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Comments: 218 + - Mobile: Researchers Beam 230Mb/sec Wireless Internet WIth LEDs on Thursday March 11, @06:38PM
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MikeChino writes "A group of scientists from Germany's Fraunhofer Institute have devised a way to encode a visible-frequency wireless signal in light emitted by plain old desklamps and other light fixtures. The team was able to achieve a record-setting data download rate of 230 megabits per second, and they expect to be able to double that speed in the near future. While the regular radio-frequency Wi-Fi most of us use currently is perfectly fine, it does have its flaws — it has a limited bandwidth that confines it to a certain spectrum and if you've ever had someone leech off of your connection, you know that it also leaks through walls. LED wireless signals would theoretically have none of these downsides."
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No upsides either (Score:5, Informative)
"Leaking through walls" isn't a bug, it's a feature; I don't want to wire my whole house for Ethernet just to have wireless in every room, as that defeats the purpose.
Re:No upsides either (Score:5, Insightful)
That's a huge upside for linking up video devices though. No interference from the neighbors, no interference from the other room.
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Re:No upsides either (Score:5, Funny)
I tried that in my epilepsy classroom and everyone had a fit.
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Re:No upsides either (Score:5, Interesting)
what if you could use the lighting that already exists in your house to do this? kinda like internet over power lines?
Retailers already use this technology to change the display tags on shelves. After hours, they send a series of codes to modulate the fluorescent lighting in such a way that it sends new data to smart shelf tags. The shelf tags display a product name and a price. Changing the prices on those shelf tags are a major operational cost of grocery retailers.
Fujitsu is one of the firms offering this. Here's Fujitsu's system [fujitsu.com].
Parent
Re:No upsides either (Score:4, Funny)
Holy shit, apparently I live in the future and I didn't realize it.
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Re: (Score:3, Informative)
You're forgetting that what you see is not the plasma (it emits mainly short-wavelength UV), but the phosphor coating (which is excited by the UV & emits visible light). The phosphor coating is specifically chosen to be (relatively) slow, in order to filter out the 50/60Hz flicker.
In theory, you could use a faster phosphor and modulate th
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More than that even if you use LED lights you have the issue of the power supplies to contend with. I bet most PSUs won't pass through high frequency modulations.
So you are talking about either rewiring your lights with a low voltage distribution system of some sort (possible but the cables get very big) or replacing the LED PSUs with something that can carry a signal across (say homeplug one side LED modulation the other)
There is also the question of what to do for the return link.
All in all nice idea but
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Leaking through walls is not always a feature. I can't get the maximum benefit of my Wifi setup because I live in an apartment building and all my neighbors have devices chattering on every channel. All their routers are probably defaulted to high power, and there's nothing I can realistically do to improve my situation except switch to 802.11n/5G, which I did, and now I'm seeing more routers on that frequency range too.
I don't want to lose my through-walls access, but if it could be heavily supplemented by
No kitty, that's my pot pie! (Score:3, Funny)
No, you can not haz beam of light interwebs. You are obviously a lolcat, and the only thing lolcats should do with beams of light is chase them. Who is a cute kitty? Who is? You! Yes you are!
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If your room has no windows.
Re:No upsides either (Score:5, Interesting)
Even if it doesn't have windows open, you can still go through a closed or even shuttered window. Telescopes replace direction antennas and have phenomenal gain and accuracy. Lasers beamed back in can return signals and don't have to be visible ( You can control transmit spectrum a lot easier than receive spectrum ). AlGaAs based photonic detectors can pick up single photons and are sensitive enough to spot light coming through a thin gap in shutters or curtains. ( think more sensitive than military NV devices ).
Now, instead of being worried about people parking in cars just up the street, you need to worry about anything you can see from your house... Thos e hills 10km away? Not far enough. The highrise across the river? Huge risk.
The good news is that tinfoil is sufficient to stop all photons, so a few rolls of tinfoil and tinfoil plated tape will be all you need to secure the wireless visible spectrum devices in your house.
Until someone burns a ten micron hole in your defenses with an infra-red laser....
GrpA
Parent
Re:No upsides either (Score:5, Funny)
People who live in glass houses shouldn't use plain text passwords.
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Just different ones (Score:5, Insightful)
LED wireless signals would theoretically have none of these downsides.
Nope, instead it'll have a whole range of different ones, such as requiring line of site.
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Forget people being a dick, how about people just innocently wandering between transmitter and reciever? Or the user himself accidentally setting something down in the way? Too many ways to screw it up.
I think we had a story about LOS wireless before, and really, same as then, the only use I can see for it is in lab environments, where you usually don't have people wandering around in undefined patterns. Attach unit to roof on a per-row basis, aim all computers in that row at that reciever, and no one can a
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With many modern remotes, you don't have to aim the remote at the device, but you can bounce it off walls and furniture and have it work great.
Tell that to my fucking Blu-Ray player. The remote for my parents' 15 year old TV worked better at wider angles.
Besides, the article mentioned Visible Spectrum. Good luck reflecting that and maintaining usefulness.
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IR is slow as hell and prone to interference from the sun! Sounds like a real winner
Re:Just different ones (Score:5, Funny)
Slashdot 57:30, If we covet making a spelling mistake for each wife, at some point we forsake other gods and we may do unto others before they can do unto us first on /..
Parent
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And losing your network connection because you were sitting at the wrong end of the conference table in your meeting would be a huge minus.
