I had an old amplifier vacuum tube I came across yesterday in my garage, so I decided to make a USB flash drive out of it. I took an old flash drive apart, and soldered wires onto the +5V and Ground lines on the back of the USB connector. I then soldered two color-changing LEDs, along with a couple of dropping resistors, onto those wires.
I broke off the bottom of the tube and opened it enough to get the flash drive and LEDs inside, then designed and 3D printed a new base on the tube, with a rectangular hole for the USB plug to fit through.
Finally, I mixed up some quick-dry epoxy and cemented it all together. Now the drive works as intended for data storage, but when plugged in, the LEDs cycle through their range of colors.
It’s a bad dual triode tube, usually used as an audio amplifier. The light is just decorative, and the only real practical use of having the tube or the lights is that it is unlikely that I’ll walk off and leave it in a computer somewhere.