arduino_st_led_brightness.inc

int brightness =0; //defined the int var brightness and set the init value,it is use to show the led light
int fadeAmount = 5; //defined int var fadeAmount,it use to set the light add/mins count

void setup()
{
 pinMode(9,OUTPUT); //set the prot 9 is output port
}

void loop()
{
  analogWrite(9,brightness); // set the port 9 use brightness
  
  brightness = brightness + fadeAmount; //change the brightness value,make led light can next loop change
  
  if(brightness == 0 || brightness == 255){
    fadeAmount = -fadeAmount; //make the light can high or low
  }
  
  delay(30); //delay 30 seconds
  
}