#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#include <Wire.h>

// Set the LCD address (usually 0x27 or 0x3F for most I2C LCDs)
LiquidCrystal_I2C lcd(0x27, 16, 2);  // 16 columns and 2 rows

// Define pin connections
const int trigPin = 9;
const int echoPin = 11;
const int buzzerPin = 8;
const int ledPin = 7; // Pin for the LED

long duration;
int distance;

// Define keypad rows and columns
const byte ROWS = 4;
const byte COLS = 4;

// Define keypad layout
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte rowPins[ROWS] = {A0, A1, A2, A3};
byte colPins[COLS] = {A4, A5, 13, 12};

// Create keypad object
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Define password and threshold distance
char password[] = "1234";
const int thresholdDistance = 20; // Adjust as needed

// Buffer to store the entered password
char passwordBuffer[5];
int bufferIndex = 0;

void setup() {
  lcd.begin(16, 2);  // Initialize the LCD
  lcd.setBacklight(1);  // Turn on the backlight
  lcd.print("Enter Password");

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(ledPin, OUTPUT); // Set the LED pin as output
  Serial.begin(9600);
}

void loop() {
  // Get distance measurement
  long duration, distance;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.0343 / 2;

  // Get password input
  char key = keypad.getKey();
  if (key != NO_KEY) {
    if (key == '#') {
      // Check the entered password against the correct password
      if (strcmp(password, passwordBuffer) == 0) {
        lcd.clear();
        lcd.print("Password Correct");
        digitalWrite(ledPin, HIGH); // Turn on the LED
      } else {
        lcd.clear();
        lcd.print("Incorrect Password");
        tone(buzzerPin, 1000, 500);
        delay(500);
        noTone(buzzerPin);
        lcd.clear();
        lcd.print("Enter Password");
        digitalWrite(ledPin, LOW); // Turn off the LED
      }

      // Clear the password buffer
      bufferIndex = 0;
    } else {
      // Add the pressed key to the password buffer and clear the LCD
      passwordBuffer[bufferIndex] = key;
      bufferIndex++;
      lcd.clear();
      lcd.print(passwordBuffer);
    }
  }

  // Check distance and trigger alarm if necessary
  if (distance < thresholdDistance) {
    if (strcmp(password, passwordBuffer) == 0) {
      lcd.clear();
      lcd.print("Alarm Activated");
      tone(buzzerPin, 1000, 500);
      delay(500);
      noTone(buzzerPin);
    }
  } 
}