A Luminescent Light Pipe Clock

Seven-segment clocks have been with us for decades, but with the advent of addressable LED lighting, maker innovation is still going strong. Terra Gilbert AKA TerraG2’s take on this venerable display method uses addressable LEDs, but instead of applying them directly behind each segment, she’s using a series of light pipes to guide photons to the correct place.

The device’s 3D-printed housing assembles to position the four digits vertically, and an off-the shelf 8x8 LED matrix facing directly up. Each section holds light pipes in place to make the 90º the turn between the two, while creating an interesting visual effect. Light pipes are cut so that they stay in their mounting holes without adhesive, though a hot glue gun is noted as optional in the instructions.

Two pipes/LEDs are used per segment, meaning that 2x7x4, or 56, LEDs are required. This leaves a small number or LEDs (8) unused… or perhaps ready for expansion!

Computing-wise, the clock runs off of a Wemos D1 mini ESP8266 board. It gets time over the network via NTP, and signals the LEDs appropriately. The setup also features an MPU-6050 IMU, which allows for user interface by simply flipping it over, switching the color palette in response.

STLs for printing are code are published here on GitHub. Given the components involved, wiring should be fairly simple, likely making it a very approachable project. Or who knows, maybe it could serve as inspiration to build something new and unique!