[time-nuts] Physical Clocks - adjusting

Mike S mikes at flatsurface.com
Thu Apr 28 06:59:33 EDT 2005

What got my interest in precision time started was adjusting clocks - especially wristwatches. I've tried to keep track of watch time vs. WWV and tweak adjusters to make them better, but it's a very long process, and I've not been particularly successful, probably due to lack of patience and diligence.

So, with that interest, I thought to put together an electronic calibrator. My thought is to use a microphone or piezo disc somehow coupled to a watch to pick up the mechanical vibrations, amplify (filter?), and feed that into a TI counter. 3e-7 gets 1/sec/month, as much as can be expected with a normal wristwatch. That should be easily done, and allow adjustment in a matter of minutes. TVB's precision wristwatch isn't practical for my purposes. :-)

A commercial unit is shown here: http://www.bmumford.com/microset.html

They have a "simple watch sensor" ( http://www.bmumford.com/mset/access/watch.jpg ), which I guess to be a piezo sensor, fixed at one end with a brass post attached to the other, which in turn protrudes through the top of the case. Mechanical vibration in a watch in contact with the brass rod would generate the signal.

Anyone with any experience with such a calibrator? My biggest concern is that there will be too much noise in the signal to get an accurate TI measurement. 

More information about the time-nuts mailing list