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White LEDs for a Brighter World 377

deepfry writes "CBC radio today featured an interview with Dr. Dave Irvine-Halliday, an engineering professor at the University of Calgary, who's developed a home lighting system for the developing world using a combination of white LEDs, pedal generators and rechargable batteries. This type of "pico-power" can make a huge difference in the lives of villagers in rural areas where being connected to a power grid is not an option and probably never will be. Read about the Light Up the World project and make a donation."
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White LEDs for a Brighter World

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  • Light up? (Score:3, Funny)

    by Anonymous Coward on Wednesday May 08, 2002 @02:58PM (#3486526)
    "Read about the Light Up the World project and make a donation."

    It ain't no joke, I'd like to buy the world a toke...
  • by rschwa ( 89030 )
    uh, ok. $1 a piece for a .1 watt bulb. sounds great. Exactly how many would I have to gang to be able to read my newspaper?

    • uh, ok. $1 a piece for a .1 watt bulb. sounds great. Exactly how many would I have to gang to be able to read my newspaper?

      Because, while that bulb only consumes 0.1 W, it gives off as much light as a much brighter incandescant bulb. I didn't see figures in the article, but one would figure that it's better than what you get with flourescent lights.

      I've replaced many of the lights in my apartment with compact flourescents. Typically, a CF bulb that outputs as many lumens as a 100 W incandescant bulb will only require 20 - 30 W. Reading a newspaper with a 20 W incandescant isn't practical, but the 20 W CF is more than bright enough.

      b&

    • Re:too expensive. (Score:5, Insightful)

      by jmv ( 93421 ) on Wednesday May 08, 2002 @03:09PM (#3486606) Homepage
      uh, ok. $1 a piece for a .1 watt bulb. sounds great. Exactly how many would I have to gang to be able to read my newspaper?

      Maybe not that many... Remember that the efficiency of a normal light bulb is very very bad, since most of its energy is dissipated as heat. I wouldn't be suprised if a 100W bulb only produced 1W of visible light.
      • Re:too expensive. (Score:4, Informative)

        by Fulcrum of Evil ( 560260 ) on Wednesday May 08, 2002 @03:27PM (#3486713)

        I wouldn't be suprised if a 100W bulb only produced 1W of visible light.

        It's usually around 3W. IIRC, flourescent runs around 25W.

      • Bingo (Score:3, Insightful)

        by SeanAhern ( 25764 )
        You're right on.

        With as long as we've had "100 watt" and "60 watt" lightbulbs, people have gotten it into their heads that the wattage rating is a measure of the light output.

        I would have to work out the physics to see if it's possible, but I don't immediately see any barrier to a .1 watt bulb of some new technology giving the same light output as a 100 watt incandescent tungsten filament bulb.
    • Here's a quote from the Web Site:

      I should point out that a single WLED provides sufficient light to easily read a book or to study with. My wife, who wholeheartedly assisted me in Nepal in 1999, has amassed ample field evidence to support this last statement. It is very significant to the developing world that these wee marvels of technology can effectively light an entire kitchen table area using less than one watt of electrical power and there are none of the attendant dreadful pollution and fire dangers associated with the use of kerosene lamps.

      Please read more of the web site before commenting. /Don

    • Re:too expensive. (Score:5, Informative)

      by suwalski ( 176418 ) on Wednesday May 08, 2002 @03:22PM (#3486677)
      What you do not realize, judging by your post, is that the average 20 mA white LED looks brighter than the average 40W 120V bulb. A single one makes an excellent flashlight. A few of them together make an awesome lightsource.
      • Re:too expensive. (Score:3, Interesting)

        by kcbrown ( 7426 )
        The measure of what it "looks" like should be how much light is reflected off an object at a given distance, not how bright the bulb itself looks. The latter is very misleading since the surface area of a typical LED is many times smaller than the surface area of a typical light bulb, so a LED can "look" much brighter compared with a 40W bulb even if the total light output is much less.
  • by TrumpetPower! ( 190615 ) <ben@trumpetpower.com> on Wednesday May 08, 2002 @03:02PM (#3486553) Homepage

    Why limit something like this to the developing world? If the developed world used low-power, high-efficiency lighting, we'd dramatically reduce the consumption of energy and non-renewable resources. If these lights are cheap enough for the poorest on the planet to consider using them, there's no doubt that they'd save the industrialized nations amazing amounts of money, as well.

