const int analogInPin = A1;
int sensorValue = 0;        // value read from the pot
int outputValue = 0;
void setup() {
  // initialize both serial ports:
  Serial.begin(57600);
    pinMode(13, OUTPUT);
  digitalWrite(13, HIGH);
}

void loop() {
  // read the analog in value:
    if (Serial.available()) {
      char inByte = Serial.read();
      if (inByte  == 'D') {
      sensorValue = analogRead(analogInPin);
      // map it to the range of the analog out:
      outputValue = map(sensorValue, 0, 1023, 0, 255);
      // change the analog out value:
      Serial.write(outputValue);
}
}
delay(100);
}