Eco Factor: Millimeter-scale sensor harvests solar energy for nearly perpetual operation.
Researchers at the University of Michigan have developed the world’s smallest self-powered sensor that can operate nearly perpetually running solely on solar energy. The system’s solar cells, processor and battery are all located in a tiny frame measuring just 9-cubic-millimeter.
The system can be used in new biomedical implants and various home-, building- and bridge-monitoring devices and could improve the efficiency and cost of current sensors designed to detect movement of track air and water quality. The sensor is based on an industry-standard ARM Cortex-M3 processor that uses about 2000 times less power in sleep mode than its most energy-efficient counterparts.
The sensor has been designed to spend most of its time in sleep mode, waking briefly every few minutes to take measurements. The designers claim that the average power consumption of the sensor is less than 1 nanowatt. The sensor can run nearly perpetually if periodically exposed to reasonable lighting conditions as its only limiting factor is battery wear-out.