microphone instead of sensor

Thread Starter

Eplanet

Joined Oct 25, 2007
42
hi dear friends
i want to make a shock sensor with microphone but you know the microphone take any voice even small i wont operate with small voice.
can you help me and any idea?
thanks
 

Wendy

Joined Mar 24, 2008
23,798
Are you going to try to measure G forces? Sounds like an interesting idea, but the little stickons do a fair job, assuming this is what you're talking about.
 

Thread Starter

Eplanet

Joined Oct 25, 2007
42
hi
no G force i want to starting alarm with touch a device that capacitor microphone inside it.
thanks
 

bertus

Joined Apr 5, 2008
22,921
Hello,

If you "shield" the microphone from surrounding sounds it could work.
You could place the microphone in a closed box attached to the part you want to sense.

Greetings,
Bertus
 

Audioguru

Joined Dec 20, 2007
11,248
Hi Eplanet,
If your sensor is a piezo transducer then it does not conduct current to bias the pin2 input of the opamp. Also the 1M resistor applies positive feedback making an oscillator.

If the opamp was biased properly and had negative feenback then its output would just be a short "tick" which is not long enough in duration to activate a DC beeper.

Here is the schematic of an e-drum preamp that uses a piezo sensor. the output pulse is stretched with a capacitor and drives the input of a computer to make any sound you want.
 

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