#include < Keypad.h >
#include < MFRC522.h >
#include < SPI.h >
#include < Wire.h >
#include < LiquidCrystal_I2C.h >
#define RST_PIN 9
#define SS_PIN 10
#define RELAY_PIN A0
#define BUZZER_PIN A1
#define APPROVAL_LED_PIN A2
#define REJECT_LED_PIN A3
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance
LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address and dimensions of the LCD
const byte ROWS = 4;
const byte COLS = 4;
char keys[ROWS][COLS] = {
{ '1', '2', '3', 'A' },
{ '4', '5', '6', 'B' },
{ '7', '8', '9', 'C' },