char x;

void setup() 
{
   Serial.begin(9600); 
   pinMode(5,OUTPUT);
   digitalWrite(5,0);
}

void loop() 
{
  if(Serial.available()>0)
  {
 
   x=Serial.read();
   if(x=='r')
   digitalWrite(5, HIGH);
   Serial.println("HIGH");
   delay(1000);
   digitalWrite(5, LOW);
   Serial.println("LOW");

  }
}