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Lighting The Future: Lasers And (Wild) LEDs
Effugas writes: "Thank Memepool for pointing everyone towards The LED Museum, an absolute geek haven if there ever was one. The Museum archives, tests, and describes the multitude of LED types out there, from Ultraviolet to Turquoise to Infrared--and, most amazingly, true full color LEDs! Apparently, I wasn't the only tech drooling over the possibilities that these devices could be put to use towards: Color Kinetics threw 75 of 'em into a spotlight can and added a surprisingly versatile digital controller with external interfaces. The result: A 16.7 Million Color Programmable Spotlight, for $500US." This is an incredible site; I look forward to when the full color LEDs (and that spotlight - Yow!) are a lot cheaper. And unaccountably, Effugas has linked that "A" to something awful.
mindpixel writes: "Sandia National Laboratories is reporting the demonstration of the first UV microcavity laser which could be used to replace gas-filled fluorescent tubes in home and commercial lighting applications. Successful penetration of the lighting market by this and LED technology by 2025 "should translate [globally] into cost savings of $100 billion a year, power generation capacity reductions of 120 gigawatts, and carbon emission reductions of approximately 350 million tons per year (assuming that all the savings come from coal-fired plants)."
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On the LED subject, I was at a Fossil store the other day and they were selling LED watches -- the ones with red numbers that you had to press a button to see...what was that, 1978 or so?
:-)
Twenty bucks, and it was even about the same size as the old ones (must have put lead or something in there to simulate the weight
I've got a few flashlight bulbs made from big LEDs - they're only red and orange, but they're pretty bright, and they can last about a week with a pair of D batteries, if you accidentally leave it on the whole time. (Of course, now I need to get new batteries...) Instructions to make your own are Here.
If you want your own personal LED flashlight, you can check out Photonlight. Way cool LED flaghlights that are visible for one mile and not much bigger around that a quarter.
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This is not the sig line you are looking for... -- Old Jedi Sig Line Trick
These SLEDs (Sound and Light Emitting Diodes) work in much the same way as a normal LED - spontaneous emission of photons from a forward biased p-n junction. But in the SLED, some of the photons of light are redirected through a resonant liquid crystal cavity, which causes vibrations of the resonant cavity at harmonics of the photon frequency. By changing the voltage applied to the liquid crystal cavity, different resonant points can be found and thus the frequency of the sound can be altered.
The researchers believe that this technology can be used to produce laptop screens which produce sounds from the screen itself, without the need for unwieldy speakers. They are also working on using lower frequencies, so that touching an image on the LED screen will produce a tactile sensation, as if you were touching the object in the image itself.
There's more stuff about SLED technology at the website of the journal Science.
two MIT alums built a 25' tall LED tower for Burning Man 2000. very impressive, both technically and artistically.
Cretin - a powerful and flexible CD reencoder
I rigged up a color-programmable fishbowl full of Christmas lights (RGB) through three dimmer switches for the same effect, much cheaper... I have noticed, however that there is a bit of a heat problem. I wonder whether LEDs would be any better in that regard.
Incandescent bulbs (Christmas lights) use a tungsten filament heated to white hot inside a vacuum.
A natural by-product of this is heat.
(Actually, truth be told, a natural by-product of an incandescent bulb is *light*; most of the energy is wasted as heat.)
A Light Emitting Diode is based on the concept that when some semiconductor PN junctions (ie. diodes) are forward-biased, they convert the energy lost to their forward voltage drop into light.
LED light actually comes from the semiconductor junction itself; it's highly efficient (85% or more), highly color-stable (the color emitted depends on the doping of the junction), has none of the thermal inertia issues associated with tungsten filaments (ie., look at a car with tungsten tail lights and an LED third brake light), and is virtually impervious to mechanical shock.
The LED is the way of the future. Your fishbowl would benefit.
I'm not sure about stagelights, though. I used to work in the sound/lighting/professional video field; I don't know how I'll like stagelights that don't feel *warm* when they shine on you!
Although, I'd never have to dig out the asbestos gloves and climb a ladder to change a hot quartz bulb during the 10-minute intermission or fart around swapping gels...
Hey, is there a Linux version of the Color Kinetics software out there? I'm just wondering, when Windows blue-screens, do their cans change to blue in sympathy?
