LEDs Lighting Up the African Darkness 182
Peace Corps Online writes "In a non-electrified society, life is defined by the sun and little is accomplished once it sets around 6 pm. Only 19 percent of rural areas in Ghana have electricity. The rest use foul-smelling kerosene lamps to light their huts, which pollute, provide little light and are major fire hazards. But now Philips has partnered with KITE, a not-for-profit Ghanaian organization, to bring artificial light to villages that have no electricity. The new Philips products include a portable lantern which provides bright white light where it is needed, the Dynamo Multi LED self-powered (wind-up) flashlight that provides 17 minutes of light from two minutes hand winding, and the 'My Reading Light,' which is a solar-powered reading light with built-in rechargeable battery. 'People can now do things in the evening,' says Harriette Amissah-Arthur, KITE's director. 'If you could only see the joy these products bring the villagers. You look at their faces; you have to see it to believe it.'"
Biased article... phillips (Score:5, Informative)
http://www.ucalgary.ca/oncampus/weekly/nov4-05/schulich-lutw.html [ucalgary.ca]
http://www.google.com/search?q=philips+lutw [google.com]
Re:At the same time, European Union bans incandesc (Score:5, Informative)
The EU has done no such thing. Yes, it banned the sale of classic lightbulbs (effective September 2012). But what you replace them with is your own choice, you are not forced into buying fluorescent tubes.
Re:At the same time, European Union bans incandesc (Score:2, Informative)
The mercury problem is easily solvable. Just institute a deposit recycling system for the fluorescents, like there exists for bottles in many countries.
By the way, am I the only one to find the light from white LEDs irritating? Somehow I find it harder to see in LED light than with alternatives, even when the light output is theoretically comparable. It is as if the frequencies in its spectrum just miss the the ones my photoreceptors are tuned into...
Re:Gunfire (Score:4, Informative)
Re:At the same time, European Union bans incandesc (Score:4, Informative)
According to wikipedia [wikipedia.org] ... assuming a coal fired plant this statement is correct - the total amount of mercury is lesser when using a CFL:
Re:Camping memories (Score:4, Informative)
I am the only one who thinks kerosene lamps actually do smell quite nice.
The smell depends on the fuel. Kerosene can contain varying amounts of sulfur and other odour-inducing substances. Better grades have less odour, and may even have some fragrances added, but cost more. I suppose that the nice-smelling varieties are less common in poorer countries. In fact, they probably mix other cheaper fuels (such as diesel) into the kerosene they do have, adversely affecting soot and smell.
I have tried it - use the meter correctly (Score:5, Informative)
My own experiments, years ago, showed that in real world use CFLs are equivalent to about four times the wattage of standard 1000 hour incandescents, whereas full size fluorescents produce maybe 5 times the output of the same wattage incandescent. Linear 8W CFLs as used on boats and caravans give about the same actual illumination as a 20W tungsten-halogen bulb, because their light output is much less directional, but then they are much better at illuminating dark corners.
Case in point: when we moved to our present house, the kitchen used 3 100W bulbs. These have been satisfactorily replaced with 3 20W CFLs for the last 20 years. As different types of CFL have evolved, there has been no deterioration in light output, though it is important to buy good quality - GE or Philips - bulbs.
I note that the cost of LEDS is now becoming comparable in lifetime cost with CFLs. The main issue is that LED drivers are relatively inefficient because most of them waste a lot of power in series resistors. What is needed is a really efficient current driver IC for LEDs. This would drive up the efficiency of conversion and make them even more useful in the Third World.
Re:At the same time, European Union bans incandesc (Score:2, Informative)
The Dulux series by Osram is marked with color temperature and CRI in one number: An 827 CFL is a 2700K light with a color rendering index >80. Osram makes compact 930 lights (CRI>90 3000K), but not (yet) in the "normal" E27 socket format. Consumers looking to replace incandescent bulbs should go for 827 CFLs, as they're the drop-in replacement with a light color and color rendering quality closest to incandescent bulbs. ("Daylight" and other color temperatures >3000K are what most people associate with sterile, cold fluorescent tube light. 2700K is the "warm" yellowish light they're used to from incandescent bulbs.)
Kerosine lamps FTW! (Score:4, Informative)
I spent some time in northern Sudan as a child. We had kerosine lamps that used wicks, and Petromax pressure lamps that used a mantle (like the Coleman lamps in the USA). As an 8-year-old I loved having my own kerosine lamp to read by in bed. Yeah, it was dim -- but in a pitch black room with dark-adapted eyes, it was plenty.
They DO pollute, they ARE a fire hazard... but the world will be a little poorer when the last kerosine lamp is gone.
Re:At the same time, European Union bans incandesc (Score:3, Informative)
It is as if the frequencies in its spectrum just miss the the ones my photoreceptors are tuned into...
Well, that's because the LEDs actually are missing (large) components of the spectrum! :-)
Even when your eyes are tricked into believing the light is white (by equally stimuling the three kinds of color-sensitive cells), the light reflected off of objects isn't "correct". Imagine two green objects. One has true green pigment, the other has a mixture of yellow and blue pigment. Both look the same under incandescent light, because the light from a glowing filament emits a full spectrum .
No!
Incandescent light is extremely blue deficient. It's not at all "full spectrum".
Colors look approximately right under incandescent illumination because your eyes are extremely good at color-adjusting the signal to the brain to compensate for the ambient light, and "most" things you tend to look at don't have sharp spectral bands. But in the case you describe, where a green color is synthesized from a blue and a yellow reflectance band, it will look very different under sunlight and incandescent light. (Look up "alexandrite", for example)
Re:Understanding of vision is incorrect (Score:5, Informative)
Birds have a 4-color system, the last I heard; mammals lost theirs when they became nocturnal, and we have not fully recovered ours because, basically, primate evolution has not had long enough for it to reappear- perhaps the selection pressure is not that great.)
Actually some humans (and presumably, other primates) do have a 4-color system. It tends to occur more frequently (but still rarely overall) in females than males, perhaps for the same reasons that color-blindness tends to be more frequent in males. If I recall correctly the extra receptor is toward the violet end, and to these people indigo is actually a different color rather than just a shade of blue.
(Compare with mantis shrimp that have 12 color channels, extending into the ultra-violet and infra-red, plus receptors to distinguish circularly polarized light.)