The full write-up is on Medium:
Lots of additional photos:
The Gerbers are up on OshPark:
- clock: https://oshpark.com/shared_projects/OE6N7Z1x
- MEMS addon: https://oshpark.com/shared_projects/KbQrsVwL
The KiCad schematics and PCB layout, as well as Gerbers are up on GitHub:
This project started on a (series of) breadboards
The low-tech LDR-driven PWM adjusting the display brightness uses a 555 timer.
I created a minimalist 3D-printed wall-mounting frame.
Turns out debugging hardware is a lot more painful and slow than software!
MEMS oscillators don't seem to come in through-hole, so this became my SMT trial-by-fire.
When the crystal circuit proved unreliable I ultimately decided a "patch" was necessary and I created a tiny little addon board with a MEMS oscillator that would slot into the crystal circuit's through holes.
Using the logic analyzer to measure the accuracy.