int prev = 0;
void setup() {
  Serial.begin(9600);
  pinMode(2, INPUT);
  pinMode(4, OUTPUT);
}
void loop() {
  int potValue = analogRead(2);
  if (potValue != prev) {
    Serial.print(potValue);
  }
  prev = potValue;
  if (Serial.available()) {
    int msg = Serial.read();
    if (msg) {
      analogWrite(4, (potValue / 16));
    }
  }
}