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PICAXE Sound Detector Circuit



The circuit above is how to hook up a microphone to a picaxe to either have it detect the presence of sound (using a digital pin) or the sound level (readadc). The question I have is in a couple spots it connects a capacitor to the middle of a resistor. Does this mean you connect it to both sides of the resistor?

sound_circuit.jpg40.52 KB

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Could someone please explain to me what the function of C2 is in this circuit? I built this with a few components slightly different and without C2. It detects sound and still operates as a distorting pre-amplifier.

It's a pretty tiny cap, so probably just there to allow high frequency noise bypass the 100kΩ resistor. As you've already discovered, not critical at all =)

I have been trying and trying but just can't get this circuit to work... I have breadboarded it alot of times and swapped out every single component. I know it is probably something easy that I just can't figure out or have understanded wrong. This damn circuit is bothering me like acid in my eyes.