Tom,
Thank you for your response. I don't think I could improve on the
accuracy of this old watch much by trying to "regulate" it. I was more
curious to see if there was any way to determine what was going on in side
it with out actually opening it.
The buttons on the side have long ceased to function their being clogged
with sweat and other detritus. Now even with it opened up the little switch
contacts inside seem to do nothing. It is set to DST so is useful most of
the year here. I tried to set it to standard time last Fall but gave up. It
was thirteen seconds fast then and now down to eleven seconds fast. I think
I will not mess with it any more till the battery dies. I have several other
toys to play with if I really need to know what time it is.
Al
I have a Timex watch that's probably seven or eight years old. It has
an
LCD readout. The buttons haven't worked in years. It looses about one
second
every three or four months. I have to take out the four microscopic
screws
in the back to get into it to set it. The only reason I hang onto it is
that
is the most accurate watch I've ever owned.
Is there some way to detect its internal frequency inductively? In the
past I have used old relay coils as inductive pickups with success, but
never with a watch.
Al
Hang on to that one; that's an unusually accurate watch.
I have been unsuccessful at picking up timing signals from a LCD watch. I
did try a webcam once but the timing resolution of an LCD display is
rather poor, in the 10 to 100 ms millisecond range. If you look a LCD
closely you'll notice how slowly the contrast transitions occur. The
acoustic, mechanical, electrical, and magnetic methods offer greater
resolution, but none of those work on LCD watches.
I wonder if a fine (sub-mm) optical sensor that tracks contrast changes in
a single segment would work. On a 7-segment display, the 'd' segment is
the best one to aim for since it changes 8 times every 10 seconds.
If you open it you may see a number of traces from the IC to the LCD with
pulse rates tied to the main oscillator. The problem here is that by
opening the case and measuring these extremely low current signals you
likely introduce a frequency offset.
When you say "set it" do you mean adjust the time or adjust the rate? One
idea to reset the time by a few seconds without opening it: raise or lower
the temperature by many tens of degrees for some number of hours or days.
/tvb
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