WiFi wireless signals used to charge mobiles

RCA showed a prototype of its Wi-Fi Hotspot Power Harvester called Airnergy that's designed to convert Wi-Fi radio signals into DC power for charging small wireless devices such as smartphones.

The small device called the Airnergy, is about 2 in. by 3 in. in size and is expected to sell for $39 to $49 this summer. RCA is working on a smaller version that would take the place of a battery inside a handheld device and would sell for around $59. That smaller version might ship in 2011, according to a demonstration at the 2010 International CES.