#include <Keypad.h>
#include <Servo.h>
Servo myServo;
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 rowPins[ROWS] = {2, 3, 4, 5};
byte colPins[COLS] = {6, 7, 8, 9}; 
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
const String correctCode = "0000"; 
String inputCode = "";
void setup() 
{
  myServo.attach(10);
  myServo.write(0); 
    Serial.begin(9600);
}
void loop() {
  char key = keypad.getKey();
  if (key) {
    Serial.println(key);

    if (key == '#') 
    {
      if (inputCode == correctCode) 
      {
        unlockDoor();
      } 
      else 
      {
        Serial.println("Wrong code");
        inputCode = ""; 
      }
    } 
    else if (key == '*') 
    {
        inputCode = "";
    } 
    else
    {
      inputCode += key;
    }
  }
}
void unlockDoor() 
{
  Serial.println("Correct code. Door unlocked.");
  myServo.write(90); 
  delay(5000); 
  myServo.write(0); 
}