Beyond WiFi: Connecting by light - The Boston Globe

Hmm…

"The technique used is to flash the light on and off, or modulate the light, to transmit data," Little said. The pulses are so rapid that they can be picked up by an electronic sensor, but not by the human eye. That allows the lamp to light a room and transmit information at the same time.

Nobody expects light-based networking to replace today's wireless radio systems, like the popular WiFi networking technology. But the BU system could use a fraction of the power of radio systems like WiFi networking. It would also offer greater privacy, because signals from a light-based network won't penetrate walls or doors, as WiFi signals do.

Beyond WiFi: Connecting by light - The Boston Globe