[time-nuts] Odd request

Neon John jgd at johngsbbq.com
Thu Jan 25 23:34:47 EST 2007


On Thu, 25 Jan 2007 16:50:46 -0500, "Mark Amos" <mark.amos at toast.net>
wrote:


>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?

Finally something I can contribute.

Any el-cheapo quartz clock movement should work with a little mod.
I've disassembled several brands and they all appear to be the same on
the inside.  A chip-on-board does the logic and a 2 coil stepping
motor drives the second hand.  The minute and hour hands are driven
through conventional geartrains.  The stepper has two coils and the
rotor turns 90 deg with each step.  All you need is a little logic to
take the one PPS and turn it into stepper commands.  Anything from a
PLA to a PIC should do.

If you didn't want to mod the clock you could build a 32khz oscillator
phase locked to the one PPS signal and feed this in place of the
tuning fork crystal.  Hard to say which would be simpler but probably
modding the clock to drive the stepper directly.

John
---
John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
Don't let your schooling interfere with your education-Mark Twain



More information about the time-nuts mailing list