Bye-Bye Batteries: Radio Waves as a Low-Power Source

July 19, 2010 | Source: New York Times

Devices and systems are being developed that consume so little power that it can be drawn from ambient radio waves from radio and television stations, WiFi systems and other sources, reducing or even eliminating the need for batteries.

Joshua R. Smith, a principal engineer at Intel’s research center in Seattle has developed a device that collects enough power from ambient radio-frequency (RF) signals to produce about 50 microwatts of DC power — enough for many sensing and computing jobs. The power consumption of a typical solar-powered calculator, for example, is only about 5 microwatts, he said, and that of a typical digital thermometer with a liquid crystal display is one microwatt.

A second device developed by Smith, powered by radio waves, collects signals from an outdoor weather station and transmits them to an indoor display. The unit can accumulate enough energy to send an updated temperature every five seconds.