D. I. Y. Watch Timing Machine.

[xyzzy]

That's the goal with a contact mic.  It picks up vibrations but not ambient sound.  Exactly what one wants for a movement microphone.

[JohnR725]

5 hours ago, CWRNH said:

Looks cool, great for voice, but I don't think it would work with watch movements.

It actually looks perfect for our application. Does not pick up audio which is exactly what we want. At least audio traveling through the air picks up vibrations. I was quite excited until I looked at the tech sheet. Everything was looking fine until I noticed how big it is. Yes I know we work on watches but soldering to something that tiny is quite challenging.

[CWRNH]

6 hours ago, xyzzy said:

That's the goal with a contact mic.  It picks up vibrations but not ambient sound.  Exactly what one wants for a movement microphone.

Okay, I see.  I have to look at it more, sorry.  I thought it directed an array of mics towards the object picking up vibrations in the air and not by actually contacting the movement.  Which I assumed would be a problem. 

[CWRNH]

A few questions.

Where do I find the actual specs of a Piezo contact mic? 

I am wondering if anyone can tell me what the actual mic element is that is used in the Vibrograf b200 microphone.

I don't quite have the understanding of exactly what the output is of the mic.  I want to design preamps but don't even know a few of the basics because I am so new to all this stuff.  I am trying to build filters to test but I don't know the input parameters or the right questions to ask to find them.  Eventually all this will be second nature but as of right now I am lacking understanding.

What is the-

Mic output and specs?

What are the specs of the PC mic input?

What is the typical gain needed overall?

 

[JohnR725]

5 hours ago, CWRNH said:

Where do I find the actual specs of a Piezo contact mic? 

I am wondering if anyone can tell me what the actual mic element is that is used in the Vibrograf b200 microphone.

You could try emailing the company at the link below. Ask them exact specifications for the Vibrograf b200 And see what happens. As it's obsolete they might actually tell you. Several years ago I know somebody who emailed them and asked for servicing information for the B100 and did get a response back. Response was normally they don't give out technical information but it's obsolete here the schematics. My amusement with that answer is that he gets the schematics. But years later on eBay I find the complete service manual for the B100. So obviously they did release that to somebody? Then yes it does have the microphone all the components how it goes together etc. But all it says for the pickup itself is that it is a single crystal. Typically with any of the schematics that I have if it shows the microphone it's the symbol of a crystal.

The easiest way to look at this would be to look at the specifications either for a crystal microphone or pretend were making a phonograph and look at the crystal pickup used in those. They should have a similar specifications to what were using.

https://www.greinervibrograf.ch/

 

 

[guidovelasquez]

6 hours ago, CWRNH said:

I am wondering if anyone can tell me what the actual mic element is that is used in the Vibrograf b200

First. About the Vibrograph microphone. It is a piezoelectric based on Rechelle's salt. In my experience, it is not as sensitive as a 27mm piezo welded to a small alligator clip.
I send 2 images. I send 2 images. The first is from Elma's professional microphone and the second from the piezoelectric disc in a small alligator clip.

Above.  Elma Mic.  

Above, Piezoelectric disc in alligator clip. In both cases a modified Pyle PP444 preamplifier was used. See the link. https://reparacionderelojes.weebly.com/modifying-pyle-pp444.html

 

Above Elma Mic.
About your question. you want to design preamps. But what application will you give it? Are they for timingmachine? or other application.
Regarding the other questions, I think they are solved by thinking about the nature of PC microphones. They are not intended for High Fidelity. But the nature of the sound of watches is not out of the range covered by these microphones.
And finally. If your preamps are intended for any of the known applications or software, they will handle decent sound from an acceptable vibration sensor, single transistor preamplifier very well. I mean WOS, TG, BIBURO, PCTM, PC-Zeitwaage 54, e-Timer and Tickoprint for android.

