An old 6 volt relay coil worked for me, main issue is needing a local backup oscillator stable enough to cope with period of signal loss/power outages.
Obviously simpler to use GPS 1PPS to derive the drive signal but that's a challenge to pick up with a coil of wire and a capacitor.
Although personally I think the gold is a bit much and doesn't tone well with the blue LEDs. I'd like to see your clock.
Also - I would suggest using regular bulbs instead of LEDs. If you can deal with the higher voltages involved, neon lamps would give it a great look.
Also, rather than a tape recorder, use one of those large doorbell "big ben" chimes instead (if you can find a really old one - from the 1960s or so - some of them used a similar motor/drum switched sequencer for the solenoid chime playing system).
It sounds very intriguing, and probably would be cool to watch function...
Anyone know if there's a video of it in action?
Maybe he'll see this post and finish the video :)
He has made a couple different ones:
Depending on how creative you wanted to get, a clock might be designed to run directly on a pulsating rectified DC supply. That would give you a sort of baseband embedded clock signal at 120 Hz. Or use two half-wave rectifiers and design the whole clock based on trinary logic, +12V/0/-12V.
Realistically, since the mains connection is hidden behind the frame, it would be easy to tap off internally a connection to the 12V AC signal from the secondary of the transformer, before it gets rectified and filtered to DC.
That said, counters aren't lightweight in that arena either...
Each digit would have 7 latches, one for each segment, and cycle through just 10 of the otherwise possible 128 states. It would be ironic to use clockless logic, making simpler latches.