MIT engineers have developed an electronic skin that works without conventional chips or batteries. The new device looks like a band-aid or duct tape, and thanks to the piezoelectric properties of the gallium nitride layer used, it can wirelessly transmit signals related to pulse, sweat and other human biological signals.
Going into the details of this e-skin, it’s a sensor embedded in a flexible semiconductor film that adapts to your skin like duct tape. At the heart of the sensor is an ultra-thin film of high-quality gallium nitride, a material known for its piezoelectric properties, which can generate electrical signals in response to mechanical shocks and mechanically vibrate in response to electrical shocks. They used gallium nitride because they found that its bidirectional piezoelectric properties opened the door for simultaneous recognition and wireless communication.
The team succeeded in obtaining a pure single crystal sample of gallium nitride combined with a conductive layer of gold to amplify incoming and outgoing electrical signals. They also showed that the device was sensitive enough to vibrate in response to things like heartbeat and sweat. These material vibrations generate signals that can be read by a nearby receiver, performing the process without traditional chips or electronic external batteries.
During testing, several volunteers wore electronic skins on their wrists and necks and used simple antennas at close range to wirelessly record the frequencies of devices capable of detecting and transmitting changes in gallium nitride surface acoustic waves. to match your heart rate.
Furthermore, the device is coupled with a thin ion detection membrane, a material that selectively attracts the target ion, sodium, for this study. With these improvements, the e-skin was able to detect and communicate changes in sodium levels when a volunteer grabbed a heating pad and started sweating.
Seo Jun-min, co-author of the study that made e-skin possible, said that because sodium was shown as a test, objective biomarkers such as glucose and cortisol could be detected if the detection membrane was modified. It has to do with your stress level. It’s a very versatile platform.”
Kim Ji-hwan, the study’s author, puts it in his position, “The chip requires a lot of power, but our device can make the system very light without a chip that consumes a lot of power. You can put it on your body like a bandage and wirelessly track your heart rate, sweat and other vital signs with a wireless reader on your phone.”
Not everyone is using wearables, but wearables are a market that never stops growing, so it’s no longer strange to see people with smartwatches that can provide information on some biological cues. Developed by MIT engineers, the e-skin goes a step further and eliminates complex components that require a lot of power and batteries to operate.