I saw this project quite a while ago and I just had to build it myself: a desk clock using analog voltmeters to display the time! The build ended up being pretty straightforward; the voltmeters are DC 5V meters that I got on eBay with an Arduino driving them. They respond perfectly to PWM when using a 10 µF capacitor to smooth out the signal.
I got to thinking though when I put together the bill of materials that I didn't want to have a clock that I would need to set all the time. So I decided to use the DCF77 radio signal, which has been used to set all sorts of clocks since the early 70s. Thankfully, there are ready-made modules and also Arduino libraries so integrating it into the project was very easy.
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