Talk about a light bulb moment.
A professor of engineering at Edinburgh University recently demonstrated for the first time to a wide audience his technology that uses common every day lights to transmit data.
Harald Haas streamed a video through a desk lamp at Ted Global 2011 at Scotland’s Edinburgh International Conference Center in July.
If commercialized, the technology not only creates a vast new application for light, but also dramatically expands our now limited wireless capacity. Imagine downloading your email from any of the 14 billion light bulbs installed in the world.
Haas’ technology swaps out our current way of transmitting data – through radio frequency – with a new approach using visible light from LED light bulbs. This is significant because we are running out of radio frequency spectrum as our appetite for wireless communication grows, Haas says. The visible light spectrum, on the other hand, is enormous, with about 10,000 times more capacity than radio frequency. Using light instead of radio frequency would give us a lot more capacity for our cell phones, wireless computers and other devices.
The energy implications are even more interesting.
First, the technology creates a new impetus for switching from incandescent light bulbs to LEDs. Until now, LED champions have argued their cause based on the light bulb’s energy efficiency. It’s a good argument, but not one that always motivates the consumer. With Haas’ technology the LED takes on new importance. LED lights are necessary because they contain a semi-conductor; incandescent light bulbs do not.
Second, the whole process of transmitting data through light is more energy efficient than using radio frequency, according to Haas. Think of it this way. We have 1.4 million cellular masts, or base stations, that now allow us to transmit data through our 5 billion cell phones worldwide. These base stations use a lot of energy, particularly for cooling, operating at only a five percent efficiency level, according to Haas. What if instead we transmitted data through the 14 billion light bulbs already installed worldwide? Haas says he’s calculated the “energy budget” and found light-based data transmission to be so efficient, it is virtually free.
“It should be so cheap that it’s everywhere. Using the visible light spectrum, which comes for free, you can piggy-back existing wireless services on the back of lighting equipment,” he says.
The technology offers some other advantages as well, particularly privacy, convenience and health assurances.
Light is more secure than radio waves. Light does not penetrate walls and radio waves do. So it appears that it would much more difficult to hack your calls via light wave than radio wave.
As for convenience, think of how you’re asked to switch off your computer on an airline, so that you don’t interfere with radio signals needed by the plane. If you were instead using the light above your seat to access the Internet, you could keep the computer on.
And last, for electric utilities, light-based transmission would eliminate customer concerns that smart meters placed on homes cause cancer. Industry research has not supported these claims. Nonetheless utility customers in some states, particularly California and Maine, have protested installation of smart meters, themselves an energy efficiency device.
How does Haas’ technology work? It all looks pretty simple. He switches on a desk lamp that uses a $3 LED light. The light beams into a hole to a receiver. The receiver detects small changes made in the light’s amplitude and converts those changes into an electronic signal. Voila! A streaming video, showing flowers opening, appears on a nearby screen. To stop the video, Haas simply passes his hand in front of the light.
Haas hopes to see the necessary microchip fitted into every lighting device: household lights, street lamps, cell phones, overhead lights on planes, traffic lights. Of course, the road to commercialization trips up many potential technologies. And he’s still working on improving data speed. (He has achieved rates of 10 MBit/s per second and hopes to achieve and 100 MBit/s by the end of this year.) But this is one to watch. See his TED talk here.
Elisa Wood is a long-time energy writer whose work appears in many of the industry’s top magazines and newsletters. She is publisher of the Energy Efficiency Markets podcast and newsletter.
So how does LiFi support two way communications?
This is hardly a major breakthrough, it is only a variation on the fibre optic technology already in use.
I can see problems with people reacting to flashing lights, even if they are theoretically too quick to be seen.
Other problems are the massive infrastructure, with all our gadgets needing optic sensors and emitters (data exchange needs a handshake, so it is never just one way)
Once transmitted, the data will have to come out of the light, once it reaches a switch or transformer (common in LED based lamps), the signal gets scrambled. The power industry has been trying to get into the telecomms market for more than 50 years but keeps hitting up against the same problems
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