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Communications Networking Technology

Polymers Brighten Hopes For Visible Light Communication 64

ckwu writes Today nearly all computers, tablets, and smartphones have Wi-Fi capabilities, receiving and transmitting data over a range of radio frequencies. But a burgeoning technology known as visible light communication could someday carry those data in the same light that illuminates a room. Now a tag team of semiconducting organic polymers is bringing that dream one step closer. When excited with a blue LED, the polymer pair helps to create white light that can be rapidly switched on and off to encode information. A proof-of-principle device using the polymers sent data at 350 Mbps over a distance of 5 cm with minimal errors, a rate 35 times faster than a commercially available phosphor used for blue-light color conversion.
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Polymers Brighten Hopes For Visible Light Communication

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  • by davidwr ( 791652 ) on Thursday February 12, 2015 @03:44PM (#49041501) Homepage Journal

    Give me a light bulb with the luminosity and color spectrum of a traditional "soft white" light bulb, the power consumption of a "100W incandescent-bulb-equivalent" LED, and an acceptably-low cost and I'll start replacing all the bulbs in my abode tomorrow.

    Bonus points if the bulbs do NOT offer any communications ability or any other I/O other than the electrical on/off switch - that way I know they aren't going to be hacked or used against me.

    • by adolf ( 21054 )

      The 100 Watt-ish LED [homedepot.com].

      The high-CRI LED [homedepot.com].

      You don't get to have both, just yet.

  • It has its places (Score:4, Informative)

    by Mal-2 ( 675116 ) on Thursday February 12, 2015 @04:02PM (#49041675) Homepage Journal

    Upsides: Unlicensed spectrum. Pretty much unenforceable even if it was licensed. Little or no bleeding over from desired coverage areas, at least indoors. Plenty of bandwidth to go around. We know the safety profile of this sort of radiation quite well also.

    Downsides: Line-of-sight only, so an AP in every room would pretty much be required (or equivalently, fiber from a central AP to every room). Probably can be degraded by "noisy" light-emitting devices, but spread-spectrum will probably get around that pretty well.

    It sounds a little like using fiber optics for the last-mile problem, only in this case it's the last-meter problem and possibly without a fiber.

    • I just can't see any use for this that beats radio except for situations where security concerns trump the hassles with line of sight.

      The AP in every room part is easy. Companies working on this want to build it into light bulb controller chips. But then how do you get the data to the light bulb? Powerline is too slow and very error prone.

      • by Anrego ( 830717 ) *

        Indeed, this looks like a solution seeking out a problem.

        Sure, it solves a small number of edge cases, but it also creates a bunch too. What if I'm watching a movie and want to turn the light off?

        • by swb ( 14022 )

          Only place this seems to make any sense is for one-way broad/multicast in a large area where you can reasonably expect to illuminate a large number of receivers.

          The example I'm thinking of is like maybe a sports stadium or other similar kind of facility where you have a lot of potential receivers with clear line of sight to overhead illumination.

      • by Anonymous Coward

        Holy shit.

        The solution is so obvious. It's right in front of our nose.

        Power over Ethernet. - Really. Why not? These new LED bulbs so efficient, why bother with mains? Get your data and your power over one cable, with existing tech!

        You won't need any new kind of switch, or new kind of cable. Low voltage power distribution over ethernet cables is already industry standard and well understood. No need for any new electrical standards or regulations either. Light fixtures already optimized to distribute light e

        • Ethernet over the domestic mains is another obvious solution but PoE seems more simple and elegant.
          I don't know if it's possible or if it's a good idea to try to fit an Ethernet-over-mains adapter in a lightbulb. BTW I say "Ethernet-over-mains" because I don't know how of a better unambiguous name, except for the French "CPL".

          PoE needs the introduction of consumer PoE switches (at 48 volts?), and you need to re-wire your building or appartment, perhaps invent a new socket.
          Ethernet-over-mains would work over

      • Another upside: nobody is going to bitch about being "exposed to radiation" from such devices. If it's in a visible part of the spectrum, it doesn't count as Deadly Radiation.

        • by Mal-2 ( 675116 )

          Another upside: nobody is going to bitch about being "exposed to radiation" from such devices. If it's in a visible part of the spectrum, it doesn't count as Deadly Radiation.

          That's what I meant when I said the safety profile is well known. Some people are hypersensitive to light, whether it's their eyes or their skin. They already know it, so this won't sneak up on them. For everyone else, it's not going to hurt them to have a high frequency signal modulated onto their light bulbs.

        • You are right. Visible light is proven harmless, unlike the unnatural Infra-red that was unknown to mankind before the transistor was invented.
      • We all use data transmission over light all the time (sort of) : IR remotes. That decently works when pointing the remote towards the direction of the device.

