Re: [time-nuts] Mechanical clock sound pickup circuit

[Jim Lux]

On 12/14/15 9:12 PM, ed breya wrote:

This may be totally ridiculous, but maybe there's another way to get a
balance wheel signal. The X-band Doppler type microwave motion detectors
can pick up various object signals in free air from quite a distance, so
maybe up close there would be enough resolution and penetration of the
metal parts of a timepiece to get a usable signal in and out. It would
tend to accentuate the fastest part of any motion - the balance wheel in
this case. I can picture setting one up with the horn pointed at the
thinnest part, likely the watch face, from maybe a few inches away - or
whatever it takes to not overload the detector. The audio detector
signal (if sufficient) could then be processed in the same way as with a
microphone sound signal.


As it happens, I have a fair amount of recent experience detecting small 
(<1mm) motions using radar.


Yes, remarkably tiny holes will let enough signal in and out, but, it's 
going to be very, very position dependent. You have a lot of multipath 
in this kind of testing, and it's easy to wind up in a null zone.


You might want to look for K-band (24GHz) units: the shorter the 
wavelength, the more phase shift you get from the tiny motion.  To put 
some numbers on it: at 3 GHz, a 1mm displacement gives you about 6-7 
degrees; at 24 GHz, you're going to be getting 50-60 degrees.


You'll be wanting some form of homodyne detector (which has the nice 
property that the phase noise of the source cancels out, so you can have 
a pretty grungy quality oscillator).  The signal you're looking for, 
though, is phase shifts occurring at a 1Hz kind of rate.  Most of the 
cheap "motion detectors" have a high pass filter  (1 m/sec at 3 cm 
wavelength is 66 Hz) and the amplifier chain is AC coupled.


You'll need a good low noise amplifier with a low 1/f knee.

For reference, a receiver gain of about 60 dB gives you a millivolt kind 
of signal from a 1mm displacement with 1mW at 3GHz from a 0.1 square 
meter target at 10 meter distance. You can scale to your situation.



You'll probably want some way to subtract out the static baseline, so 
your high gain amplifier stages don't need enormous dynamic range. In my 
radars, I do this with an adjustable "leakage" path from Tx to Rx.  You 
could probably do it with a movable metal target next to your 
clock/watch and you adjust it for a null.



You probably also want a I/Q output: if you think about the signal 
you're receiving, it's a slowly moving vector that spans a fairly small 
phase angle (because it combines a very large static response from stuff 
that's moving plus a little tiny moving component). If that vector 
happens to point at 90 degrees to your I axis only, then you're great: 
the variation shows up in the I axis. But if the vector happens to point 
parallel to the I axis, the motion is very small.


With I/Q, you can  either do a arctan demodulation, or you can rotate 
the signal to make the variation largest (basically using the sin x=x 
approximation for small x)









Ed
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Re: [time-nuts] Mechanical clock sound pickup circuit

[ed breya]

This may be totally ridiculous, but maybe there's another way to get a 
balance wheel signal. The X-band Doppler type microwave motion detectors 
can pick up various object signals in free air from quite a distance, so 
maybe up close there would be enough resolution and penetration of the 
metal parts of a timepiece to get a usable signal in and out. It would 
tend to accentuate the fastest part of any motion - the balance wheel in 
this case. I can picture setting one up with the horn pointed at the 
thinnest part, likely the watch face, from maybe a few inches away - or 
whatever it takes to not overload the detector. The audio detector 
signal (if sufficient) could then be processed in the same way as with a 
microphone sound signal.


Ed
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Re: [time-nuts] Mechanical clock sound pickup circuit

[Chuck Harris]

Let's be serious here.  Radar is the wrong part of the E-M
spectrum.  Use light.  It is cheap, easy to detect, and
there are plenty of reflections to go around.

Or better still, listen to the tic.  Then you don't even
have to open the case Which brings this full circle.

-Chuck Harris

Jim Lux wrote:

On 12/14/15 9:12 PM, ed breya wrote:

This may be totally ridiculous, but maybe there's another way to get a
balance wheel signal. The X-band Doppler type microwave motion detectors
can pick up various object signals in free air from quite a distance, so
maybe up close there would be enough resolution and penetration of the
metal parts of a timepiece to get a usable signal in and out. It would
tend to accentuate the fastest part of any motion - the balance wheel in
this case. I can picture setting one up with the horn pointed at the
thinnest part, likely the watch face, from maybe a few inches away - or
whatever it takes to not overload the detector. The audio detector
signal (if sufficient) could then be processed in the same way as with a
microphone sound signal.


