Polymers Brighten Hopes For Visible Light Communication

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.

Comments

Heck, I'll settle for white light

[davidwr]

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.

Re:Heck, I'll settle for white light

[Anonymous Coward]

No, you won't, because what you want is available, minus the unrealistic requirements that you have only to justify why you won't switch.

Re:Heck, I'll settle for white light

[Anonymous Coward]

$20 before sales tax or shipping for the Cree ... which is 4 hours of labor, after tax, at minimum wage, or 5 days of grocery budget for a single person who is living on minimum wage. I don't think it's affordable yet, when compared to a $0.60 incandescent.

Re:Heck, I'll settle for white light

[Anonymous Coward]

Where have you been? Exactly what you're asking for has been out for almost two years.

Go pick up a Cree or Philips bulb with "Warm" on the package.

You'll get an instant-on bulb with a color cast every bit as "Warm" as any incandescent you've ever seen. Only it will consume less than 1/10th the power, last dozen of times longer. Don't go overboard, though. They tend to be reeeeeealy conservative on the "Equivalent" light rating. If you go by that you'll likely end up with a bulb way brighter than you're used to.

Don't take my word for it. Check out this guy's youtube channel.

https://www.youtube.com/user/electronupdate/videos

He tears down and checks the performance of modern LED lights. The stuff that's been coming out since early 2014 is vastly improved and a whole lot cheaper. Cree, in particular, really hits sweet spots when it comes to price/performance/build quality.

Re:Heck, I'll settle for white light

[Anonymous Coward]

Yes, someone who thinks they need to pay $20 for an LED bulb would be expected to fail at calculating that that would still save them money. Par for the course, don't worry.

Re:Heck, I'll settle for white light

[hey!]

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.

Re:Heck, I'll settle for white light

[An Ominous Coward]

Yes to Cree, no Philips. Too much IP lawyering at Philips.

Re:Heck, I'll settle for white light

[Anonymous Coward]

The Crane LED isn't comparable to an incandescent. LED lights create a lot of bright directional light, which is annoying.

Re:Heck, I'll settle for white light

[adolf]

The 100 Watt-ish LED.

The high-CRI LED.

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

Re:Heck, I'll settle for white light

[Anonymous Coward]

I like LEDs and use a lot of them (I don't care about the energy savings much, but I like not having to change them as often, especially the recessed ceiling lights I have to get a ladder for). But it's total BS to say they're really conservative on the equivalent light ratings; that's hardly worth looking at. The only reliable guage is to look at the rating in Lumens; it's the only brightness rating the manufacturer really has to stand by (because "equivalence" is subjective). A soft white 60W incandescent has about 750-800 Lumens, but I've seen plenty of LEDs trying to claim 60W equivalence that only put out 500-600 Lumens, sometimes even as low as 400. I haven't changed over in bulbs for ceiling fans or several other fixtures that require ceiling-fan size bulbs either, because it's virtually impossible to find a compact enough LED that puts out over 300 or so Lumens.

LED is getting there, but there's still work to do, especially for things other than standard form-factor lamp bulbs and recessed overhead lights. As far as I know, for example, there's absolutely no LED that can take the place of the 35W PAR16 120V bulbs in the reading light board over my bed (they'd have to be dimmable, but I don't know of any that are even non-dimmable).

Re:Heck, I'll settle for white light

[Anonymous Coward]

This ceiling fan A15 bulb puts out 500lm. Incidentally Home Depot claims 60W equivalence. You'll find that the "standard" lumens for a given wattage of incandescent bulb vary with the style and size of the bulb. 810lm is the output of an A60 incandescent 60W bulb, but other styles give less light, which is immediately obvious when you consider the amount of light absorbed by the relatively bigger lamp base of a smaller bulb, for example. Particularly for ceiling fan bulbs, higher vibration tolerance probably means thicker filaments and lower efficiency as well, so you are probably getting 60W equivalence with that bulb, but A15 60W, not A60 60W. Buying a small LED bulb with the same lumens as the highest output incandescent bulb, regardless of size, will probably get you a significantly brighter light than you were shopping for.

You'll have to be more specific about the reading light, or is this what you're looking for: Sylvania 72677 PAR16 LED 8W 120V dimmable.

Re:Heck, I'll settle for white light

[Anonymous Coward]

Please stop buying century old wasteful crap technology just for the sake of being a contrary little bitch.

