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4 minutes ago, luiazazrambo said:

any chance you could post a schematic? 

It's a rather clever design isn't it? When I disassembled the microphone and photographed it I unfortunately very deliberately did not photographed the numbers. I sure there was a deliberate reason, why did that like? Like where would be the fun of reverse engineering it if I had the numbers something along those lines. So no I do not have the schematic. But how hard could it be to figure out it's only two transistors. A couple of surfacemount components which I think I did photograph how many combinations could we have?

 

56 minutes ago, luiazazrambo said:

is no DC:

Then actually there is DC as it's plugging into the input of the computer that's expecting a capacitive microphone so it's supplying the DC. One of the components may be a capacitor I'd have to look at the original photograph.

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@  luiazazrambo
So many posts, but I still do not understand what you are planning to do:
- connect a piezo microphone to a sound card?
- or something else?

It helps much to have a bit of electronic knowledge!

Regarding the discussed piezo bimorph:
- connecting it to a timing machine input without preamp is ok. Its input expects a piezo, has the right sensitivity and resistance.

-  connecting it to a computer soundcard mic-input without preamp is a technical error! 
Why? The piezo impedance is 700 pF (datasheet). The soundcard input resistance is 2.2 kOhms. Directly connected they form a highpass that suppresses all signals below 100 kHz! No watch ticking left then 😞

The simple 1-transistor circuit, proposed by Guido and me, matches both, forms a signal filter for watch sound and supplies amplification.

However it seems to be too simple for you. So you have to continue searching 🙂

Frank

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Hi Frank,

My intention has not changed since my first post on this topic. I want to use my microphone with open source TG and now with WOS. So far I like the one transistor solution the best working example, and it is not too simple, it is too difficult. 😄 Remember, "simple is beautiful". 

I asked many question not just because I want to make my microphone work, but i want to understand the principles and the ideas behind designs ppl used. I want to learn. Why rochelle salt was used in the past? Why one transistor, why two? Why piezo, why the green bimorph? If bimorph, how to use it properly? Does it matter how you glue it? Why Mark and Jamez reported with the green bimorph that they have not used pre-amp? I thought that that green bimorph has some magic property - as both of them used it - which would allow us to leave pre-amp behind. It turned out that Mark actually has a pre-amp, which he possibly did not know about. Or maybe his setup has changed since his post in 2014 and the videos published years later, but what about Jamez?

I am in the process to order transistors, piezos and possibly the green bimorphs too and I might do some experiments with them as time allows. I might even grow my own crystal if the lock down will last long. 😄

Best regards,

Lui

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23 minutes ago, luiazazrambo said:

Why one transistor, why two?

One transistor you get in the range of 30-40 dB of gain.  Two transistors will get you 60-80 dB of gain.  More gain for less sensitive sensor...less gain for more sensitive sensor.

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2 hours ago, luiazazrambo said:

Hi Frank,

My intention has not changed since my first post on this topic. I want to use my microphone with open source TG and now with WOS. So far I like the one transistor solution the best working example, and it is not too simple, it is too difficult. 😄 Remember, "simple is beautiful". 

I asked many question not just because I want to make my microphone work, but i want to understand the principles and the ideas behind designs ppl used. I want to learn. Why rochelle salt was used in the past? Why one transistor, why two? Why piezo, why the green bimorph? If bimorph, how to use it properly? Does it matter how you glue it? Why Mark and Jamez reported with the green bimorph that they have not used pre-amp? I thought that that green bimorph has some magic property - as both of them used it - which would allow us to leave pre-amp behind. It turned out that Mark actually has a pre-amp, which he possibly did not know about. Or maybe his setup has changed since his post in 2014 and the videos published years later, but what about Jamez?

I am in the process to order transistors, piezos and possibly the green bimorphs too and I might do some experiments with them as time allows. I might even grow my own crystal if the lock down will last long. 😄

Best regards,

Lui

I thought the same at first about the green bimorph. I thought it was "holy grail". Unfortunately in my country there is no way to find it and even impossible to request it overseas, since they do not send it. 
Thanks to Ryder @24h, who sent it to Guatemala, I realized that it is no better than a piezoelectric disc.
Go ahead .... It is one of the reasons for our existence: "ask ourselves questions and seek the answers .... seek the truth"

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22 minutes ago, guidovelasquez said:

I realized that it is no better than a piezoelectric disc.

It is a piezo. It has two piezo sheets glued together (that's why bi...).  Piezo discs are the same build, just one plate is brass, not piezo (cheaper!). Theoretically it produces half the voltage of a bimorph - not much difference!
 

