Can radio waves kill the need for batteries?
Researchers capture radio waves to power small electronics.
Wed, Jul 28, 2010 at 08:58 PM
Rather than make a more environmentally friendly battery, Matt Reynolds has dedicated his research to finding an alternative. According to the NY Times, Reynolds may have discovered a way to harness radio waves from the air to power small devices.
According to the article, Reynolds has developed a prototype of a warning device for hardhats that beeps when “dangerous equipment is nearby,” a device that is battery free and runs off radio waves. Reynolds and partner Jochen Teizer are developing wireless transmitters to send out the radio waves to microprocessors nearby with hopes of “reducing or even eliminating the need for batteries.”
The article reports on several other companies doing similar work. One, Powercast, sells transmitters and receivers that use radio waves to power devices that “monitor room temperature in automatic systems that control heating and air-conditioning."
The ability to use radio waves to power devices is new for several reasons. The article reports that radio waves “dilute” very quickly, but modern “silicon technology” makes electronic devices very efficient, so even a small amount of energy can power them up. The trick now is to create devices that can do more things with less power, to fully maximize the use of these radio waves or other power sources from the environment.
The Times reports that the air around us has no shortage of radio waves to tap into. Everything from our Wi-Fi modems to our cell phone antennas sends out potentially useful “ambient radio waves.” The article says the radio waves could potentially offer as much energy as AAA batteries. In one example, an Intel radio wave harvester collected enough power for 50 microwatts, enough for “many sensing and computing jobs,” according to the Times.
The article ends by citing Reynolds, who is excited about the potential of future devices to operate free from temperature and battery lifetime constraints. The Times quotes Reynolds as saying that, through alternatives to battery power, “devices … can live on and on.”