Cropped view of man checking his smartwatch or fitness tracker while working out outdoors, panorama

Body heat could directly charge wearable devices

Image credit: Milkos/Dreamstime

Scientists in the US have developed a mini-wearable device that is capable of charging up using heat from the human body.

The stretchy gadget, developed by a team at the University of Colorado Boulder, can be worn as a ring or a bracelet. It features generators to convert the body’s internal temperature into electricity.

Currently, the technology can only produce about one volt of energy for every square centimetre of skin space, according to the researchers. This is less than what most existing batteries provide but could still be enough for small electronics such as a watch or a fitness tracker.

Although the gadget is still in its early stages, Jianliang Xiao, a professor of mechanical engineering at the university who came up with the idea, believes it could be on the market within five to 10 years. 

A thermoelectric power generator worn as a ring

A thermoelectric power generator worn as a ring

Image credit: University of Colorado Boulder

“Whenever you use a battery, you’re depleting that battery and will, eventually, need to replace it,” he said. “The nice thing about our thermoelectric device is that you can wear it and it provides you with constant power.

Professor Jianliang Xiao added: “The thermoelectric generators are in close contact with the human body and they can use the heat that would normally be dissipated into the environment.” 

Last year, engineers at the University of Glasgow developed a flexible supercapacitor that can be used to replace the electrolytes found in conventional batteries with sweat.

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