This Clock Plots the Time in UV Letters on Glow-in-the-Dark Film

Everyone needs to keep track of the time, so it’s hardly surprising that clocks are one of the most ubiquitous devices in the world. That means there’s a lot of room for personalization, and Imgurian Tucker Shannon took that idea and ran with it to build this gorgeous UV-plotting clock.

The concept is simple: a UV LED is used to plot the time in luminescent letters onto glow-in-the-dark film. That film is on a reel, and a motor pulls it around from the LED to the front, so the time can be seen. The LED is on a vertical motorized axis, so it just needs to move up and down as the glow-in-the-dark film passes by. But, just because the concept is straightforward, that doesn’t mean the build is easy.

Shannon started by modeling all of the components in Solidworks, which is a popular CAD package for professional engineers. He then 3D-printed prototype parts to test the design. The original design called for a standard lead screw on the LED’s vertical axis, but that moved too slowly. So, the design was updated with a custom helical-slotted shaft that acts like a lead screw with an extremely long pitch.

Unlike most of the projects we see, Shannon didn’t keep the 3D-printed parts — those were just prototypes. The clock’s final mechanical parts were all machined in Shannon’s university’s metal shop. The wood base was also custom-made and finished with stain and varnish. That was a good choice, because the machined parts look gorgeous.

For the electronics, Shannon used a Raspberry Pi Zero W which controls two stepper motors through drivers. Those stepper motors are used to spin the glow-in-the-dark reel and the vertical LED axis. The finished product looks amazing, and seems to work flawlessly.