While with each passing year, sensors and wearable devices get smaller, they still lack comfort for the wearer. Such systems need to operate on heavy batteries and other power sources. Now researchers at Massachusetts University Amherst have created sensors which can be operated by the skin of the wearer.
“We use the human skin, which consists mostly of water, as a conductor,” said Sunghoon Ivan Lee, a researcher and assistant professor of computer science at UMass Amherst. “Yet a big chunk of conductive material is human skin, and there is little difference between the signal wire and the ground wire. So, as a signal wire, we use the skin, and air as the ground.
UMass states that the self-powered sensors can be ultra miniaturized and ergonomically built for putting on specific areas of the body, such as a eye, an ear or even a tooth.
It’s an unattainable technological innovation with conventional in-device batteries. Which is why Lee and his team believe their research can lay the groundwork to transform existing architectures and spawn a new generation of on-body sensors.
“We ‘re working on a method that shrinks devices in size so that they can be mounted on small sections of the body,” said Lee. “And because you don’t have to change the batteries, there’s a variety of ways to improve and expand wearable sensors.”
The team originally started their study when they wanted to learn how the stroke survivors were using their limbs. “If we could put a sensor on the finger, we could obtain clinically relevant information on impairment level,” Lee said. However, there was a small problem. The sensors were too bulky, and the batteries took up too much space.
So, they began to look for ways to make the sensors smaller , lighter, more flexible and more energy efficient. They have found their answer in the skin’s natural conductive properties.
While this new sensor is limited to wrist and finger uses, other technology applications may result in small wearable sensors placed inside the tooth or ear of a person, Lee said. Dentists could get a better understanding of the pressure or moisture levels of lost teeth. The ear sensor, on the other hand, could carry signals relating to muscle, eye and brain activities.