void setup() {
  // put your setup code here, to run once:
pinMode (11, OUTPUT);
pinMode (A3, INPUT);
Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
int x=analogRead (A3);
Serial.println("x:");
Serial.println(x);
int y=map(x, 0, 1023, 0, 255);
Serial.println("y:");
Serial.println(y);
analogWrite (11, y);
delay (1000);
}