Seeking suggestion for Mic & Preamp

Thread Starter

JDC

Joined Feb 29, 2008
3
I seek a circuit suggestion for the following application:

I want to place a small microphone on the outer surface of a pipe adjacent to a zone that has turbulent flow of liquid moving through it, i.e. the microphone serves as a stethoscope.

I seek a suggestion for a microphone selection and preamp circuit powered by 5VDC, with an amplified output of the microphone input, i.e. 0 to about 5volts. I wish to send the pre-amp output to a frequency counter. I will [later] correlate the frequency to volumetric flow rate of liquid through the pipeline. I do not care much about waveform. I simply want to have a 0-to-5 volt AC output that feeds my 0-to-5 volt pulse counter.
 

beenthere

Joined Apr 20, 2004
15,819
The Wikipedia article - http://en.wikipedia.org/wiki/Contact_microphone - is hardly definitive, but the microphone type is probably more suited to your interest.

Besides using some similar device, you might consider a bit of experimentation before going to a final design.

Be aware that it is quite trivial to reduce a higher voltage waveform to a 5 volt level. Don't start off blocking all paths but one.
 

Thread Starter

JDC

Joined Feb 29, 2008
3
Thank you beenthere,

It seems that a piezo contact microphone element, whose output is sent to a 5VDC-sourced comparator input, may cause the comparator output to be a 0 or 5VDC output depending on the presence, or absence, of vibration acting on the piezo element, true?

The comparator output may be received by a pulse counter.
 

beenthere

Joined Apr 20, 2004
15,819
I would want to characterize the signal before proceeding to final design. The contact mic is probably one of the devices that are suited to your application.
 
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