Chinese professor builds Li-Fi system with retail parts

NETWORK WORLD ^ | November 05, 2013 07:07 AM ET | Michael Kan, IDG News Service

[Utilizer]

Chinese professor Chi Nan has built her own Li-Fi wireless system that can use LED lights to send and receive Internet data.

"I bought the lights from Taobao," she said, referring to the Chinese e-commerce site.

The professor from Fudan University showed off the technology on Tuesday at the China International Industry Fair in Shanghai. Unlike traditional Wi-Fi routers that use radio signals, Chi's system relies on light to send and receive data wirelessly.

Others scientists, especially in the U.K., have also been researching the technology, and dubbed it "Li-Fi". But rather than develop specialized hardware, Chi bought off-the-shelf retail parts to create her system.

[Utilizer]

This looks interesting. I happen to have quite a few LEDs laying about, and wonder if I can adapt an old network card or hub to utilize similar technology to work with them instead of wires or RF?

[G Larry]

“Li-Fi”?

Isn’t that part of Obamacare marketing?

[E. Pluribus Unum]

This looks interesting. I happen to have quite a few LEDs laying about, and wonder if I can adapt an old network card or hub to utilize similar technology to work with them instead of wires or RF?

Light is RF.

And any network is only going to be line-of-sight.

Light doesn't pass through walls.

[Zathras]

I built something very similar back in Jr HS.
Another Chinese scam looking for funding.

[dadgum]

Old tech for networking. Limited to line of sight. Limited throughput. Used IR.

[Utilizer]

Light is RF.

Beg to differ, mate. Started out on CB transceivers, and 27MHz RF is not "Light" by any stretch of the imagination.

As far as not passing through walls, for between rooms all you need is a light pipe with convex ends. Or an Active Repeater, if you do not mind the latency. External, who doesn't know what an "Antenna" is?

[AlmaKing]

Why do you say Light is RF?

Can you express your frequency ranges for each?

[Utilizer]

Old tech for networking. Limited to line of sight. Limited throughput. Used IR.

IR has gotten quite a bit more refined and powerful these days, and Blue LEDs (or ultraviolet) have greater inherent bandwidth.

[petro45acp]

By off the shelf, is this simply taking a fiber-optic card, attaching external LED (CREE 4 for some real throw), and directing it over line of sight?

Nice idea. Android app for sending and receiving Morse works similarly, if brightly using the camera’s led flash to emit.

More fun.

[dadgum]

Best possible use would be point-to-point pipe between separate buildings.

[E. Pluribus Unum]

[Democrat_media]

interesting

[Utilizer]

Many moons ago, back in high school we used to build transceivers using flashlight bulbs for communicating. Not much fidelity to them, but fun and you could use stronger bulbs with higher voltages and lenses for greater range.

LEDs are already pretty strong off-the-shelf, and look at the inherent range a simple LED flashlight already has.

[Windcatcher]

I toyed with the idea of building something like this, but I was thinking of using LED’s for signal acquisition and off-the-shelf CD-player IR lasers for high-bandwidth transmission. The CD auto-focus mechsnism would have to be adapted to multiple-axis pointing and focusing.

[Utilizer]

That is the "Wavelength" function. I defy you to provide details of a standard RF transistor that can detect the ElectroMagnetic radiation of "Light".

I have five and ten gigahertz transceivers, and none of them can detect light at any frequency.

[Paradox]

The directionality of this could be interesting, but for that, I would go with a modulated low power laser.

[E. Pluribus Unum]

Beg to differ, mate. Started out on CB transceivers, and 27MHz RF is not "Light" by any stretch of the imagination. As far as not passing through walls, for between rooms all you need is a light pipe with convex ends. Or an Active Repeater, if you do not mind the latency. External, who doesn't know what an "Antenna" is?

Radio waves and light are just different wavelengths on the electromagnetic spectrum.

[Windcatcher]

A photodiode can of course detect light, but good luck getting any bandwidth out of it (grin). I think CD laser pickups are the way to go since they give you almost everything you need.

[SoothingDave]

27MHz RF is not "Light" by any stretch of the imagination.

He said light was RF. He did not say all RF was light.