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Polymers Brighten Hopes For Visible Light Communication

Posted by timothy on from the hope-is-measures-in-photons dept.

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.

7 of 64 comments (clear)

  1. Heck, I'll settle for white light by davidwr · · Score: 3, Insightful

    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.

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    1. Re:Heck, I'll settle for white light by hey! · · Score: 2

      Well, how much would it cost you to operate that incandescent for about four hours a night?

      We'll round that up to an even thirty hours a week, since 10 hours of operating a 100 watt lightbulb is, conveniently, 1 kw-hour. On average that would cost you $0.375/week. Over the course of a year you $19.50 for the incandescent, and $2.95 for the LED. So you're about even after a year.

      But I agree a year is a long time for someone on the minimum wage to wait for his payback, especially because incandescents burn out all the time. Sure eventually be better off but $20 is a lot to ask from someone who has to work 2 2/3 hours to make that. Fortunately he can buy a four pack of 100 w replacement bulbs for about $12, and get his payback in a lot less time (considering he'll need to buy several incandescents over the next year). Once he's switched over to CFLs he can much better afford to replace them with LEDs as they fail, because he's saving so much on electricity. Of course he may opt to continue with CFLs until LEDs come down a little more.

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  2. It has its places by Mal-2 · · Score: 3, Informative

    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.

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    1. Re:It has its places by jonsmirl · · Score: 2

      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.

    2. Re:It has its places by swb · · Score: 2

      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.

  3. No applications in Telecom by Shatrat · · Score: 2

    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.

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  4. Molecularly interesting, applications not so much by dsgrntlxmply · · Score: 2

    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?