    Frankly, I suspect we'd do more for the developing world by adopting this sort of thing for ourselves--which is not to say, of course, that we shouldn't encourage them to skip our wasteful ways in favor of the right way to do things.

    b&

    • The problem with white LED's is that they can be inconsistent in their color. If you will recall they are made by placing a small amount of white phosphorus on the light emitting element of a high powered blue LED. When the phosphorus is bombarded by blue photons it emits photons that make up the rest of the visible light spectrum. The issue with manufacturing white LED's is that it is difficult to make white LED's that are consistent in their color and brightness. Too little phosphorus and the LED's light can look a little blue. Too much phosphorus and the LED is dimmer than a good white LED. If the phosphorus is placed off center the light produced by the LED varies in color and brightness. Of course their are grades of LED's, but the higher quality LED's cost more. Some people in developed nations might find these quality variations unacceptable. Now don't get me wrong there are some places where I could stand the inconsistencies of white LED's, like in a garage, a hallway, or some other room where tasks are done that do not require the color to be consistent. I would find it annoying to have inconsistent light in some place where I would be reading though. For that matter while I cannot be sure as I do not use makeup, applying makeup might be difficult in light that has color and intensity variations.
      • Yup they would be great as a porch light or outdoor lighting.

      • applying makeup might be difficult in light that has color and intensity variations

        Oh, I agree. Theres nothing worse than going out wearing blue lipstick when you meant it to be purple. Really makes you look like a prat... ;-)
      • My PC has plenty of red and green LEDs, so why both with this phosphorus addition to try to make it white? Doesn't blue+red+green = white?
        Just stick 50 of each together in interleaved and let them blend to white..
        What I dont really get either is why these lights for sale at theledlight.com cost so much? Is the cost for brightness or what? It seems that standard LEDs used in PC cases and other blinky status lights on almost anything electronical cost a lot less.
    • Go buy some now: theLEDLight.com [theledlight.com]

      My biggest problem with these bulbs is finding ones that have a nice, soft light. I don't want my bed room looking like an office. I spend enough time there as it is. Does anyone have experience with how 'pretty' the light from these is?
      • Re:Go buy some now. (Score:3, Interesting)

        by dolanh ( 64212 )
        Oh well, no modding power for me this time :)

        I partially solve this issue with the compact flourescents in my house by choosing lampshades with a warm characteristic like Japanese paper lanterns.

        As most photographers follow, the "temperature" of the light is really what determines how "pretty" you consider it. Incandescent is way down the spectrum from flourescent. I don't really know where LED is, but I imagine it's closer to the latter than the former.
      • Seems like the biggest problem is that a bulb that provides light equivalent to a 30 watt incandescent is $190!! Thats a little steep when you can get compact flourescents for around $8.
    • Frankly, I suspect we'd do more for the developing world by adopting this sort of thing for ourselves

      A quick Google search turns up The LED Light [theledlight.com], and they have a collection of "bulbs" that fit into 120 Volt AC sockets [theledlight.com] (That would be them things in yer house, at least in the US)

      Very expensive though - "36 LED bulb...comparable to a 30 watt incandescent bulb" costs $190.

      Another site I've run into in the past is LEDTronics [ledtronics.com] which looks more in line with the geek need for way too much information, and component-level purchasing. I can just see the mod case now...

  • by swagr ( 244747 ) on Wednesday May 08, 2002 @03:04PM (#3486567) Homepage
    What about fire?
    • The time cost to gather fuel for a fire in some areas is quite high. Stove efficiency is a similar topic. In parts of India the woman+children spend hours each day gathering fuel for cooking. Here is a typical article about stove efficiency [farmradio.org].

      Save the family and hour a day in fuel gathering and give them enough light to read at night and school+studying becomes a possible choice.
  • by ayden ( 126539 ) on Wednesday May 08, 2002 @03:05PM (#3486573) Homepage Journal
    I remember listenig to NPR back in November that some lighting company donated it's services to redesign the lighting for the Jefferson Memorial in Washington, DC. Apperently, part of the redesign involved using 20,000 white LEDs to light up some of the dimmer areas. They also replaced all the amber sodium vapor lights. The overall result? The Jefferson Memorial is better lit than it ever has been AND an 80% energy cost savings.
  • by chill ( 34294 ) on Wednesday May 08, 2002 @03:06PM (#3486580) Journal
    One way to bring down the cost would be to sell them in the developed world. A finished product, that could screw into a standard light socket, but use 1/100th the power to provide the same light would sell well in the U.S.

