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White LEDs for a Brighter World
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."
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
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Light to starve by
I'd do something interesting, but my server can't handle a slashdotting.
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.
Do not look at laser with remaining good eye.
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
$25 to never need to balance on top of that stepladder in the kitchen again? Sounds like a deal to me. I could even see $50. Be even nicer if these don't have the flicker issues of flourescents (which is why I won't use them for reading or near the computer). And it beats the hell out of the RF units, which would kill both my phone and my network.
--Dave Rickey
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.
I saw this guy present this project a few months ago (as a presentation for Engineers Without Borders) 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!
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The significant problems we face cannot be solved by the same level of thinking that created them. -Einstein
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.
... 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.
As for the WLED's not being produced in that country
"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 can't be good, be good at it!
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.
just my blog and pix
Um, how do you think fluorescent lights do it? EYou sure don't get white light out of then by default; you have to use a phosphor.
White LEDs will work exactly the same way; use a UV LED and shine it on a phosphor. Blammo! All we need is a decent UV LED, and we're getting close.
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
Jade Mountain Alternative Energy Devices
You're half right - Actually the ballast is also there to limit the current flowing through the tube.
What (roughly) happens is:
You turn the power on.
The starter heats the two filaments, via the ballast, at either end of the tube for a few seconds, and then breaks that circuit. Since there was current flowing through the ballast , and the ballast is inductive (well, the old types)
a high voltage kick is produced, which is placed across the tube, which fires it.
That great.
Except that the problem is that the voltage required to maintain the arc inside the tube is a lot less than the voltage to start the arc, so you need to regulate the current through the tube to stop it from blowing up. The ballast, being inductive, presents a nice resistance at the mains frequency of 50/60Hz, which limits the tube current under normal operating conditions.
Anyways, that's how I remember it.
Those new-fangled solid state ones might as well be magic - they have the same effect, but how is a different matter.
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.
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.
Morphing Software
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.
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