Potentiometers

I will use two potentiometers for delay input and input for microphone sensitivity. Here is a simple drawing:

potentiometer

The maximum resistance of the potentiometer is not relevant. You can imagine this as two serially connected resistances and the arduino input is in between them. The voltage is divided between the two resistances according to their values. You can read about this in more detail here.

For setting the delay we need precise settings on the potentiometer. Simple potentiometers turn only ones which makes the setting really difficult. So I will use a precision potentiometer that tuns at least 10 times until it gets from zero to maximum resistance. For microphone sensitivity I don’t need that high precision, so I will use a simple cheap potentiometer for that.