This is a Pomodoro timer with a fixed 25-minute session. It features two buttons: one for start/pause, and another to display the total time you've been focused since startup. When the session ends, the device vibrates and blinks so you won't miss the alert. The code is written in pure assembly language, with no third-party libraries using the old good and simple AVR Studio 4. It is powered by a 3.7V Li-Po rechargeable battery. To charge it, you will need to build a charging cable using a TP4056 module.