MIT Engineers Develop a Chip-Free Wireless E-Skin
The MIT team devised a new kind of wearable sensor that communicates wirelessly without requiring onboard chips or batteries.
Engineers from MIT have developed a new wearable sensor that doesn't require a microcontroller or batteries to function. Most wearable sensors communicate via embedded Bluetooth chips, RF or Wi-Fi and are powered by small batteries. As new technology continues to become miniaturized, conventional chips and power sources will likely be too bulky for next-gen wearables, which are becoming smaller and thinner with increased flexibility. To overcome those issues, the team devised the novel e-skin that replaces the onboard microchip and battery power in favor of piezoelectric capabilities.
"Chips require a lot of power, but our device could make a system very light without having any chips that are power-hungry," explains Jeehwan Kim, an associate professor of mechanical engineering and materials science and engineering at MIT's Research Laboratory of Electronics. "You could put it on your body like a bandage, and paired with a wireless reader on your cellphone; you could wirelessly monitor your pulse, sweat, and other biological signals."
The wireless e-skin was designed using an ultra-thin gallium nitride film that responds to mechanical strain with an electrical signal and vibrates in response to an electrical impulse. The film was manufactured using single-crystalline samples of gallium nitride, paired with a conductive layer of gold to boost the income and outgoing electrical signals. Gallium nitride is known for its piezoelectric capabilities, which allow it to emit an electrical signal in reaction to mechanical strain and vibrate in response to an electrical impulse. This enables the e-skin to monitor heart rates, sweat, breath and other biofunctions and wirelessly transmit that data simultaneously.
According to the engineers, the wearable sensor can vibrate in response to a person's heartbeat and the salt in their sweat, which produces an electrical signal that could be interpreted by a nearby receiver, allowing the device to communicate sensor data without a chip or battery.