What type of LED for black annunciator?

I'm going to buy bulk LEDs from ebay rather than paying $2-5 each for them from my local store. The only thing is I am testing with very low brightness LEDs which are probably too low (20-80Mcd) for my needs. But the ones on ebay are some, retina blowing intensity, like 5-10,000Mcd!!!! I'm afraid that these will act like x-rays against my printed annunciator legends, and nothing short of led sheet will block the light around the cut-out.

I also heard that ultra-bright LEDs were generally recommended. But as I'm making my own annunciator filters, I need to use the lowest annunciator power that looks good without having to use 10 layers of filter to block the light.

I'm sure most of you who purchased panels will be using LEDs, so what spec did you go for, especially if you're using a hand-made annunciator or korry indicator.

Thanks in advance

Paul

Hey Paul. First thing I would do is decide on the leds you are going to use. Then build a test circuit and keep dropping the voltage to the leds with different resistors until you get the desired effect. Do you have pictures of your annunciators?

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Originally Posted by Bob Reed

Hey Paul. First thing I would do is decide on the leds you are going to use. Then build a test circuit and keep dropping the voltage to the leds with different resistors until you get the desired effect. Do you have pictures of your annunciators?

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Thanks Bob, that sounds like sensible advice. I'm using the Phidgets LED64 unit, well I was planning on it but it appears to be defective. I know these have are designed to allow LEDs to plug straight in and have built-in current limiting resistors. I guess that doesn't stop adding extra resistance if they're too bright, although I actually need two LEDs per output so will have to give this more thought.

I will grab some pics of my prototype annunciators. I left the to dry last time I worked on them, and have a new technique I'd love to try.

I used the Phidgets 64 cards on the OH I built for Radcliffe in VA. I put 2 leds per output by hooking them up in parallel. There have been no problems and it works great.

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Originally Posted by Bob Reed

I used the Phidgets 64 cards on the OH I built for Radcliffe in VA. I put 2 leds per output by hooking them up in parallel. There have been no problems and it works great.

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I'm sure I have a defective LED64 board as I'm using regular LEDs and not managed to get one working yet. However they do work in other Phidget boards, so the LEDs are ok

I have been caught using leds with not enough output, so my advice is to get high power ones then you can always drop the voltage back to get the right intensity you need. I use leds that are between 500 and 3500 Mcd.
Regards..................Brian W.