I'm working on a design to have a microphone on Arduino board for sound detection (clapping sound etc). I see there are lot of circuits floating on internet but almost everyone has an output to ADC pin on Arduino. On my design, all the ADC pins are exhausted (using 6 PIR sensors), so i'm left with digital pins.
How can i use an analog microphone on digital pin, can it be done through peak detection circuit? Can anyone share a reference schematic?
Also, an audio amplifier is required or can i get this done through a rail to rail opamp with good slew rate?