accerelometers

M

Michael Peters

Guest
I'd like to use accelerometers as contact microphones, so to speak, to
record subtle sound waves inside of things.

Can anyone shed light on accelerometers for sound recording, how and where
to get them for how much money?

It seems that they weren't made for sound recordings in the first place, so
I suspect one would need either special ones made for sound recording, or
converters of some kind.

Also, there seem to be different kinds of these devices - a while ago I've
read of people making recordings of insects using accelerometers fastened to
the tree twigs that the insects sat on - and today I read of Bill Fontana
who records metal objects (bridges) using an accelerometer with a magnet:
http://www.krimson-news.com/kcnndiaries/SidSmith.shtml



-Michael
www.michaelpeters.de
 
Michael Peters wrote:

I'd like to use accelerometers as contact microphones, so to speak, to
record subtle sound waves inside of things.

Can anyone shed light on accelerometers for sound recording, how and where
to get them for how much money?
Click to expand...
The most similar application that I know are the so called knock
sensors. They are piezoelectric accelerometers (actually they are
microphones with a mass applied to the moving part) and they are used to
detect "knocks" (detonation waves that follow the spark ignition) in
gasoline/diesel engines. Maybe if you use this as search string, you may
find something useful...

--
- asd -
 
dalai lamah wrote:
Michael Peters wrote:

I'd like to use accelerometers as contact microphones, so to speak, to
record subtle sound waves inside of things.

Can anyone shed light on accelerometers for sound recording, how and where
to get them for how much money?

The most similar application that I know are the so called knock
sensors. They are piezoelectric accelerometers (actually they are
microphones with a mass applied to the moving part) and they are used to
detect "knocks" (detonation waves that follow the spark ignition) in
gasoline/diesel engines. Maybe if you use this as search string, you may
find something useful...
Click to expand...
Another product to search for is alarm system window break detectors.
 
dalai lamah wrote:
The most similar application that I know are the so called knock
sensors. They are piezoelectric accelerometers (actually they are
microphones with a mass applied to the moving part) and they are used to
detect "knocks" (detonation waves that follow the spark ignition) in
gasoline/diesel engines.
Click to expand...
I made myself a nice little accelerometer using three 10p piezo
microphone/ sounders (the birthday card sort) soldered together in the
form of a tetrahedron, with a ball of blu-tack in the middle. A little
maths to resolve the direction, and off you go.

Paul Burke
 
On Wed, 08 Dec 2004 08:49:32 +0000, Paul Burke wrote:

dalai lamah wrote:

The most similar application that I know are the so called knock
sensors. They are piezoelectric accelerometers (actually they are
microphones with a mass applied to the moving part) and they are used to
detect "knocks" (detonation waves that follow the spark ignition) in
gasoline/diesel engines.

I made myself a nice little accelerometer using three 10p piezo
microphone/ sounders (the birthday card sort) soldered together in the
form of a tetrahedron, with a ball of blu-tack in the middle. A little
maths to resolve the direction, and off you go.
Click to expand...
How well does it work?
--
Best Regards,
Mike
 
Active8 wrote:

I made myself a nice little accelerometer using three 10p piezo
microphone/ sounders (the birthday card sort) soldered together in the
form of a tetrahedron, with a ball of blu-tack in the middle. A little
maths to resolve the direction, and off you go.



How well does it work?
Click to expand...
Pretty abysmally I suppose, but good enough for the cheap demo of
vibration detector alarm that I was doing for a prospective customer,
i.e. I could show him that I could detect the unit moving, tell if the
move was vibration or the thing was being picked up or rotated, tell him
that the (simulated) Diesel had stopped. The project went no further,
but that's another story.

I'm sure that with a bit of development it could be quite OK for many
similar applications.

Paul Burke
 
Paul Burke wrote:
I made myself a nice little accelerometer using three 10p piezo
microphone/ sounders (the birthday card sort) soldered together in the
form of a tetrahedron
Click to expand...
I'd like to see a gemetrical diagram of a tetrahedron with only
three corners. Sounds kinda self-contradictory. Did you omit the
4th corner?
 
"Michael Peters" <mp@michaelpeters.de> wrote in
news:cp46vl$vh0$03$1@news.t-online.com:

I'd like to use accelerometers as contact microphones, so to speak, to
record subtle sound waves inside of things.

Can anyone shed light on accelerometers for sound recording, how and
where to get them for how much money?

Check out Bruel & Kjaer. See http://www.bkhome.com/bk_home.asp . They
Click to expand...
have an article about how they used an accellerometer to measure a cat's
purr.


--
Sooner dot boomer at gbronline dot com
 
On Tue, 7 Dec 2004 13:16:53 +0100, "Michael Peters" <mp@michaelpeters.de>
wrote:

I'd like to use accelerometers as contact microphones, so to speak, to
record subtle sound waves inside of things.
Click to expand...
You can also use Piezo

http://rocky.digikey.com/WebLib/Measurement%20Specialties%20Inc/Web%20Data/Piezo%20Film%20Sensors.pdf



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/
 
On Wed, 08 Dec 2004 18:41:48 -0500, Boris Mohar wrote:

On Tue, 7 Dec 2004 13:16:53 +0100, "Michael Peters" <mp@michaelpeters.de
wrote:

I'd like to use accelerometers as contact microphones, so to speak, to
record subtle sound waves inside of things.

