It turns out that humans have a reliable power source right at their fingertips. The ends of your fingers contain the highest number of sweat glands in the body and they produce sweat constantly, though it's not typically noticeable because the sweat evaporates almost instantly.
To make use of this perspiration, scientists at the University of California, San Diego have created a thin, flexible device, like a Band-Aid, that wraps around your fingertips to harvest energy, even when you’re sleeping. These new devices generate 300 millijoules of energy per square centimeter during a night’s sleep – enough to power a wristwatch for a day. Wrap all 10 fingers and the output goes up exponentially.
The device could be used to power wearable sensors that could measure anything from a runner’s rate of acceleration to a diabetic’s glucose levels. Power can also be generated from light finger presses, meaning that activities such as typing, texting, or just tapping your fingers can become sources of useful energy.
“We want to show that this is not just another cool thing that can generate a small amount of energy and then that’s it,” explained one of the researchers. “We can actually use the energy to power useful electronics such as sensors and displays.”
The Body Electric:
- The sensors pick up lactate from sweat using foam containing an enzyme that oxidizes the lactate, thus generating electricity.
- Elements contained within the human body, including sodium, potassium, calcium, and magnesium, all have a specific electrical charge, which means they can be used to generate electricity.
- Irregular electrical currents can prevent heart muscles from contracting correctly, which can cause a heart attack.