int outPin = 11;
int val;
int arpPoison = 0;
int red;
 
void setup()
{
  pinMode(outPin, OUTPUT); // sets the digital pin as output
  Serial.begin(9600);
  Serial.flush();
}
 
void loop()
{
  // Read from serial port
  if (Serial.available())
  {
    val = Serial.read();
    Serial.print(val);
    if (val == 'A') 
    {
       arpPoison = 1;
       for(red = 0; red <= 255; red+=5)
       {
         analogWrite(outPin, red);
         delay(30);
       }
       while (arpPoison == 1)
       {
         for(red = 255; red >= 25; red-=5)
         {
           analogWrite(outPin, red);
           delay(30);
         }
         for(red = 25; red <= 255; red+=5)
         {
           analogWrite(outPin, red);
           delay(30);
         }
         val = Serial.read();
         Serial.print(val);
         if (val == 'R')
         {
           arpPoison = 0;
           for(red = 255; red >= 0; red-=5)
           {
             analogWrite(outPin, red);
             delay(30);
           }
         }           
       }
    }
  }
}