    Especially with all the noise about power shortages and rolling blackouts.

    Selling them in the U.S. and the rest of the developed world would go a long way towards creating enough demand for serious mass production.
    • Where do you get your information? Do you make it up? What makes you think that a white LED lamp that produces as much light as a fluorescent lamp would use 1/100th the power?

      White LEDs are only about twice as efficient as modern fluorescent bulbs, and less efficient then high pressure sodium lighting. They're also way more expensive to purchase than fluorescent bulbs.
      • And of course the big advantage of fluorescent tubes is that they can run of AC, which is already wired into the house, if every LED array required a transformer to fit in standard socket, the efficency of the system would drop fast.

        Personally I hate the light from flurorescent tubes, and will stick to my nice halogen lights.

        James
      • The number was a rough guess. Assume a 40w lamp uses, I dunno, 40w of electricity. Then assuming that the picture on the page was showing an actual lamp -- with an array of 10 LEDs, each consuming 0.1w of power, that works out to 1w of power.

        That right there is a 1/40 ratio. Factor in the *much* longer MTFB, the reduction in heat energy emitted, etc. and it is a damn good ratio.

        Yes, I would like to see a lumens output rating on the LEDs for a better comparison. I've seen reports of 120 lumens from a 5W white LED package. A standard 40w is 460 lumens.

        So, that is only a 1/2 ratio, which isn't good. However, factor in the much longer life and reduction in heating and it adds up.

        For a bit more info:
        http://www.eet.com/story/OEG20001212S0034
        http:// www.efi.org/articles/bulbs.html
        http://www.lumile ds.com/newsandevents/news_index.h tml?page=http://www.lumileds.com/newsandevents/rel eases/press04-14-02.htm
      • by AnotherBlackHat ( 265897 ) on Wednesday May 08, 2002 @04:59PM (#3487258) Homepage
        Last year, the numbers were something like this;

        Lumens/Watt;
        85-95: 32 watt T8 fluorescent
        60-65: standard F40T12 cool white fluorescent
        48-60: compact fluorescents
        20: T3 tubular halogen
        15-19: white LED
        17: standard 100 watt incandescent
        6: incandescent night light bulb (7w)
        6: incandescent flashlight bulbs

        The very best white LEDs are still under 35 lumens/watt, or about 1/2 the efficency of a flourencent. They have been steadily improving however, and around 2004 should surpass them.

        But not today.

        -- this is not a .sig
    • Compact fluorescent bulbs are a very good alternative. They come in many shapes and sizes, last roughly 7000-10000 hours and use about 75% less power then incandescent. I've seen 5 packs of bulbs at warehouse clubs for under $19.
      They are getting physically smaller and cheaper all the time.
  • by Bonker ( 243350 ) on Wednesday May 08, 2002 @03:07PM (#3486586)
    About a year ago, I got a kitsch keychain from a vendor who was trying to sell software to my company. We didn't purchase the software, but I have held onto that keychain.

    Let me describe it. It's oval in shape, about 3cm long by about 2cm across and 1 cm thick. Inside the body of the keychain, which is clear vinyl, you can see the mechanism that makes it so neat, which is a small watch-type battery, a very small resistor, and one of the newer white LED's. The clear plastic vinyl is red, so when you squeze the thing, it's light is very slightly pink.

    Now, here's the thing that makes me keep this around. This little piece of what I would othewise call 'crap' is brighter than my 'keychain-size' Mag Light! I can easily read by or do computer maintenance with this toy. If I had five or six of them, I could reasonably light a room for however long the batteries lasted.

    White LED's are the wave of the future, IMHO. They're cheap in terms of production and electricity cost. I also understand that they're significantly easier on the environment than incandescent bulbs or flourescent tubes. Unless you overload it with current, which I understand is very difficult since many come with tiny regulators in the form of attached IC's, they don't burn out, making replacement costs plummet.

    Make my next lightbulb a white LED
    • by dachshund ( 300733 ) on Wednesday May 08, 2002 @03:18PM (#3486655)
      You can buy a similar product here [photonlight.com]. I'm not sure exactly sure if the white bulb is an LED, but it's bright as hell and it's lasted me a couple of years on a single watch battery (with no signs of fading.)

      They also make an IR version, for those of you with night vision goggles. And no, I don't work for the company, but I'm really impressed with their product.

