pwm

byte led_pwm=3;
void setup()
{
  // put your setup code here, to run once:
  pinMode(led_pwm,OUTPUT); 
  randomSeed(analogRead(0));
  Serial.begin(9600);
}

void loop()
{
  int val;
  analogWrite(led_pwm,val=random(135)+120);
  Serial.println(val);
  delay(random(100));
  // put your main code here, to run repeatedly:
}