#include <Keypad.h>

const int ROW_NUM = 4;     // four rows
const int COLUMN_NUM = 4;  // four columns

char keys[ROW_NUM][COLUMN_NUM] = {
  { '1', '2', '3', 'A' },
  { '4', '5', '6', 'B' },
  { '7', '8', '9', 'C' },
  { '*', '0', '#', 'D' }
};

byte pin_rows[ROW_NUM] = { 9, 8, 7, 6 };       //connect to the row pinouts of the keypad
byte pin_column[COLUMN_NUM] = { 5, 4, 3, 2 };  //connect to the column pinouts of the keypad

Keypad keypad = Keypad(makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM);

const String password_1 = "1234";  // change your password here
const String password_2 = "2222";  // change your password here
const String password_3 = "3333";  // change your password here
String input_password;

int RELAY = A2;
int sendData = 10;
void setup() {
  Serial.begin(115200);
  input_password.reserve(32);  // maximum input characters is 33, change if needed
  pinMode(RELAY, OUTPUT);
  pinMode(sendData, OUTPUT);
  digitalWrite(sendData,LOW);
}

void loop() {
  char key = keypad.getKey();
  if (key) {
    Serial.println(key);
    if (key == '*') {
      input_password = "";  // reset the input password
    } else if (key == '#') {
      if (input_password == password_1 || input_password == password_2 || input_password == password_3) {
        Serial.println("The password is correct, unlocking the door in 20 seconds");
        digitalWrite(sendData,HIGH);
        Open();
        delay(5000);
        digitalWrite(sendData,LOW);
        Closee();
      } else {
        Serial.println("The password is incorrect, try again");
        digitalWrite(sendData,LOW);
      }

      input_password = "";  // reset the input password
    } else {
      input_password += key;  // append new character to input password string
    }
  }
}

void Open() {
  digitalWrite(RELAY, HIGH);
}
void Closee() {
  digitalWrite(RELAY, LOW);
}