    • You're describing a Photon Light. You can buy them at ThinkGeek! [thinkgeek.com]

      I love them. I keep 2 on my keychain at all times. You just never know when you might need one. The last CAT5 drop I was doing, the power went out (I was working in a thunderstorm). Thanks to my Photon Light, I was able to finish the drop with no problem at all. 2 White LEDs and I had more than enough light to keep working for over an hour straight.
    • They're cheap in terms of production and electricity cost.

      Then why the hell are they so expensive? Check out the prices on available white LED replacements for incandescent bulbs, here [cetsolar.com] for example although there are other vendors. The light equivalent of a 40W bulb will run you almost $200! I'm not even certain that's worth it even if it does last 100,000 hours.

      • This [thesustain...illage.com] place offers 17 led bulbs(comperable to a 25w bulb) for $39, but they wont sell to developed nations(usa).

        This [ccrane.com] place has 20 led bulbs for $60.

        here [oksolar.com] is a place that has dimmer(?) bulbs for 30-35 bucks.

        here [shoplifestyle.com] are some really cool sunlight powered outdoor led lights for $80.

    • Check out http://www.arcflashlight.com

      The Arc AAA is a great little light that is very rugged, waterproof, runs off a single AAA battery with good longevity (using a step-up voltage regulator) and *very* bright. I have a couple of these - been carrying one on my keyring for about 6 months and its never failed me. White LEDs are great..
  • Finally (Score:2, Interesting)

    by yasth ( 203461 )
    Light to starve by
  • i don't know about developing countries, but think about how much good it would do to get the overweight sedentary people here in the US off their asses and on a bike. Aside from energy savings, think of the savings from improving health
  • by Lumpy ( 12016 )
    Yes they are bright, but they make horrible area lighting. the most efficient lighting to date is still the compact flouresent and Cold Cathode flouresent lighting. It has the greates lumens per watt output compared to anything. White led's look bright, but are a concentrated beam, that same beam spread out to a 180Deg will be worthless. There used to be "tests" in home-power magazine that claimed white led's were superior.. but forgot to take into effect that the other lamps also lit up the room instead of a white spot on the bench aimed at the sensor.
  • Neato Stuff (Score:4, Interesting)

    by mikers ( 137971 ) on Wednesday May 08, 2002 @03:19PM (#3486657)
    I didn't take any courses from this prof, but some of my friends in school did.

    What he is doing is kindof neat... He wants to equip poor villages (in places like Nepal) with electric lighting that better utilizes the minimal generating capacity they have.

    I know you can get white LEDs as replacements for flashlights that will increase the battery life approximately 20x. For those Petzl headlamps a standard Duracell battery will give you about 6H of light with a standard bulb, but is rated at 100H with a superbright LED. And as far as I know the superbright gives you equivalent illumination - just at higher efficiency.

    When I was in Nepal a few years ago, most rural villages would have power (all from hydroelectric) but it was unpredictable and unreliable. Also the generators were small and there were limits on how many bulbs each place could have. Replacing regular bulbs with white leds would save power - and make battery backups realistic.

    Thats one way out of the dark.

    m

  • Many developing countries are in very sunny locations. Solar panels are really getting cheaper. For example, plastic solar cells [california...center.org] that can be "painted" onto clothing are strong enough to power portable radios. I bet they'd be powerful enough to charge up that battery that runs the LEDs.

    A very interesting read about solar is From Space to Earth [california...center.org], which discusses the use of and need for solar power in developing countries.

    One thing that is clear is that power in rural areas is greatly needed for things like well pumps; powering reading lights is great, but it would be better used for true necessities. (though light becomes necessary when you need to fix that broken well pump...)

  • by Have Blue ( 616 )
    Who's seen Soylent Green? :P
  • How many of you have ever seen a white LED light, much less read by one? I saw one in one of those Sharper Image type stores a while back. It was a flashlight that had a light that reminded me of a cross between flourescent and those annoying blue headlights.

    I realize they are efficient, but they are just not very pleasant. They might be useful as porchlights, but I wouldn't want to sit in a room with one and read for any length of time. Also, LEDs are probably not made in those countries. Simply giving them things is not going to encourage development (assuming that you think development is a good thing). I think we are better off educating the 3rd world then just giving them things. Educate them in math and language, and then they can solve their own problems, and in a way that will be suited to their culture, without contributing to the growing disatisfaction with the "imperialist" West. If you have to give them lights to educate them, give 'em good old incandescent/battery lamps. Kids won't be encouraged to learn under those annoying white lights.

