But such devices are typically worn as bracelets, which means their use can be limited. As the researchers of this new effort note, most personal health monitoring devices have been handicapped by their batteries. The researchers found a way to build the new monitor, which has yet to be officially named, without the need for any sort of battery at all.
The key to powering the new device was capturing the small amount of energy that is emitted by a smartphone or tablet that makes use of NFC—a type of technology that employs electromagnetic induction between antennae inside of portable devices.
Radio frequencies are used to transmit information, which, as the researchers discovered, could be used as an energy source, making the use of a battery unnecessary.
Getting rid of the battery allowed the team to create a device that is no thicker than an ordinary decal—it is flexible and adheres to the skin, collecting information about the body that is then transmitted wirelessly to a nearby device.
The device has LEDs situated on the skin side that shine into and onto the skin—the light reflected back is used to measure heart rate, changes to skin colour and oxygenation levels. It also has a dye-based light sensor for measuring ultraviolet light and another sensor for monitoring skin temperature.
One major drawback of the monitor is the requirement that the phone or tablet providing the NFC power be just a few inches away—such as carried in a shirt pocket. Another option involves using a dedicated NFC device that offers more power. The researchers believe that their monitoring device would prove useful in health-care facilities and eventually to the population at large.
