const int analogInPin = A0;
const int analogOutPin = 9;
    
int sensorValue = 0;
int outputValue = 0;

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

void loop() {
  // get analog value
  sensorValue = analogRead(analogInPin);
  // mapping value
  outputValue = map(sensorValue, 0, 1023, 0, 255);
  // change output value
  analogWrite(analogOutPin, outputValue);
  // print the results to the Serial Monitor:
  Serial.print("sensor = ");
  Serial.print(sensorValue);
  Serial.print("\t output = ");
  Serial.println(outputValue);

  delay(2);
}