Re: Heck, I'll settle for white light

[Anonymous Coward]

Neck too long for the Par16, more like
http://t.homedepot.com/p/GE-35-Watt-Halogen-PAR16-Curio-Flood-Light-Bulb-35PAR16CURIO-PQ/100493734/

Ceiling fan bulb is better than I've seen, and catching up. When I can find them in 3000k vs the 2700k, which looks kind of sickly to my eyes, I'll probably start switching those as well.

Re: Heck, I'll settle for white light

[Anonymous Coward]

Well, there are these and these. No idea if they're any good though.

Re:Heck, I'll settle for white light

[Blaskowicz]

I got one LED bulb, and it was to put it over the shitter - perfect, as the fixture sometimes flickers for an unknown reason and a LED doesn't care about it. So one bulb gave me a decade+ of shitter lighting investment, no more failures.

For the bulbs which would most need replacement - they immediately light up the room in such a way you can see shit everywhere and look for lost keys etc. - the LED bulbs would be a crappy replacement, because the cost is multiplied and there's no upgrade in lighting performance.
Availability of affordable and working 2700K LED bulbs is nice, but 4000K or 5000K with a wide and full spectrum would be nice (as opposed to spiky spectrum of CFL). 2700K with a good spectrum (I assume?) means it won't do any better job than incandescent.

For "ambient" lighting which does runs for hours on, I already have CFLs there, I give less shit about the spectrum and it's not like I have a choice there.

Re:Heck, I'll settle for white light

[Blaskowicz]

You're right, but how silly that we can't buy a 100W LED bulb (or even a 60W) yet we can buy a freaking 100000 watt car and waste a ton of power with it. Go figure.

Re:Heck, I'll settle for white light

[Blaskowicz]

*light bulb I meant, sorry.

Re:Heck, I'll settle for white light

[Anonymous Coward]

I used to know somebody like you. I wonder if he's grown up yet.

Re: Heck, I'll settle for white light

[Anonymous Coward]

$.375/kWh? That's outrageously high...

Re: Heck, I'll settle for white light

[hey!]

I was figuring .125/kWh for 30 hours/week.

Re:Heck, I'll settle for white light

[Agripa]

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.

The economics for the more expensive bulb fall apart when replacement costs are considered when they both fail considerably before their rated lifetime do to dirty power. Bulbs where I am have a half-life measured in months. The only bulbs that last are on an online UPS.

Even California noticed that this was a problem because the high efficiency bulbs did not last nearly as long as marketing predicted.

One word, son...

[Anonymous Coward]

Plastics.

Re:One word, son...

[grimmjeeper]

Exactly how do you mean?

soft white?

[Anonymous Coward]

Frost post?

It has its places

[Mal-2]

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.

Re:It has its places

[jonsmirl]

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.

Re:It has its places

[Anonymous Coward]

How is this line-of-sight only? Find me one pitch black shadow in your room where you would want to use a mobile device. Also, slightly unrelated, I think plastic optical fibers could be a useful thing, because there's no expensive splicing involved, and with more research into visible light data transmission, they could replace copper and fiber for very short distances where electrical isolation is desired.

Re:It has its places

[Anrego]

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?

Re:It has its places

[bondsbw]

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

Re:It has its places

[swb]

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.

Re:It has its places

[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 evenly over a room.

The most expensive, troublesome, failure prone, heat producing part of the bulb - The AC/DC converter can be done away with in exchange for a DC-DC converter that's already bog standard in any sort of electronics that requires multiple voltages. Likely smaller, and more efficient too. Better to handle AC/DC conversion back at the POE switch. (One large efficient well built converter in an environment where it can be thermally managed is likely much better than dozens of tiny ones in enclosed spaces up in the ceiling panels)

Re:It has its places

[Applehu Akbar]

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.

Re:It has its places

[Anonymous Coward]

If it is just using two symbols to send its signal, then ~300 Mbit/s is ~3 ns a bit, so about three feet. If your room has reflections that differ by a couple of feet falling on the various surfaces, you'll have multi-path problems.

Re:It has its places

[Mal-2]

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.

Re:It has its places

[Anne Thwacks]

You are right. Visible light is proven harmless, unlike the unnatural Infra-red that was unknown to mankind before the transistor was invented.

Re:It has its places

[Blaskowicz]

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 it. Wifi 60GHz will be pseudo line-of-sight (with some multipathing) but it's not there yet ; I don't know about the cost in $ and power. Will be a ton faster than that visible light technology but won't work on tiny cheap devices.

