brightness

 void setup() {

  // put your setup code here, to run once:

 pinMode(3,OUTPUT);

 Serial.begin(9600);

}

void loop() {

  // put your main code here, to run repeatedly:

  int i;

  for(i=0;i<255;i=i+10)

  {

    Serial.println(i);

    analogWrite(3,i);delay(100);

  }

  for(i=255;i>=0;i=i-10)

  {

    Serial.println(i);

    analogWrite(3,i);delay(100);

  }

}