Seven segment display

Big 3D printed RGB LED seven segment display clock

Links

• Firmware source code - GIT My custom C++ firmware check this out
• youtube.com - Segmented Displays by Posy
• Wikipedia Seven-segment display Contains standard segment naming
• Segment design SVGs

Parts

• WS2811 Aliexpress White PCB Ordinary, 5m 60 IP30

Design / planing / idea phase

I got further interested in 7-segmented displays after a fellow hacker made a project with it, and i wanted to explore my fondness of this delightful concept. I decided to make a clock with it, but this is a concept that has been done before. So i wanted some twist on the concept, and remembered this wonderful video: youtube.com - Segmented Displays by Posy. Hence i chose a design (Classic black) optimized for displaying numbers, but also one that still retained the boxy look. Credit to the designer Michiel de Boer(Posy).

TODO Wire diagram

Diffusion

I tested both clear and white PLA with different layer heights by printing squares. Then i moved onto the distance. I determeined 2 layers of white PLA at a distance of 1.5 cm. was a good compromise.

Wiring

First segment level shifter

The ESP-01 operates at 3.3v for it's data output pin. However the WS2812B chip takes 5V input. This can be fixed "correctly" by using a level shifter, however a simpler way is to let the first segment handle the conversion. This means the first segment will glich, it can be hidden away, and skipped in the firmware.

Firmware

Fading effect

I chose to add a slow fade effect as to not disturb ones peripheral vision.

Color change timelapse

The color changes hue overtime, but it does so slowly, as to not be noticeable.

I've later changed this color hue to be derived from the time of day, so it will always have the same color at the same time of day. This change was easy to implement, due to my use of HSV See this commit

Now your brain can become wired to think, wow the clock is red, it's pretty late, i should go home.

Hour change animation

I've also added a rainbow vomit animation once an hour, that intentionally grabs your attention, to make you more aware of the passing time. As it's easy to lose track of time.

CAD

Files

• Project box
  • Box - FreeCAD
  • Box - STL
  • Lid - STL
• Digit
  • Digit - FreeCAD
  • Digit top diffuser - STL
  • Digit bottom - STL

Digits

I used FreeCAD to design a bottom and top piece based on the SVG files.

Box

A simple box was fabricated, manufactured on the worst 3D printer, with free fillement, and promptly hidden away in the cable tray.

I used this GRABCAD model License: GRABCAD Non-Comercial Licenses

2026 update - Tone down colors

I've toned down the saturation of the colors, to be more tasteful, the 100% saturation colors looked a bit tacky. Code commit with change

Comments

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