As it happens, I have a fair amount of recent experience detecting small (<1mm)
motions using radar.

Yes, remarkably tiny holes will let enough signal in and out, but, it's going 
to be
very, very position dependent. You have a lot of multipath in this kind of 
testing,
and it's easy to wind up in a null zone.

You might want to look for K-band (24GHz) units: the shorter the wavelength, 
the more
phase shift you get from the tiny motion.  To put some numbers on it: at 3 GHz, 
a 1mm
displacement gives you about 6-7 degrees; at 24 GHz, you're going to be getting 
50-60
degrees.

You'll be wanting some form of homodyne detector (which has the nice property 
that
the phase noise of the source cancels out, so you can have a pretty grungy 
quality
oscillator).  The signal you're looking for, though, is phase shifts occurring 
at a
1Hz kind of rate.  Most of the cheap "motion detectors" have a high pass filter 
 (1
m/sec at 3 cm wavelength is 66 Hz) and the amplifier chain is AC coupled.

You'll need a good low noise amplifier with a low 1/f knee.

For reference, a receiver gain of about 60 dB gives you a millivolt kind of 
signal
from a 1mm displacement with 1mW at 3GHz from a 0.1 square meter target at 10 
meter
distance. You can scale to your situation.


You'll probably want some way to subtract out the static baseline, so your high 
gain
amplifier stages don't need enormous dynamic range. In my radars, I do this 
with an
adjustable "leakage" path from Tx to Rx.  You could probably do it with a 
movable
metal target next to your clock/watch and you adjust it for a null.


You probably also want a I/Q output: if you think about the signal you're 
receiving,
it's a slowly moving vector that spans a fairly small phase angle (because it
combines a very large static response from stuff that's moving plus a little 
tiny
moving component). If that vector happens to point at 90 degrees to your I axis 
only,
then you're great: the variation shows up in the I axis. But if the vector 
happens to
point parallel to the I axis, the motion is very small.

With I/Q, you can  either do a arctan demodulation, or you can rotate the 
signal to
make the variation largest (basically using the sin x=x approximation for small 
x)








Ed
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Re: [time-nuts] Mechanical clock sound pickup circuit

[Andrea Baldoni]

Hello.
One answer for all.

> Peter
> The watch or clock produces many sounds during its operation and the issue
> is selecting the required one.  As you wish to investigate the timing

I noticed it, unfortunately it seems that often the different sounds are very
similar in level. I'm thinking about to make a multichannel system to take
maybe advantage of the phase.

> Chuck
> You can see things like irregular spacing of the teeth on the escapement
> wheel, and irregular spacing of many of the later wheels and pinions.

> By adjusting the gain of the amplifier stages, and the resulting
> shift in threshold, you can select out noises of different loudnesses.

I see that the software solutions out there mimic the capabilites of the
original printing machines (you gave a very nice description of!).
This is extremely interesting in the horological sense; my goal instead is to
obtain a single signal out of the many, the more representative of the actual
balance movement as possible, to measure its own jitter.

> Bob
> You *may* find that moving the passband of the mic up above 4 KHz helps 
> things a
> bit.

I found that the energy goes up to 20kHz in my setup (further, I cannot
measure). I thought that being a very short "click", it's the
sound equivalent of a step function, filtered by the elastic response of the
contact surfaces, bearings, case, piezo pickup, etc... Surely not all watches
are the same (in particular those made of plastic), I should investigate
further, or the assumption of step function is not correct from the start.

Actually the preamp has a highpass filter at 10kHz and the ambient noise has
been completely eliminated.

> Dave
> Someone is in the process of writing open-source watch timing software.
> You may want to look into it.

Thank you for the link, it seems good to do experimenting and troubleshooting
of the audio capture part.

> Alexander
> to get a reliable digital signal from a noisy analog signal is the most
> reliable way to use an analog PLL with a linear multiplier type phase detector
> ...
> low pass filter or integrator, the price of the method is that it also
> eliminates the phase-noise of the the input signal, .

In effect I'm exactly interested in the phase noise of the source, adding
the least possible noise in the capturing process. The varying
sound levels coming from the watch from tick to tick and the different sounds
coming because of different mechanical parts interactions make this a
challenge. The various timing machines instead focus to those different
sounds to infer the mechanical condition of the movement.

