Communications of the ACM
Using Light to Send Data Across the Room
Harald Haas, a computer science professor at the University of Edinburgh, demonstrated Li-Fi technology, which uses light to transmit data wirelessly.
Photo courtesy of James Duncan Davidson/TED
Visible light communication continues to attract academic and commercial interest because light-based technology is practical, economical, and would provide an alternative to wireless communications networks that use radio spectrum.
University of Edinburgh professor Harald Haas recently demonstrated a prototype visible light communication device at the TEDGlobal conference, using a table lamp with a light-emitting diode bulb to transmit a video of blooming flowers that was then projected onto a screen behind him. Haas built the Li-Fi device with inexpensive off-the-shelf parts. It had no antennae, and the video immediately paused when he stuck out his hand to block the light from the receiver and when he turned the light away from the receiver.
Haas believes he can increase the speed from about 10 Mbps to 100 Mbps by the end of the year. Light-based data transmission technology would enable wireless communication without the need for radio gear, and it would lessen the risk of data leaving an office. Signals would be able to piggyback on lights already in use such as street lamps, car headlights, or room lighting.
From The New York Times
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