#include <Wire.h>// library to invoke I2C protocol
#include <LiquidCrystal_I2C.h>//library to interface the I2C breakout board with the LCd display
#include <Keypad.h>// the matrix keypad library
#include <Servo.h>

Servo myServo;
char sandi[3] = {'9','4','5'};

int a = 0;
char customKey[3];

const byte ROWS = 4;// number of rows on the keypad
const byte COLS = 4;// number of columns on the keypad

char hexaKeys[ROWS][COLS] = {  // mapping the keys to characters
  {'1', '2', '3', 'A'},        
  {'4', '5', '6', 'B'},        
  {'7', '8', '9', 'C'},        
  {'*', '0', '#', 'D'}         
};

byte rowPins[ROWS] = {9, 8, 7, 6}; //Arduino pins connected to row pins of the keypad
byte colPins[COLS] = {5, 4, 3, 2}; // Arduino pins connected to column pins of the keypad

Keypad customKeypad = Keypad(makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS);//associating the arduino pins that are connected to 
                                                                                 //the keypad to the various characters

LiquidCrystal_I2C lcd(0x27, 16, 2);  // associating the LCD with the I2C Serial bus

void setup()
{
  myServo.attach(11);
  lcd.backlight();//setting up the LCD's backlight
  lcd.init(); // initialise the LCD
  Serial.begin(9600);//initialise Serial communication
}

void loop(){
  customKey[a] = customKeypad.getKey();//awaiting key press
  if (customKey[a])//checking whether a key is press
  {

    lcd.setCursor(a, 0); //setting printing position on the LCD
    lcd.print(customKey[a]);//print the key pressed on the LCD
     Serial.println(customKey[a]);//print the pressed key on the Serial monitor
    
    if(customKey[0]==sandi[0]&&customKey[1]==sandi[1]&&customKey[2]==sandi[2]){
           myServo.write(180);
           delay(1000);
           lcd.clear();
    }
    
    a++;
    if(a>=3){
          delay(1000);
          lcd.clear();//clears the LCD
          a = 0;
    }
    myServo.write(90);
  }
}