#include <Keypad.h>

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,20,4);

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, 18, 19, 23 }; // Pins connected to C1, C2, C3, C4
uint8_t rowPins[ROWS] = { 2, 4, 16, 17 }; // Pins connected to R1, R2, R3, R4

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

void setup() {
  lcd.init();
  lcd.backlight();
  Serial.begin(9600);
  
  lcd.setCursor(0,0);
  lcd.print("Hello ");
  lcd.setCursor(3,1);
  lcd.print("esp32");
}

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

  if (key != NO_KEY) {
    lcd.setCursor(3,2);
    lcd.print(key);
  }
}