LED's; How bright is too bright?

[somunny]

When I bought the LED's to light the buttlons on my current cabinet, I thought "no such thing as TOO bright".  So I picked up some 8000mcd bulbs. 

Then I saw a friend's LED flashlight.  I don't know what the rating was on the LED's but you couldn't look directly at if you valued your retinas.

I have not had a chance to wire them up yet but I'm just curious if anyone else has used LED's around this same rating and could share their thoughts on the matter.  I suppose I could experiment with different resistors and get it dimmed down.  Just wondering what kind of light show I'm in for...

Steve

[juggle50]

Well I'm still experimenting with this stuff too.  From what I understand, mcds are not the only indicator of brightness.  According to Joymonkey and Randy Luminous flux is an important factor when lighting buttons which is a calcutlated by both mcds and beam angle.   They talk about it more in this thread http://forum.arcadecontrols.com/index.php?topic=49222.0

Whether it's too bright or not depends on what you are lighting.  I used red 8000mcd leds with a 30 degree beam angle to light up my player one and two buttons.  They work great because the hard plastic of the button really defuses the light and you can see them well even during to day.

Now if you stick those in the bottom of a happs translucent and they have a 15 degree viewing angle they will create a spotlight effect and really blind you.

Like I said, I'm not the expert but I hope that helps a little.

[somunny]

Thanks for the link.  Lots of good info there.

The LEDs are 45 degree so hopefully they should disperse the light enough.  I suppose the bulbs in the flashlight I saw had a pretty narrow dispersion angle.  Makes sense.

Steve

[ShinAce]

3000 mcd or more will pretty much 'blind' you when looked at from directly on top....

[whammoed]

You can always use a higher ohm resistor if they are too bright.  You can make them as dim as you want with the right resistor.

[MYX]

It can never be too bright. Laser beams should shoot out of your CP. 

Seriously though, If you are using a LEDWiz, you can also turn down the brightness value.

[somunny]

Thanks for the info.  I'm gonna hook 'em up and if they're too bright, I'll put another resistor value in series until I get what I'm looking for.

If it's Pink Floyd at the Lazarium then so be it!

Steve

[Tahnok]

It can never be too bright. Laser beams should shoot out of your CP. 

When done, your CP should look something like:

[southpaw13]

Interesting----is there something simple you can put in-line to adjust the brightness?  I have the same problem with them shooting up to the ceiling.  I got them hooked up to 12v with a resistor.  How can I do brightness control without an LEDWIZ?

Thanks,
Southpaw

[somunny]

Interesting----is there something simple you can put in-line to adjust the brightness?  I have the same problem with them shooting up to the ceiling.  I got them hooked up to 12v with a resistor.  How can I do brightness control without an LEDWIZ?

Thanks,
Southpaw

Higher value resistor will dim it down (or kill it all together if the resistance is too high).  I don't know what your LED values are but I would think that you could use this calculator;

http://led.linear1.org/1led.wiz

... and drop the amount of current that you want.  If you're passing 30mA now, try using a resistor that will only pass 15 or 20 mA.

Steve

[Timoe]

I actually have to remember to not look directly at my trackball, its that bright.

One 4 cluster superbright blue LED.

The incandescent is unacceptable but the LED is a retina burner!

[juggle50]

Will it reduce the life span of the led to put in a resistor higher than the rated forward voltage?  I've heard that underpowering an led is poor of the the led.  I'snt putting a resistor on to dim the led essentially underpowering it?

I just ordered some of these.  http://www.superbrightleds.com/cgi-bin/store/commerce.cgi?product=LEDS&cart_id=9034441.25713
Scroll down to "led lense".  These claim to turn the led into a 180 degree viewing angle.  I am going to experiment with them as soon as I get them. 

Also, if you've got enough try sanding down the tops of the led's, this takes the  edge off the "spotlight."

Finally, don't forget the Knevel method of building plastic washers and mounting two to the sides.  Some people find this effective.

[whammoed]

Dimming the LED will actually make it last longer.  It reduces the heat generated at the source and will lengthen its usefull life.

[somunny]

I just finished converting a freebie pc power supply into a variable bench supply.  I'm going to put together a mock-up and see how bright these suckers are...

Steve

[southpaw13]

How did you convert the power supply?

[somunny]

How did you convert the power supply?

http://wiki.ehow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

Nice tutorial.  And it only took a few hours and about $11.00 spent at Fry's (I had a couple of the required components laying around already).  Works like a charm!

Anyway, after running a small LED array it's apparent that the bulbs were going to be a little too bright.  The main offender was the translucent yellow button as it doesen't seem to block as much as the red one.  Another 56 ohm resistor inseries dimmed it a bit, but the best results came from using the old 'sandpaper scuff' trick.  They'll do.

Steve

[juggle50]

Dimming the LED will actually make it last longer.  It reduces the heat generated at the source and will lengthen its usefull life.

Gottcha, thanks for setting me straight whammoed.

[Tahnok]

Dimming the LED will actually make it last longer.  It reduces the heat generated at the source and will lengthen its usefull life.

Gottcha, thanks for setting me straight whammoed.

Yes, except LED life isn't your biggest worry. If you're running LEDs within their limits, they should last longer than your CP.

[whammoed]

Dimming the LED will actually make it last longer.  It reduces the heat generated at the source and will lengthen its usefull life.

Gottcha, thanks for setting me straight whammoed.

Yes, except LED life isn't your biggest worry. If you're running LEDs within their limits, they should last longer than your CP.

Most likely they will.  Running non stop the LEDs will last over 11 years.