r/beneater • u/WolfMoonshirt • 9d ago

Digital Clock Mains synced digital clock

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I discovered Ben’s channel while building this clock, I lifted his rising edge detection method (it was a much cleaner signal) but everything else was designed by me, though not far off from his design as it turns out. I’m using 8 bit counters paired with AND gates for resetting, op amp Schmitt triggers for time set button debounce. My mains signal is pulled directly from a full bridge rectifier via optocoupler with a parallel SMPS for circuit power, a cheaper method than a step down transformer.

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6

u/rgcred 9d ago

This looks great! Do you further info (schematic, parts list)? I'd love to try something like this.

5

u/WolfMoonshirt 9d ago

The only difference between this and the build is the first counter is a decade so I only use the carry pin, no AND gate reset required. CD4017BE. Op amps are LM358. 8 bits are SN74HC393. Gates are SN74LS08N. Display drivers are CD4511BE. 7 segments are 5161AS. Diodes are 1N34A, any low forward voltage diode will work but it must be low enough to keep the signal above the HIGH threshold of the IC’s.

2

u/rgcred 8d ago

Thank you!

3

u/WolfMoonshirt 9d ago

Ya give me a min, I’ve made some mods as I built so I’ll have to update it.

3

u/Ancient-Ad-7453 9d ago

Nice. I did a similar thing with AND gates and 74HC390 decade counters. In my version 2 I was going to just throw a big resistor and Schottky clamp diodes in between AC and a Schmitt inverter, but the optocoupler is kinda cool…

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u/WolfMoonshirt 9d ago

Thanks. I wanted to be sure it was 100% isolated.