Three watts of light

[Rob]

http://led.linear1.org/justdiy-three-watts-of-light/

What do you think? It looks pretty cool to me.

[sanjed]

I think there was another link earlier in the week for this by the man himself.

I find it fascinating that LED's are running so hot that you need a full on heat sink like that for them nowadays.

Good walkthrough, I would want to use these to model daylight as best i could for a desk illumination setup.

Simple, but effective.

[12volt dan]

I like it

 How much light is it? By that I mean what does it compare to in say an incandesent?

[justDIY]

It is hard to say what its incandescent equivalence would be, but it doesn't hold a candle to a 20 watt halogen puck light I have here on the bench.  by itself in a dark room, the led casts a fair amount of light, but in the day time, you can't see the reflected light more than a few feet away.  On the other had, emitted light is awesome ... these things are difficult to look at from across the room... which means they'd make ideal indicators and signal lamps (think blinding tail-lights)

I designed the light more as an exercise rather than anything practical - I eventually want to package it to use as decorative lighting somewhere, but need to get a better understanding of the cooling needs first

the heat sink gets quite warm without a fan, but a small 50-60mm fan running at 5volts keeps the heat sink around ambient

here are the ratings as best I can tell - these are borrowed from another 1 watt led, so grain of salt applies.

25c @ 350 mA
blue 470 typ nm 10 lm
red 625 typ nm 25 lm
green 530 nm 25 lm

but I don't think its as easy as adding 10 + 25 + 25 = 60 lumens