void setup() {
  // put your setup code here, to run once:
  pinMode(3, OUTPUT);
  pinMode(A1, INPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  int x=analogRead(A1);
  Serial.print("x: ");
  Serial.println(x);
  int y=map(x,0,1023,0,255);
  Serial.print("y: ");
  Serial.println(y);
  analogWrite(3,y);
  delay(100);
}