Tiny Time 2 PCB Watch

No, Tiny Time 2 is not a new movie that your three-year-old will want to replay over and over; it’s actually a minimalist watch with 12 LEDs arranged on a PCB-like a clock face. In order to check the time, the user presses its button, and a series of flashing lights reveals the hour and minutes.

The analog-style watch is based on a Microchip ATtiny85 along with a Maxim Integrated DS2417 RTC module, which uses a 32.768 kHz crystal to keep accurate time. Since the tinyAVR chip can be put to sleep when not actually displaying time with the LEDs, the device can run for many years without changing its CR2032 battery.

This is a huge improvement over creator David Johnson-Davies’ earlier version, which relied on the ATtiny85 alone for timekeeping — meaning a battery life of around a month, with less-than-perfect accuracy.