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

[Max Robinson]

In the United States we can buy analog quarts watches from Wal-Mart for 
under 15 dollars.  When the battery dies you don't even bother to replace it 
you just buy a new watch, unless...the one you have is very good.  There is 
a lot of variation and buying one is the luck of the draw.  They can be as 
bad as 1 minute a month and they always seem to be gaining.  Right now I 
have one that gains about 2 seconds a month.  I fully intend to see if it is 
possible to replace the battery when it runs down.  Counting motor pulses 
seems to be a little impractical because it would take 12 days to get to 1e6 
accuracy.

Regards.

Max.  K 4 O DS.

Email: max at maxsmusicplace.com

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----- Original Message ----- 
From: "Tom Van Baak" <tvb at LeapSecond.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Tuesday, April 15, 2014 8:52 AM
Subject: Re: [time-nuts] Measuring the accurcy of a wrist watch


>> Some research has shown that there is an comparable instrument for ANALOG
>> quarz watches. As far as I understand it does not try to detect the quarz
>> frequency but detects magnetic pulses from the step motors that move the
>> hands of the watch.
>>
>> Has anyone of you ever tried to do this in a time nuts laboratory?
>
> Ulrich,
>
> Yes, this works well, for both those with seconds hands (one magnetic 
> pulse per second) and those with only minute/hour hands (one or two steps 
> per minute). A large coil of wire is all you need. Have a look at the 
> watch timing tools and sensors at http://www.bmumford.com/microset.html or 
> http://www.bmumford.com/mset/modelwatch1.html
>
> Here's an example using a magnetic sensor: 
> http://leapsecond.com/pages/Junghans/
>
> /tvb
>
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