Q: How do you stream a movie to a laptop that’s offline?
A: Turn it into light pulses that can be transmitted by a standard LED lamp -- and then rig up a domestic solar panel to turn the signals back to video.
An Edinburgh professor has given what he said was the first public demonstration of "LiFi", or "Light-Enabled Wi-Fi", beaming a movie over the air to a laptop using only an LED lamp.
At the Royal Institution's Faraday Lecture Theatre in London -- where Michael Faraday first demonstrated electromagnetism -- Harald Haas, professor of engineering at Edinburgh University, gave a live demo of LED-based broadband that he says will soon be a viable alternative to Wi-Fi.
Using a standard LED light to transmit video as fluctuating light signals, and a domestic solar cell to receive the light signals, Haas used an offline laptop to show footage of rolling clouds on a monitor. He said the signal could be "transmitted at up to 50MB per second", faster than most home broadband systems, and would help provide internet connectivity to areas that are currently off the grid. "We expect to go to market with this in two or three years," he told the audience at a TEDSalon where he presented the technology.
The video signal is converted into a fluctuating light output and sent via the LED lamp. The LED can send large amounts of data in what to the human eye simply looks like white light.
WIRED covered Haas’s work in a long feature in the February 2012 edition. WIRED explained that Haas's discovery is "based on a subset of optical technology called visible light communication (VLC), or Li-Fi, as it has been dubbed. VLC exploits a hack of human perception: light-emitting diodes can be switched on and off faster than the naked eye can detect, causing the light source to appear to be on continuously. Rapid on-off keying enables data transmission using binary code: switching on an LED is a logical '1', switching it off is a logical '0'. Thereby flows the data."
At the time, we called his team's work "scientifically groundbreaking: it proves that large amounts of data, in multiple parallel streams, can be transferred using various forms of light (infrared, ultraviolet and visible)"... It could let us download movies from the lamps in our homes, read maps from streetlights and listen to music from illuminated billboards in the street."
Haas has commercialised his team’s research by co-founding a company called pureLiFi, where he is chief scientific officer. In January this year, the company announced a £1.5 million fundraising at a reported £14 million valuation, with investment from London & Scottish Investment Partners, the Scottish Investment Bank and Old College Capital.
Haas gave a TED talk in July 2011 where he demonstrated an earlier version of his work.
This article was originally published by WIRED UK
