Private
06.2024 – 01.2025 (7 months)
Description
Several years ago I saw in Instructables how somebody made a 7 segment clock where segments were moving in and out causing shadows. That made me very curious about this method and I decided to try my own approach.
Project summary
In this project I designed, built and programmed a 7 segment clock where the segments are mechanically moved in and out. The shadow makes the segments visible and one can read the symbols. Almost everything is 3D printed and the assembly is very simple.
My responsibilities
CAD design
PCB design
Assembly
Programming
Results
It took me some time to come up with the idea to use a 3d printed screw and a nut for the kinetic movement. That considerably simplifies the mechanical part of the clock. The only limitation is the speed, it requires several turns before the segment has moved enough. Additionally I used simple and cheap, however slow 28byj-48 stepper motors.
Each digit has 7 segments, thus 7 motors and each motor requires 4 pins for rotation. In the end a lot of digital pins are needed for all the connections. In order to simplify the electrical assembly I designed a PCB that makes wiring much easier. Nevertheless, there are still several cables that go from one PCB to another. Moreover the motor wires are quite long and it still looks quite messy behind the clock.
The mechanical movement works as intended. The only limitation is the grinding noise due to the printing orientation. If it would be possible to print the segment in another direction the noise would be fully eliminated and the friction almost eliminated. Nevertheless, one can hear the noise mainly during the homing when all the motors are running.
The main feature to see the digits is the shadow. I assume one could make the dials thicker so that the shadow is stronger. On top of that the light direction is very important. I noticed that when I moved between the light source. In the end one needs to be creative to use the clock, however for me that’s a feature.
Other than that I am happy with the outcome. The design is simple to rebuild and it doesn’t require expensive nor complicated parts.
Used tools
SW: Fusion 360, Arduino IDE
HW: 3d printer, Arduino, ESP, stepper motor, shift registers
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