    • White LED's have come a LONG way. They now actually sell several different WLED's that have varying tempreture ratings to them. From soft white to the very blueish light you mention.

      As for the WLED's not being produced in that country ... so what. Eventually someone WILL build a plant there when they realize the tremendous demand that has been created. Then as people aren't running around collecting fire wood, or sitting around in the dark they can actually then BE educated by reading etc.

      "Kids won't be encourged to learn under those annoying white light" Um how do you know. Maybe it is only annoying to "us" because we are used to using innefficient incandescent bulbs. And you would rather us give them those rather than LED's? So instead of giving them one of our imperialist invenetions that is usable with their meager power production capacity you would rather us give them one that sucks every available bit of juice they have. Riiiiight that is good thinking.
    • If you had read the article, you would know that the main thrust of this initiative is to allow people in developing to study for more hours in the day -- precisely what is needed for the education you suggest.

      For spot lighting, a white LED is 100 times as efficient as an incandescent light. Have you ever used a mechanically-powered torch? Quite a bit of effort is required to produce a useful beam (which is even then hard to keep constant).

      I would suggest that LEDs are not "annoying" to children who may never have seen a lightbulb in their life, or not spent significant time under one.

      Children in developing countries are quite enthusiastic about the learning thing, unlike many Western societies where school is something dreaded, and they wouldn't dare touch an encyclopaedia (or even a book!) at home.

  • Home pedal power via bicycle generators was written of in Harry Harrison's Make Room, Make Room (aka Soylent Green) [talmud.de]. Edward G. Robinson pedaled away throughout the movie" [geocities.com] to generate the home power.


  • Having lived in a developing country for several years, I can appreciate this groups efforts and the technological advances made here but...

    Where I lived (a rural part of Thailand) very few if anyone would have used the generator. Why? Because they can rent car batteries from a business down the road for all their electrical needs (which are very few - a few flourescent lightbulbs and occasionally TV).

    In my case, the business was hooked up to the power grid for recharging batteries but I also saw even more remote places where they had a generator (gas? Diesel? Never checked) for the same purpose.

    Having participated in harvesting rice, I really doubt any farmer would want to hop on their pedal-powered generator at the end of a day of back-breaking field work to charge up their batteries for a night of bad soap operas.

  • I've bought and used these LED's before. You can find them cheap here [allelectronics.com].
    I've built a few things with these and they are impressive. A solar cell, two AA rechargable batteries and one of these lights can be put to use just about anywhere.
  • In Kenya, there are several private companies that are selling solar panels to do the same sort of thing, except without all that nasty stationary bike stuff. Just pop the solar cell on the roof of your hut and you're in business. Turns out its not that terribly expensive, even by African standards. Currently you have some options if you're in a rural area in Kenya, and by some, I mean two, that being, taking your car battery to a charging station, or making payments on a solar panel. Its not a tough choice.
  • Still a ways to go (Score:5, Informative)

    by horati0 ( 249977 ) on Wednesday May 08, 2002 @03:49PM (#3486839) Journal
    I work in the lighting industry with conventional means of producing light (florescent, incandescent, etc) and have done some testing on LEDs. The most important thing to realize is that the light being produced is not a pure "white" light.

    Typically the manufacturer will use a blue LED and coat the outside of the lens with a yellow broadband phosphor, which when the blue light is filtered through it, appears white. True white is extremely difficult (and expensive) to produce; it's still years away and it has to do with the ability of the diodes to produce certain wavelengths of light.

    As far as efficiency, yes, LEDs are quite effecient at producing light at a given (low) wattage but they are still not as bright as conventional light sources. The rating of an LEDs efficiency is measured in lumens per watt; a bulb with a higher lumen per watt rating is more efficient than that of a lower one. At this point, red LEDs are the most efficient, which is why many applications that use LEDs (exit signs, car turn signals, etc) are red.

    Manufacurers claim a 100,000 hour life span of LEDs. What most of them fail to mention is that to acheive this, the power supply that the LEDs are attached to has to be set at a low current. Low current means decreased brightness. If the current is increased past the manufacurers recommended setting, you will get higher brightess but the lifespan will be cut short severely. Not to mention the fact that many LED applications where companies are touting 100,000 hour lifetimes (approximately 10 years) haven't been around that long to confirm or deny it.

