Broadcasting Broadband Data Using Desk Lamps?

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This is so stupid, like you could ever use a desk lamp for broadband. Wait. What? This is actually possible? Oops..nevermind. ;)

The signal would be generated in a room by slightly flickering all the lights in unison. No one would be bothered by this because the rate of modulation would be millions of times faster than a human eye can see. Since visible light can't go through walls like radio, there would be no unwanted interference from stray signals and less worry of outside hackers.
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So they can transmit from your room lights to somethign like a laptop, cool... but how would a laptop transmit data back?

You're still going to need a radio transmitter to send data the other direction.
 
Having a radio transmitter isn't impossible now. You can simply have a flashing light bulb mounted that takes feed from the laptop to send data out, like how you do light signaling...
 
how do you know when the intervals begin/end.. if their is packet loss?

you can use any signal for 0/1s but its much more complex than this. if the packets fail and have to be sent back what a mess.

i dont see how light flashes would be bidirectional communication. this could lead to huge packet loss.

however if you used it for Morse code... you could do it so fast they would never know "what blinked" so in that case... for short signals you probably could do long distance light communications in the military.
 
jroe52 said:
how do you know when the intervals begin/end.. if their is packet loss?

you can use any signal for 0/1s but its much more complex than this. if the packets fail and have to be sent back what a mess.

i dont see how light flashes would be bidirectional communication. this could lead to huge packet loss.

however if you used it for Morse code... you could do it so fast they would never know "what blinked" so in that case... for short signals you probably could do long distance light communications in the military.
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How is that any different than for Ethernet or WiFi? It's only the medium that's changed. The protocol's the same.
 
Heard about this a couple months ago. Cool stuff. I'd like to see it in action, even if it doesn't end up being viable for regular consumers.
 
"Since visible light can't go through walls like radio, there would be no unwanted interference from stray signals and less worry of outside hackers."

Unless, you leave your blinds open, or your blinds don't block all light, or you have a glass wall or light leaks under your door or... wtf kind of statement is that? Granted you would have to have line of sight to hack, but this would be easier to spot at night.
 
BloodyIron said:
How does this work with CFLs? LEDs? Do you have to use incandescents?
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They mentioned this in the article.

from article said:
Incandescent and fluorescent bulbs can't flicker fast enough, so all the lights would have to be LEDs. Although commercial LEDs have a limited bandwidth of only a few MHz, Vučić and her colleagues were able to increase this bandwidth ten-fold by filtering out all but the blue part of the LED spectrum. With the visible wireless system built in their lab, they downloaded data at a rate of 100 Mbit/s. They have now upgraded the system's receivers and are getting 230 Mbit/s, which is a record for visible wireless using commercial LEDs.
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230Mb/s doesn't seem all that impressive. Faster than 54Mbps, sure, but CAT 5e/6 still has it beat at 1Gb/s.
 
BallerX said:
fluorescent lights already flicker at 60Hz and you don't notice. I don't see epileptics dropping all around me at the grocery store.
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I can see the flicker at 60hz.... that is super easy and very annoying.

And don't even get me started on CRT TVs and monitors.... can't stand anything under
75hz due to the flicker, 85hz or higher is preferred thank you very much.
 
EchtoGammut said:
"Since visible light can't go through walls like radio, there would be no unwanted interference from stray signals and less worry of outside hackers."

Unless, you leave your blinds open, or your blinds don't block all light, or you have a glass wall or light leaks under your door or... wtf kind of statement is that? Granted you would have to have line of sight to hack, but this would be easier to spot at night.
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And we ALL know how well line of site junk works... anybody else care to share their horror stories about IR wireless mice, keyboard, and gamepads?
 
cyclone3d said:
And we ALL know how well line of site junk works... anybody else care to share their horror stories about IR wireless mice, keyboard, and gamepads?
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You can always wire this Light-WiFi into your house's circuitry so every light in the house emit signals. Might want to keep the outside light on a separate circuit though hehe.
 
cyclone3d said:
I can see the flicker at 60hz.... that is super easy and very annoying.

And don't even get me started on CRT TVs and monitors.... can't stand anything under
75hz due to the flicker, 85hz or higher is preferred thank you very much.
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You are seeing the CRT flicker because it's flickering out of sync with everything else. When you jack up the refresh rate on the CRT it's fast enough that you don't see the out of sync anymore.
 
Meh...

Hmm... I wonder how signals are transmitted over fibre optic cables... ah, a laser is turned on and off to represent the data. These guys are just shooting the signal through the air, that's all.

As others have stated, unless the complete chain of transmission is optical, there will always be some leakage when the signal is the lower frequency ranges that will "pass through walls" and be detectable.
 
"visable light cant go thru walls" Then where does it go when you turn off the switch? :D

And I think I saw a thing on the net long ago that said the human eye can see up to about 240hz on a video display.
 
Bohica69 said:
You are seeing the CRT flicker because it's flickering out of sync with everything else. When you jack up the refresh rate on the CRT it's fast enough that you don't see the out of sync anymore.
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If that was the case I wouldn't be able to see it with the lights off and only the desktop of Windows up.... but I can.
 
As soon as they said synergy in the 2nd sentence, I stopped reading.
 
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