“And the sensitivity of our film is so high that it can detect these changes,” added Kim, who is now an assistant professor at the University of Cincinnati.
Wireless technology makes it possible for a person’s blood pressure, heart rate, glucose levels, and activity levels to be easily communicated from the sensor to the smartphone for additional analysis, making wearable sensors incredibly common.
The majority of wireless sensors currently communicate using embedded Bluetooth chips, which are powered by tiny batteries.
How does the new sensor work?
Gallium nitride, a substance recognized for its piezoelectric capabilities, which allow it to both emit an electrical signal in reaction to mechanical strain and vibrate mechanically in response to an electrical impulse, forms the sensor’s core in the form of an ultrathin, high-quality film.
The researchers discovered that they could employ gallium nitride’s two-way piezoelectric characteristics for sensing and wireless transmission at the same time.
The scientists created pure, single-crystalline samples of gallium nitride, which they combined with a gold conducting layer to enhance any incoming or outgoing electrical signal.
They showed that the substance could vibrate in response to a person’s heartbeat and the salt in their sweat and that the vibrations produced an electrical signal that could be interpreted by a nearby receiver. This allowed the device to communicate sensor data without a chip or battery wirelessly.
“Chips require a lot of power, but our device could make a system very light without having any chips that are power-hungry,” said the study’s co-author, Jeehwan Kim, an associate professor of mechanical engineering.