    LEDs are not going away, however. It's not a question of if they go mainstream, it's when. And I have no problem with that, it's just that from what I have observed, the manufacurers are dispensing half-truths and outright lies about this stuff. People take it for gospel because big companies are developing the technology (GE and HP-funded Agilent come to mind) so they figure it must be true.

    Whatever. It's reall not going to make that much difference in the long run. Just want people to know there's more behind it.
    • The other contributing factor for red LEDs replacing red lamps is that "red" incandescent lamps are white incandescent bulbs with red filters in front. The filtering substantially lowers the emitted light per unit input power, increasing the advantage of red LEDs.
  • they've had LED lighting systems for homes and swimming pools for years now. The pedal generators and rechargable batteries are a new idea. But LED lighting systems have been around. However they are quite expensive.

    You get a bed of white LEDs in your basement, and you use fiber optics to bring the ligh to different places in your home. Works really well for swimming pools, and is most often used there, because it doesn't bring electricity near the water.
  • Found this on google, of course

    http://www.ccrane.com/120_volt_white_led_bulb.asp [ccrane.com]

    An led array that screws into regular fixtures. A little pricey at US$59.95, but it it never burns out, the your total cost would be 59.95/infinity, or is my math wrong? ;)
  • My question about LED's is this: Can I use a dimmer? It seems like an LED would have to be either On or Off. Is that the case?

    If so, perhaps someone will invent a lightbulb where when only a small amount of current is applied that one or two LEDs come on. As more current is supplied more come on. Possible?
  • It occurs to me that this extreme level of efficiency just begs to be hooked up to an array of solar cells, not an exercise cycle.

    Solar cells have been underutilised as a source of energy due to the low yield.

    This seems like a nice and symbiotic combination of different technologies... "Hey, the solar cells don't give me much electricity, but the white LEDs illuminating the office building don't need all that much anyhow. W00t!"

  • And for all the geeks who like lights.. or something : http://www.thinkgeek.com/stuff/gadgets/lights.shtm l
  • by mrroot ( 543673 ) on Wednesday May 08, 2002 @04:04PM (#3486950)
    using a combination of white LEDs, pedal generators and rechargable batteries.

    Nothing innovative about this, the Professor was using pedal generators to power ALL KINDS OF THINGS while shipwrecked on Gilligan's Island [gilligansisle.com] back in the late 60s / early 70s.
  • I saw this guy present this project a few months ago (as a presentation for Engineers Without Borders [ewb-isf.org]) and it is really important work.

    One of the biggest problems in third world countries is that taking care of food and water is an all day task. There is no time for learning to read and write during the daylight hours. These lights allow people the opportunity to learn to read and write after the sun has set.

    This is a very important task if we hope to help the people in remote areas. The target areas tend to be areas with no electricity, no running water, and very few fascilities at all.

    And I have seen the LEDs that he uses light light up a mid-to-large size lecture theatre to the point that I could read a paper in fornt of me, 5 rows away from the source!

    -----
  • If folks in the US want to send them a donation, what's the minimum practical amount given conversion fees?

    I know that for many European countries check cashing/currency conversion fees can easily be more than the actual value of a check, and while I'm sure it's much simpler (and cheaper) between the US and Canada I'm also sure that there will be some charges.

    So, what's a practical level?

  • I for one would be interested in seeing a benchmark between this [slashdot.org] and the white LED's we're talking about here.

  • http://ledmuseum.home.att.net/ledleft.htm Seriously cool site.
  • on slashdot a year ago orso,
    I remember there was a big light, that consisted of multiple leds (thought about 100-300) that you could program with your pc. It could change color to all the colors you wanted. I believe the casing was black and it costed about $600.
    I was searching for this item last week, because I wanted it for my new house, but I couldn't really find it, perhaps someone bookmarked it, or knows a simular light?

    Thanks in advance.
  • by pmz ( 462998 )
    Wouldn't it be really neat to have computer room floor tiles each with a tight grid of white LEDs under a clear plastic covering? Imagine a computer room with these floor tiles and a single IBM server standing in the middle...
  • I don't post often but when I read the headline of this topic, I wanted to add my two cents. After reading the article and everyone's posts (most posts being irreverent or poop-joke related) I have finished another chapter on my book of human ignorance.

