New RF technology potentially eliminates the need for wearable batteries

Researchers at the Future Interfaces Group have developed a new technology that could shake up wearable electronics by eliminating the need for batteries. Dubbed "Power-over-Skin," this clever approach uses the body's natural RF energy at 40 MHz to keep devices running, powered simply by touching your skin.

Developed by Andy Kong, Daehwa Kim, and Chris Harrison from Carnegie Mellon University, this innovation tackles a long-standing issue in wearables—the reliance on batteries that add extra bulk and need regular recharging. With their approach, devices can work off the body's own RF transmission abilities without invasive methods.

The team put a lot of effort into fine-tuning receivers to be practical in size, weight, and overall design while still being energy-efficient. These receivers can go anywhere on the body and even integrate into existing devices like smartphones or AR headsets. Using a capacitive coupling, this setup can work through clothing, meaning your gadgets could pull power from your pocket.

During demos, the researchers successfully powered a range of small devices, such as:

• A Bluetooth ring with joystick functionality
• A medical patch for tracking health data over time
• A sun exposure monitor with an e-ink display
• LED-equipped accessories for decorative effects

The highest power output reached 1.53 mW, while the lowest measured 5.3 μW. Through-clothing transmission was possible, though it wasn't quite as efficient as direct skin contact.

This technology could pave the way for battery-free wearables that are thinner and lighter and reduce reliance on rare earth minerals needed for battery production. While the current power output is geared for low-energy applications, it's a promising step toward more eco-friendly wearables.

Future applications might include AR/VR headsets, fitness trackers, and medical devices—anything that can function within the power limits of this system.