int pir_pin = 13;
int buzzer_pin = 11;
void setup() {
  // put your setup code here, to run once:
  pinMode(pir_pin, INPUT);
  pinMode(buzzer_pin, OUTPUT);
  Serial.begin(9600);

}

void loop() {
  // put your main code here, to run repeatedly:
  int value = digitalRead(pir_pin);
  if (value == HIGH) {
    tone(buzzer_pin, 900, 3);
    Serial.println("Motion Detected");
  }
  else {
    tone(buzzer_pin, 0, 2);
    Serial.println("Motion NOT Detected");
  }

}