Small OLED and LCD screens are cheap enough now that you can use them in virtually any project, but for decades seven-segment displays were the go-to solution when you needed to display numerical digits without spending a lot of money. As such, many makers have a nostalgic fondness for their appearance. You can, of course, still purchase them and use them in your projects. Or, you can follow Debra’s lead and pay homage to those classic displays with an edge-lit seven-segment display.
At first glance, and without a sense of scale, Debra’s design looks like a traditional seven-segment display. Each digit is broken up into the requisite seven line segments, and there are six digits to make it usable as a clock. But in actuality, this display is much larger. It’s also completely transparent, and the digits — or even individual segments — can be shown in any color. That’s because those segments are actually edge-lit using a strip of Adafruit NeoPixel-style individually-addressable RGB LEDs. Those shine through clear acrylic to illuminate the necessary segments.
If you want to build your own edge-lit seven-segment display, Debra has provided very detailed instructions on how to do so. You will need access to a precise laser cutter, because the acrylic parts all fit with very tight tolerances. After cutting all of your parts, you can insert the LED strips into their mounting locations. The opposite side of each segment is covered in non-conductive foil tape in order to eliminate bleed over between segments. Debra used an Adafruit ItsyBitsy M4 Express to control the LEDs, but you can use just about any microcontroller development board. She has also provided the code to make it all work.