#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
LiquidCrystal_I2C lcd(32,16,2);
char hex[4][4]={
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte row[4]={2,3,4,5},col[4]={6,7,8,9};
Keypad k(makeKeymap(hex),row,col,4,4);
int led=13,buzz=12;
String pass="5678",temp="";
void setup()
{
  lcd.init();
  lcd.setCursor(0,0);
  lcd.backlight();
  lcd.print("press any key...");
  Serial.begin(9600);
  pinMode(led,OUTPUT);
  pinMode(buzz,OUTPUT);
}
void loop()
{
  char ch=k.getKey();
  if(ch && ch!='*' && ch!='#')
  {
    lcd.backlight();
    temp=temp+ch;
    Serial.println(temp);
    lcd.setCursor(0,1);
    lcd.print(temp);
  }
  if(ch=='*')
  {
    if(pass==temp)
    {
      digitalWrite(led,HIGH);
      digitalWrite(buzz,LOW);
      lcd.setCursor(0,0);
      lcd.print("password correct");
    }
    else{
      digitalWrite(led,LOW);
      digitalWrite(buzz,HIGH);
      lcd.setCursor(0,0);
      lcd.print("password incorrect");
      lcd.setCursor(0,1);
      lcd.print("try again press #");
    }
  }
  if(ch=='#')
  {
    temp="";
    digitalWrite(led,LOW);
    digitalWrite(buzz, LOW);
    lcd.clear();
    lcd.noBacklight();
    lcd.backlight();
    lcd.print("press any key");
  }

}