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

LiquidCrystal_I2C lcd(0x27, 16, 2);

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

byte rows[4] = {19, 18, 5, 17};
byte cols[4] = {16, 4, 0, 2};

Keypad keypad = Keypad(makeKeymap(keys), rows, cols, 4, 4);

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0, 0);
}

void loop() {
  char k = keypad.getKey();
  if (k) {
    lcd.print(k);
    delay(10);
  }
}