Jan 30, 2009

Free RF energy harvesting from sources like WiFi

VIA treehugger

One of Intel's focuses for eco-technology is increasing our ability to harvest free energy sources from the sun to kinetic energy. This also includes RF energy harvesting from sources like WiFi, cell phone towers and TV signals.

Intel has just let loose details on a technique for harvesting ambient RF energy. The researchers powered a wall-mounted household weather station with an LCD screen using a TV antenna pointed at a local TV station.

The Intel researchers aimed a TV antenna at a TV station 4 km away, and harvested enough energy to power a mini weather meter. The technology used for this technique is an extension of that used in off-the-shelf RFID tags in which the tag reader supplies power to the otherwise unpowered ID tag.

With gadgets becoming more and more energy efficient, the idea of using RF energy harvesting to power them is closer to reality...though it will be quite awhile before we have gadgets on the market powered through this method.

Details about the experiment:

The Intel Researchers set up a TV antenna on a balcony with line of sight to the KING-TV tower 4.1 km away. The TV station broadcasts on channel 48 between 674 and 680 MHz with an effective radiation power (ERP) of 960 Kw. The TV antenna used was a UHF log periodic with 5 dBi gain connected to a 4 stage charge pump power harvesting circuit of the same design as that found in an RFID tag. Across an 8 KOhm load the team measured 0.7V, corresponding to 60 microwatts of power harvested. That was enough to drive a thermometer/hygrometer and its LCD display, which is normally powered, by a 1.5 volt AAA battery.

Intel is also focused on energy harvesting from indoor and outdoor ambient light, waste heat from both systems and human bodies, mechanical and kinetic energy. The company feels that by developing technologies that utilize a hybrid power architecture - including alternative energy, better power delivery, better power management and an adaptive system - the use of electronics can be cheaper and lighter on the planet. With that in mind on all their eco-technology research, Intel is working hard to be a leader in better ways to run systems. We're pretty excited to see what more they roll out in the near future.

Via Gizmag