FINISHED FINAL

#include <LiquidCrystal_I2C.h>
#include <SPI.h>
#include <MFRC522.h>
#include <Servo.h>
#include <Keypad.h>
#define SS_PIN 10
#define RST_PIN 9
constexpr uint8_t greenLed = 16;
constexpr uint8_t redLed = 15;
MFRC522 mfrc522(SS_PIN, RST_PIN);   // Create MFRC522 instance.
Servo Tahm;
LiquidCrystal_I2C screen(0x3f,16,2);
int i=0;
char initial_password [4]={'4','4','2','1'};
int key_pressed = 0;
char password[4];
const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
char keys[ROWS][COLS] = {
  {'1','2','3',},
  {'4','5','6',},
  {'7','8','9',},
  {'*','0','#',}
};
byte rowPins[ROWS] = { 8,7, 6, 5}; //connect to the row pinouts of the keypad
byte colPins[COLS] = { 4, 3, 2,}; //connect to the column pinouts of the keypad
Keypad keypad_key = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );
//Keypad keypad_key = Keypad( makeKeymap(keys), row_pins, column_pins, rows, columns);


void setup()
{
  screen.begin();
  screen.setBacklight((uint8_t)1);
  Serial.begin(9600);   // Initiate a serial communication
  SPI.begin();      // Initiate  SPI bus
  mfrc522.PCD_Init();   // Initiate MFRC522
  Serial.println("Searching for a card.");
  Serial.println();
  Tahm.attach (14);
  Tahm.write (0);
  msg();
}
void msg() {
  screen.clear();
  screen.print(" Scan");
  screen.setCursor (0,1);
  screen.print ("  a card..");
}
void loop()
{
  // Look for new cards
  if ( ! mfrc522.PICC_IsNewCardPresent())
  {
    return;
  }
  // Select one of the cards
  if ( ! mfrc522.PICC_ReadCardSerial())
 {
    return;
  }
  //Show UID on serial monitor
  Serial.print("UID tag :");
  String content= "";
  byte letter;
  for (byte i = 0; i < mfrc522.uid.size; i++)
  {
     Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");
     Serial.print(mfrc522.uid.uidByte[i], HEX);
     content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));
     content.concat(String(mfrc522.uid.uidByte[i], HEX));
  }
  Serial.println();
  Serial.print("Message : ");
  content.toUpperCase();
  if (content.substring(1) == "20 90 E6 89") //change here the UID of the card/cards that you want to give access
  {


    Serial.println("card matched");
    Serial.println();
    screen.clear();
    screen.print (" card matched");
    delay (2000);
    screen.clear ();
    screen.print ("enter passcode");
    int i=0;
    while (i<4)
    {
    key_pressed = keypad_key.getKey(); // Storing keys

    if (key_pressed)
    {
      password[i++] = key_pressed; // Storing in password variable
      screen.print("*");
      delay(5);
    }
    }
      delay(200);
      if (!(strncmp(password, initial_password, 4))) // If password is matched
      {
        screen.clear();
        screen.print("Pass Accepted");
        Tahm.write(90); // Door Opened
       digitalWrite(greenLed, HIGH);
        delay(3000);
      digitalWrite(greenLed, LOW);
       Tahm.write(0); // Door Closed
        screen.clear();
        i = 0;
     msg();
      }
      else    // If password is not matched
      {
        screen.clear();
        screen.print("Wrong Password ");

      digitalWrite(redLed, HIGH);
       delay(3000);

     digitalWrite(redLed, LOW);
        screen.clear();
        i = 0;
 msg();
      }
    }

//
//    Tahm.write (0);
//    delay (5000);
//    Tahm.write (179);
//    msg();

 else   {
    Serial.println("card denied");
    screen.clear();
    screen.print (" Byeee");
    delay(5000);
    msg();
  }
}