DARPA smart sensor powered by the infrared it is designed to detect

Researchers at Northeastern University have developed a next-generation smart sensor for the Defense Advanced Research Projects Agency (DARPA) that is capable of identifying infrared (IR) wavelengths — without having to have its own always-present power source. Instead, the smart sensor is powered by the same infrared wavelengths for which it's designed to look. The sensor was developed as part of DARPA's Near Zero Power RF and Sensor Operation (N-ZERO) program and could be used for a wide range of things, including detecting approaching human bodies or fuel-burning cars, identifying wildfires before they become uncontrollable, or pairing with laser sources for new types of remote control and communication applications. The sensors are based on tiny mechanical switches that are triggered by specific wavelength of lights. When this happens, they utilize the energy contained in these wavelengths to mechanically close a pair of electrical contacts, creating a low-resistance electrical connection between a battery and a load.