//analogWrite

int led = 9;           // the PWM pin the LED is attached to
int brightness;    // how bright the LED is
String inputString = "";         // a string to hold incoming data
boolean stringComplete = false;  // whether the string is complete

void setup() 
{
  pinMode(led, OUTPUT);
  Serial.begin(9600);
  inputString.reserve(100);
}

void loop() 
{
  //analogWrite(led, brightness);
  if (stringComplete) 
  {
    brightness =inputString.toInt() ;
    analogWrite(led, brightness);
    Serial.print(inputString);
    inputString = "";
    stringComplete = false;
    delay(100);
  }
  
}

void serialEvent() 
{
  while (Serial.available()) 
  {
    char inChar = (char)Serial.read();
    inputString += inChar;
    if (inChar == '\n')
    {
      stringComplete = true;
    }
  }
}