Motion alarm

// Motion alarm
// Is someone walking by? Then the red LED blinks and the buzzer sounds.

const int PIR_PIN = 2;      // OUT from the motion sensor on pin 2
const int BUZZER_PIN = 8;   // S from the buzzer on pin 8
const int LED_PIN = 13;     // Red LED on pin 13 (through the resistor)

void setup() {
  Serial.begin(9600);
  pinMode(PIR_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  Serial.println(F("Sensor warming up... stand still!"));
  delay(10000);             // The sensor needs a moment to get used to the room
  Serial.println(F("Alarm is on."));
}

void loop() {
  if (digitalRead(PIR_PIN) == HIGH) {     // Motion seen!
    Serial.println(F("Motion! ALARM!"));
    for (int i = 0; i < 5; i++) {         // Beep and blink 5 times
      digitalWrite(LED_PIN, HIGH);
      digitalWrite(BUZZER_PIN, HIGH);
      delay(150);
      digitalWrite(LED_PIN, LOW);
      digitalWrite(BUZZER_PIN, LOW);
      delay(150);
    }
  }
  delay(100);
}