I'm thinking to process the signal through an antilog amplifier so
peaks will be sharper.

> Azelio
> Maybe this can be useful to make the pick-up:
> http://www.meas-spec.com/downloads/LDT_Series.pdf

Initially I thought it could have been possible to infer clock ticks by
the fact there is a moving mass inside it, but they are (fortunately) so
perfectly balanced, that they don't vibrate on the scale of the Hz/tens of Hz
those flexible piezo films are aimed to pickup.
The only thing you can pickup is the "noise" coming from the contact surfaces,
on a totally different frequency scale they are not sensible to.

Best regards,
Andrea Baldoni
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Re: [time-nuts] Mechanical clock sound pickup circuit

[Azelio Boriani]

Maybe this can be useful to make the pick-up:

http://www.meas-spec.com/downloads/LDT_Series.pdf

they can be found also on the usual auction site.

On Sat, Dec 12, 2015 at 10:28 PM, Alexander Pummer  wrote:
>
> Once upon the time there was a "Vibrograph", see nice pictures here:
> https://www.google.com/search?q=vibrograph=isch=u=univ=X=0ahUKEwigtcmSn9fJAhUW8GMKHVNyAMcQsAQIHA=1760=888
> ,which picked up the sound of watches, clocks, and the watch maker was able
> to set the watch very accurately, these machines did not used any fancy DSP
> despite that they worked very well, I myself used one some 55 years ego in
> Switzerland,.
> to get a reliable digital signal from a noisy analog signal is the most
> reliable way to use an analog PLL with a linear multiplier type phase
> detector  [ at least one input of the phase detector must be linear e.g. a
> transitional gate [cd4016 and it's derivatives ], the noise could be
> filtered out with a low pass filter or integrator, the price of the method
> is that it also eliminates the phase-noise of the the input signal, .
> That was the method which was used by the Vibrograph.
> 73
> LJ6UHN
> Alex
>
>
> On 12/12/2015 7:15 AM, Dave Martindale wrote:
>>
>> Someone is in the process of writing open-source watch timing software.
>> You may want to look into it.
>>
>> It was announced here:
>>
>> http://forums.watchuseek.com/f6/open-source-timing-software-2542874-post21977314.html#poststop
>>
>> It contains these links:
>> First the goodies. Here are Windows binaries
>> http://ciovil.li/tg.zip
>> and here is the full source code
>> https://github.com/vacaboja/tg
>>
>> Apparently this software is better at dealing with noisy signals from
>> microphones than Biburo.  Since it's open source, you can see what it's
>> doing internally.  It expects an analog input, and does its own filtering
>> to find the interesting edges within the sound of each tick.
>>
>> The precision with which you can time events is likely to be limited by
>> the
>> frequency response of your sensor and the amplifier.  If that's limited to
>> 20 kHz, a standard PC sound card is adequate.  For up to 80 kHz or so, you
>> can buy a relatively inexpensive USB "audio interface" that digitizes at
>> 192 kHz (typically 24 bit resolution).  At somewhat higher cost, you can
>> get professional audio interfaces that accept an external clock source.
>>
>> - Dave
>>
>>
>> On Fri, Dec 11, 2015 at 1:44 PM, Andrea Baldoni 
>> wrote:
>>
>>> Hello!
>>>
>>> I decided to do some experiments with mechanical clocks, so I worked a
>>> little
>>> on picking up escapement ticking sound, with the idea of processing it
>>> and
>>> obtaining a "clean" digital pulse to feed a counter.
>>>
>>> So far, I have not yet been able to find the best way to obtain a digital
>>> pulse,
>>> but I have already built the preamp for the piezoelectrick pickup, that
>>> I used to feed the mic input of a PC sound card for spectrum analysis.
>>>
>>> The timing could eventually be done in software because the whole idea of
>>> measuring watches by picking up their noise almost surely doesn't allow
>>> high
>>> resolution anyway, but I will plan to try hardware solutions as well in
>>> the
>>> future. I hope to be able to measure the jitter of the clock, but it will
>>> be
>>> very hard.
>>>
>>> In the meantime, with the free software Biburo you can download here
>>>
>>> http://tokeiyade.michikusa.jp
>>>
>>> you can regulate your wrist watch.
>>>
>>> Best regards,
>>> Andrea Baldoni
>>>
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>>> time-nuts mailing list -- time-nuts@febo.com
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>>> and follow the instructions there.
>>>
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>> -
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 2016.0.7294 / Virus Database: 4483/11164 - Release Date: 12/12/15
>
>
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[time-nuts] Mechanical clock sound pickup circuit

[Andrea Baldoni]

Hello!

