#include <Keypad.h>
#include <LiquidCrystal_I2C.h>

const byte I2C_ADDR = 0x27;
const int LCD_COLUMNS = 20;
const int LCD_LINES = 4;

LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);


const uint8_t ROWS = 4;
const uint8_t COLS = 4;
char keys[ROWS][COLS] = {
  { '1', '2', '3', 'A' },
  { '4', '5', '6', 'B' },
  { '7', '8', '9', 'C' },
  { '*', '0', '#', 'D' }
};

uint8_t colPins[COLS] = { 5, 4, 3, 2 }; // Pins connected to C1, C2, C3, C4
uint8_t rowPins[ROWS] = { 9, 8, 7, 6 }; // Pins connected to R1, R2, R3, R4

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


String text;
String pwd = "1234";

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
}

void loop() {
  char key = keypad.getKey();

  if (key != NO_KEY && key != '#') {
    char car = key;
    text = text + car;
    lcd.print("*");
  }

  if (key == '#') {
    lcd.clear();
    if (pwd == text) {
      lcd.print("PWD correcto");
      text = "";
    } else {
      lcd.print("PWD incorrecto");
      text = "";
    }
  }
}