int pir=6; //d6
// #define pir 6
void setup() {
  // put your setup code here, to run once:
  pinMode(pir,INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  int a = digitalRead(pir);
  if(a==HIGH){
    digitalWrite(13,HIGH);
    delay(1000);
    digitalWrite(13,LOW);
    delay(1000);
  } else {
    digitalWrite(13,LOW);
  }
}