int pir=12;
int buzz=11;

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

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