Very low consumption ultra small size 1-minute timer for watch clock

[neazoi]

Hi, I would like to try building an analogue watch and I need a precise 1 minute timer to trigger a tiny motor or any other electromechanical actuator to advance the minutes.
Obviously, since it is a watch, battery saving and circuit voltage, are important.
Also size is important.
I have found these circuits, but they need 5v and I was thinking of a single cr2032 (or larger capacity) button Li-ion cell.
Any suggestions?
Thanks

 

[BradtheRad]

There's the MM5369 IC. It divides 3.579545 MHz (common color tv crystal) down to 60Hz.
To obtain 1 minute divide further by 3600.
8 pins. Runs on 3-18V according to Forrest Mims Engineer's Notebook page 38.

 

[KlausST]

Hi,

You said you want to build an analog clock. But all the circuits are digital.
So I assume you want to build an "analog looking" clock with a digital time base.

Many of the RTCs you can buy have an output. You may configure it to output a 1s clock. Rather precise and designed for low power.

Other good time bases are
* mains frequency. It is not very precise, but rather accurate over a year.
* some RF signals. Here in Germany we have a DCF77 (77 500Hz) from an atomic clock, used for precise clocks.
* almost any microcontroller. Maybe you find one to program it for you. (Run from a 32768 Hz XTAL, maybe just a timer configured to generate the signal, no main loop running). Could be an 8 pin THM IC....

Klaus

 

[FvM]

MHz crystal is causing unnecessary current consumption. Use 32 kHz watch crystal instead. CD4000 CMOS run well from 3V lithium battery, as said.