    As U.S. citizens, we live in a wasteful society of throw-away everything and unlimited (we think) natural resources. When you go home tonight, make a note of how many lights you have on in your house. If you live alone, this will be a good test to see how much energy you use, if you have family members, roommates, etc you can also monitor the total energy consumption in your house. OK, so you got five lights on and you are the only one home. Now add the energy used to power your fridge, microwave, water heater, stereo, dishwasher, TV, computer(s), aquarium, Nintendo, space heater, furnace, the list goes on. Are all these items 100% necessary? of course, this America and we demand convenience 24/7.

    I am no better than you, I waste energy and it bugs me to go outside and watch the power meter spinning like a twirling dervish when I got the guys over for band practice. But I am aware of what I use and I do my best to conserve energy. I live in the NW US and we have lots of hydro-electric power plants on the Columbia, I am not a save-the-salmon radical but I don't want to see all the changes we make on the environment in the name of power generation to go waste on every single light in my house. If there is a new technology to limit energy use, I am all for it. In fact I have a few solar panels and few devices (lights & a TV) that I can use with my "free" power. In our lifetime, home-based power plants (natural gas-hydrogen based fuel cells, PV, wind power, etc) will become popular and necessary in many highly populated areas. Third world countries need this technology now since its price is low and their living conditions are so medieval compared to ours that any change for them is better than nothing. Our turn is coming soon.

    My fifteen minutes are up. Here are some other links on energy-related websites/products.

    Home Power Magazine [homepower.com]

    Jade Mountain Alternative Energy Devices [jademountain.com]

  • I can't be the only one who has one, since everybody else I meet on the trail raves about them:

    The Petzl Tikka -- $40 'white' LED headlamp; the best innovation in outdoors equipment in decades:
    http://www.petzl.com/petzl/publicFamille ?id=LAMP&r ub=sport
  • by Goldenhawk ( 242867 ) on Wednesday May 08, 2002 @06:03PM (#3487524) Homepage
    After hunting around for a reasonably-priced reading spotlight to mount in the minivan for my kids to read after dark, I couldn't find anything that was (1) bright and clear at low wattage (2) priced under $100US (3) small enough to hide in the trimwork. Then putzing around Radio Shack one day, I saw the rack of white LEDs, and decided to give them a whirl.

    I bought 6 WLEDs for about $30, a couple 100-ohm resistors and 1K trimmer pots for current limiting and dimming, and went home. Half an hour and a few solder joints later, I had mounted the 6 LEDs shining thru holes in my overhead panel, pointed at my steering wheel area (hey, first I helped MYSELF, not the kids). I found that I could run three LEDs, with a voltage drop of about 3.5V each, in series with the fixed 100 ohm resistor and a trimmer pot. So two sets in parallel worked well. I couldn't wait until nighttime.

    After dark, out to the van I went. Switch on - WOW.

    First impression - the color was all wrong. Until I realized that I'm so used to yellow light that pure white was almost distracting. But the light was BRIGHT and very crisp. From about 18 inches from LEDs to reading material, with only 6 LEDs, I had more light than with the original dome light 20 inches away, and the color was perfect - I could enjoy reading material with photos, without straining to see the colors. The pool of light was about 15 inches across. The LEDs I used are rated at 30deg beam spread (to the point of half brightness) so that seemed about right for six lights pointed a bit apart from each other. Best of all, unlike a dome lamp, there was NO spillover light to the rest of the interior - with the light on I could still easily see out the front to drive. Don't try that for long with a glaring dome lamp.

    One other thing was worth noting - there were faint yellow/blue bands in the pool of light, noticable only when looking at a large mostly blank page. This is probably due to the blue LED/yellow phosphor combination used to make white light.

    The biggest problem was cost. At Radio Shack prices of $4.99 each, I couldn't affort enough LEDs to do the other five seating locations. But it was still far cheaper than a quality aircraft-style reading lamp, and just as bright. If I wanted more brightness, I can easily add more LEDs.

    Check out this link - http://www.theledlight.com - for some really cool ideas, parts, kits, assembled lamps, all based on LED technology. Really cool, and a LOT cheaper for the bare LEDs than Radio Shack. About $2.50 or less each.

    Soon I'm going to order some bulk WLEDs from them - and light up the rest of the vehicle interior.
  • Great. More light polution. The developing world will get lights and the developed world will get brighter..

    What stars???

    usa at night [nasa.gov]

    There are already groups [darksky.org] for keeping the night dark.

If I have seen farther than others, it is because I was standing on the shoulders of giants. -- Isaac Newton

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