Empower Yourself

Have you ever thought about how wasteful it is to have batteries in nearly every portable electronic device around you — even the ones that are only used infrequently? From TV remotes to wireless earbuds and even hobbyist tools like digital calipers, everything has its own battery. But what are those batteries in the remote doing when you are not changing the channel? A whole lot of nothing. But even still, these batteries all slowly lose their charge (or ability to hold a recharge), then have to be replaced.

That is a recipe for landfills loaded with toxic chemicals and a steady leak in your wallet. But the always entertaining group at Pedro Lopes’ lab at the University of Chicago (who ever said fun goes there to die?) has come up with a very interesting solution to this problem. Their system, called Power-on-Touch, removes batteries from individual devices, and instead makes you the battery. With Power-on-Touch, energy is wirelessly supplied to nearby devices during physical interactions, which for many devices is the only time it is needed.

The system consists of two primary components: a wearable transmitter, and battery-free receiver-tags embedded in devices. The wearable, which is designed to be worn in places like the back of the hand or on a fingernail, contains a power coil and a battery. When a user brings their hand near to a device, the wearable transmits energy through inductive coupling, much like how wireless phone chargers work.

Power-on-Touch is more than just a little trick to ditch batteries in low-power devices. The researchers specifically engineered it to also support more demanding components, like actuators. That means the system can power things like haptic feedback devices, motors, or electromagnets. To make this work across a wide range of use cases, they developed specialized coil designs, including omnidirectional spherical coils and compact pancake-shaped ones that integrate nicely into everyday wearables.

While Power-on-Touch offers a lot of promise, Duracell may not be quaking in their boots just yet. Inductive power transfer is inherently less efficient than wired power, and very close proximity is required for energy transfer to occur. Also, existing devices must be modified to support wireless power reception, which may affect their design or size. And of course, for this to scale up, everyone would need to wear a transmitter.

Still, the concept could ultimately change how we think about power delivery in interactive systems. By shifting the power supply from the device to the user, Power-on-Touch offers a compelling and scalable step toward a smarter, cleaner, and more sustainable future.