The logical and high-tech solution would be to simply use an RTC which has a precision 1Hz output! Or, you could use a receiver for the time signal radio service wherever you are on the planet. Is there some reason you don't even reveal which continent you are on?
I was thinking of an RTC, but that would be sort of cheating and an oxymoron. (and expensive) (A very precise clock to drive a homemade not-so-precise clock?)
US of A. I don't want the radio. I think I have decided on a crystal.
How about this, though?:
Send the 32.768kHz to a 12 bit counter, now we have 32,768/2^12 = 8. Then get a decade counter, and tie 'Q7 to reset. Then, when counter reaches 8th output, it "overflows." Would this give me a fairly precise 1Hz clock?
If you have a 12 bit counter, why not go all the way to 15?
Line frequency is not that accurate - I have Bose CD clock radio that is always gaining time because it runs from line frequency. Great sound, always fast.
Whenever I put a multimeter frequency counter on the mains here, it has always come back fast, you can see it doing a slow drift between 60Hz up to about 62.5 if I recall.
For the purposes of long-term time accuracy, power mains frequency is just as accurate as the NITS Atomic Clock. Because all the utility companies maintain the grid frequency against WWV.
Yeah that 'NITS' atomic clock isn't all it's hyped up to be
To satisfy my curiosity (which you're obviously under no obligation to do...), can you point to something that documents this? Oh wait, here it is: Utility frequency - Wikipedia
Digikey (where I'm buying from) only sells minimum 880. How about a cheaper 14-bit unit with a toggle (2-bit) connected to the output? 2^14*2 = 32.768kHz.
But eight dual flip flops would be 16 flip flops total... 2^16 = 65536. I'm looking for 2^15. If I use seven dual flip flops, what should I use to take the frequency from 2hz to 1hz?
I just hit my self in the head b/c I realized I am being WAY to harsh on myself. I'll just use a 65.536kHz crystal and use a dual 8-bit (16 bits total) binary counter to bring it down to 1 hz.