Edited March 20, 2021 by guidovelasquez
error de redacción

[guidovelasquez]

1 hour ago, JohnR725 said:

https://www.greinervibrograf.ch/

 

http://www.geocities.ws/dushang2000/Vibrograf/Vibrograf B200 User Manual.pdf

[xyzzy]

12 hours ago, JohnR725 said:

It actually looks perfect for our application. Does not pick up audio which is exactly what we want. At least audio traveling through the air picks up vibrations. I was quite excited until I looked at the tech sheet. Everything was looking fine until I noticed how big it is. Yes I know we work on watches but soldering to something that tiny is quite challenging.

Beyond the size, I believe MEMS devices are quite fussy about how they are soldered.  So for prototyping, one would get a coupon, like the VM1000 eval coupon.  But I don't see anyone offering the coupon for the VA1200.  Maybe it's too new.

[JohnR725]

4 hours ago, guidovelasquez said:

Vibrograph microphone. It is a piezoelectric based on Rechelle's salt

As far as I can tell everything covering a rather sizable time span they're basically all the same thing. They all physically look the same square with the leads attached. They all seem to have an aversion to moisture. 

Evolution of the sensors? Conveniently unhelpful for us I disassembled the microphone and the base which has the model number is now somewhere else. Reasonably sure this is a Vibrograph

It's an interesting design plastic case italicized on the inside for shielding. The sensor assembly is mounted the black plastic piece that just slides in. The protruding probes as I'll call them go through  soft basically like grommets. Then their motion Limited by the black plastic say they can't go very far and then the grommets they go through limit their motion also. Both sensors are identical they appear to be epoxy glued to the probe and they do not connect or the glue is. Otherwise it makes the wiring extremely confusing. You'll notice each one of the probes has been soldered and that goes to one of the terminals so that's the ground that also goes to one side of one of the sensors. Then both sensors are basically connected in series which I find is interesting

Then I assume that all that circuitry was there because their  coils on the other side because I assume this would do tuning fork watches. But it took the circuit board out there are no coils that circuitry is just for the pickup. It appears to have quite a few little tiny transistors  which is what happens when you don't have an op amp.

[JohnR725]

4 hours ago, guidovelasquez said:

http://www.geocities.ws/dushang2000/Vibrograf/Vibrograf B200 User Manual.pdf

Yes it's nice I have one. Now let's see you pull a rabbit out of the hat? I assume they named it the same thing so we need a (Vibrograf B200 Technical information). At least that's what it says on my B100 as opposed calling it a service manual. I'm not going count the pages but there's probably at least 100 pages here every single aspect of that timing machine. But other than crystal for the pickup that's it for specifications.

[JohnR725]

2 hours ago, xyzzy said:

Beyond the size, I believe MEMS devices are quite fussy about how they are soldered.  So for prototyping, one would get a coupon, like the VM1000 eval coupon.  But I don't see anyone offering the coupon for the VA1200.  Maybe it's too new.

They're not the only ones making microphones like this.

For instance at the link below there is one. Then there should be one of these lurking in the house someplace according to the receipt that I'm looking at I purchased it in October 2018. It should be lurking in one of the boxes of miscellaneous electronic components that looked nifty and should go into a project someday in my lifetime.

https://www.digikey.nl/product-detail/en/knowles/SPU0410LR5H-QB-7/423-1139-1-ND/2420983

[xyzzy]

7 hours ago, JohnR725 said:

They're not the only ones making microphones like this.

https://www.digikey.nl/product-detail/en/knowles/SPU0410LR5H-QB-7/423-1139-1-ND/2420983

That's not quite the same.  That is a normal MEMS microphone.  It has a port on the bottom and is designed to pick up vibrations in the air, i.e. sound, through that port.  These are quite common now and your earbuds, smart speaker, noise cancelling headphones, etc. probably all use them.

The VA1200 is billed as a "voice accelerometer".  It has no port.  It's designed for the device itself to be physically vibrated.

MEMS accelerators are of course also quite common now too and used in cell phones.

I guess there is something about the VA1200 that makes it more suited to pickup up accelerations from bone conducted speech vs which direction on a phone is currently "down".  That seems to be close to what a timegrappher mic should also do.

