Read a potentiometer

Wiring

The center pin is the wiper: rotating the knob changes the voltage read by the ADC.

Code

const int potPin = A0;

void setup() {
  Serial.begin(9600);
}

void loop() {
  int raw = analogRead(potPin);
  int mapped = map(raw, 0, 1023, 0, 255);
  Serial.print("raw=");
  Serial.print(raw);
  Serial.print(" mapped=");
  Serial.println(mapped);
  delay(50);
}

Open Serial Monitor at 9600 baud and rotate the potentiometer — values should change monotonically from 0 to 1023 (aside from noise at the extremes).

Filter noise

For more stable reads, compute a moving average over 8 samples:

long readFiltered() {
  long sum = 0;
  for (int i = 0; i < 8; i++) {
    sum += analogRead(potPin);
  }
  return sum / 8;
}

Creative uses

• Control LED brightness via PWM on pin 9
• Modulate an oscillator frequency in Pure Data via Serial → OSC (later tutorials)