Either way, these guys are set to give Intellibeam, RoboScan, etc. a run for their money. Most of the times I ever used those, it wasn't for the tacky little gobos or the fact that they'd follow a target: it was because they changed color *quickly*, certainly faster than conventional cans with a gel reel setup.
Fire and Meat. Yummy.
Anyhow, twice I accidentally ran the power from my 5V 1A power supply directly through them. Their tops popped off instantly. The first one was a jumbo, and the top of it bounced off my glasses. Good thing I was nearsighted and had to wear glasses or it might have gone into my eye! (The second one was just an itty bitty, and nothing memorable.)
So if you're bored of microwaving AOL CDs, then get out those old junk 2400 baud external modems, rip out the LEDs, and hook 'em up to a 5 volt power supply!
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"Open source is good." - Steve Jobs
"Open source is evil." - Microsoft
Check it:
NASDAQ LED Array pix
NASDAQ LED Array Article
ABC LED Array PR
Snickersnee3: Build your own 3-watt Luxeon Star headlamp from scratch
are available from www.theledlight.com. They make single and multi LED bulb replacements that fit into standard flashlight bulb sockets. Get 10X the battery life, plus ridiculously long bulb life (100,000 hrs). They will even fit maglites. I have no idea why companies are still making flashlights with traditional bulbs-- there doesn't seem to be any downside at all! (These bulbs cost $20 more than other bulbs, but if you've ever used a maglite regularly, you know how often the bulbs burn out-- why else would they have a spare in the handle? You'll get your money's worth by saving on batteries and replacement bulbs.)
I wonder if you arranged 800x600 of these things on a grid (assuming the price drops significantly) we could actually see LED projectors in the future! Sounds like a promising alternative to LCD, huh? Then maybe I can watch projected movies on my big loft wall without spending US $10,000.
Uhhh... No. If you made an array of LEDs and wanted to project them, you'd still need a lens.
To do it more reasonably, just make the 800x600 grid direct-viewable in whatever size that you want.
Problem 1: Average current to each LED is, let's say, 15mA. 800x600x0.015A = 7,200 amps. Evidently, this is going to have to be multiplexed somehow. (Oh, yeah, that's 7,200A *per color*, since I didn't multiply that number by three for each of the primary colors. (I assume you want each pixel to be three color.)
Assuming the average forward voltage drop per LED is 2.0V, that's a total consumption of 14.4kW. With the cost of a kWh of electricity where I am hovering around $0.06, watching the X-Files would cost me $8.64 in electricity. Per color! ("Maw, we's is goan' hafta winna lottery before we is can afford ta turn on th' whole TV set... 'ntil then, it's Jerry Springer 'n green only.") And that's just for the LEDs, not the support electronics.
Problem 2: Let's say these are three-color T-1 3/4 LEDs. And let's say that you've somehow figured out a way of wiring them to each other that doesn't occupy any display real estate.
A T-1 3/4 LED is about 1/4" in diameter. If you have 800 of them in a row, that's gonna be 200 inches long. 16.66 feet. 600 LEDs tall: 150 inches; 12.5 feet. A 16.6 x 12.5 foot screen. Or, using Pythagorean Theorum to figure out how they'd advertise it if it were a TV set, 20.78 feet diagonally. 249.36 Viewable Inches! On Sale Now! (Got space for it?)
LEDs vary from lot to lot, factory to factory. Blue on one side of your display with be different from the blue on the other side. At the same time, it'll be difficult to get your driver system to be adjusted flat across the entire color spectrum. You will have color purity issues. Look at a big LED display board in a public place now; few of them even approach the scope and resolution that you're talking about. And they're all spotty. There's a gorgeous example on the Paramount Theater at Toronto's Richmond and John Streets.
Finally, 800x600 is 480,000 LEDs. Each one is gonna cost you at least a buck (three color T-1 3/4), even in quantity. Each one is going to take you at least 30 seconds to solder into place (realistically, doing it by hand). Got 240,000 minutes (that's 4,000 hours; 166 days)? And we haven't even looked at the support electronics.
Just wait another 20 years or so until a stadium somewhere is being demolished, and scoop the JumboTron out of it. They're not LED-based, they don't have the same resolution, but they're pre-built and they look really good.
Fire and Meat. Yummy.
