#define PIN_ANALOG_IN  34  //the pin of the Potentiometer

void setup() {
  Serial.begin(9600);
}
 
void loop() {
  int adcVal = analogRead(PIN_ANALOG_IN);
  double voltage = adcVal / 4095.0 * 3.3;
  Serial.printf("ADC Val: %d,  \t Voltage: %.2fV\n", adcVal,  voltage);
  delay(200);
}