Wearable and Self-Powered Sensor Technology
Remote health monitoring will become more reliable, safer, and less expensive with wearable sensor technology that will harvest energy from the human body through devices developed at the Engineering Research Center (ERC) for Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST), funded by the NSF and based at North Carolina State University.
Health-monitoring systems allow people to leave the hospital and still be observed by their doctors. Wearable devices developed at ASSIST can harvest energy from the body’s heat or motion, enabling them to operate indefinitely. The sensors monitor and transmit signals produced by the body as well as environmental factors such as temperature and humidity.
The Center has developed three wearable devices using silver nanowires— strain/pressure sensors, bioelectronics sensors, and antennas— that are patterned and inlaid in rubber substrate. Another sensor can monitor ozone, which is important to asthma patients, and operates at room temperatures unlike other ozone sensors, thus reducing power demands enough that the sensor could be self-powered from a body’s energy.
Other advances from ASSIST include low-leakage supercapacitors that can be used to store the small levels of energy harvested from a body, enabling devices to operate at times when new energy is unavailable, such as when a patient is resting. Researchers also have developed a flexible thermoelectric energy generator (TEG) that can be integrated into a wearable band or patch to generate usable electrical energy from body heat, one of the sources of energy ASSIST harvesters are relying on to power the Center’s wearable electronics.
Researchers at ASSIST partner institutions have developed a chip specifically optimized for self-powered, battery-free wearable electronics. The chip converts harvested energy from the human body to be stored in the supercapacitors, and can work with multiple sensors and an on-chip radio that transmits the data collected from a multitude of sensors to a base station.