My little dilemma with LEDs shining through a label

[PeterPan]

Hey folks,

I've used small 3MM low current (2ma) LEDs like the Vishay TLLR4401 in may many project, whenever I had a low current requirement, in cases where the LED was protruding slightly through the enclosure. But recently, in order to make one of my pedal products more resistant to liquid spills, I have tried something different. Instead of letting the LED protrude through to the outside, I have covered the holes with a laminated label that covers the entire product. The labels are printed to be mostly black except for the text, and some round unprinted (white) areas where the LEDs will shine through. So holes are still drilled in the enclosure, but now the light from the LEDs must pass through the label to be seen. Unfortunately, even though the label material is not really opaque, it does cut down on the light from the LEDs unacceptably. I already know I could solve this with brighter LEDs, but probably won't find them in the low current category. But, up to now I've been using LEDs with diffused lenses. If I can find a version of these low current LEDs with clear lenses rather than a diffused lens, do you think they would do a better job projecting the light forward, so it would do better at getting more light through my labels?

Just fishing for ideas here. There are 8 LEDs in a row, so if I can make this work, I will have the benefit the perfectly aligned indicators and a completely spill resistant pedal, without having to insert individual covers for each LED.   

[armdnrdy]

The answer is maybe.

You might want to check the viewing angle as well. It sounds like you need a tight viewing angle...maybe 15 degrees. If you use a wider angle...you're illuminating the side of the hole for no reason!

[PeterPan]

Thanks armdnrdy, I'll consider that when I look at the specs. The diffused version I'm using now is probably the worst possible in that regard, because I think their inherent viewing angle is something like 120 degrees!

[armdnrdy]

Have you considered tiny rubber "O" rings around the LEDs to seal the LED holes from the inside of the enclosure.
The bottom of an LED has a natural stop for the O ring.

[Jdansti]

Try sanding the curved end of the LED flat. Just hold it with out your fingers and rub it on a piece of sandpaper. It will be trial and error as to how far into the LED you can go.

[mth5044]

Try sanding the curved end of the LED flat. Just hold it with out fingers and rub it on a piece of sandpaper. It will be trial and error as to how far into the LED you can go.

Came to say this. Get more of the LED in contact with the laminated covering.

[graylensman]

I'm more interested in learning why the pedals need to be spill-resistant.

[Brisance]

I'm more interested in learning why the pedals need to be spill-resistant.

drunken jams with beer?

[Perrow]

Playing while kayaking?

[PeterPan]

Try sanding the curved end of the LED flat. Just hold it with out your fingers and rub it on a piece of sandpaper. It will be trial and error as to how far into the LED you can go.

maybe, but that would make for a very tight fit. The top of the enclosure is the part that unscrews to take the unit apart, and up until now the LEDS just fit through the holes suspended on their own leads from the PCB. If its too tight a fit, then the top will just push the LEDs down and bend the leads when its assembled.

[GibsonGM]

Try sanding the curved end of the LED flat. Just hold it with out your fingers and rub it on a piece of sandpaper. It will be trial and error as to how far into the LED you can go.

maybe, but that would make for a very tight fit. The top of the enclosure is the part that unscrews to take the unit apart, and up until now the LEDS just fit through the holes suspended on their own leads from the PCB. If its too tight a fit, then the top will just push the LEDs down and bend the leads when its assembled.

Sounds like you need to up the hole size by 1/32" or so, then...trial & error...personally, I think LED bezels are pretty slick.  If you put it in correctly, it is QUITE beer resistant, as long as you go "Oh crap!!!" and grab a towel and wipe it down.   
Seal with silicone for better seal.    Nothing is perfect - beer will still go thru your holes for pots, too.

The label idea is nice, for other reasons to me, tho (aesthetics).   Looks like you'll have to do the sanding trick plus hole widening...or go to brighter LED.

[R.G.]

Light pipes glued into the top over the nominal position of the LEDs make it waterproof. Punch holes into the laminated label over the light pipe position.

LED viewing angle gives it some positional tolerance on the LED-to-light-pipe positioning.

High(er) photonic efficiency.

[PeterPan]

Sounds like you need to up the hole size by 1/32" or so, then...trial & error...personally, I think LED bezels are pretty slick.  If you put it in correctly, it is QUITE beer resistant, as long as you go "Oh crap!!!" and grab a towel and wipe it down.   
Seal with silicone for better seal.    Nothing is perfect - beer will still go thru your holes for pots, too.

The label idea is nice, for other reasons to me, tho (aesthetics).   Looks like you'll have to do the sanding trick plus hole widening...or go to brighter LED.

Thing is, this is the receiver part fo a wireless controller for other pedals, so its completely sealed on top except for those LEDs. And honestly? I even though i was just trying it out, the aesthetics of the laminated label idea is very good. Really couldn't get much better appearance wise.  So i want to work on this some before I give up on the idea.

The brighter LEDs you mentioned, I can try that right away on some of the LEDs, because they are driven by a buffer. For those I can just drop the series resistor. Two others though that are drive right from an MCU that only has 2 mA available, that will require some circuit revision to accomplish. Hopfully some better focused LEDs will come to my rescue.

[armdnrdy]

I now have the distinction of giving R.G. his very first "like" out of the thousands to come!

Yes...light tubes. I've seen them used on industrial control cabinets and on home audio equipment.

The Lite-Bright technology.

http://www.digikey.com/product-detail/en/LPA-C081301S-10/67-1839-ND/515482

[PeterPan]

I'm more interested in learning why the pedals need to be spill-resistant.

drunken jams with beer?

That too! :-). Honestly though, anything going on a pedal board needs to have some protection. Hell, IO can remember playing in a hot sweaty place once, and having one little drop of sweat fall from my brow onto an old BOSS pedal that had a crack, and instantly it totally shut down. Good thing it was the last song in the set!

[Jdansti]

Do they make little relays that use <2mA?  If so, you could control the LED with the relay, although this might be impossible without major mods if your LEDs are board mounted.

[Perrow]

Do they make little relays that use <2mA?

They're called transistors.

[armdnrdy]

Do they make little relays that use <2mA?  If so, you could control the LED with the relay, although this might be impossible without major mods if your LEDs are board mounted.

Controlling LEDs with a relay, switch, or transistor isn't gong to change the power consumption of the LED.

[Jdansti]

Do they make little relays that use <2mA?  If so, you could control the LED with the relay, although this might be impossible without major mods if your LEDs are board mounted.

Controlling LEDs with a relay, switch, or transistor isn't gong to change the power consumption of the LED.

Correct, but you can run power straight from the power supply through the relay contacts to the LED.

[armdnrdy]

This is from the OPs first post.

"I've used small 3MM low current (2ma) LEDs like the Vishay TLLR4401 in may many project, whenever I had a low current requirement"

If I recall correctly...the OP had another thread going that included pictures and explained what this thing is.
It is a portable switcher. Battery powered. This is why he wants to use low current LEDs.
It doesn't matter where in the circuit the LEDs are connected...they will draw the same amount of current.