3 hours ago, luiazazrambo said:

I asked many question not just because I want to make my microphone work, but i want to understand the principles and the ideas behind designs ppl used. I want to learn. Why rochelle salt was used in the past? Why one transistor, why two? Why piezo, why the green bimorph? If bimorph, how to use it properly? Does it matter how you glue it? Why Mark and Jamez reported with the green bimorph that they have not used pre-amp? I thought that that green bimorph has some magic property - as both of them used it - which would allow us to leave pre-amp behind. It turned out that Mark actually has a pre-amp, which he possibly did not know about. Or maybe his setup has changed since his post in 2014 and the videos published years later, but what about Jamez?

Ok, you have many questions but cannot sort all the information collected in the web. 
My advice is: read a book about electronics (... for beginners)! 
You will get structured knowledge instead of becoming confused by all the unstructured info bits in the web.

My second advice: start making instead of pondering too long. You will advance quickly by experience.

Frank

 

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4 hours ago, guidovelasquez said:

I realized that it is no better than a piezoelectric disc.

Not entirely a true statement. The only reason we even know what it is I dissected the clip on microphone used with the software found at the link below. Then if you're trying to squeeze it in a tiny space it is better.

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

You can see better pictures of their microphones here

https://www.etimer.net/

 

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On 11/27/2015 at 1:45 PM, svorkoetter said:

Guido, I will try your file. I believe you that the wav file is perfect (it's fairly easy to create such a perfect wav file), but the device you're playing it on (my sound card) is not perfect.

 

Regarding the penny, the only way to know if it is exactly 19.05 mm is to measure it with a known accurate ruler or caliper. What you are proposing is like measuring it using another penny.

 

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8 hours ago, luiazazrambo said:

I asked many question not just because I want to make my microphone work, but i want to understand the principles and the ideas behind designs ppl used. I want to learn. Why rochelle salt was used in the past? Why one transistor, why two? Why piezo, why the green bimorph? If bimorph, how to use it properly? Does it matter how you glue it? Why Mark and Jamez reported with the green bimorph that they have not used pre-amp? I thought that that green bimorph has some magic property - as both of them used it - which would allow us to leave pre-amp behind. It turned out that Mark actually has a pre-amp, which he possibly did not know about. Or maybe his setup has changed since his post in 2014 and the videos published years later, but what about Jamez?

A lot of questions up there? I'll list your questions out and answer them if I can

Why rochelle salt was used in the past? 

The simple answer is it's what they had available at the time.  The Piezoelectric A fact makes for a really good microphone for watches it small compact. Then since are asking so many questions. As a reminder the word microphone may not actually be technically correct. We're attempting to pick up the vibration that the watch generates which happens to be in a audio frequency range. The microphone itself preferably picks up zero audio because otherwise there's all sorts of background noise typically in a room. Or even the old days with the paper tape machines they were making a clicking printing sound you definitely did not what the microphone picking up its own printer. So were attempting to sense a vibration in an audio range.

I think in one of the really early machines they attempted the use of carbon microphone. But there physically bigger and don't work as well. One of the nice things with piezo They can be relatively small and not entirely picky on how their mounted sort of and they seem to work quite nicely. Plus I'm sure the original ones were adopted from something else there are available relatively cheap. I'm guessing the original square pick up his exact same one found in audio microphones so they didn't have to make something new and different.

why the green bimorph?

Because someone was attempting to make a easy to make pickup and they were trying to squeeze it in a physical space. Not that you can't squeeze the disc into a small space but the green sensor is much smaller. Also the original person who made the microphone was in the UK for all the green sensors appear to be and the relatively cheap if you buy him in very huge quantities. They just hard to get for the rest of us.

Does it matter how you glue it?

Yes according to the technical sheet it does. Which is why if you look at the original pickup that we have it does appear to be glued at one end to have a cantilever of effect like it's supposed to. And everywhere else we see a similar type mounting at least if you want it to work correctly.

Why Mark and Jamez reported with the green bimorph that they have not used pre-amp?

Some more I thought I snipped out the images but I can't find him because conveniently I don't name them correctly.  this just means I don't have any images for us right now. If you look Marks video carefully when you get the green sensor and pay attention to where the wires go they disappear off and there's a whitish object in the bottom corner of the microphone housing. Mark doesn't see it because he's not looking for it. As to the other person I don't know maybe you should try it be easy enough to just wire one up and plug it into the computer and see if it works.

One of the ways to answer questions is to do experiments to try things to see what works and doesn't work.