And having the signal stop at the wall but not at the window sounds like a major ding to the "huge plus", not to mention a recipe for a false sense of security.
In either case you'd have to secure your wireless network in a traditional fashion. So, why not just do that, and get the benefit of non-line-of-sight communication too?
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Oh Great (Score:2)
Now everything I own, from my Star Wars light saber to my Krusty the Klown glow-in-the-dark alarm clock, could potentially with wireless signal. Oy carumba
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That's actually been a documented problem in some devices with status LEDs, which inadvertently leaked information [cnet.com] due to being tied directly to the (serial) data line, rather than a low-pass filtered version of it.
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Blast from the past (Score:5, Funny)
It's the return of IrDA!
Fraunhofer juggernaut (Score:2, Informative)
http://en.wikipedia.org/wiki/Fraunhofer_Society [wikipedia.org]
(anon, copied from wiki, I just thought people should be more aware that Fraunhofer is an amazingly huge beast.
FhG owns MP3 (Score:3, Informative)
Great! (Score:2)
You won't notice it (Score:2)
So now I'll have a strobe light effect every time I check my email!
As long as the modulation they use on the LEDs is DC-free, your eyes won't pick up this strobing. A traditional light bulb flickers at 100 or 120 Hz, and you probably don't notice it. So you definitely won't notice flicker that's a million times faster.
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Since they got 230MB per second, you can safely assume that the modulation will be in the gigahertz. Good luck seeing that. If they use something like 8B/10B encoding, then they will get a guaranteed 50% duty cycle, so there will never be any brightness variation visible to the human eye.
An idea that's been around (Score:3, Interesting)
US patent 6,542,270 [uspto.gov] ("Interference-robust coded-modulation scheme for optical communications and method for modulating illumination for optical communications"), issued April 1, 2003, assigns direct sequence spread spectrum-type codes to each overhead fluorescent light, so that communication and location-determination can be performed. The chip frequency of the coding scheme is fast enough that there is no human-audible or -visual effect, and supportable by electronic ballasts.
Utterly Stupid.... (Score:3, Insightful)
If you really want to use optical communocation you might as well go infrared so you don't need to see it, similar to your TV remote.
Then you have all the problems (visible light or infrared) of orientation, line of sight and similar.
Hopefully the creator of this gadget has not quit their day job.
utterly stupid.
What I want to know is: (Score:4, Funny)
I RTFA (Score:3, Interesting)
I RTFA. It says that they achieve the bandwidth by filtering out the blue light. This makes sense, as white LEDs are actually blue LEDs with phosphors added to get the other colors. Phosphors are similar to glow-in-the-dark stuff, so they retain light for a little while. Presumably, the blue filter is only needed over the receiver.
The one questions is: how does your laptop equipped with this technology talk back? Will your laptop have a multi-watt emitter on the top (read "bright white light") lighting up the room for the upstream traffic?
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The one questions is: how does your laptop equipped with this technology talk back? Will your laptop have a multi-watt emitter on the top (read "bright white light") lighting up the room for the upstream traffic?
Naw, it's like some satellite internet connections. You use the LED for download, and upstream you use dialup. I'm sure it'll catch on. :)
Oh, and ... (Score:4, Informative)
Those interested in this LED-based technology can check out the IEEE 802.15.7 Visible Light Communication Task Group [ieee802.org]. Members of the Fraunhofer Institute are regular contributors to the standard.
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In that case, it's bound to be cool. And by cool, I mean patent encumbered.
BTW, {nitpick} it's not "the" Fraunhofer Institute, it's "Fraunhofer Society [fraunhofer.de]," within which are various institutes [fraunhofer.de]. Probably the most famous is on the internet is the Fraunhofer Institute for Integrated Circuits (Fraunhofer IIS) in Erlangen, whence came the mp3 standard. But the one responsible for Visible Light Communication is Fraunhofer HHI [fraunhofer.de] in Berlin. {
I accidentally (Score:2)
This is great... but... (Score:3, Funny)
big whoop (Score:5, Funny)
We do the same thing at work with Interns and flashlights.
I remember a DIY LED netsystem.... (Score:5, Informative)
IrDA died for a good reason. (Score:3, Insightful)
Digital video (Score:5, Funny)
I assume the 230Mb/s is for stuff like delivering digital video to your TV without plugging cables.
"Wow, this movie looks even better in digital!"
"Here, let me turn the lights out so we can wa...oh."
Desk lamps, OK, that's one way (Score:3, Interesting)
Now how do we communicate the other way ? Like from the laptop back to the router ? How do I twiddle the house lights from there. Inquiring minds want to know.
BTW what kind of light sensor did they use ? Cheap hopefully.
Bandwidth Meter (Score:3, Funny)
Downloading from couch with laptop facing "array" across room, 100% signal strength
Dog walks into room between laptop and array, 30% signal strength while dog passes
Child walks in room and stands in front of you to talk to you, 0% signal strength until conversation ends, or kid dies for cutting off your slashdot post mid submit!
Wife walks in with credit card bill with pr0n charges, array gets smashed and you get served.
No good can come from this!
1975 here we come... (Score:3, Funny)
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According to TFM, the flickering is slight enough to be imperceptible by humans. So unless epileptics have superhuman sensitivity to tiny light variations, I doubt they will notice anything either.
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Don't worry, the flicker rate is so fast not even Bobby Fischer would complain about it.
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