I decided to do some experiments with mechanical clocks, so I worked a little
on picking up escapement ticking sound, with the idea of processing it and
obtaining a "clean" digital pulse to feed a counter.

So far, I have not yet been able to find the best way to obtain a digital pulse,
but I have already built the preamp for the piezoelectrick pickup, that
I used to feed the mic input of a PC sound card for spectrum analysis.

The timing could eventually be done in software because the whole idea of
measuring watches by picking up their noise almost surely doesn't allow high
resolution anyway, but I will plan to try hardware solutions as well in the
future. I hope to be able to measure the jitter of the clock, but it will be
very hard.

In the meantime, with the free software Biburo you can download here

http://tokeiyade.michikusa.jp

you can regulate your wrist watch.

Best regards,
Andrea Baldoni
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Re: [time-nuts] Mechanical clock sound pickup circuit

[Chuck Harris]

Back in the day, companies, like Vibrograf, Greiner, Elna, L, all
made timing machines that were based on the same principles.

The machines used a crystal, or tuning fork frequency reference, and
divided it down for the various standard (and not so standard) watch
beat rates.  The divided reference signal was used to turn a synchronous
motor, which rotated a drum which had a single turn loop of wire wound
around it, in the fashion of a "one turn per drum width" screw thread.

The watch's movement was clamped into a mount that had a piezoelectric
element, usually a rochelle salt crystal, that turned the small
vibrations into an electric representation that was fed to a chain
of amplifiers, filtered to amplify only the audible component until
it was large enough to trigger a tiny little thyratron tube.

The thyratron tube was set so that when the impulse exceeded a
variable threshold, it would fire, and would discharge a capacitor
into a solenoid for an instant, and pull in the armature that caused
a metal "bale", that was as wide as the drum, to strike the wire that
is wrapped around the rotating drum.

Because this wire essentially proceeded along the drum as it rotated,
the intersection of the wire, and the bale formed a scanning element,
not unlike the beam on a CRT oscilloscope.

To record the impulse, a paper tape was fed between the rotating drum,
a typewriter ribbon, and the metal bale.  When the metal bale "ticked",
it pushed the ribbon against the paper, and the travel was stopped by
the rotating wire wrapped on the drum, and an ink mark was made.

Ok, why all this complexity?

The idea was to, tick-by-tick, record the difference between the watch
movement's escapement's noise and the smooth flow of time embodied by
the crystal/tuning fork/dividers, etc..

By adjusting the gain of the microphone's amplifier stage, and as a
result, the threshold of the printer, the watchmaker could observe
quiet repeating noises all the way down to the pretty noisy tick of
the watch.

When you look at these actual traces, your squishy ware's DSP can
easily see the slope of the group of traces, which is the rate of the
watch, and any rhythmic variations of the individual "ticks" recorded
on the paper.

You can see things like irregular spacing of the teeth on the escapement
wheel, and irregular spacing of many of the later wheels and pinions.

By adjusting the gain of the amplifier stages, and the resulting
shift in threshold, you can select out noises of different loudnesses.
And the speed of the thyratron, and charged capacitor allowed multiple
strikes of the bale during each tick.

You can see the noise made by the impulse jewel touching the tuning
fork, and the noise made by the pallet jewels touching the escapement
wheel...  Lots of very interesting things that indicate the quality of
the movement, and the state of its lubrication... as well as a nearly
instantaneous indication of the rate of the watch, as it sits in the
various "positions" (dial up, dial down, pendant up, down, right left...)

All of this from the feverish minds of horologists back at the dawn of
the vacuum tube.

I would suggest that any programming you use for your tools do similar
things.

-Chuck Harris

Andrea Baldoni wrote:

Hello!

I decided to do some experiments with mechanical clocks, so I worked a little
on picking up escapement ticking sound, with the idea of processing it and
obtaining a "clean" digital pulse to feed a counter.

So far, I have not yet been able to find the best way to obtain a digital pulse,
but I have already built the preamp for the piezoelectrick pickup, that
I used to feed the mic input of a PC sound card for spectrum analysis.

