A Group of Researchers from UC San Diego Jacobs School of Engineering have created a thin and flexible wearable that can generate electricity using sweat. It can be used to power small electronics
The electricity is generated once your finger starts to sweat. You stick the thin strip onto your fingertip, you can wear this strip while typing, using your phone, playing the piano or even sleeping. It will also generate extra power when you press on it.
“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,” – Co-First Author Lu Yin, a nanoengineering PhD student in a release.
Yin explained why the fingertip was chosen:
“The reason we feel sweatier on other parts of the body is because those spots are not well ventilated. 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.”
“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 and the study’s senior author in the release.“The goal is that this wearable will naturally work for you and you don’t even have to think about it.”
Decoding the Device
You can wrap the strip around your fingertip like a Band-Aid and the electrodes inside of it absorb the sweat and convert it into electrical energy. Underneath these electrodes is a chip that helps generate additional electrical energy when tapped or pressed on.
When worn for 10 hours of sleep, the device was able to collect 400 millijoules of energy, during one hour of use of a computer keyboard and mouse, it collected 30 millijoules. This is from just one fingertip. If the device is strapped on the rest of the fingertip it can generate 10 times more energy.
“Compare this to a device that harvests energy as you exercise,” explained Yin. “When you are running, you are investing hundreds of joules of energy only for the device to generate millijoules of energy. In that case, your energy return on investment is very low. But with this device, your return is very high. When you are sleeping, you are putting in no work. Even with a single finger press, you are only investing about half a millijoule.”
The team has planned more studies to combine the device with other energy harvesters and create new self-powered wearable systems.