You can build a digital clock with a large 7-segment display, a Feather RP2040, and CircuitPython -- no internet required! For time keeping, this build uses the DS3231 Real Time Clock module for precise and accurate timing.

Full Tutorial

https://learn.adafruit.com/digital-clock-with-circuitpython/

Code on GitHub

https://github.com/adafruit/Adafruit_Learning_System_Guides/blob/main/Digital_Clock_with_CircuitPython/code.py

1.2in LED 7-Segment Display

https://www.adafruit.com/product/1271

Feather RP2040

https://www.adafruit.com/product/4884

DS3231 RTC STEMMA QT

https://www.adafruit.com/product/5188