Futuristic news | We can harvest "Electricity"! | just "Tap"

 

A new wearable device turns the touch of a finger into a source of power for small electronics and sensors. Engineers at the University of California San Diego developed a thin, flexible strip that can be worn on a fingertip and generate small amounts of electricity when a person’s finger sweats or presses on it.

This type of device is the first of its kind, said co-first author Lu Yin, a nanoengineering Ph.D. student at the UC San Diego Jacobs School of Engineering. “Unlike other sweat-powered wearables, this one requires no exercise, no physical input from the wearer in order to be useful.

This work is a step forward to making wearables more practical, convenient and accessible for the everyday person.”The new wearable energy harvester is described in a paper published July 13 in Joule.
The device also generates extra power from light finger presses—so activities such as typing, texting, playing the piano or tapping in Morse code can also become sources of energy.

“We envision that this can be used in any daily activity involving touch, things that a person

 would normally do anyway while at work, at home, while watching TV or eating,” said Joseph Wang, a professor of nanoengineering at the UC San Diego Jacobs School of Engineering and the study’s senior author. “The goal is that this wearable will naturally work for you and you don’t even have to think about it.”
The device derives most of its power from sweat produced by the fingertips, which are 24-hour factories of perspiration. It’s a little-known fact that the fingertips are one of the sweatiest spots on the body; each one is packed with over a thousand sweat glands and can produce between 100 to 1000 times more sweat than most other areas on the body.

“The reason we feel sweatier on other parts of the body is because those spots are not well ventilated,” said Yin. “By contrast, the fingertips are always exposed to air, so the sweat evaporates as it comes out. So rather than letting it evaporate, we use our device to collect this sweat, and it can generate a significant amount of energy.”
But not just any sweat-fueled device can work on the fingertip. Collecting sweat from such a small area and making it useful required some innovative materials engineering, explained Yin. The researchers had to build different parts of the device to be super absorbent and efficient at converting the chemicals in human sweat into electrical energy.

Yin worked on this project with UC San Diego nanoengineering Ph.D. students Jong-Min Moon and Juliane Sempionatto, who are the study’s other co-first authors, as part of a team led by Wang, who is also the director of the Center for Wearable Sensors at UC San Diego. Wang and his team pioneered sweat-fueled wearables 8 years ago. Since then, they have been building on the technology to create new and better ways to power wearables using sustainable sources, such as the wearers themselves and their surroundings.

This latest energy harvesting technology is especially unique in that it could serve as a power source anytime, anywhere. It does not have the same limitations as, say, solar cells, which only work under sunlight, or thermoelectric generators, which only work when there’s a large temperature difference between the device and the surroundings.