Taking a cue from automatic watches that rely on the energy generated by the wearer, researchers at the University of California, Irvine (UCI) have created a battery-free wearable that can monitor vital signs in real-time. So far, their prototype can only track the wearer’s pulse, but, according to a paper published by the research team, the technology can be used to measure a range of biometrics such as blood pressure and body temperature with a simple switch of a sensor circuit. All without a battery or an external power source.

So how does the wristband device get its power? Two ways: finger tapping and smart devices. With the first, the wearer merely has to tap on the wristband to power up the sensory circuit, prompting the user’s pulse rate to appear on an LED display. With the second, the user holds the wristband near a mobile device such as a smartphone or a tablet to draw power, as well as wirelessly transfer data between the wristband and the device — an example of embedded near-field communication (NFC) technology. Through the data transfer, the wearer’s biometric information is displayed on the screen of the smartphone.

UCI researchers say triboelectric nanogenerators (TENGs) — which can convert mechanical energy into electricity — provide the self-powering properties for the devices via pressure or thumping. To make these TENGs, the device’s creators turned to MXenes, an ultra-thin 2D material with remarkable mechanical and electrical properties. Bendable and stretchable, MXene layers have considerable energy-storing abilities and can be formed into TENGs through 3D printing. Then, these printed nanogenerators can create voltage by applying pressure or tapping.

This is a dream device for those who seek far-flung adventures, and perhaps even the mild camping enthusiast. UCI researcher Rahim Esfandyar-Pour says, “Imagine you’re out working in a remote location — anywhere, the desert on a mission, in mountains hiking, or even a space station, for example — and you need to keep track of your health information on demand, or there’s an incident, and you need to monitor someone’s vital signs urgently and accurately…This self-powered and wireless device allows you to do that.”

While this technology seems a way off from hitting the market, we shouldn’t expect it to be priced beyond accessibility when it does. Esfandyar-Pour adds, “It’s made with low-cost and flexible materials and can be tailored to meet a variety of wearable bioelectronic sensors’ requirements.”