Use reed switches behind the clock face and magnets on the (presumably) different length hands instead of hall sensors. NTP sync once per day is more than adequate for household timekeeping - it might drift a few seconds here and there, but that’s fine for most people?
replyYeah, reeds make more sense. I’d stagger them so that when the hour is at 12, minute at 3, second is at 6, all three reeds (wired in series) wake the microcontroller.
reply