Streaming video with the power of LEDs

The same diode light that powered the wrist-calculator in 1980s classrooms is growing into something much more formidable. A Berlin research team is using the technology to stream HD video across a room. Michael Dumiak paid a visit.

Streaming video with the power of LEDs
Photo: Fraunhofer Institute

Light-emitting diodes, or LEDs as they are commonly known, are small semiconductors that generate light when an electronic current is sent through a junction onboard the device. Scientists have managed to make them more and more powerful in the past few months.

Check out some LED art in our picture gallery

Researchers at the Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute have now managed to set up an array of LEDs in a panel that can light up a 10-square-metre room and transmit wireless data to laptops. It is, in essence, a kind of optical alternative to WIFI.

This optical networking works by modulating the LED panel very rapidly – turning it on and off faster than the human eye can see – which encodes data into a digital stream of ones and zeros. “We want to make clear that you can use off-the-shelf, normal white-light LED chips for data transmission,” says Anagnostis Paraskevopoulos, an intra-machine communication expert who has been working on the network.

Working with Siemens and the French Telecom Orange Lab, the team were able to stream lossless data at 100 megabits per second at a maximum range of ten metres.

Paraskevopoulos explains the idea is not to try to replace the standard microwave and radio WIFI routers found in your house or in more generous airports and hotels.

Instead, it would offer an alternative when such networks aren’t desired, as in a hospital, or don’t work. It may also be possible to create combinations and so-called mesh networks which extend the range and power of the light transmissions.

But it’s early days yet. If something blocks the light-stream to the laptop, the data rate goes down, Paraskevopolous says, although the light is able to reflect off ceilings and floors. He admits that boosting the data rate will also take some complex tinkering.

But the engineer believes LEDs are capable of a lot more than light-stream networks. The team isn’t using LEDs because of any particular wavelength property. “It’s because we believe that in five to ten years all lighting will be based on LED,” he says.

The European Union is currently phasing out the traditional incandescent lightbulb, while LED lighting is also getting cheaper, brighter and more appealing to consumers.

There are alternatives, like the compact fluorescent bulbs and others, but LEDs are already becoming more prominent in everyday lighting—in car headlamps, kitchen appliances, street signs, bridges and buildings.

German manufacturers and architects are trying to stay ahead of the curve in diode-based design. “This kind of lighting is competitive, marketable and has enormous energy-saving potential,” says Sven Kühne, marketing chief at the Austrian-based design group Bartenbach Lichtlabor. Bartenbach recently worked with German and Austrian sound designers to create a prize-winning video conference room using LED lighting; Kühne says the firm is using diodes in about 80 percent of new research and development.

At September’s electronic trade fair IFA in Berlin, the Siemens group made a big show of the LED touches in its new large appliances. “Our refrigerators are fitted with LEDs in nearly each category,” a Siemens spokeswoman said. “But we’re still facing challenges in other product categories in terms of heat resistance or light colour.”

Bartenbach’s Kühne says diodes will become more and more prevalent in Germany, and the potential is apparently limitless. The firm’s next big project is an immense clock tower in Mecca, Saudi Arabia, that will use no fewer than two million LEDs.

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