[time-nuts] RE; New Wrist watch

[John Lofgren]

Unfortunately I don't have that article, anymore, but I remember the basics from it.  The author used one of the Radio Shack piezo sounder elements as the pickup.  It was one of the 3 wire styles designed for an external oscillator circuit.  I think it might have been around 1 cm diameter.

The part I can't remember is the amplifier.  It could have been a PLL or may have just been a high gain video amplifier, like the MC1350.

Anyway, if somebody wants to look for the article it was somewhere in the 1985 to 1995 timeframe.

There are also commercial tools from Horotec and others built for this purpose.  Just google "watch tester" and you'll find a host of products.

-John




-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Robert LaJeunesse
Sent: Wednesday, September 12, 2012 7:49 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] RE; New Wrist watch

If I recall correctly it was in RF Design magazine many years ago that a 
short article included a schematic for using an ultrasonic sensor and selective 
amplifier (narrowband PLL?) to pick up the 32KHz vibration and convert it to a 
measurable signal. I'd expect a normal microphone to pick up way too much 
extraneous noise such that the 32KHz could not be successfully recovered.
 
Bob L.

________________________________

From: Azelio Boriani azelio.boriani at screen.it

Interesting: trying to "hear" a low frequency crystal using a microphone...
it should be hard: the crystal has to make the case vibrate and this is
energy consuming (unless it resonates). I don't expect to pick up nothing,
except the step motor driving the hands.

On Wed, Sep 12, 2012 at 9:45 AM, Hal Murray <hmurray at megapathdsl.net> wrote:

> Has anybody "listened" to such a watch?  (with a microphone)
>
> Can you hear both the 32KHz basic timekeeping as well as the "tick" when
> the
> second hand takes a step?
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