Last week's International CES in Las Vegas saw the appearance of the RCA Airnegy, a dongle-sized device that claimed to recharge mobile phones by using WiFi signals. The company said they'd demonstrated Airnegy taking around 90 minutes to charge a BlackBerry Bold from one-third battery capacity to full. RCA says the 'WiFi hotspot power harvester' device will go on sale later this year for $40 (around £25), with plans to incorporate the entire technology in a battery next year.
However initial enthusiasm for the device has turned to scepticism, with a number of online commentators pointing out the difficulty of generating enough power by harvesting 2.4GHz WiFi signals. One suggested that battery charging would take years, not hours.