int pir = 12;
int buzzpin = 11;

void setup() {
  // put your setup code here, to run once:
  pinMode(pir, INPUT);
  pinMode(buzzpin, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  int value_of_pir = digitalRead(pir);
  if(value_of_pir == HIGH) {
    tone(buzzpin, 500,3);
  } else {
    tone(buzzpin, 0, 1);
  }
}