[time-nuts] 1903 Railroad self-Winding / Self-setting Clock

Hal Murray hmurray at megapathdsl.net
Sat Nov 1 01:49:06 EDT 2014

We had something like that in school when I was a kid.  (many years ago)

I remember occasional click-click-click... as it got reset.

mpb45 at clanbaker.org said:
> I am wondering what the easiest approach to this might be?    I suppose I
> could take the 1-sec pulses from a GPSDO (Trimble Thunderbolt ?) and count
> 3600 of them to generate a momentary reset 3VDC signal.   In any event, I
> thought I would pass this by the Time-Nuts gang to see if any feedback is
> available as to what the least complicated (simplest) way might be to
> accomplish this. 

Counting to 3600 won't work with leap seconds.  :)

I don't know the details of how a pulse sets the clock hands.  I assume it 
can't set the time to a fraction of a pendulum swing so I don't see much use 
for something fancy like a GPSDO.  But this is time-nuts, so anything is 

I'd probably split the project into two parts.  One is to keep good time on a 
computer, say something like a Raspberry Pi.  You can use the net, or a low 
cost GPS unit, or something fancy like a GPSDO.

The second part is how and when to generate the pulse.  You can use GPIO 
pins, or modem control signals.

You could use an old PC, but the payback due to reduced power will pay for a 
Raspberry Pi in a year or two depending on your power rates and how much 
power your old PC burns.

These are my opinions.  I hate spam.

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