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The picture shows a 2mm wooden board, 4.63mm deep and 9.86mm wide. Below the board there is 3mm clearance for wires. Above the board, there is 5mm of free "air space". Behind the wooden board is a 2×7mm aluminum plate. The board is suspended on the left and right (cut off for visualization) by 3mm aluminum plates.

I would like to mount an LED somewhere on the board or the aluminum plate behind. I could also mill into the suspending aluminum on the left side, if that helps with mounting.

What is a good mounting option?

Already, I looked at the Mouser EU catalog, but close to 40,000 LED products is overwhelming, and unfortunately for many products pictures are bad or missing. I was thinking about a classic dome shaped through-hole LED, but I don't think I can securely fasten this. It should be safe to touch.

Nice to have, but not mandatory:

  • Multi-color LED, e.g. an RGB one.

  • Replaceable LED.

Brightness should be that of a typical keyboard status LED, i.e. not super bright.

3D illustration

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  • \$\begingroup\$ A single LED in this space? How bright does it need to be (is it indicating something or providing light)? What sort of power do you have available (mains, battery)? You can easily fit a single 5050 surface mount LED in this space... \$\endgroup\$ – JYelton Jul 8 '13 at 14:32
  • \$\begingroup\$ @JYelton Question updated. \$\endgroup\$ – feklee Jul 8 '13 at 14:53
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I'd suggest a surface mount LED and some glue. They are available in sizes from almost-to-small-to-see up to huge-enough-to-be-used-for-a-car-brake-light. Also available in any color you want. Here are some smaller varieties:

SMT LEDs

You might attach small wires directly to the LED, or attach the LED to a small PCB and attach wires in turn to that. Or, you might make a one-off PCB with some copper-clad board and a razor blade. Depends on where you want the wires, and what your production methods are, I suppose.

Another possibility is to mount the LED behind the panel, and bring the light through the panel with a hole or a lightpipe. See this page from the Mouser catalog for some ideas.

enter image description here

There are also square LEDs that will fit in that space nicely, which could be mounted simply by cutting the right sized hole. Then either glue it in place, or stick some perfboard on the backside of your panel, and solder the LED to that to hold it in place. If you must have a replaceable LED, you could probably find a way to mount a header behind the panel, and shove the LED leads into it, and friction will be enough to retain the LED if you don't have extreme vibration.

square LEDs

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  • \$\begingroup\$ Your link to the Mouser catalog page is of great value! I never looked at their printed/PDF catalog so far, but it looks like information is clearly arranged, for the given case much better than in their web shop. Except there is one big downside, in fact a nightmare: Measurements are in inches, where I need mm. Instead of 3mm as diameter, for example, they write: 0.115 \$\endgroup\$ – feklee Jul 8 '13 at 16:23
  • \$\begingroup\$ @feklee welcome to our world! :) \$\endgroup\$ – Phil Frost Jul 8 '13 at 17:06
  • \$\begingroup\$ I still haven't solved my particular problem. But I believe this question provides good general advise, and so I marked it as accepted (for now). \$\endgroup\$ – feklee Jul 16 '13 at 12:30
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SMD + lightpipe is the way most manufacturers handle LED indicators nowadays due to the flexibility of application. If this a one time project, wire and glue wil do it, if you need a repeteable solution you can use an adhesive FPCB with the LED on it.

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  • \$\begingroup\$ Valuable advice! However, as it's indeed a one time project, I want to avoid a circuit board entirely. Another story: There is also a micro-B USB port in the project. At first, I thought about getting a cheap SMD receptacle and an SMD-DIP adapter board, until I realized the price of that board. Cheaper is a rugged USB port that is screwable and that doesn't need an adapter board. \$\endgroup\$ – feklee Jul 8 '13 at 21:47

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