But I see the -6dB peak of the sensitivity is about 2 kHz - 3 kHz and it's -16 dB at 6 kHz.  So maybe it's too tuned to human speech and won't do so well at escapement ticks or Khoisan languages.

[JohnR725]

10 minutes ago, xyzzy said:

But I see the -6dB peak of the sensitivity is about 2 kHz - 3 kHz and it's -16 dB at 6 kHz.  So maybe it's too tuned to human speech and won't do so well at escapement ticks or Khoisan languages.

Yes I was well aware that it's different I did read the tech sheet I got super excited other than the size.

Then my reading skills are obviously lacking. Casually when you look at the specifications everything looks really really nice until you pointed out the numbers above? Then looking at the frequency chart it looks really nice until you look at the numbers carefully realize that it's definitely an issue.

Several years ago I read an interesting Chinese paper on timing watches and basically the suggestion was the Frequencies below 1000 cycles are Not needed. Which is why when I made one of the amplifiers I have I just filtered off everything below 1000 cycles and it works fine. But you look at the frequency chart which I now attaching looks nice and linear in the range that we could care less about and very nonlinear in the range that we do care about.

 

[praezis]

Looks like a nice mic to pick up ambient noise and ignore watch esc noise   Do we want that?

Re Seignette piezo:

My experience differs from Guido's. Commercial mics, if still ok, supply higher signal levels than a piezo disc. If they are so insensitive as described above, they are deaf. I saw this on younger crystals than B200, deaf or reduced sensitive crystals are rather the rule with old devices.

Frank

[CWRNH]

On 4/20/2020 at 8:50 PM, guidovelasquez said:

I have tried this Bimorph component. But the microphones of the 70's machines used very sensitive glass.
You can also try an electric piezo disc. the problem is with the disc is that there is no room for it in the vibrograph microphone unit

 

 

 

 

 

 

 

How well did this Bimorph component work?  Was it close to the original vibrograf?  What exactly is it and where would I find one?  Please, and thank you. 

As you know, nobody sells the vibrograf mic crystal, only option is to rebuild the original.  There must be some way to get a component that will work the same. 

[CWRNH]

Nome info I found.

https://www.steminc.com/piezo/PZ_property1.asp

https://www.steminc.com/PZT/en/piezoelectric-bimorph-sound-pickup-5-khz

https://www.steminc.com/PZT/en/piezo-ceramic-bimorph-15x15x06mm-4-khz-wire-lead

Edited March 21, 2021 by CWRNH

[guidovelasquez]

8 hours ago, praezis said:

My experience differs from Guido's. Commercial mics,

I have no arguments for the experience of Frank @praezis his trajectory is one of respect.
And I will agree with his observations and contributions. What I can definitely say is that it is very difficult for us to improve the commercial microphones of the old time machines. These are my observations.
1.- They are perfectly insulated or shielded to eliminate noise from electromagnetic sources.
2- its design is aimed at the most important frequencies in the sound of the clock.
3.- The cables from the pick-up to the unit are perfectly shielded.

[xyzzy]

Wow, so many piezos.  One could spend months trying different ones.

I see bunch described as ultrasonic sensors.  Add I understand it, collisions of hard things, like an escapement tooth and a pallet jewel, produce sounds in the ultrasonic range.

Most PC sound hardware can do 192 kHz recording now.  Good enough, in theory, to get to 96kHz, but that assumes the analog components pass those frequencies, which is likely a significant assumption, given the care with most PC audio hardware is designed and built and that humans can't hear those frequencies anyway.

But an amplifier could also be built to heterodyne the ultrasonic spectrum down to the 0-24kHz range.

Maybe the signal is cleaner up higher?

[JohnR725]

2 hours ago, CWRNH said:

How well did this Bimorph component work?  Was it close to the original vibrograf?  What exactly is it and where would I find one?  Please, and thank you. 

Was thinking we recently talked about the green sensor? Then I remembered we did we discussed the mounting it's critical how it's mounted otherwise it doesn't work very well.