Re:It has its places

[Blaskowicz]

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 existing cabling and lightbulb sockets!, but performance may break down with more than a handful devices on the network, and in some situations it doesn't work or doesn't work well, or it leaks out to the neighbour. PoE would be immune to these latter issues.

No applications in Telecom

[Shatrat]

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.

Maybe stupid question of the day

[argStyopa]

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?

Re:Maybe stupid question of the day

[Shatrat]

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.

Re:Maybe stupid question of the day

[SethJohnson]

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 might reduce energy consumption.

Wifi has a pretty considerable fixed cost. Similar to RFID. It might be possible to reduce that expense with a non-radio communication channel. Imagine if your toll tag shot an LED flashed unique signal to a road sensor... It might carry a cheaper unit cost than the typical RFID toll tag schemes.

The developers of this aren't thinking it will replace wifi where wifi is good. They're looking to fill the gap where wifi is bad.

Re:Maybe stupid question of the day

[Charcharodon]

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 would be nice for your smart phone. Just line it up at the data point on the other device you are connecting to and you'd have a fast direct connection between devices.

I can see this being very useful in situations that can bring Wi-Fi and cell service to it's knees. Large public venues, airports, etc. I've on many occasions wanted to weep trying to use Wi-Fi points that were melting under the number of people trying to connect to them with smart phones. Having a hot spot under every overhead light would be a Godsend.

Using this instead of a cabling run would be handy when you need to route your network across an area but don't what wires all over the place and Wi-Fi wouldn't be practical.

Re:Maybe stupid question of the day

[Richy_T]

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.

Re:Maybe stupid question of the day

[Shatrat]

Seems like a solution looking for a problem to me.

People said the same thing about the laser for decades.

Re:Maybe stupid question of the day

[bugs2squash]

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.

Re:Maybe stupid question of the day

[Richy_T]

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.

always enjoy a Wrestling Reference

[turkeydance]

http://en.wikipedia.org/wiki/T...

Why have I seen this before?

[mitcheli]

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?

Re:Why have I seen this before?

[Anonymous Coward]

That wasn't white light, like you would use for indoor lighting. If you want to modulate the normal room light to transmit data, you need a white light source which can be modulated with a sufficiently high frequency to allow for acceptable throughput. White LEDs are a combination of a blue LED and yellow phosphor, which together create a spectrum that is close enough to that of an incandescent light to be used as a room light. The blue LED in that light can be modulated quickly, but the phosphors which are used today can't. The intensity of the yellow light emitted by the fluorescent plastic mentioned in the story follows the blue light source more quickly and thus allows more data to be transmitted per second.

Re:Why have I seen this before?

[Anonymous Coward]

Furbies used acoustic networking. Apparently photodiodes cost too much.

Re:Why have I seen this before?

[Howitzer86]

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).

Forget Polymers ...

[Cmdr-Absurd]

...I'm holding out for transparent aluminum.

Re:Forget Polymers ...

[sh00z]

...I'm holding out for transparent aluminum.

http://en.wikipedia.org/wiki/Aluminium_oxynitride

Molecularly interesting, applications not so much

[dsgrntlxmply]

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?

Future Brain Exploit

[Anonymous Coward]

I can just picture a follow-up articles in a few years: "Blackhat presenter demonstrates induced epilepsy in audience"

NFC instead of WIFI?

[grimmjeeper]

I'm guessing with the short distances this is a replacement for radio frequency near field communication rather than a substitute for wifi.

Geeks Everywhere begin buying black drapes

[Anonymous Coward]

For, uh, evening internet browsing, as it were.

Visible Light Communication

[msauve]

You mean, like a readin' and a writin'? Pretty fancy stuff, there!

Re:Visible Light Communication

[Anonymous Coward]

More like "One if by land, two if by sea."

Err... IR?

[Anonymous Coward]

What's so much better about this vs IR?
I know we only had 4Mb/s on FIR IRDA, but was that a limitation of the IR or just of the modulation scheme?

Same tech announced every year since at least 2010

[Walking The Walk]

Haven't we seen this technology before on Slashdot? Yep, here we go: 2014, 2013, 2012, 2011, 2010.

Re:Molecularly interesting, applications not so mu

[Thagg]

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 research to talk about things that would happen in stars of unconventional configurations; when they were really broadcasting to the USSR that the US scientists had solved problems with hydrogen bombs that put them far ahead.

Re:Same tech announced every year since at least 2

[Thagg]

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