Inspired by this concept, I made my own Pomodoro Timer, with an Arduino of course ;) I made a prototype, with a breadboarded Arduino and only a Lego casing around the display, but it could also be built into a proper case of course.
When connecting to power, it will automatically start counting down 25 minutes (default). When your time is up, you will hear a beep and the timer shuts its display down. With one press on the button and you can start a new session. When pressing the button multiple times, you can switch the count-down period.
The timer had to be super-easy to operate, so it only has one button. This button will make the timer:
- Reset the current session when already counting down;
- Switch to a different count-down period (25 (default), 45, 5 or 15 minutes);
- Start a new session when stopped.
The display I used is a 3-Wire LED Module from DFRobot.