The reason we know about the existence of the sensor is it's used with some software found at the first and second link below. I had the opportunity to dissect their clip on microphone discovered the sensor and tracked it down. Also we know from other sources that this is the sensor they use in all their devices. In addition to using it with their clip on sensor if you send an existing timing machine microphone it's upgraded with one of these sensors and their circuitry.

 

 

Original people using the sensor and their software

https://www.etimer.net/

http://www.delphelectronics.co.uk/products.html

The next to links or where it can be purchased from either the UK which I interpret to be the primary distributor which ships just about everywhere in the planet except the US. The next link is the US distributor. Even if it shows zero quantity in stock I is went ahead and ordered it and they came a few weeks later so that didn't seem to be an issue of having it in stock or not. Then yes you do have to purchase five of them even if it has a individual price.

https://export.rsdelivers.com/product/rs-pro/bm15015-06hc/rs-pro-vibration-sensor-15c-55c-dimensions-15-x/0285784

https://www.alliedelec.com/product/rs-pro-by-allied/285784/70637796/?keyword=70637796

Then my best guess is there the original distributor of the sensor. I can't tell if they're the original manufacturer or basically the sole distributor but in a case I do believe there the source.Which probably suggests we could ask them questions and probably purchase thousands of them.

https://lprs.co.uk/products/sensors/vibration-sensors.html

RS PRO Vibration Sensor.pdf

[guidovelasquez]

2 hours ago, CWRNH said:

the problem is with the disc is that there is no room for it in the vibrograph microphone unit

About the bimorph sensor, my opinion, is that I had more expectations about it than it actually has. I have experimented with piezoelectric discs and apart from the commercial microphones of the timegrapher machines, they are the ones that give the best results. I only have one that he gave me @24h. And I have treated it very carefully so as not to ruin it. I replaced the glass of the commercial microphone of the machine in the photographs, but taking into account that I run a very high risk of ruining it, which I do not want. When doing the test I obtained very low results, without modifying anything in the application chain. It may be that you need to repeat the experiment.

Above my skeleton watch with the bimorph sensor in Elma Mic.

Above my skeleton watch with the Elma professional Vintage microphone.

Above adapting a piezoelectric disc cut to the Elma microphone. I have no results but I remember that it was larger than the bimorph, but smaller than the Elma microphone.

Above the cut disk and the original crystal of Elma.

It is possible that I did not perform the tests to high standards.

 

[guidovelasquez]

57 minutes ago, xyzzy said:

1 hour ago, xyzzy said:

n amplifier could also be built to heterodyne the ultrasonic spectrum down to the 0-24kHz range.

It is possible that this document can assist in the design of the microphone and preamp.

 

WCE2007_pp624-629 Espectro Reloj.pdf

[CWRNH]

1 hour ago, guidovelasquez said:

 

WCE2007_pp624-629 Espectro Reloj.pdf 839.64 kB · 3 downloads

That is an awesome paper, I have looked through it many times.

[xyzzy]

Very interesting.  What I take away from that is that the main components of the sound are from the resonant modes of the components in the movement.  I.e., the pallet is vibrating like a tuning fork when the impulse jewel hits it.

It looks like most of the energy is in the 5-22 kHz range.  TG uses a HPF at 3 kHz.  Maybe it could be higher?  It might also makes sense to allow it to be changed based on the movement.

However, they only captured audio at 48 kHz, so any higher modes than 22 kHz aren't used.  There could be energy at higher frequencies, or more importantly, a better signal to noise ratio vs the background.

[JohnR725]

11 hours ago, guidovelasquez said:

 

WCE2007_pp624-629 Espectro Reloj.pdf 839.64 kB · 8 downloads

What's interesting about the above paper is that there was a second one?  I'm attaching the second one it has more pages has some different stuff.

 

Signature Analysis of Mechanical Watch Movements.pdf

[guidovelasquez]

9 hours ago, JohnR725 said:

hubo un segundo?

Excellent, Very grateful, I was not aware of this longer article.