[time-nuts] Odd request
Tom Van Baak (mobile)
tvb at LeapSecond.com
Thu Jan 25 22:12:11 UTC 2007
> Time-nuts
>
> I appreciate the comments regarding horological obsession. Mine started with a desire for an accurate master
> oscillator for my ham shack (built and use a couple Shera GPSDO's) and has blossomed into a much broader interest
> in time (Ex tempus, sapientia?)
>
> This has led me to a silly quest. I'd like to use a traditional clock face and hands as an output device for a
> 1PPS signal from my GPSDO.
>
> I know this is a very broad question, but does anyone have advice on where I might start hacking (or making) a
> mechanical clock face to accomplish this? Is there a simple clock design that I could start with to build my own?
> Maybe replacing a pendulum or escapement with a solenoid? Any examples to work from?
>
> Mark
This is one reason the older model HP 5065A and 5061A
with Patek analog clocks are so desirable; they pre-date
LED, LCD, or VFD clock displays.
But one easy way to do it today is start with a $5 standard
quartz clock display. 1) Either run a precise synthesized
32 kHz signal into it (replacing the xtal), or drive the little
bipolar stepper yourself.
A 50 millisecond +1.5 VDC pulse is all you need; next
second give it a -1.5 VDC pulse, etc. This is a few lines
of code for a microcontroller. I've got pictures of this
somewhere on my web site, I think.
See also Bryan's cool stuff at:
http://www.bmumford.com/clocks/emindex.html
Some of us have driven traditional pendulum clocks with
GPS or atomic 1PPS. Another cute one is to take an
old Western Union, US Naval Observatory, SWCC
(Self-winding Clock Company) clocks and sync them
using a GPS-divided 1PPH (one pulse per hour) pulse.
See Mitchell's SWCC page at:
http://www.telechron.com/
Also, here's what "USNO time" meant in the 1930's...
http://www.leapsecond.com/history/usno.htm
/tvb
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