////Advanced burglar alarm security system with the help of PIR sensor, buzzer &
//keypad. (Alarm gets disabled if correct keypad password is entered)
#include <Keypad.h>
const int PIR_PIN = 1;       
const int BUZZER_PIN = 13;    
const int LED_PIN = 12;     
const int LEDG_PIN = 11;
const int LEDY_PIN = 10;
const int PASSWORD_LENGTH = 4; 

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] = {2, 3, 4, 5}; 
byte colPins[COLS] = {6, 7, 8, 9}; 

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

char password[PASSWORD_LENGTH + 1] = "4321"; 
char enteredPassword[PASSWORD_LENGTH + 1]; 

bool alarmEnabled = true; 

void setup() {
  pinMode(PIR_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(LEDG_PIN, OUTPUT);
  pinMode(LEDY_PIN, OUTPUT);
  digitalWrite(LEDY_PIN, HIGH);
  Serial.begin(9600);
}

void loop() {
  // Check PIR sensor for motion
  if (digitalRead(PIR_PIN) == HIGH && alarmEnabled) {
    digitalWrite(LEDY_PIN, LOW);
    triggerAlarm();
  }

  // Check for keypad input
  char key = keypad.getKey();
  if (key != NO_KEY) {
    if (key == '#') { // Check if enter key is pressed
      if (checkPassword()) {
        alarmEnabled = false; // Disable the alarm
        digitalWrite(LEDY_PIN, LOW); // Turn off LED indicating alarm status
        digitalWrite(LEDG_PIN, HIGH);
        delay(2000);
        digitalWrite(LEDG_PIN, LOW);
        digitalWrite(LEDY_PIN, HIGH);
        Serial.println("Alarm disabled");
      } else {
        digitalWrite(LEDY_PIN, LOW); // Turn off LED indicating alarm status
        digitalWrite(LED_PIN, HIGH);
        delay(2000);
        digitalWrite(LED_PIN, LOW);
        digitalWrite(LEDY_PIN, HIGH);
        Serial.println("Incorrect password");
      }
      memset(enteredPassword, 0, sizeof(enteredPassword)); // Clear entered password buffer
    } else {
      if (strlen(enteredPassword) < PASSWORD_LENGTH) {
        enteredPassword[strlen(enteredPassword)] = key; // Add entered key to the buffer
        Serial.print("Entered: ");
        Serial.println(enteredPassword);
      }
    }
  }
}

void triggerAlarm() {
  digitalWrite(BUZZER_PIN, HIGH);
  digitalWrite(LED_PIN, HIGH);
  Serial.println("Intruder detected! Alarm activated!");
  delay(5000); // Alarm duration
  digitalWrite(BUZZER_PIN, LOW);
}

bool checkPassword() {
  return strcmp(password, enteredPassword) == 0;
}