blue led at night

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I think everyone who uses those newer blue leds has experienced the nice colour during the day and the somewhat high intensity at night.:cool:

Wouldn´t it be nice if it (the led) would change it´s intensity according to the available light?

Does anybody have an idea how this could be done (LDR etc.) in a simple way?

You could drive the LED with a current source that uses a photocell to vary the drive to the LED. In bright light it can be made to shine brightly and in darkness, it can be made dim. You'll have to put the photocell somewhere that it can see the room light level (front panel?).

Lots of el cheapo night lights do this...

thank you all,

for the replies, they confirm what I already figured out but what I would really like is an answer like:

"buy this ldr, use a bc547 a 30VA trannie and 1k, connect them like this and it will work ":)

This thread was opened because I really don´t have time at the moment (or because I´m too lazy) to fiddle around with different types of ldr´s and do a lot of experimenting :D


I got ... use to it. Living in city all my life, I can sleep in day light and have REM sleep. ... hehe.

I face LED inward and use indirect illumination. Use like white strip of paper or tape.

You can cut off the top of LED and sand it real well. Make that translucent. I think it would look more professional. BLED is a tad too bright anyways.

I switched my power LED from my computer and used a blue LED from Radio Shack. Whenever I turn my computer on at night, I can easily walk over to the lamp to turn it on. Also the blue LED is bright enough to diffuse other LEDs in my computer. The hard drive LED light has a tint of purple color then diffused to red-pink in the middle. The one piece clear plastic for all the LEDs makes a bright color to be diffused to other LED outputs.

If you don't want to use a bright color to diffuse other LED outputs. Then you can use electrical tape or duct tape. You can also use a T-shirt to cover the bright LED. Got to help Jason with his t-shirt plan.:D
I think my light would look even better.;)


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