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

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 }; 
uint8_t rowPins[ROWS] = { 9, 8, 7, 6 }; 

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

LiquidCrystal_I2C lcd(0x27,20,4);  

void setup()
{
  lcd.init();
  Serial.begin(9600);                      
}


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

int computateKey(char){
  Serial.println("hi");
}