Your next smartwatch could be battery-free – and powered by your skin

• Power-over-Skin developed by researchers at Future Interfaces Group
• Technique transmits power to wearables using the human body
• Paves the way for battery-free devices powered through skin contact

Self-winding watches have existed for a century, but manufacturers are still searching for ways to make modern wearables battery-free. A new research paper from Carnegie Mellon University could have the answer: scientists have developed a technique to power the next generation of wearable tech via skin contact.

Researchers at Future Interfaces Group have found a way to deliver power to wearable devices through the human body. The method is called Power-over-Skin, and it could be the gateway to a future where the best smartwatches no longer need a built-in battery.

In simple terms, the method sends power from a single battery-powered transmitter worn on the body to a range of battery-free devices attached to the skin. Research has found that the human body effectively conducts 40 MHz RF energy, which is what Power-over-Skin relies on to distribute power through the skin.

Researchers Andy Kong, Daehwa Kim, and Chris Harrison found they could deliver power from a single transmitter across the whole body. They also found that the amount of power they could deliver depended on the proximity of the transmitter and receivers. For example, having a transmitter on the forearm with a receiver on the wrist netted higher microwatts.

In their tests, the researchers were able to power an LED earring, a calculator, and a Bluetooth ring with a joystick control. They also experimented with building transmitters into existing objects, including a smartphone, a VR headset, and a shoe. Because the…