“We bought a railway station clock from a flea market and were a bit crestfallen when nothing happened when we plugged it in,” explains Martin. “The nice man who sold it seemed adamant that it worked, so after a bit of reading, I found out that it was waiting for a signal from a ‘Mutteruhr’.”
As the duo explain in their YouTube video, often when you see such clock in a station setting, there is a delay between the second hand reaching 12 and the minute hand advancing; this is because the clock is waiting for an electrical pulse from the ‘Mutteruhr’, or mother/master clock. This pulse drives the minute hand forward and then the second hand is free to complete another cycle.
Martin and Vanessa had purchased what was essentially a secondary clock – ineffective without a mother clock. To get it working, they decided to build a mother clock themselves with a few additional components and some code running on a Raspberry Pi Pico microcontroller.
Read More: Pico railway clock | Blogdot.tv