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Wireless Internet Access Uses Visible Light, Not Radio Waves
An anonymous reader writes to tell us that a company has demonstrated a new form of wireless communication that uses light instead of radio waves. "Its inventor, St. Cloud resident John Pederson, says visible-light embedded wireless data communication is the next step in the evolution of wireless communications, one that will expand the possibilities in phone and computer use. The connection provides Web access with almost no wiring, better security and with speeds more than eight times faster than cable."
Radio waves are part of the light spectrum?
It's called free space optics. The technology has been around a long time, in fact, and for a while it was fairly common on laptops. It was called IrDA, and though it was fairly short range you could use it to transfer files, establish a TCP/IP connection, etc.
I remember playing a Starcraft game with an iMac G3 and PowerBook G3. A friend and I used AppleTalk over IrDA. Unfortunately it was rather awkward since they had to line up, but we figured out you could bounce the infrared beam with mirrors. So we didn't need ethernet, we could play wirelessly...this was in 1998, long before 802.11b became mass-market.
Take off every sig. For great justice.
For how many decades does my university use laser links to our dorms? For how many decades do we have infra red data transmission, e.g. in remote controls?
Radio isn't another color of light, color only applies to the visible spectrum. Way to correct a technical error with another technical error.
Visible light doesn't, probably. But "light" is a term that can be used to refer to the whole of the EM spectrum.
If it works out as Pederson plans, his project would replace the need for fiber optic wires that run underground and in buildings. The cost savings alone in construction and wiring make it impressive, St. Cloud Mayor Dave Kleis said.
âoeRight now, we are going through a tremendous amount of fiber optics. If this can move and transmit with light rather than cable, there is significant savings in that alone,â Kleis said.
Now, given that they're essentially the same technology, I can't see how this would be faster than fiber. But if by "cable" when talking about speeds, he does mean DOCSIS, then that's easy. 10 Gigabit ethernet is already more than 20 times faster than EuroDOCSIS 3.0, 8-channel, and most varieties of 10GbE run over fiber.
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Uhhhh...radio waves propagate at the speed of light too, being made out of light and all.
However, higher-energy light has a higher frequency. Higher frequency = higher bandwidth. (and, not-so-coincidentally, higher power consumption)
It's been investigated but the technology just won't work out. Light sensors have a strong speed/intensity tradeoff. Even with a several-inch wide lens you can't collect enough light to drive a sensor at more than a few kilobits/sec. And people hate to keep pointing the sensor at the opposite party.
And if the room has LED or CCFL lighting the interference from those is mighty intense.
for completeness' sake http://cictr.ee.psu.edu/CICTRnews/White%20LED/Researchers%20Envision%20an%20LED-Powered%20Wireless%20Network%20%20PwC%20TelcomDirectNews_com.htm
1.) There is TCP/IP over Infrared (IrDA) and comes standard on Windows and works also in Linux.
http://web.pdx.edu/~mendyke/ip7780.html
2.) there are many laser link systems out there.
I even worked on one.
http://www.dnull.com/zebraresearch/company-mail.html
3.) The 802.11 standard also includes the 802.11 Infrared (IR) Physical Layer. 802.11 IR defines 1Mbps and 2Mbps operation by bouncing light off ceilings and walls to provide connectivity within a room or small office. This infrared version of the standard has been available since the initial release of the 802.11 standard in 1997.
4.) Spectrix Corporation of Mundelein, Illinois had a proprietary solution for this. I think they are out of business now.
http://books.google.com/books?id=QZrrXcs1R9gC&pg=RA1-PA207&lpg=RA1-PA207&dq=%22Spectrix+Corporation+%22&source=bl&ots=kMxMofcTd7&sig=qd4QvwoREWQloJKwnpmp63j-Z-I&hl=en&sa=X&oi=book_result&resnum=4&ct=result
If you explore the link above from the book "Wireless Computing" By Ira Brodsky Published by John Wiley and Sons, 1997. This book goes in a lot of detail about many IP over optical solutions available at that time.
I am always doing that which I can not do, in order that I may learn how to do it. - Pablo Picasso
Reading along here, I came to wonder what would happen if someone block the light source such that it is no longer visible? Would the signal then be completely lost? My previous experiences with light is that they struggle to travel through walls... Wouldn't this limit the utility value and application areas of such a system?
Different matter has different absorption properties. Visible light can travel through quite a few kinds of matter, such as certain plastics and glasses. Likewise infrared light travels through other materials. There are materials that block other wavelengths as well, although a lot of them we probably aren't as aware of because their absorption properties for non-visible wavelengths probably haven't been thoroughly tested.
Curiosity was framed, Ignorance killed the cat.
So if you ask someone to "turn on the light," what are you referring to? The radio? ;)
When pitting "light" against "radio" waves, the implication seems to be plain that he's talking about visible light.
1996 called. It wants its HP NetBeamIR Infrared Ethernet Access Point back.
IR access points have been around for years, and they work OK. They can even be made to work through diffuse reflections, so you don't have to have a clear line of sight. But you need a lot of access points to cover a space.
Here's the previous article:
http://mobile.slashdot.org/article.pl?sid=08/10/09/1843247
There's a bigger team at Boston University that's been working on this technology.
I particularly like their plans for use in cars. I can imagine combining this with nano piezoelectric technology to create roadways that use passing car vibrations to power illuminated markings that can also transmit road condition information to passing cars or link their light-based inter-car networks around corners and over hills.
The future's so bright, I gotta wear shades that decode and display ambient porn...
Not hard?
I rather suspect you have never installed let alone retro fitted a cage. EMF leaks everywhere, replace all windows with metaled glass, all doors need to be backed up, any vents need mesh, plastic pipes etc etc etc.
It's a nightmare which is why emf shielded buildings are usually built to spec by specialists.
> So if you ask someone to "turn on the light," what are you referring to? The radio? ;)
Actually, an incandescent lamp does produce radio waves, as well as other frequencies, IIRC. However...
> When pitting "light" against "radio" waves, the implication seems to be plain that he's talking about visible light.
Indeed. In context, it seems obvious that "light" here means visible light, which is after all by far the most common meaning of the word. Yes, the word "light" can also mean electromagnetic radiation in general, but for that matter it can also mean understanding or insight, and yet somehow it's obvious from context that these are not the intended meanings in this case.
Cut that out, or I will ship you to Norilsk in a box.