define TRIG_PIN 9
define ECHO_PIN 8
define LED_PIN 13

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(9600);

  // Configure pins
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);

  Serial.println("Distance Sensor Initialized!");
}

void loop() {
  // Trigger the ultrasonic sensor
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  long duration = pulseIn(ECHO_PIN, HIGH);

  float distance = duration * 0.034 / 2; // Speed of sound = 0.034 cm/us

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

  if (distance > 0 && distance <= 200) {
    digitalWrite(LED_PIN, HIGH);
  } else {
    digitalWrite(LED_PIN, LOW);
  }

  delay(100); // Small delay for stability
}
      

LiquidCrystal_I2C lcd(0x27, 16, 2); // Set the I2C address (0x27) for a 16x2 LCD

void setup() {
  Serial.begin(115200);  // Start Serial Monitor

  // Pin configuration
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(PIR_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);

  // Initialize LCD
  lcd.begin();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Distance:");

  Serial.println("HC-SR04 + PIR + LCD Initialized!");
}

void loop() {
  // === Ultrasonic Sensor Logic ===
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  long duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.0343 / 2;

  // === PIR Motion Sensor Logic ===
  int pirState = digitalRead(PIR_PIN);

  // === LED Control Logic ===
  if ((distance > 0 && distance <= 200) || pirState == HIGH) {
    digitalWrite(LED_PIN, HIGH); // Turn ON LED
  } else {
    digitalWrite(LED_PIN, LOW);  // Turn OFF LED
  }

  // === Display on LCD ===
  lcd.setCursor(10, 0);
  if (distance > 0 && distance < 400) {  // Display valid distance range
    lcd.print(distance);
    lcd.print("cm ");
  } else {
    lcd.print("Out of Range ");
  }

  lcd.setCursor(0, 1);  // Second line: Motion Status
  if (pirState == HIGH) {
    lcd.print("Motion: Detected ");
  } else {
    lcd.print("Motion: None     ");
  }

  // Debugging output
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  Serial.print("PIR State: ");
  Serial.println(pirState == HIGH ? "Motion Detected" : "No Motion");

  delay(500); // Wait for stability
}