Wireless Internet by Flicking Lights On and Off

By Marcus Yam
published

As long as they don't install the clapper.

Last year we learned about a sort of wireless internet network that operates through the blinking of lights.

Now it's a reality in the city offices of St. Cloud, Minnesota. Local startup company LVX System installed in six city buildings a form of wireless internet that doesn't rely on the 802.11 standards. Instead, it uses flashing lights – sort of like morse code.

Unlike morse code, however, the flashing lights come on and off so quickly that they are imperceptible by the eye. The lights come from LED fixtures overhead, which also double as lighting for the city workers. The light fixtures consume about 36W and provide the same sort of illumination as a 100W fluorescent fixture.

Modems on desktops receive and transmit lights back up towards the lighting fixtires.

Data bandwidth isn't by any means great, as the current technology is only able to deliver about 3Mbps. Wi-Fi is much faster, but the lighting method is more secure and less prone to interference.

Read more from the AP.

Marcus Yam
Marcus Yam
Marcus Yam served as Tom's Hardware News Director during 2008-2014. He entered tech media in the late 90s and fondly remembers the days when an overclocked Celeron 300A and Voodoo2 SLI comprised a gaming rig with the ultimate street cred.
35 Comments Comment from the forums
  • jhansonxi
    Interesting but nothing new. IrLAN has been around for a while and it was proven a long time ago that the LEDs on modems can be used to monitor communications remotely.
    Reply
  • Demonslay335
    I think this is a brilliant idea, but it may have some adverse effects. For example, even though the lights are flashing faster than the eye can perceive, I wonder if it would still have effects on a person's eye since it is a flashing light still, just like LCD monitors still have effects on people because of this.

    Also, I would still find the security to be bad in terms of reliability. "Heya John, how's it go... oh no, I just covered your modem with a folder and you lost all of that data you were just uploading, too bad!" And you could probably confuse or scramble someone's data by flashing a flash light across the room... I do realize there's an equivalence of all of that with WiFi though, with jammers and all, but it would be much less genius to have a laser pointer on you, lol.
    Reply
  • TheWhiteRose000
    when I saw saint cloud I was like.
    YES!!!
    Then I saw Minnesota and went.
    Aww!!!
    Reply
  • mavroxur
    Demonslay335I think this is a brilliant idea, but it may have some adverse effects. For example, even though the lights are flashing faster than the eye can perceive, I wonder if it would still have effects on a person's eye since it is a flashing light still, just like LCD monitors still have effects on people because of this.


    The rate at which the LED's change state is MUCH faster than an LCD's refresh rate. For a data rate of 3Mbps you're talking probably closer to a 5MHz switching rate to take into account error correction code and protocol losses. That is much faster than humans can perceive.
    Reply
  • alextheawesome
    TheWhiteRose000when I saw saint cloud I was like.YES!!!Then I saw Minnesota and went.Aww!!!I said YES!! to both. Teehee.
    Reply
  • nevertell
    How can you secure such a network ? Does it use WPA ? :D
    Reply
  • Hellbound
    ""Earlier this year we learned""
    It is Jan 1st you know... :P
    Reply
  • Marcus Yam
    Hellbound""Earlier this year we learned""It is Jan 1st you know...Whoops! (I wrote this one in 2010.)
    Reply
  • iamtheking123
    To me this seems like a classic engineering waste of time: mild cool-factor but there's already solutions available that are better in every way.
    Reply
  • ProDigit10
    the bandwidth could get bigger, when using tri or quad color leds.
    Nothing can get inbetween the direct path of transmitter and receiver, without seriously slowing down the transfer, and unless you're physically shielded, its pretty easy to tap off the connection from another laptop,as signals could be received many feet away, perhaps even half a mile away from the source.

    On the laptop/netbook/intelligent phone or whatever receiving device, something like a .25mW led should be sufficient to transmit back to the source, if you're sitting relatively close under the light.

    The good thing is there won't be any harmful radiation floating around.
    Reply