The Mandelbear's Musings

A New Old Idea - Economist.com

WHEN most people switch on a desk lamp, they usually want a little extra illumination. But not John Goodey, an engineering student at Oxford University. When he flicks the switch and turns on his lamp, a sensor on his desk downloads music tracks digitally encoded within tiny flickers in the lamp's light. The music is then relayed through a pair of nearby speakers. This unusual set-up offers a glimpse of a future in which light, rather than radio waves, is used to send information. The concept, known as optical wireless or free-space optics (FSO), promises better security and higher data-transfer rates (up to 10 gigabits per second) than existing radio-based communications technologies, says Dominic O'Brien, a leading engineer in the field and Mr Goodey's research supervisor at Oxford.

FSO is already used in a few niches: to connect networks in nearby offices without having to string cables between them, for example. But plans are afoot to extend the idea into a number of new areas. For example, the subtle flickering of car headlights and tail-lights could be used to transmit speed and braking information to other vehicles, to help prevent collisions. Traffic lights could alert cars when they are about to change, or broadcast the latest congestion update to waiting vehicles. In the home, FSO could be used together with interior lighting to provide extremely fast internet downloads. Since light does not travel through walls, there would be no need to worry about neighbours snooping on your e-mail, or piggybacking on your broadband connection.

Obviously nobody told them about windows -- although they're mentioned later in the article.

That said, it's still a cool technology; laser diodes and LEDs make it easy and cheap these days.