The programmable spotlight looks like it'd be great as a darkroom light - you can turn it to red whenever you're ready to work, and back to a more natural light when you're finished.
Also, at 11 years of rated bulb life it might make a really good home lamp! Plus you have the bonus of whatever lighting color suits your mood.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
The 30 watt (equivalent) bulb is $190. I was going to scoff about how that was WAY to expensive but then I did the math:
Assume I live for 50 more years. Further assume that I have the light on 8 hours/day, 365 days/year. That's 2920 hours/year * 30 watts = ~87kWh/year. Times 50 years is 4380kWh. Multiplied by, say, $.06/kWh is $260! Add the money for the bulbs themselves (which keep burning out) and we are talking about $300 for lifetime use of a single bulb! (unless someone points out the sure-to-exist flaws in the above)
The LED bulb uses 1/10th the power so the 50 year cost must be $26 added to the $190 one time cost is just $220.
Problems, though:
1) I couldn't find anything higher than a 30 watt (equiv) bulb on their site. Does nothing higher exist?
2) The cost isn't amortized over my lifetime. This causes two subproblems:
a) If I move, I better take the bulbs with me or I don't reap the savings
b) The cost is all upfront--meaning I have to buy costly bulbs when I am young and (certainly) poor so I can save money when I am old and (hopefully) rich.
Therefore, prediction: Until using LEDs becomes either cheap or mandatory, only ultra-enviro's will be using them.
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An abstained vote is a vote for Bush and Gore.
Non-meta-modded "Overrated" mods are killing Slashdot
(Hey Ryan! Here's your proof!)
If they can have a few of these in a "can" to make a multicolor spotlight, what would be the chances of using 3 of these just like the 3 individual colored lamps used in front projection TV's? Would it be cost effective if it could be done?
No. The issues again are resolution, the physical size of the LEDs, the current required t feed them, and the cost of the LEDs and their driver logic.
Considering first off that an LCD display is basically a large integrated circuit, if LEDs were made as large ICs like this, it would be possible. But an LCD pixel really uses no current: like CMOS logic, it's a potential-operated high-impedance device. There's actually very little energy used; it just passes light from the backlight selectively. However, an LED matrix panel like you'd need for this would still be a current-operated device. The device would generate its own light - and heat. While an LED is a very efficient way to make light, they need a certain threshold current to be useable. This threshold current is sufficient that the display would guzzle huge amounts of power.
There are ways to multiplex the display to get around that, but by the time an LED array is big enough in resolution to compete with today's technologies, the driver circuits are incredibly large, with huge component counts. While CRT drive circuits are unweildy (flyback, deflection, cathode drives and stuff), they're nothing compared to what this thing would require. Sure, the LED matrix wouldn't need a 30kV power supply to drive an accelerating anode (like an CRT does). Instead, the LED matrix would require drive circuits that were capable of supporting 307,200 LEDs. And that's for a paltry 640x480 display in only one color. You'd need 921,600 LED junctions for 640x480 with RGB.
The only way it would be practical to build this would be a large LED matrix as a single array. Production yield rates, current requirements and cooling are the issues that I see with that. If you think a PIII Xeon is a pig, wait 'til you see a single chip that big.
Alternate video projection technologies are far more refined:
CRT projectors (like Sony's venerable VPH-1040 and 1270, Zenith/Aquastar, some Barco models) offer excellent resolution, good brightness and are flexible to a wide variety of different input signals. Downside: cost, size, limited lifespan of expensive projection CRTs, limited portability due to need to adjust convergence with each time they're moved relative to the screen.
LCD projectors (most of the little table-top projectors being offered in computer magazines) offer portability because of small size and weight, as well as the fact that they're no tougher to set up than a slide projector. Disadvantages: limited resolution, don't adapt very well to being used at varying resolutions, limited brightness due to technological limits on how hot you can make an LCD sheet, uses conventional projector bulb which usually fails at the worst possible time.
