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Re: Microphone risk factors

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Don Y:
> On 5/12/2017 8:02 AM, Michael Kellett wrote:
>>> What I'm looking for are guidelines that might be common to all
>>> such "transducers" with *specific* refinements that would
>>> apply to different technologies.  Most of the information I've
>>> found specifies those refinements in terms of cost or
>>> *signal* characteristics (use this for lots of dynamic range
>>> in signal; use that for a flat response; etc.)
>>
>> There are so many different factors that affect reliability that
it's
>> not possible to help without more information.
>>
>> For example:
>> Many of the tiny mics (including most MEMS devices)  have very small
>> holes for the sound to get in - they are very susceptable to dirt. A
>> nice big traditional moving coil microphone with a 1.5" diameter is
not
>> much upset by mouse crap sized particles but may  have other issues.
>>
>> The MEMs mics are likely to be the most realible in terms of random
>> failures in benign conditions (because of the very automated and
>> controlled manufacturing process.)
>>
>> So if you tell us what you want to do with it it may be possible to
>> help.
> 
> You're looking at it the wrong way.  I want to know what can
> possibly be done WITH a microphone as a cheap transducer to
> decide how I can apply them.
> 
> You'd like me to say "I want to deform a piece of metal; how
> can I do that?"
> 
> Ans:
> - wack it with a hammer
> - bend it with some pliers
> - swage it in a hydraulic press
> - heat it to its melting point and drape it over a form
> - selectively add/remove material to affect the net deformation
> 
> I, instead, am saying, "Hammers are cheap.  What sorts of things can
> I do with them?  And, what are the things that will cause a hammer
> to fail or be contraindicated in a particular application."
> Ans:
>     "You could use it to deform a piece of metal..."
>     "You could use it as a paperweight..."
>     "You could use it to drive a nail..."
>     "You could use it as a tourniquet..."
> 
> [Ask yourself what uses you can devise for a microphone (or any
> other transducer of your choosing).  If you can't come up with
> a dozen (or score), you're not trying!]
> 
> As I mentioned previously, a friend uses them in qualifying new
> engines -- "listen" for characteristic sounds of valve/lifter/rocker
> noises instead of pulling the valve covers off after every N hours
> of simulated wear.
> 
> Another firm has a device that uses a microphone to determine the
> structural integrity of telephone poles.
> 
> Putting a microphone on a hot engine block exposes it to a different
set
> of stresses than holding it against a telephone pole.

OK - I finally get what you are after but I'm not that interested in
playing - 
I spent a fair chunk of my early engineering career designing and making
microphones and that branched out into accelerometers and from there we
moved into making knock sensors and supension control systems and then
to shock recorders and then the company went bust (15 years ago) and I
do other stuff now.

If I had a really good off the wall idea about using microphones I
wouldn't share it here :-)

But - more seriously - the question is just too open.

The only slightly novel thing I've considered recently is using some
cheapo ST MEMs mics with a frequency response up to 40kHz+ to make an
anemometer.

MK

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Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-10 21:27 -0700
  Re: Microphone risk factors Phil Allison <pallison49@gmail.com> - 2017-05-10 21:39 -0700
  Re: Microphone risk factors jrwalliker@gmail.com - 2017-05-11 07:01 -0700
    Re: Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-11 11:06 -0700
      Re: Microphone risk factors piglet <erichpwagner@hotmail.com> - 2017-05-12 09:02 +0100
      Re: Microphone risk factors "Michael Kellett" <nospam@invalid.com> - 2017-05-12 16:02 +0100
        Re: Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-12 09:37 -0700
          Re: Microphone risk factors "Michael Kellett" <nospam@invalid.com> - 2017-05-12 18:08 +0100
            Re: Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-12 11:02 -0700
              Re: Microphone risk factors Phil Allison <pallison49@gmail.com> - 2017-05-12 17:44 -0700
              Re: Microphone risk factors Terry Newton <nbill@bellsouth.net> - 2017-05-13 17:19 +0000
                Re: Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-13 11:57 -0700
                Re: Microphone risk factors Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-13 19:12 +0000
                Re: Microphone risk factors Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-14 08:40 +0000
                Re: Microphone risk factors Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-14 09:17 +0000
                Re: Microphone risk factors Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-14 10:49 +0000
                Re: Microphone risk factors Terry Newton <nbill@bellsouth.net> - 2017-05-13 19:26 +0000
                Re: Microphone risk factors (OT -- long) Don Y <blockedofcourse@foo.invalid> - 2017-05-13 13:37 -0700
            Re: Microphone risk factors "dcaster@krl.org" <dcaster@krl.org> - 2017-05-13 11:06 -0700
              Re: Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-13 12:11 -0700
              Re: Microphone risk factors krw@notreal.com - 2017-05-13 20:36 -0400

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