#define LDR_PIN 2          // Your LDR digital pin
#define BUTTON_PIN 7       // Button input pin
#define LASER_PIN 6        // Laser control pin (output)
#define LED_PIN 5          // LED indicator pin
#define BUZZER_PIN 9       // Buzzer pin

bool laserOn = true;       // Laser starts ON
bool lastButtonState = HIGH;
bool lastBeamState = HIGH; // to track changes and avoid flooding serial

void setup() {
  pinMode(LDR_PIN, INPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);  // Button with pullup resistor
  pinMode(LASER_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  digitalWrite(LASER_PIN, HIGH);  // Turn laser ON at start
  digitalWrite(LED_PIN, LOW);
  noTone(BUZZER_PIN);

  Serial.begin(9600);
}

void loop() {
  bool buttonState = digitalRead(BUTTON_PIN);

  // Toggle laser on button press (detect LOW to HIGH transition)
  if (buttonState == LOW && lastButtonState == HIGH) {
    delay(1000);  // debounce
    laserOn = !laserOn;
    digitalWrite(LASER_PIN, laserOn ? HIGH : LOW);
    Serial.print("Laser turned ");
    Serial.println(laserOn ? "ON" : "OFF");
  }
  lastButtonState = buttonState;

  // Read LDR digital pin to detect beam break
  int ldrState = digitalRead(LDR_PIN);

  if (laserOn) {
    if (ldrState == LOW) {
      // Light detected (beam unbroken)
      digitalWrite(LED_PIN, HIGH);   // LED ON = safe
      noTone(BUZZER_PIN);            // Buzzer OFF

      if (lastBeamState != LOW) {
        Serial.println("Beam OK - Light detected");
        lastBeamState = LOW;
      }
    } else {
      // Dark detected (beam broken)
      digitalWrite(LED_PIN, LOW);    // LED OFF
      tone(BUZZER_PIN, 1000);        // Buzzer ON at 1000 Hz

      if (lastBeamState != HIGH) {
        Serial.println("Beam Broken - No light detected");
        lastBeamState = HIGH;
      }
    }
  } else {
    // Laser OFF, turn off LED and buzzer
    digitalWrite(LED_PIN, LOW);
    noTone(BUZZER_PIN);
  }
}