//set pin numbers
 
const int ledPin = 2;
const int buzzerPin = 3;
const int ldrPin = A0;
 
void setup () {
 
  Serial.begin(9600);
 
  pinMode(ledPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(ldrPin, INPUT);
}
 
void loop() {
 
  int ldrStatus = analogRead(ldrPin);  //read the state of the LDR value
 
  if (ldrStatus >= 900) {
 
    tone(buzzerPin, 100);
    digitalWrite(ledPin, HIGH);
    delay(100);
 
    noTone(buzzerPin);
    digitalWrite(ledPin, LOW);
    delay(100);
 
    Serial.println("----------- ALARM ACTIVATED -----------"); 
  }
  else {
 
    noTone(buzzerPin);
    digitalWrite(ledPin, LOW);
 
    Serial.println("ALARM DEACTIVATED");
  }
}