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There’s power in places you might never think to look. That’s not a metaphor: you can literally generate power through regular movement, essentially grabbing actual electricity that would have been wasted otherwise. A recent study from the National University of Singapore found that friction between the skin and another material could provide a pretty decent amount of power, which could, once optimized with a few years of research and testing, actually help to power devices such as wearables.
The most well known category of these types of generators are “piezoelectrics.” Piezoelectric power is not really new; it’s likely the type of power that’s used in your (traditional) watch today. Essentially, piezoelectricity works because a voltage (an electric charge) is created due to the mechanical stress of certain kinds of crystals. That’s a complex way of saying that you can turn some kinds of crystals into batteries when you squeeze them.
A similar, but new, variety of this, and the one that has exciting implications for powering devices, is called triboelectrics. In triboelectrics, instead of squeezing one object, an electrical charge is created when two dissimilar objects rub together. You can think of it in the same way that static electricity works: when you rub a balloon on your head, it creates an electric charge, which leaves when you touch something (or someone) else, creating a shock. But the National University of Singapore team wants to instead collect that electrical charge and use it to power devices.
According to the science organization Spectrum IEEE, the team, led by professor Chengkuo Lee, “demonstrated that the new device can be used as a wearable self-powered sensor to track the user’s motion and activity.” And what’s a logical choice for one of those two dissimilar objects? How about skin?
As a potential source for tribolectric power, skin has lots of upsides. For one thing, you don’t have to build a second object into a tribolectric device if you’re already using the user’s skin as one of them. Also, “skin as a triboelectric material has a high tendency to donate electrons or get positively charged, which is important in improving the performance of the device,” Lee’s graduate student Lokesh Dhakar told Spectrum IEEE.
According to Spectrum IEEE, the team tested the technology by making a sort of corrugated rubber surface laced with gold film. By tapping the surface, the skin generated a whopping 0.8mW of power. The material could be made into a patch that could be placed nearly anywhere on the skin to power a tracking sensor and eventually possibly a larger device.
Could this technology ever help power wearables without the need to charge batteries? “Using the body and the skin to power future gadgets and wearables may be the most logical and efficient approach,” says futurist Gray Scott. Scott envisions a future of wearable computer suits powered by these piezoelectric devices sewn right into fabrics. But in the near term, he thinks there are still some obstacles to overcome. “Powering watches may be difficult because they touch such a small skin surface area,” he says. But companies are already experimenting with smart watchbands that include extra power for smartwatches. Maybe one day, these tribolectric devices could get that power from our own skin.
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