int ldr = A5;          // LDR connected to analog pin A0
int buzzer = 7;        // Passive buzzer connected to digital pin 7
int relay = 6;         // Relay module connected to digital pin 8


int ldrValue = 0;

void setup() {
  Serial.begin(9600);
  pinMode(buzzer, OUTPUT);
  pinMode(relay, OUTPUT);
}

void loop() {
  ldrValue = analogRead(ldr);
  Serial.print("LDR Value: ");
  Serial.println(ldrValue);

  // ---- Range 1: 70 - 150 ----
  if (ldrValue >= 70 && ldrValue <= 150) {
    digitalWrite(relay, HIGH);  // Relay ON
    tone(buzzer, 550);          // Passive buzzer tone 550 Hz
  }

  // ---- Range 2: 160 - 400 ----
  else if (ldrValue >= 160 && ldrValue <= 400) {
    digitalWrite(relay, LOW);   // Relay OFF
    noTone(buzzer);             // Stop buzzer
  }

  // ---- Range 3: 410 - 550 ----
  else if (ldrValue >= 410 && ldrValue <= 550) {
    digitalWrite(relay, HIGH);
    delay(300);                 // On for a moment
    digitalWrite(relay, LOW);
    delay(300);                 // Off for a moment
    tone(buzzer, 770);          // Tone 770 Hz while toggling
  }

  // ---- Outside all ranges ----
  else {
    noTone(buzzer);
    digitalWrite(relay, LOW);
  }

  delay(100);
}