// Pin Definitions
#define LDR_AO A0      // LDR Analog Output
#define LDR_DO 2       // LDR Digital Output
#define PIR_PIN 3      // PIR Sensor Digital Output
#define TRIG_PIN 9     // Ultrasonic Trigger
#define ECHO_PIN 8     // Ultrasonic Echo
#define POT_PIN A1     // Potentiometer Output
#define BUZZER_PIN 10  // Buzzer Control Pin

void setup() {
  // Initialize Serial Monitor
  Serial.begin(9600);

  // Configure Pins
  pinMode(LDR_DO, INPUT);    // LDR Digital Output
  pinMode(PIR_PIN, INPUT);   // PIR Sensor Output
  pinMode(TRIG_PIN, OUTPUT); // Ultrasonic Trigger
  pinMode(ECHO_PIN, INPUT);  // Ultrasonic Echo
  pinMode(BUZZER_PIN, OUTPUT); // Buzzer Control Pin

  // Initial State of Buzzer
  digitalWrite(BUZZER_PIN, LOW);
}

void loop() {
  // 1. LDR Readings
  int ldrAnalog = analogRead(LDR_AO); // LDR Analog Output (0-1023)
  int ldrDigital = digitalRead(LDR_DO); // LDR Digital Output (HIGH/LOW)

  Serial.print("LDR Analog: ");
  Serial.print(ldrAnalog);
  Serial.print(" | LDR Digital: ");
  Serial.println(ldrDigital);

  // 2. PIR Sensor Readings
  int pirState = digitalRead(PIR_PIN); // Detects motion (HIGH/LOW)
  Serial.print("PIR Motion Detected: ");
  Serial.println(pirState ? "Yes" : "No");

  // 3. Ultrasonic Sensor Readings
  long duration, distance;
  digitalWrite(TRIG_PIN, LOW); // Ensure trigger is low
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH); // Send 10µs pulse
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  duration = pulseIn(ECHO_PIN, HIGH); // Measure echo duration
  distance = (duration * 0.034) / 2;  // Calculate distance in cm

  Serial.print("Ultrasonic Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // 4. Potentiometer Readings
  int potValue = analogRead(POT_PIN); // Potentiometer Output (0-1023)
  float potVoltage = potValue * (5.0 / 1023.0); // Convert to voltage
  Serial.print("Potentiometer Voltage: ");
  Serial.println(potVoltage);

  // 5. Buzzer Logic
  // Buzzer triggers if:
  // - PIR sensor detects motion
  // - LDR DO (Digital Output) goes LOW (darkness detected)
  // - Ultrasonic sensor detects distance < 20 cm
  if (pirState == HIGH || ldrDigital == LOW || distance < 20) {
    digitalWrite(BUZZER_PIN, HIGH); // Activate buzzer
  } else {
    digitalWrite(BUZZER_PIN, LOW); // Deactivate buzzer
  }

  delay(500); // Wait for 500ms before the next loop
}