The timing could eventually be done in software because the whole idea of
measuring watches by picking up their noise almost surely doesn't allow high
resolution anyway, but I will plan to try hardware solutions as well in the
future. I hope to be able to measure the jitter of the clock, but it will be
very hard.

In the meantime, with the free software Biburo you can download here

http://tokeiyade.michikusa.jp

you can regulate your wrist watch.

Best regards,
Andrea Baldoni



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Re: [time-nuts] Mechanical clock sound pickup circuit

[Bob Camp]

HI

You *may* find that moving the passband of the mic up above 4 KHz helps things 
a bit. 
An analog high pass filter that rejects normal speech and low frequency rumble 
ahead of the detection
process wold be the old school way to do it. 

The degree to which that helps depends a bit on the tick that your escarpment 
makes. There is no
real guarantee that it’s got energy up above 4 KHz. They often do, but that’s 
not a guarantee. 

Bob

> On Dec 11, 2015, at 1:44 PM, Andrea Baldoni  wrote:
> 
> Hello!
> 
> I decided to do some experiments with mechanical clocks, so I worked a little
> on picking up escapement ticking sound, with the idea of processing it and
> obtaining a "clean" digital pulse to feed a counter.
> 
> So far, I have not yet been able to find the best way to obtain a digital 
> pulse,
> but I have already built the preamp for the piezoelectrick pickup, that
> I used to feed the mic input of a PC sound card for spectrum analysis.
> 
> The timing could eventually be done in software because the whole idea of
> measuring watches by picking up their noise almost surely doesn't allow high
> resolution anyway, but I will plan to try hardware solutions as well in the
> future. I hope to be able to measure the jitter of the clock, but it will be
> very hard.
> 
> In the meantime, with the free software Biburo you can download here
> 
> http://tokeiyade.michikusa.jp
> 
> you can regulate your wrist watch.
> 
> Best regards,
> Andrea Baldoni
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Re: [time-nuts] Mechanical clock sound pickup circuit

[Peter Torry]

Andrea,

The watch or clock produces many sounds during its operation and the 
issue is selecting the required one.  As you wish to investigate the 
timing function may I suggest that you incorporate some form of level 
control to eliminate minor signals and allow only the strong sounds from 
the escapement.  You will find that even these will vary dependant upon 
the amount of drop each pallet has and if it is in beat.  It may be 
interesting for you to have a look at the various watch timing machines 
that are available and see if any ideas spring to mind.
I use a home-made system but various software and hardware solutions 
exist such as http://home.teleport.com/~gregsa/clocks/wtm/index.htm and 
http://www.delphelectronics.co.uk/products.html


Good luck with your experiments.

Peter



On 11/12/2015 18:44, Andrea Baldoni wrote:

Hello!

I decided to do some experiments with mechanical clocks, so I worked a little
on picking up escapement ticking sound, with the idea of processing it and
obtaining a "clean" digital pulse to feed a counter.

So far, I have not yet been able to find the best way to obtain a digital pulse,
but I have already built the preamp for the piezoelectrick pickup, that
I used to feed the mic input of a PC sound card for spectrum analysis.

The timing could eventually be done in software because the whole idea of
measuring watches by picking up their noise almost surely doesn't allow high
resolution anyway, but I will plan to try hardware solutions as well in the
future. I hope to be able to measure the jitter of the clock, but it will be
very hard.

In the meantime, with the free software Biburo you can download here

http://tokeiyade.michikusa.jp

you can regulate your wrist watch.

Best regards,
Andrea Baldoni


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Re: [time-nuts] Mechanical clock sound pickup circuit

[Dave Martindale]

Someone is in the process of writing open-source watch timing software.
You may want to look into it.

It was announced here:
http://forums.watchuseek.com/f6/open-source-timing-software-2542874-post21977314.html#poststop

It contains these links:
First the goodies. Here are Windows binaries
http://ciovil.li/tg.zip
and here is the full source code
https://github.com/vacaboja/tg

Apparently this software is better at dealing with noisy signals from
microphones than Biburo.  Since it's open source, you can see what it's
doing internally.  It expects an analog input, and does its own filtering
to find the interesting edges within the sound of each tick.