You can also use Piezo

http://rocky.digikey.com/WebLib/Measurement%20Specialties%20Inc/Web%20Data/Piezo%20Film%20Sensors.pdf
Click to expand...
I still can't understand why the OP doesn't just use contact microphones
as contact microphones.

Oh, well.

Thanks,
Rich
 
On Thu, 09 Dec 2004 02:37:42 GMT, Rich Grise <rich@example.net> wrote:

On Wed, 08 Dec 2004 18:41:48 -0500, Boris Mohar wrote:

On Tue, 7 Dec 2004 13:16:53 +0100, "Michael Peters" <mp@michaelpeters.de
wrote:

I'd like to use accelerometers as contact microphones, so to speak, to
record subtle sound waves inside of things.

You can also use Piezo

http://rocky.digikey.com/WebLib/Measurement%20Specialties%20Inc/Web%20Data/Piezo%20Film%20Sensors.pdf


I still can't understand why the OP doesn't just use contact microphones
as contact microphones.

Oh, well.

Thanks,
Rich

Who be OP?
Click to expand...
--
Boris Mohar
 
I read in sci.electronics.design that Clifford Heath <no@spam.please>
wrote (in <31pdbuF3epsilU1@individual.net>) about 'accerelometers', on
Thu, 9 Dec 2004:
Paul Burke wrote:
I made myself a nice little accelerometer using three 10p piezo
microphone/ sounders (the birthday card sort) soldered together in the
form of a tetrahedron

I'd like to see a gemetrical diagram of a tetrahedron with only
three corners. Sounds kinda self-contradictory. Did you omit the
4th corner?
Click to expand...
'hedron' means 'face', not 'corner'. A tetrahedron has four triangular
faces. If you fix three discs together in 3 dimensions, the fourth face
is void.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
On Wed, 08 Dec 2004 21:53:31 -0500, Boris Mohar wrote:

On Thu, 09 Dec 2004 02:37:42 GMT, Rich Grise <rich@example.net> wrote:

On Wed, 08 Dec 2004 18:41:48 -0500, Boris Mohar wrote:

On Tue, 7 Dec 2004 13:16:53 +0100, "Michael Peters" <mp@michaelpeters.de
wrote:

I'd like to use accelerometers as contact microphones, so to speak, to
record subtle sound waves inside of things.

You can also use Piezo

http://rocky.digikey.com/WebLib/Measurement%20Specialties%20Inc/Web%20Data/Piezo%20Film%20Sensors.pdf


I still can't understand why the OP doesn't just use contact microphones
as contact microphones.

Oh, well.

Thanks,
Rich

Who be OP?
Click to expand...
In general, Original Poster. In this case, according to the thread,
"Michael Peters".

Hope This Helps!
Rich
 
On Thu, 09 Dec 2004 09:26:06 +1100, Clifford Heath wrote:

Paul Burke wrote:
I made myself a nice little accelerometer using three 10p piezo
microphone/ sounders (the birthday card sort) soldered together in the
form of a tetrahedron

I'd like to see a gemetrical diagram of a tetrahedron with only
three corners. Sounds kinda self-contradictory. Did you omit the
4th corner?
Click to expand...
OK, three-fourths of a tetrahedron. ;-)

Cheers!
Rich
 
Clifford Heath wrote:

I'd like to see a gemetrical diagram of a tetrahedron with only
three corners. Sounds kinda self-contradictory. Did you omit the
4th corner?
Click to expand...
Three sides, the fourth being open. I couldn't see what a fourth sensor
would contribute.

Paul Burke
 
On Thu, 09 Dec 2004 08:56:32 +0000, Paul Burke <paul@scazon.com>
wrote:

Clifford Heath wrote:


I'd like to see a gemetrical diagram of a tetrahedron with only
three corners. Sounds kinda self-contradictory. Did you omit the
4th corner?

Three sides, the fourth being open. I couldn't see what a fourth sensor
would contribute.

Paul Burke
Click to expand...
I can't see why a tetrahedral shape would be a good idea. I would put
the three at right angles, and extract the information for each axis
without recourse to trig.

d

Pearce Consulting
http://www.pearce.uk.com
 
Don Pearce wrote:

I can't see why a tetrahedral shape would be a good idea. I would put
the three at right angles, and extract the information for each axis
without recourse to trig.
Click to expand...
Yes, but (a) it looked nice and (b) it held the ball in place.

Paul Burke
 
On Thu, 09 Dec 2004 10:30:07 +0000, Paul Burke <paul@scazon.com>
wrote:

Don Pearce wrote:

I can't see why a tetrahedral shape would be a good idea. I would put
the three at right angles, and extract the information for each axis
without recourse to trig.


Yes, but (a) it looked nice and (b) it held the ball in place.

Paul Burke
Click to expand...
How come it didn't fall out the open side?

d
Pearce Consulting
http://www.pearce.uk.com
 
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