Sound Level Meter

[harsha_oak]

Guys,

I,m helping a couple of school students in doing their high school project

I need a sound level meter which can give output in terms of voltage based on the ambient sound. I found this circuit in the URL mentioned below. I've built the circuit but not getting any output irrespective of the change in ambient sound.

http://hop.concord.org/s1/ext/s1em.html

Can you help me in clarifying as to why it is not functioning or are there any circuits available for this purpose.

 

[davenn]

hi there
welcome to the forums

well it mite be a really good idea for you to show us some pics of your construction
Maybe we mite see some wiring faults you have made ??

cheers
Dave

 

[Arouse1973]

You may need a capacitor and bleed resistor on the output. If the sound changes quickly then the voltmeter might not be fast enough to capture it.
thanks
Adam

 

[KrisBlueNZ]

That circuit should work OK. Post some photos of your construction.

What kind of microphone did you use? You need an electret type - a small cylindrical thing with a hole in one end and two solder connections at the other, one of which is connected to the metal part. This is the negative side and needs to be connected to the 0V rail of the circuit.

 

[harsha_oak]

thanks all guys. i was able to contact the researcher who built the circuit who suggested a few changes. Will implement these and keep you guys posted on the progress.