Featuring a minimalist design the ATtiny85-based Tiny Time Watch uses 12 LEDs, arranged like a clock face, to show the time analogue-style. The design and code are based on the work of Mr. David Johnson-Davies
The Easy Way: At exactly 3:50 AM or PM pull the plastic strip up away from the battery in the direction of the arrow. By default when first powered up the watch is set at 3:50.
To show the time you press the button on the watch face, and the time is then displayed for four seconds. It lights one LED to show the hour, and flashes another LED to show the minutes to the nearest five minutes, like the hour and minute hands on a clock. If only one LED lights up you know that both hands are pointing to the same hour mark.
The Tiny Time watch uses the ATtiny85’s built-in oscillator, fine-tuned to get it as accurate as possible, and the watch keeps time to within a couple of minutes over 24 hours. You can adjust the time by holding down the button for more than four seconds.