This shows the construction of the first two that I made as a way to evaluate the PCB etching process outlined in another Instructable. My idea is to use these as indicator lamps in some other projects.
My son insisted that I enter it into the LED contest because he wants a TV-B-Gone kit, so be sure to vote it up if you like it. (Click the + icon at the top of this page)
You should open this pre-requisite Instructable in a new tab or window: http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/
It is the method used to do the etching in this instructable and has the added bonus of giving the PCB's a nice green tint.
Eventually I will make stained wood and brushed aluminum enclosures for these. I also plan to make use of these as indicators on some projects. (They are actually quite significantly brighter than they appear in the pictures)
Step 1: Gather materials
- Ultraviolet LED's - I got 200 for $10 on eBay. I think cool backlight effects could be made with any LED combination you like, my preference just happens to be UV.
- Fluorescent acrylic - McMaster carries this, as do alot of industrial supply houses. I got mine for $0.99 in the form of a tacky cutting board from a thrift store. Again, green is my preference, but the material comes in a couple of fluorescent colors. I think that maybe I'd like to try red, too.
- Standoffs - I used #8 threaded couplers
Step 2: Layout the top board
You can be pretty free laying out the top, just be sure to stay far enough back from the edges to clear your stand-offs and Remember to reverse your image for etching!
Step 3: Etch the top board / Layout the bottom board
You will need to decide:
1.) How many UV LED's you want to use
2.) Where to place the LED's
3.) How to supply the power to the LED's
I took a little 1-LED coin-cell flashlight and replaced the white LED with a UV LED. This allowed me to shine from behind the board to see what different placements would look like. Bending the LED's over (rather than have them aimed at 90 degrees to the board) gives more coverage.
Once you have decided where to placed the LED's you need to decide where to place the battery (or power wires). You can get PCB-mount coin-cell holders - I cut a piece of battery contact from and old lamp, bent it, and riveted it to the board for one contact. The other contact is just a large pad on the board.
If you wonder why there are so many parallel traces on mine, it is because I wanted to see how well traces of different widths would come out of the etch.
Step 4: Etch & solder the bottom board / Cut acrylic
This doesn't have to be pretty since it's only purpose is to diffuse and fluoresce in the background. In fact, I scuffed it up with some 100 grit sand paper to help diffusion.
Step 5: Assemble / Gape and genuflect
A picture of my first UVIL assembly is below.
Also is a (wiggled, blurry) picture of the Olivian UVIL backside showing the roller limit switch I added so that you can turn it off just by laying it down. I wanted to use a tadly mercury switch but didn't have one on hand. Incidentally, The Olivian UVIL bottom PCB also used a sharpie pen as resist (rather than toner transfer)