#include <Keypad.h>
#include <Servo.h>
#include <LiquidCrystal_I2C.h>
#define ROW_NUM     4  // four rows
#define COLUMN_NUM  4  // four columns
#define SERVO_PIN 8
#define Password_Length 8 
int signalPin = A4;
char Data[Password_Length]; 
char Master[Password_Length] = "123A456"; 
byte data_count = 0, master_count = 0;
char keys[ROW_NUM][COLUMN_NUM] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte pin_rows[ROW_NUM] = {13, 12, 11, 9};    // GIOP19, GIOP18, GIOP5, GIOP17 connect to the row pins
byte pin_column[COLUMN_NUM] = {7, 6, 5, 4}; // GIOP16, GIOP4, GIOP0, GIOP2 connect to the column pins

Keypad keypad = Keypad( makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM );

const String password_1 = "555444"; // change your password here
const String password_2 = "564255";  // change your password here
const String password_3 = "545423";  // change your password here
String input_password;
int angle = 0;
LiquidCrystal_I2C lcd(0x27, 16, 2); 

Servo servo;
void setup() {
  lcd.init(); 
  lcd.backlight(); 
  pinMode(signalPin, OUTPUT); 

  Serial.begin(9600);
  servo.attach(SERVO_PIN);
  servo.write(angle);  
  
}

void loop() {
  lcd.setCursor(0,0); 
  lcd.print("Enter Password:"); 
  delay (100);
  char key = keypad.getKey();

  if (key) {
  Data[data_count] = key; 
  lcd.setCursor(data_count,1); 
  lcd.print(Data[data_count]); 
  data_count++;
    Serial.println(key);

    if (key == 'B') {
      input_password = "";
      lcd.clear(); 
      clearData();
    } else if (key == 'A') {
      if (input_password == password_1 || input_password == password_2 || input_password == password_3) {
        Serial.println("Valid Password => unlock the door");
        lcd.print("Correct");
        clearData();
        if (angle == 0)
          angle =180;
        else //if(angle == 90)
          angle = 0;

        // control servo motor arccoding to the angle
        servo.write(angle);
        Serial.print("Rotate Servo Motor to ");
        Serial.print(angle);
        Serial.println("°");
        delay(5000);
        if (angle == 0)
          angle =180;
        else //if(angle == 90)
          angle = 0;
          servo.write(angle);
        Serial.print("Rotate Servo Motor to ");
        Serial.print(angle);
        Serial.println("°");
      } else {
        Serial.println("Invalid Password => Try again");
        lcd.print("Incorrect");
      
        clearData();
      }

      input_password = ""; // reset the input password
    } else {
      input_password += key; // append new character to input password string
    }
  }
}
void clearData()
{ 
while(data_count !=0)
{ 
Data[data_count--] = 0; 
} 
return; 
}