[time-nuts] My Casio G-Shock watch and other fun stuff
brooke at pacific.net
Thu Jun 21 12:09:07 EDT 2007
I've recently been interested in bats and have a heterodyne type ultrasonic
down converter to listen to the local ones. When tuned near 32 kHz I can hear
the crystal in the IMP2 slave clock driver.
I'm looking into building an ultrasonic microphone based on the transducer that
was used in the Polaroid Sonar cameras. These have a much broader frequency
response than the electrect condenser microphones used in the bat detector, but
need a clean 200 VDC bias supply. This setup could just "listen" to the
crystal in a watch.
http://www.prc68.com/I/Bats.shtml <- Bats
http://www.prc68.com/I/SETSC.shtml#IMP2 <- IMP2 slave clock driver
http://www.prc68.com/I/PSOSC.shtml <- Removing the sensor from a camera
Tom Van Baak wrote:
>>How was that data taken with, a Microset or some other way?
>>It's interesting in that it shows the rate was not adjusted.
> Since that watch is quartz analog I used a magnetic pickup
> to detect the 1PPS. Amplified, this then went into a 53131A
> counter using a GPS 1PPS as reference. I collected data
> for a couple of weeks, including hiding the wristwatch inside
> a metal soup can to force it to fail to sync with WWVB.
> It's harder to pull this off with a LCD digital watch. One must
> resort to optical detection (as Jim described in this thread)
> or possibly direct audio or RF monitoring of the faint 32 kHz
> oscillator signal.
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