#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
int LED = 12 ;
LiquidCrystal_I2C  lcd(0x27 , 16 , 2);

const byte ROWS = 4;
const byte COLS = 4;

char keys[ROWS][COLS] = {
  {'1','2','3','a'},
  {'4','5','6','b'},
  {'7','8','9','c'},
  {'*','0','#','d'}
};
byte rowPin[ROWS] = {9,8,7,6};
byte colPin[COLS] = {5,4,3,2};

Keypad keypad = Keypad(makeKeymap(keys), rowPin , colPin , ROWS , COLS);
void setup() {
  // put your setup code here, to run once:
lcd.begin(16,2);
lcd.backlight();
lcd.print("Use KeyPad : ");
delay(2000);
lcd.clear();
lcd.setCursor(0,0);

pinMode(LED , OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
char keys = keypad.getKey();

if(keys) {
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Entered : ");
  lcd.print(keys);

  digitalWrite(LED , HIGH);
  delay(100);
  digitalWrite(LED , LOW);
  delay(100);
}
}