Lamp with RGB

bobisculous

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I am wanting to make a small Desk lamp with LEDs of course. A buddy of mine did this but he used a single 1Watt Luxeon as the light producer. Although thats really neat, I am wanting to attempt to 'step out on the edge' or somthing like that I suppose. My goal, to creat a small desk lamp that doesnt need to produce alot of light, but makes white light by combining Red, Green and Blue LED Light. Has anyone ever tried making white light in this way? I am told that I may need to do some expirimenting with resistors because some LEDs may not put out the same amount of light. Is this going to be a easy and simplified task or will end up being a nightmare /ubbthreads/images/graemlins/rant.gif to try? And I am up for a slight nightmare if it pays off. It would for sure be pretty kewl looking, I know that. Thanks for your advice,
Cameron
 

IsaacHayes

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Well, red produces more light for less engergy. So you'll need to power the blue more and the green more as well. Or simalar. You'll have to hand tune to get white as each led's Vf, output, and wavelength will vary. Not worth the trouble unless you're doing it just because you can.... Or you want to have knobs to turn the power up/down and produce any color you want...
 

PhotonWrangler

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I think you're better off with white LEDs for a reading lamp. If you combine discreet RGB LEDs, you're going to have the issue of getting all three sources converged so that you don't wind up with annoying colored shadows.

I'd recommend experimenting with one of those Lightwashers from Color Kinetics first. It's an inexpensive RGB lamp that's adjustable for any color including white (sort of, because of the issue I mentioned).
 

Doug Owen

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[ QUOTE ]
bobisculous said:
My goal, to creat a small desk lamp that doesnt need to produce alot of light, but makes white light by combining Red, Green and Blue LED Light. Has anyone ever tried making white light in this way?

[/ QUOTE ]

Of course. Like all 'great ideas' somebody's already been there (probably a lot of folks in fact). In this case Don K has and wrote it all up for us, complete with ratios already sorted out. Try "How Many Red, Green, and Blue LEDs to make White" subtitled 'and how much current they need'.

Takes a lot of the fun out of it, IMO, but there ya go....

Doug Owen
 
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