[time-nuts] Measuring the accurcy of a wrist watch

Robert Darlington rdarlington at gmail.com
Fri Apr 18 14:48:37 EDT 2014


Commercially they use piezo transducers ("bender disks") in direct contact
with the watch to hear them tick.  I did my best to build one up several
weeks ago.  I could hear ants walking but my cheap swiss movement was just
too quiet.  It was amazingly quiet, even going through a preamp and dialing
the vertical amp to 11 on the scope.  They must have them sized for
resonance a little closer to the spectrum given off by the movement.

-Bob


On Fri, Apr 18, 2014 at 9:43 AM, Chris Albertson
<albertson.chris at gmail.com>wrote:

> On Thu, Apr 17, 2014 at 11:12 PM, Hal Murray <hmurray at megapathdsl.net
> >wrote:
>
> >
> >
> > Steel makes very good springs.  Are there any non-magnetic materials that
> > are
> > close?
> >
>
> I think they can use some kind of non-magnetic stainless steel
>
> Also this might be a moot point because I got a good strong signal by
> placing the watch on top of the guitar strings.  I did not have to restring
> the guitar.   The wall clock works even some inches away.  You don't have
> to get really close to the magnets.   If you were building a sensor, just
> use a plain iron core and 1/4 pound of #40 wire
>
> >
> >
> --
>
> Chris Albertson
> Redondo Beach, California
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