Wireless charging isn't anything new, but it usually requires direct contact if not cables. But in Seattle, six houses have been rigged up to provide power to small devices using Wi-Fi routers.
Researchers from the University of Washington in Seattle have fitted out these houses with devices which can convert the energy held in Wi-Fi signals into electricity. They do that using a rectifier, which seizes the oscillating signals in the data streams and turns it into a direct current, before boosting it using a DC-DC converter. The energy's used to power things like temperature sensors and (admittedly low-resolution) cameras. The research, which demonstrates the systems working over a period of 24 hours, is published on the arXiv servers.
The main difficulty, according to the researchers when they spoke to New Scientist, was providing constant power delivery. Wi-Fi routers only transmit when they have data to send, which means that devices only receive power when someone's using the Internet. If there's a long lull in traffic, devices might not receive all the power they need. The obvious solution, which the researchers seized, was to send dummy data all the while -- but it would be easy enough in the future to create smart systems that could ask to be charged as and when they needed it.
Before you get carried away, it's doubtful that your Wi-Fi router will be charging your laptop any time soon. The Federal Communications Commission limits routers to pumping out signals of just 1 watt; a MacBook Air charger supplies 45 watts. New Scientist points out that some companies are creating devices that create Wi-Fi-like signals to carry power without carrying information in order to skirt the regulation -- and they can deliver up to 20 watts.
But for now, a unified Wi-Fi power distribution network that can power all your gadgets is still a way off. Still, even powering the small sensors around might be a start, especially in the actually-smart smart home. [arXiv via New Scientist]
Picture: Jasinthan Yoganathan/Flickr