Then they'll your questions he didn't ask about optical microphones? Supposedly they work better than capacitive microphones. Here's just an example would probably have to design something special in other words steal the optical part and bounce it off the pickup but the watch pushes against as a wild guess.

https://www.sintef.no/en/projects/2010/micro-optical-microphones/

 

 

 

 

 

 

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5 hours ago, JohnR725 said:

As a reminder the word microphone may not actually be technically correct.

Completely agree. Actually although it is a microphone, technically it is a vibration sensor. It is difficult to pick up the waves that travel in the air from the sound of a watch. The best way to avoid background noise in a work room will be an efficient vibration sensor that captures these from the closest to their source.

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15 hours ago, JohnR725 said:

As a reminder the word microphone may not actually be technically correct.

According to IEEE Std 100-1996

Microphone: An electroacoustic transducer that responds to sound waves and delivers essentially equivalent electric waves.

I would say that a piezo sensor could be designed so that sound waves would cause the necessary flexing to produce "electric waves."  However, in common parlance, piezo devices are generally not referred to as "microphones."  Piezos are most effective when there is a mechanical interface between the piezo and the thing being sensed.

At the end of the day, it may be just splitting hairs.

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I attached the data sheet of the piezos made by Murata, on page 7 you can see the relation between the size and the resonant frequency. Also note that the plate can be something else than brass, last line is nickel alloy and it has a lower resonant frequency than brass.

piezo.JPG.1e83c408613cb23f5f34412d1d16793c.JPG

piezo_.pdf

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17 hours ago, LittleWatchShop said:

I built this about a month ago, I think. Just using an electret microphone, I got a pretty good signal with two stages of amplification.

2021-02-22 16_17_14-Photos.png

I printed a separate housing for the microphone and am posting some scope output using it. 

2021-02-23 10_12_48-Photos.png

SDS00007.png

SDS00006.png

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8 hours ago, luiazazrambo said:

I attached the data sheet of the piezos made by Murata,

If you realize the piezoelectrics here ARE NOT SOUND SENSORS, they are sound producers.
In the 1970s when quartz watches arrived, I had my first contact with piezoelectric discs. And they were always buzers. Over time I realized that they can be used as vibration sensors.

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2 hours ago, guidovelasquez said:

And they were always buzers. Over time I realized that they can be used as vibration sensors.

Indeed, the piezos that I used when originally developing Watch-O-Scope uses piezos taken out of a greeting card's speaker as their microphones.

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20 hours ago, LittleWatchShop said:

According to IEEE Std 100-1996

Microphone: An electroacoustic transducer that responds to sound waves and delivers essentially equivalent electric waves.

I would say that a piezo sensor could be designed so that sound waves would cause the necessary flexing to produce "electric waves."  However, in common parlance, piezo devices are generally not referred to as "microphones."  Piezos are most effective when there is a mechanical interface between the piezo and the thing being sensed.

At the end of the day, it may be just splitting hairs.

Doesn't this just verify that I was correct? We're not trying to pick up audio so in which case we do not need a microphone.

Then you might find the link below interesting

https://www.shure.com/en-US/performance-production/louder/the-history-of-crystal-microphones-and-artifacts-from-the-shure-archives

 

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2 hours ago, LittleWatchShop said:

So far (though I have tried), I have not been able (though I have tried) to prove you incorrect on any topic!

We have an interesting problem here would don't we? I have a heck of a lot of experience and knowledge in horology and in Horology your relatively new. Don't worry I'm sure you can find some place where I'm wrong.

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This may be a "tired" thread, but I still keep playing around with my sensor.

I did not have any decent piezos in my lab (hard to believe...I have everything else!), so I ordered some.

The two-transistor circuit needed a high impedance, so I added a JFET front end.  Had WAY too much gain, so I dialed the last two stages down.  May need to reduce it a little more.

Nice result.

Now, no background audio noise sensed (like with the electret), but guess what?  It senses me walking across a carpeted floor!!  I even have the sensor sitting on a rubber pad.

2021-02-28 13_32_39-Photos.png

Edited by LittleWatchShop
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1 hour ago, LittleWatchShop said:

This may be a "tired" thread, but I still keep playing around with my sensor.

I did not have any decent piezos in my lab (hard to believe...I have everything else!), so I ordered some.

The two-transistor circuit needed a high impedance, so I added a JFET front end.  Had WAY too much gain, so I dialed the last two stages down.  May need to reduce it a little more.

Nice result.

Now, no background audio noise sensed (like with the electret), but guess what?  It senses me walking across a carpeted floor!!  I even have the sensor sitting on a rubber pad.

2021-02-28 13_32_39-Photos.png

What diameter did you order?
From testing I found that the smaller the diameter, the better the "quality". Seems to pick up even less background noise and static the smaller you go.

Edited by 24h
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