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Researchers Beam 230Mb/sec Wireless Internet WIth LEDs
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."
"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.
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.
It's the return of IrDA!
http://en.wikipedia.org/wiki/Fraunhofer_Society
(anon, copied from wiki, I just thought people should be more aware that Fraunhofer is an amazingly huge beast.
Fraunhofer Society (FhG) is the organization that owns the MP3 patents and licenses them through RCA.
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!
US patent 6,542,270 ("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.
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.
www.effectiveelectrons.com "chips that work" Analog, RF, Mixed Signal
What happens if you cross the beams?
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?
"-1 Troll" is the apparently the same as "-1 I disagree with you."
Those interested in this LED-based technology can check out the IEEE 802.15.7 Visible Light Communication Task Group. Members of the Fraunhofer Institute are regular contributors to the standard.
I'm an epileptic you insensitive clod!
We do the same thing at work with Interns and flashlights.
...called Ronja, only 10-mbits/sec, but ~1.4km range, and it could all be built by yourself. Quite cool IMO. You can find out more info (on the now bit dated) site here: http://ronja.twibright.com/
That's actually been a documented problem in some devices with status LEDs, which inadvertently leaked information due to being tied directly to the (serial) data line, rather than a low-pass filtered version of it.
In case they hadn't noticed, IrDA is dead for a good reason. The fact that the last two versions of it are much faster than Bluetooth (2.x) is irrelevant, it's too much of an inconvenience for most of its potential users in comparison to Bluetooth. It was great before Bluetooth came about and I used the latest versions of it with my old phone because it was much faster than Bluetooth, and I never had a problem with it for that purpose. Most potential users prefer the convenience of Bluetooth though, for obvious reasons. My new phone doesn't have IrDA, and hardly any new phones do, and as far as consumers go, that technology is all but dead. I can see LED networking going the same way.
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."
Caveat Emptor is not a business model.
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.
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!
Geez, I played with LED data links when I was in high school and LEDS came in all colours provided that it was red. Years later I used the power LED of a device (woohoo, we had green too by then) for a debug data link. Now you *really* got to get off my lawn...
Excuse me, but please get off my Pennisetum Clandestinum, eh!