#include <Keypad.h>

// Define the keypad matrix
const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {14, 15, 16, 17};   // connect to the row pinouts of the keypad
byte colPins[COLS] = {18, 19, 20, 21};   // connect to the column pinouts of the keypad
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Define PIR motion sensor pin
const int pirPin = 9;

// Define buzzer pin
const int buzzerPin = 8;

// Store the current password
char currentPassword[5] = "1234";

// Flag to track if the alarm is active
bool alarmActive = false;

// Function to activate the alarm
void activateAlarm() {
  digitalWrite(buzzerPin, HIGH);
  Serial.println("Alarm activated!");
  delay(500);
}

// Function to stop the alarm
void stopAlarm() {
  digitalWrite(buzzerPin, LOW);
  Serial.println("Alarm stopped");
  delay(500);
}

// Function to check if the entered password is correct
bool checkPassword() {
  Serial.println("Enter password:");
  
  char enteredPassword[5];
  int passwordIndex = 0;
  while (passwordIndex < 4) {
    char key = keypad.getKey();
    if (key != NO_KEY) {
      enteredPassword[passwordIndex++] = key;
      Serial.print('*');
    }
  }
  enteredPassword[4] = '\0';

  if (strcmp(enteredPassword, currentPassword) == 0) {
    Serial.println();
    Serial.println("Password correct!");
    return true;
  } else {
    Serial.println();
    Serial.println("Wrong password!");
    return false;
  }
}

void setup() {
  // Initialize Serial communication
  Serial.begin(9600);
  
  // Initialize the keypad
  keypad.setDebounceTime(50);

  // Initialize the PIR motion sensor
  pinMode(pirPin, INPUT);

  // Initialize the buzzer
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  // Check for motion
  int motion = digitalRead(pirPin);

  if (motion == HIGH && !alarmActive) {
    activateAlarm();
    alarmActive = true;
  }

  // Check for keypad input
  char key = keypad.getKey();

  if (key == '#') {
    if (alarmActive && checkPassword()) {
      stopAlarm();
      alarmActive = false;
    }
  }
}