Making a UV Exposure Box

I’ve been wanting one of these for a while for some other projects I have planned. Previously I’ve (ab)used an old EEPROM eraser box, but (a) I wanted something a bit larger and (b) it isn’t mine and is a bit of a faff to get to right now.

I did some Googling and found this project which seemed pretty good. I didn’t need it quite so large, so I reduced the size of the box a bit.

I acquired a 5M strip of ‘5050’ UV LEDs from Ebay, and a 12V 5A DC power supply. The original project specified ‘5050’ LEDs as they’re more powerful, but I don’t think it described why this was the case. As it turns out ‘5050’ is just the dimensions of the LEDs (5.0mm x 5.0mm in this case): larger LEDs => more UV output!

Anyway, I cut the spool up into 13x350mm strips of LEDs (make sure to only cut ’em at the indicated cutpoints!).

I stuck them into the lid of the box (they’re sticky-backed) with roughly a 1-strip space between them. Then I used a Dremel to cut a small hole at the end of each and soldered a separate wire onto them. I wired them in parallel since I didn’t want any weird power drop problems towards the end of the strip.

On the top side of the lid, I soldered the wires into two “bunches” and then soldered the two bunches together.

I wanted the power connector to be reasonably solid, so I designed and 3D printed a quick enclosure for it, and added a 12V power socket:

If you look at the above picture, you’ll see I screwed up in the design slightly. I meant the two circled slots to be an attachment point for the strain relief cable tie, but I managed to put them on the wrong side! Annoying, but it’ll be fine: I couldn’t be bothered reprinting it.

Any way, with that all done, I drilled four extra holes in the lid for the enclosure and bolted it on (I put some heatshrink plastic on the bolts to prevent any sort of shorting). Finally, I hot glued the cables into their holes to provide a bit more stability.

This is the exterior view of the box in use: there’s a small amount of leakage from the wiring holes, but I’m not that concerned. I can always drape some cloth over it.

The interior view looks really cool, but I won’t be leaving it like this very often!

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