charging would rely on a huge change in direction by phone manufacturers for it to work – from functionality to efficiency – smaller, less powerful devices are very much within sight for practical application.
Steve and his team have been working on using smart materials in shoes to power wearable technology.
He says: “We are looking at converting shoe insoles that act both as a sensor and an energy harvester. This has been developed to act as a self-powered pedometer, power transmissions for indoor localisation and potentially monitor foot pressure and distribution.
“The sensors can calculate how active you are, they can let people know where you are and it is all self-powered. It works by the force of your foot as you walk, squashing this material and generating electrical energy.”