Your next smartwatch might not need a battery and could run on the energy from your skin.
Power-over-Skin uses the human body to transmit energy.
Researchers at Carnegie Mellon University have developed an innovative technique called Power-over-Skin, which allows wearable devices to be powered through contact with the skin. This advancement is significant as it aims to enable current devices, which typically rely on batteries, to operate without them, paving the way for a future where top smartwatches do not require integrated batteries.
The Power-over-Skin approach involves transmitting energy from a portable, battery-operated transmitter to various devices designed to be in contact with the skin. This method takes advantage of the human body's ability to conduct radio frequency (RF) energy at 40 MHz, allowing for efficient energy distribution.
A team of researchers, including Andy Kong, Daehwa Kim, and Chris Harrison, managed to send energy from a single transmitter throughout the body, discovering that the amount of energy transmitted is affected by the proximity between the transmitter and the receivers. For instance, placing the transmitter on the forearm and the receiver on the wrist enabled more effective power transmission.
During their experiments, the scientists were able to power multiple devices, such as LED earrings, a calculator, and a Bluetooth ring with joystick control. They also explored the possibility of integrating transmitters into everyday objects like smartphones, virtual reality headsets, and shoes. Since the connection to the skin is capacitive, this technology can also work even through clothing, such as placing a transmitter in a pocket.
The advantages of Power-over-Skin are notable. By eliminating the need for built-in batteries, wearables can become smaller and lighter, potentially facilitating their use in various applications. One example mentioned is a thin medical patch that could continuously monitor health metrics without requiring battery replacement.
This approach also has environmental benefits, as it would allow multiple devices to be powered from a single energy source, thereby reducing the resources needed for the manufacturing of individual batteries.
As the technology advances, improvements in energy delivery efficiency are expected. While it is unlikely that Power-over-Skin will be capable of supplying enough energy for high-power devices, it is anticipated to be used in smartwatches and fitness trackers in the near future. Experiments have shown that this technique can power microprocessors, digital displays, and wireless communication modules, provided they are optimized to operate with this technology.
One aspect that deserves attention is the potential health impact of using RF energy through the body. However, the tests reported no discomfort or pain among participants. If it is confirmed that there are no adverse effects from prolonged exposure, Power-over-Skin could revolutionize the design and powering of wearable devices.
