andycivil's video: UV LED upgrade meets glow-in-the-dark tape

WARNING: UV light can damage the eyes. Limit your exposure, and don't look straight into the beam! I got this glow-in-the-dark duct tape and I was playing with it to see what activated it best, and I got a surprising answer. The red laser pointer was pathetic and did nothing. A regular white LED did work a bit, but a blue LED was pretty good. I figured that the shorter the wavelength, the better, so I tried an ultraviolet LED and it was awesome. It was especially striking because to our eyes it doesn't look like the LED is bright at all. So I followed the route that most people take when they find something that works: I made a bigger one. I ordered some UV LEDs from AliExpress for pocket change, and they duly arrived a couple of weeks later. I chose a dollar-store flashlight that had the same size LEDs for the UV upgrade. If you're going to copy me, choose a flashlight that comes apart; I was going to use this one, but I couldn't find a way to pry it open without breaking it. Unsoldering the old LEDs is the only thing that needs a special tool - I'm lucky to have this solder sucker, but solder wick would do. Maybe I should present this as a 'how-to' guide, but really there's nothing to it, just switch the LEDs and get the polarity right. OK, all reassembled - let's give it a whirl. Here's a pattern of Buckyballs I happen to have that'll make a good mask. I'm quite happy with that.