A Password Lock Using Keypad and Servo Which Opens the Lock When the Correct Password Is Entered and Beeps the Buzzer When Wrong Password Is Entered.

Assume that the lock is a servo motor . The servo motor shaft rotates 40 degrees if the entered password is accurate . IF incorrect password is entered the servo will rotate 180 degrees and the buzzer will tone up.

arduino uno board -1

piezo buzzer -1

servo motor -1

keypad (4x4) -1

jumper wires

I have attached above a picture of the complete circuit which i designed using TinkerCAD. The image is self- explanatory.

#include <Servo.h>

#include <Keypad.h>

Servo servo;

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] = {9, 8, 7, 6};

byte colPins[COLS] = {5, 4, 3, 2};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

String password = "";

bool isLocked = true;

String unlock = "1234";

void setup()

{

 pinMode(11,OUTPUT);

 servo.write(0);

 servo.attach(10);

 Serial.begin(9600);

}

void loop()

{

 char key = keypad.getKey();

 if(key != '*' && key != NO_KEY){

  password += key;

  Serial.println(password);

 } else if(key == '*' && password.length() == 4){

  checkPassword();

  password = "";

 } else if(key == '*' && password.length() < 4){

  password = "";

 } else if(key == '*' && password.length() > 4){

  password = "";

 } 

}

void checkPassword(){

 if(unlock == password){

  isLocked = false;

  servo.write(40);

  delay(15);

 } 

 else{

  isLocked=true;

  servo.write(180);

  delay(15);

  tone(11,200);

  delay(2000);

  noTone(11);

  delay(2000);

 }

 }