#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
LiquidCrystal_I2C lcd(0x27,20,4);
const byte bar = 4;
const byte kol = 4;

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

byte barPin[bar] = { 9, 8, 7, 6 };
byte kolPin[kol] = { 5, 4, 3, 2 };

Keypad keypad = Keypad( makeKeymap(tbl), barPin, kolPin, bar, kol);
char customKey;
int num = 0;
int password = 11;
int redPin = 13;
int greenPin = 12;
int cursor=0;
void setup() {
  lcd.init ();
  lcd.setBacklight(HIGH);
  pinMode(redPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
}

void loop() {
  lcd.setCursor(0,0);
  lcd.print("Input Password");
  customKey = keypad.getKey();


  switch(customKey) {
    case '0' ... '9':
      lcd.setCursor(cursor, 1);
      num = num*10 + (customKey - '0');
      lcd.print(customKey);
      if (cursor<15) {
      cursor++;}
    break;

    case '#':
      if(num == password) {
        lcd.setCursor(0,1);
        lcd.print("Access Accepted ");
        digitalWrite(redPin, LOW);
        digitalWrite(greenPin, HIGH);
      }else{
        lcd.setCursor(0,1);
        lcd.print("Invalid Password");
        digitalWrite(redPin, HIGH);
        digitalWrite(greenPin, LOW);
      }
    break;

    case '*':
      digitalWrite(redPin, LOW);
      digitalWrite(greenPin, LOW);
      num = 0;
      lcd.clear();
    break;
  }
}