Finally, the Hughes/JVC Image Light Amplifier video projectors. These things are nuts. They combine the best features of a CRT projector with more conventional projection technology. They were developed for NASA to use at Mission Control in the 1960s, and have been continually refined ever since. Can display huge images visible in full sunlight. Very flexible as to resolution of the incoming image. Problems: cost over $500,000. The last one I set up took a 240V 200A power drop. Has a large xenon projector light that takes 20 minutes to warm up, relies on expensive and limited-life projection CRTs to draw an image onto special LCD "image light amplifiers". Fragile optics to split light from xenon projector bulb, pass it through three ILAs which serve as the screens for the projection CRTs, filter it into primary colors and then shoot it out three separate lenses to the screen. Weighs over 600 lbs. Requires convergence and purity adjustments to align it to the screen. Causes severe eye damage if you accidentally look into any one of the lenses. Suitable only for long-term installation in very large facilities.
Even so, to put the LED projector into perspective, the Hughes/JVC projector is far better adapted to your living room.
Biggest I've ever had in my living room was a Sony VPH-1272. And that was a gorgeous floor-to-ceiling movie. Too bad it was before the DVD came out, and I had to cope with VHS.
Fire and Meat. Yummy.
You're right about colored LED's being more efficient than the white ones. You can also get colored LED replacement bulbs for your flashlights at www.theledlight.com. Their prices and stats are unusual too-- they have white LEDs at 18,000mcd, green at 30,000, and blue at 9,000. Additionally, the white, blue, and green LED replacement bulbs they sell cost exactly the same ($24.35). I know that at your local electronics shop they will charge you an arm and a leg for blue LEDs-- these are possibly (although I couldn't find the info he mentioned) blue LEDs with some sort of coating on them. Anybody got more info?
Indeed. The old style whites were four chips giving roughly equal output of red, green and blue. The new whites are blue chips with a yellow phosphor coating. Depending on how much you pay for them you can avoid the bluish ring or yellowish center some of these new whites can be heir to.
Snickersnee3: Build your own 3-watt Luxeon Star headlamp from scratch
I used to work in an electronics supply shop about ten years ago (Electro Supplies, Stockport, UK). I used to like to mess about with various LEDs to make window displays. Some of my favorite simple ones:
:)
/. is taken from has a link to a pretty cool LED oscilloscope:
/ articl3.htm
:)
-Spelling things out using 7 segment displays.
-We used to sell a simple kit that ran seven LEDs off a digital counter IC that produced an effect like the front of KITT from Knight Rider, or a Cylon from Battlestar Galactica. A cool variation on this was to replace the visible-light LEDs with infra-red ones and have the kit hidden somewhere in view of a CCTV camera - you couldn't see anything when looking around the shop, but the camera, being IR sensitive, showed it up brilliantly - we confused a lot of people with that one!
-Wiring a bunch of flashing LEDs (built-in flasher ciruit, operates off 12vdc) in parallel and mounting them in a line. Because none of them flash at exactly the same rate, you get a great 'visual beats' effect (I don't know the proper term). They would flash at seemingly random rates, and then patterns would emerge - alternate flashing, all flashing at the same time, lights running from one end to the other, running from the centre to the ends - I still like to trance out to that effect (you get the same thing with a line of cars with their indicators flashing, or a line of those flashing bollards around roadworks).
The Memepool entry that this
http://www.geocities.com/SiliconValley/Lakes/7156
I remember reading how to build an even cooler one that used a vertical strip of LEDs, and a mirror mounted on a motor that reflected the LED strip. The speed of the rotating mirror was the timebase and the LED strip showed the amplitude!
[Happosai]
This comment looks like a hoax. It contains fake url in it. It claims nonsence clear to enyone knows that light frequency's 1E12 times greater than one of sound. Nevertheless it's moderated Interesting and Insightful, by two different moderators I suppose.
I believe Sig11 is right: /. moderation is broken.
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Every secretary using MSWord wastes enough resources
Does this mean I can get true color images in my LiteBrite?
has none of the thermal inertia issues associated with tungsten filaments (ie., look at a car with tungsten tail lights and an LED third brake light),
I don't understand. Do you mean that hot things stay hot?
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Men with no respect for life must never be allowed to control the ultimate instruments of death.
GW Bu
Check out SLOAN optoelectronics they have a .PDF outlining LED replacement for incadescent light
INCANDESCENT REPLACEMENT LED LAMPS. I found these thru Allied Electronics catalogue, page 679. They retail for around $10
This is one example out of many, I don't work for Allied nor Sloan; Feel free to look this up in any electronic component shop like Future-Active etc...
