Output format is hh:mm:ss (including the ":")
For example:
Demo:
https://www.youtube.com/watch?v=EGtifa36_Ck
Components:
- Arduino Uno R3
- Expansion
- Solderless Breadboard MB-102
- Mini Board
- Jumper Wire x 18
- Matrix Led 8x8
- USB Cable
- Battery 9V Cable (or even better a powerbank 10000mAh - turns out it consumes a lot of battery)
- Key Switch (Button)
Connections:
Connect button to D1 and 5V
P.S. As for that background in the pictures, I glue the boards and the arduino on an old laptop motherboard. :)