When stationed in dangerous, rural areas, the last thing soldiers should worry about is replacing a dead battery. That’s one reason why the Defense Advanced Research Projects Agency, or DARPA, is interested in developing devices that use virtually no power at all.
DARPA has a vision to employ a network of miniaturized sensors in remote locations. But the cost of maintenance would be tremendous, unless the sensors could last many years on very little power.
Matteo Rinaldi, associate professor of electrical and computer engineering at Northeastern, has just the answer. He was awarded a grant to build a new type of sensor that consumes no power whatsoever in standby mode. When the sensor recognizes a specific infrared wavelength signature, it uses the tiny amount of power contained in the infrared radiation to wake itself up. Then it triggers an “output wake-up bit,” or a voltage signal, that could alert soldiers or others to an event of interest, such as an approaching vehicle.