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Vote Inanimate Carbon Rod in 2000
As cool as it would be to use something like this in a theatrical production. I don't think it's feasable until they pump up the output.
The specs read as: 46 footcandles at 3ft
15 footcandles at 6ft
6 footcandles at 9ft.
A 23 degree source four (from ETC, one of the best theatre lights around)
does 15342 footcandles at 3ft
3835 footcandles at 6ft
1704 footcandles at 9ft.
So as much as infinite color control would be nice, I need more power or no body in the audience is going to see it.
For those know in-the-know, Something Awful is an often hilarious page of humor written by one Rich "Lowtax" Kyanka, and is somewhat game-oriented in much of its humor. One featured page is "Cranky Steve's Whorehouse" which reviews Quake (and its descendants, relatives) maps that are truly and hellaciously awful. One hallmark of bad maps, and this one in particular is the overuse of colored lighting.
So imagine what happens when everywhere you go, the same type of people who write these godawful Quake maps get the bright idea to use these multicolored lights in real life?
Right
-Tal
Shake and shake
the ketchup bottle.
None will come,
and then a lot'll.
LED != LCD
// for that matter
Science_mag.find( "SLED" ) == -1;
An LED laptop screen would be interesting, though. Just not very good resolution-wise.
ZZ
Actually, a friend of mine works at ColorKinetics and the patent they have is on the specifc process they use to control the color of the LED, not the full color LED itself. To me, this seems to be a reasonable patent, as the process was a new concept a few years ago, and are now focusing their business on developing the applications of this technology, partiuclarly in te entertainment and retail industry. If I'm not mistaken, this is the sort of thing that patents are supposed to allow new companies to do. If you've ever actually seen on of their rigs in action, I think that you would agree that they have come up with a clever device. What this will do to the process of color application is pretty amazing.
He used one or more of these DSPs, a whole lot of 'spotlight' LEDs and an infrared port to build a mirror-ball like LED light bulb that plugged into a regular house light bulb socket.
The OS (etc) was beamed to it via IR, and since the LEDs were multi-level (ie grey-scale) he could dynamically project bitmaps onto the surrounding walls, as well as doing other special effects. I think it had a small mic so it could pulsate effects to music.
Way cool, but too expensive (at the time), so only the prototype got built.
[Antispam] Kill the x in my email address to reply
main() {1;}
You forgot one:
Indeed I did, thank you.
Digital Light Projector - brand name for a technology developed by TI. Basically, you have a chip with an array of micro-mirrors that you use to deflect light from a projector. These are a lot brighter than LCD displays.Yeah; I've heard of them, but I've never actually seen one. It sounds like it takes the best of the Hughes/JVC (xenon bulb for the main projection), arrayed video device like an LCD display (oh well, can't be perfect), and adds to that the fact that the display element neither creates the light (like a CRT projector), nor does it have to transmit it (like an LCD projector). It strikes me that the fact that the light doesn't actually pass through the imaging element would save it from a lot of heating. Even if it does heat up, since it's reflective, you could spackle a huge heatsink or even a liquid cooling system to the back of the reflective imaging device, if you need to pass a lot of light across it. This is an exciting projector.
They were kind of pricey ($50k), but are starting to make inroads in the portable presentation projector market.$50k is about what a new VPH-1270 was going for, last time I was involved with them. (Yeah, I'm sure they've been discontinued now.) So, that sort of money doesn't seem to be too badly out of line. I assume it's a single imaging system, too, meaning that you wouldn't have to do convergence of the individual colors.
Last time this came up, I found some models for $9k-$5k.It sounds to me like these things are basically in competition with the LCD projectors, but are brighter because the imaging device would be less concerned with heating. I'd expect they'll still have many of the same resolution problems as an LCD display (ie. ever try to run 640x480 on your 800x600 notebook screen?), but with a few advantages that will make them take over. Eventually. There's inertia to overcome.
It's stuff like this that reminds me why I've always loved Texas Instruments.
Fire and Meat. Yummy.
What's really cool is somebody *noticed* I credited Memepool. I discovered the site from one of the rare times they were credited, and I've been impressed beyond words ever since.
Mind you, I didn't flat out copy the Memepool story--but I'd have never found out about the Color Kinetics product line without 'em.
--Dan