You likely see analog clocks every day, paying them no mind beyond to get a glimpse of what time it is. What if, however, you were to arrange 24 of them in a 3 x 8 grid, with carefully controlled hour and minute hands? This would allow you to display virtually anything in something akin to a 7-segment LCD screen. While the idea seems like it would be possible, though extremely difficult, temporal hacker extraordinaire Wojtek Kosak has actually built such a device.
The clock array is seen the videos below, demoing how it can display different four-digit numbers. It can also show the temperature, even forming a “°C.” Each clock face is designed to be able to work on its own, and a schematic for the PCB used is found on the project’s write-up.
Clock housing and hands are 3D-printed out of PLA filament, and use a BKA30D double-shaft stepper motor to enable each to spin independently. In addition to the unusual stepper motor, the ATmega328PB microcontroller used here may also be new to readers. This is not the same as the -P version used on many Arduino boards, and adds the ability for PWM control on nine or even 10 channels. Each clock face communicates with the others via an I2C bus, providing coordination among the 24 units without an exorbitant amount of wiring.