This is just simple darkroom timer and stopwatch:

Code: https://github.com/lo1ol/DarkroomStopwatch
Demo: https://youtube.com/shorts/RGO38ZYOplA?feature=share

Main features:

1. Energy efficiency. Device should last for 4 mothes
2. Display has backlight
3. Simple and ergonomic: device has two big buttons and encoder

You need 2 PLA plastics and TPU-95 (for stub)

Project has Fusion 360 files: you can easily change what you want

Bambu Lab

Bambu P1S

No

Yes

0.4

30