A school clock from the 1950s  brought back to life with a new  custom digital controller.

Project Details

When I first came across this clock I immediately fell in love with its aesthetic. Inspecting it, I quickly realized that it wasn’t a conventional clock, but what I didn’t realize at the time was that it was an old slave clock, likely from an old school. With no real electronics knowledge I had no idea how to make it work but I decided to see if I could.

I discovered that it used a 24v power supply to pulse an electromagnet every minute in order to advance the minute hand. There was no turning the clock back – it could only go forward, once per minute, with a loud “ka-chunk” noise. Enlisting the help of my dad, we came up with a basic circuit that pulsed the power every minute and it worked well.

Over the next few years as my interest in electronics grew with my other projects, I decided to revisit the clock. It still worked well but I decided to make it a bit more accurate and clean the circuit up. 

I designed a custom circuit board with an onboard AVR microcontroller and a real time clock module which gave it a much higher degree of precision over the previous analog circuit. A small 14×2 character display with some buttons to set the time on the clock module was also added in case the RTC battery ever died. 

Project Client

Personal project


PCB design & assembly

Firmware design

Let’s work together!

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