        Biggest non-security concern : 2.4GHz is sometimes very seriously saturated. I tried free wifi at the most central downtown square : it's the kind of experience where you can barely access the portal and maybe google's home page but any google search or loading a bigger web page than that will fail.

        There's Wifi 5GHz but smarphones don't even support i

    • by bondsbw ( 888959 )

      Another downside, you need to keep that light on all the time (at least when you're using the signal).

  • by Shatrat ( 855151 ) on Thursday February 12, 2015 @04:11PM (#49041727)

    Before anyone says anything about fiber optics, this is useless for any application other than short range wifi/bluetooth replacement type technologies. The attenuation of light in fibre has a minimum around 1550nm, infra-red. Shorter wavelengths experience high attenuation due to scattering. Longer wavelengths have more absorption.

  • OK, while I'm certainly down with a "because we can" sort of answer, I'm trying to understand how/why this would be better than wifi?

    Right now, my office is served by a wifi AP that covers essentially my whole home - multiple rooms, levels, etc. While I guess I can see limited security benefits to having something carried on visible light (ie able to be limited to a single room easily) it doesn't seem like for the bulk of wire-free communication circumstances that this would really be useful?

    • by Shatrat ( 855151 )

      This could be a low power way to sync your phone with your watch or your watch with your TV or your TV with your robotic vacuum cleaner. Wifi has a lot of complexity built in, and uses a lot of power. This could also have some niche applications in noisy environments like electrical utilities.

      • by Richy_T ( 111409 )

        OK. So now why is white better than blue? Or, indeed, the IR that was once fairly common in phones in the late 90s?

        Oh, I see. They want to use the room lighting to do this? Seems like a solution looking for a problem to me.

        • by Shatrat ( 855151 )

          Seems like a solution looking for a problem to me.

          People said the same thing about the laser for decades.

          • by Richy_T ( 111409 )

            True enough. And it may well be the solution to a real problem that isn't recognized or possibly even invented yet. I don't think using light fixtures as data communication channels is likely to be it though.

        • I would have thought that they would be better off creating a number of single-color sub-channels and spreading data across them. I would think that white light would have group delay problems.
    • TFA doesn't do a good job of suggesting the wide-open potential held by photonic communication. It is mostly staring at this topic with the same focus as your comment here-- how to stream data in a living room.

      If you consider the requirements of wifi, you'll see some obstacles that limit its applications. For "internet of things" devices, wifi demands a bunch of electricity from a device that you might want to deploy in an electricity-poor environment. Think solar-powered device. Photonic communication m
    • I can see any number of short range no wires connections that would be handy:

      Playing a game with a controller that typically is pointed at the screen of a TV/monitor.

      I work in the aircraft maintenance field. 90% of our system failures come from bent pins in connectors. If the connector was just a pair of LEDs and sensors that don't actually touch that would be amazing. You also wouldn't have to worry about wireless connections being hackable or RF getting into places where it causes problems. Same w

  • Didn't I have a calculator or some other kind of gadget that transmitted by red LED when I was a kid? Wasn't it a Furby?
    • Maybe it was a Palm Pilot. The red LED transmitted at a frequency just beyond normal human eyesight (except for the very young... which you might have been).
  • ...I'm holding out for transparent aluminum.
  • by dsgrntlxmply ( 610492 ) on Thursday February 12, 2015 @04:23PM (#49041873)
    It's an interesting curiosity in a molecular sense, but is it really justified for application? Why not let room lighting be done with something optimized for luminous efficiency and subjective color, and data transfer be done in the infrared where we have cheap emitters and optical filters? Why burden a bulk illumination power supply with also being a modulator in the 10^8Hz realm?
    • by Thagg ( 9904 )

      It's not particularly uncommon for an article about a scientific breakthrough to be almost satirically misleading.

      If this really works, for instance, it could be a revolution in television design; far better than the quantum dot technology that people are adapting now. But, if the article was about TVs then it the responses would all go in a million directions (comparisons to plasma, talking about energy star ratings, whatever).

      Back in the 50's, it was pretty common for scientists doing nuclear weapons res

  • I'm guessing with the short distances this is a replacement for radio frequency near field communication rather than a substitute for wifi.
  • You mean, like a readin' and a writin'? Pretty fancy stuff, there!
  • Haven't we seen this technology before on Slashdot? Yep, here we go: 2014 [slashdot.org], 2013 [slashdot.org], 2012 [slashdot.org], 2011 [slashdot.org], 2010 [slashdot.org].
    • by Thagg ( 9904 )

      Yes on the light-based-communication, but no on the use of frequency-shifting polymers...that's new.

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