Two separate and identical elements are used which consist of a stepper motor driven spiral, magnetic vertical slider and steel ball bearing. The ball is attracted to the magnet on the slider and the pair are lifted by the spiral as it rotates with the time indicated by its position and markings on a vertical scale.

When the ball/slider combination reaches the top of its travel the ball is knocked off the slider by the spiral.

The slider falls to the bottom and the ball rolls down the spiral to be met at the bottom by the slider were the process repeats.

The reference start (home), position for the spiral and the slider are verified by hall sensors and magnets.

All this is controlled by a Raspberry Pi Pico with RTC and LCD used for both time setting and display in 24 hour mode.

The specific LCD display was chosen due to its small size and integrated push buttons negating the requirement for standalone buttons.

This is all housed in an acrylic and wooden case.

Supply current at 5V (static typ. 42mA), (active typ. 260mA).