ELEGOO Keypad lock Powered by Arduino

/******************************************************************
|| @name ELEGOO Keypad lock
|| @date 2021.09.03
|| @version 1.0
|| @author Giovanni Gentile
|| @contact www.projectg.it
||
|| @description
|| Open the door by unlocking the servo motor.
|| Digit the right code on the keypad. Reset by using '#' or '*'
|| Fine tune the code: int closeServo
||                     int openServo
||                     char* password = "putyourpassword";  
|| Connect to the USB for debugging (9600 baud) 
||
|| @connections
|| Servo pin 10
|| Keypad pin fron 2 to 9
||        row:  9, 8, 7, 6
||        cols: 5, 4, 3, 2
|| Green Led: pin 11
|| Red Led: pin 12
|| Piezo: pin 13
|| 
*******************************************************************/

#include <Keypad.h>
#include <Servo.h>

Servo myservo;  // create servo object to control a servo
int closeServo = 125; // Adjust the fine movement
int openServo = 20; // Adjust the fine movement

const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns

//define the two-dimensional array on the buttons of the keypads
char hexaKeys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

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

//initialize an instance of class NewKeypad
Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS); 

// PASSWORD MANAGER
char* password = "456730AA";  // change the password here, just pick any numbers/letters
int lengthpwd = 8; // change the length of the password
int carriage = 0; 
int attempt = 0;

// LED and sound
unsigned int redLed = 12;
unsigned int greenLed = 11;
unsigned int piezo = 13;
unsigned int note = 800;
// Millis
unsigned long previousMillis = 0; // will store last time LED was updated
int ledState = LOW;             // ledState used to set the LED
// constants won't change:
const long interval = 800;    

void setup(){
  Serial.begin(9600);
  myservo.attach(10);  // attaches the servo on pin 10 to the servo object
  myservo.write(closeServo);
  
  pinMode(redLed, OUTPUT);
  pinMode(greenLed, OUTPUT);
  digitalWrite(redLed, 1);
  tone(piezo, note, 20);
  delay(500);
  digitalWrite(greenLed, 1);
  tone(piezo, note, 20);
  delay(500);
  digitalWrite(greenLed, 0);
  digitalWrite(redLed, 0);
  
}
  
void loop(){
  char key = customKeypad.getKey();
  unsigned long currentMillis = millis();
  
  if (key){
    tone(piezo, note, 20);
    Serial.println("");
    Serial.println("________________");
    Serial.print("Button pressed: ");
    Serial.println(key);
    Serial.print("Carriage: ");
    Serial.println(carriage);
    Serial.print("Attempt: ");
    Serial.println(attempt);
    Serial.println("_______________");
    
    attempt++;
  }

  if (key == '*' || key == '#')
  {
    carriage = 0;
    attempt = 0;
    myservo.write(closeServo);
    Serial.println("Clear");
    tone(piezo, 800,300);
    delay(80);
    tone(piezo, 800,100);
    delay(80);
    tone(piezo, 700,100);
    delay(80);
    tone(piezo, 600,100);
    delay(100);
    digitalWrite(redLed, 1);
    digitalWrite(greenLed, 1);
    delay(200);
    digitalWrite(redLed, 0);
    digitalWrite(greenLed, 0);
  }

  if (key == password[carriage])
  {
    carriage ++;
    Serial.println("--> Right!");
  } 

  if (carriage == lengthpwd)
  {
    Serial.println("--> Bingo! <--");
    carriage = 0;
    attempt = 0;
    myservo.write(openServo);
    tone(piezo, 600,100);
    delay(50);
    tone(piezo, 700,100);
    delay(50);
    tone(piezo, 800,100);
    delay(60);
    tone(piezo, 800,100);
    delay(80);
    tone(piezo, 800,300);
    for (int i = 0; i < 6; i++) {
      digitalWrite(greenLed, 1);
      delay(200);
      digitalWrite(greenLed, 0);
      delay(100);
    }
    digitalWrite(greenLed, 1);
  }

  if (attempt >= lengthpwd) {
    Serial.println("--> Not the right code! <--");
    digitalWrite(redLed, 1);
    tone(piezo, 450, 100);
    delay(100);
    tone(piezo, 400, 200);
    delay(500);
    digitalWrite(redLed, 0);
    carriage = 0;
    attempt = 0;
  }

  if (carriage > lengthpwd)
  {
    Serial.println("Superior");
    carriage = 0;
  }
  if (currentMillis - previousMillis >= interval) {
   // save the last time you blinked the LED
   previousMillis = currentMillis;

   // if the LED is off turn it on and vice-versa:
   if (ledState == LOW) {
     ledState = HIGH;
   } else {
     ledState = LOW;
   }

   // set the LED with the ledState of the variable:
   digitalWrite(redLed, ledState);
}
}