The precision with which you can time events is likely to be limited by the
frequency response of your sensor and the amplifier.  If that's limited to
20 kHz, a standard PC sound card is adequate.  For up to 80 kHz or so, you
can buy a relatively inexpensive USB "audio interface" that digitizes at
192 kHz (typically 24 bit resolution).  At somewhat higher cost, you can
get professional audio interfaces that accept an external clock source.

- Dave


On Fri, Dec 11, 2015 at 1:44 PM, Andrea Baldoni 
wrote:

> Hello!
>
> I decided to do some experiments with mechanical clocks, so I worked a
> little
> on picking up escapement ticking sound, with the idea of processing it and
> obtaining a "clean" digital pulse to feed a counter.
>
> So far, I have not yet been able to find the best way to obtain a digital
> pulse,
> but I have already built the preamp for the piezoelectrick pickup, that
> I used to feed the mic input of a PC sound card for spectrum analysis.
>
> The timing could eventually be done in software because the whole idea of
> measuring watches by picking up their noise almost surely doesn't allow
> high
> resolution anyway, but I will plan to try hardware solutions as well in the
> future. I hope to be able to measure the jitter of the clock, but it will
> be
> very hard.
>
> In the meantime, with the free software Biburo you can download here
>
> http://tokeiyade.michikusa.jp
>
> you can regulate your wrist watch.
>
> Best regards,
> Andrea Baldoni
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] Mechanical clock sound pickup circuit

[Alexander Pummer]

Once upon the time there was a "Vibrograph", see nice pictures here: 
https://www.google.com/search?q=vibrograph=isch=u=univ=X=0ahUKEwigtcmSn9fJAhUW8GMKHVNyAMcQsAQIHA=1760=888 
,which picked up the sound of watches, clocks, and the watch maker was 
able to set the watch very accurately, these machines did not used any 
fancy DSP despite that they worked very well, I myself used one some 55 
years ego in Switzerland,.
to get a reliable digital signal from a noisy analog signal is the most 
reliable way to use an analog PLL with a linear multiplier type phase 
detector  [ at least one input of the phase detector must be linear e.g. 
a transitional gate [cd4016 and it's derivatives ], the noise could be 
filtered out with a low pass filter or integrator, the price of the 
method is that it also eliminates the phase-noise of the the input signal, .

That was the method which was used by the Vibrograph.
73
LJ6UHN
Alex

On 12/12/2015 7:15 AM, Dave Martindale wrote:

Someone is in the process of writing open-source watch timing software.
You may want to look into it.

It was announced here:
http://forums.watchuseek.com/f6/open-source-timing-software-2542874-post21977314.html#poststop

It contains these links:
First the goodies. Here are Windows binaries
http://ciovil.li/tg.zip
and here is the full source code
https://github.com/vacaboja/tg

Apparently this software is better at dealing with noisy signals from
microphones than Biburo.  Since it's open source, you can see what it's
doing internally.  It expects an analog input, and does its own filtering
to find the interesting edges within the sound of each tick.

The precision with which you can time events is likely to be limited by the
frequency response of your sensor and the amplifier.  If that's limited to
20 kHz, a standard PC sound card is adequate.  For up to 80 kHz or so, you
can buy a relatively inexpensive USB "audio interface" that digitizes at
192 kHz (typically 24 bit resolution).  At somewhat higher cost, you can
get professional audio interfaces that accept an external clock source.

- Dave


On Fri, Dec 11, 2015 at 1:44 PM, Andrea Baldoni 
wrote:


Hello!

I decided to do some experiments with mechanical clocks, so I worked a
little
on picking up escapement ticking sound, with the idea of processing it and
obtaining a "clean" digital pulse to feed a counter.

So far, I have not yet been able to find the best way to obtain a digital
pulse,
but I have already built the preamp for the piezoelectrick pickup, that
I used to feed the mic input of a PC sound card for spectrum analysis.

The timing could eventually be done in software because the whole idea of
measuring watches by picking up their noise almost surely doesn't allow
high
resolution anyway, but I will plan to try hardware solutions as well in the
future. I hope to be able to measure the jitter of the clock, but it will
be
very hard.

In the meantime, with the free software Biburo you can download here

http://tokeiyade.michikusa.jp

you can regulate your wrist watch.

Best regards,
Andrea Baldoni

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[time-nuts] Mechanical clock sound pickup circuit

[Mark Sims]

And check out Bryan Mumford's stuff at bmumford.com 
  
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