Microphone

The microphone is a basic electret mic, with a build in amplifier so the voltage will be at a level which you can directly read using the Arduino ADC (Analog-Digital Converter).

Note that the amplifier circuit uses a bit of power. Running on battery you will get a few days, but not much more than that. This makes it really suitable for situations where power will be available some, or all of the time. You might also think about solar power..?

Sample code is in microphone.ino, which expects this wiring:

The current audio intensity will be displayed on the LED in real time.