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Smart Door Lock System - Prototype

Updated: May 22

In this rapidly growing era of technology, it is important to provide security to our doors. In this prototype, there will be password encryption. On pressing the correct password, the door opens and if the password entered is incorrect then the door remains closed.

Hardware requirements:

Arduino UNO:

Arduino UNO
Arduino UNO

The Arduino is a programmable microcontroller, it's an open-source electronics proto-type platform. It interacts with the user by receiving input with the aid of sensors and provides the output employing LED, buzzer, etc.,

In order to know more about the Arduino UNO, refer to this article.

Jumper wires:

Jumper wires
Jumper wires

Jumper wires are used to establish connections between different components in the circuit.

4X4 Keypad:

4x4 membrane keypad
4x4 membrane keypad

A 4x4 matrix keypad is used as an input device that takes inputs from the users. It consists of 16 pins in total with four rows and four columns. On pressing a key, a connection will be established between the corresponding row and column between which the switch is placed.

Check this project of 4*4 Keypad as well - Link.

16*2 LCD:

16*2 LCD
16*2 LCD

LCD- Liquid Crystal Display is an electronic module that uses liquid crystal to produce a visible image. It is the basic module that is generally used in DIY and circuits. The display segments are affordable and simply programmable.



A breadboard is a flat piece of wood that is provided with holes that allow users to build a circuit including the components and connections without the need for soldering due to which it is reusable and finds its best usage for the students who are new to build circuits. The holes in any horizontal line will be in series whereas the vertical holes remain at an equipotential state. There are different sizes of breadboards available in the market which include "full size", "half - size" and, "mini size" breadboards.

Servo motor:

Servo motor
Servo motor

A servomotor is a rotary or linear actuator that allows for precise control of angular or linear position, velocity, and acceleration. A servomotor is a closed-loop servomechanism that uses position feedback to control its motion and final position.

Software requirements:

Arduino IDE:

Arduino IDE logo
Arduino IDE logo

The Arduino Integrated Development Environment (IDE) is a cross-platform application (for Windows, macOS, Linux) that is written in functions from C and C++. It is used to write and upload programs to Arduino compatible boards, but also, with the help of third-party cores, other vendor development boards.

Circuit connection:

Circuit connection involves the following steps:

  • R1-R4 pins of the keypad are connected to 9-6 PWM pins of the Arduino UNO respectively.

  • C1-C4 pins of the keypad are connected to 5-2 PWM pins of the Arduino UNO respectively.

  • DB4-DB7 pins of the LCD are connected to 13-10 PWM pins of the Arduino UNO respectively.

  • D0 of the Arduino is connected to the Regester select pin of the LCD.

  • D1 of the Arduino is connected to the Enable pin of the LCD.

  • The Power and ground of the LCD are connected to positive and negative terminals of the breadboard respectively.

  • The Read/ Write pin of the LCD is connected to the negative terminal of the breadboard.

  • LED Anode pin of the LCD is connected to the negative terminal of the resistor.

  • LED Cathode pin of the LCD is connected to the ground.

  • The Contrast pin of the LCD is connected to the positive terminal of the LCD.

  • The Signal pin of the servo motor is connected to the A0 pin of the Arduino.

  • Power and ground pins of the servo motor are connected to 5V and ground respectively

Code :


The LCD present will instruct the user to enter the password, if the password is entered correctly, then the servo motor will open the door and displays a text saying- welcome home. if the entered password does not match with the original password then the door will remain closed along with a text on LCD saying- access denied.

Video By- Vishwa Raj V


See also:

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Content Written by-

Name - Kiranmai Chigurupati

Portfolio Link - click here


Informative and concise! LearnElectronics India always delivers quality content.


Anushka Gupta
Anushka Gupta
Jul 20, 2023

Learn Electronics India's blog on the Smart Door Lock System prototype is simply outstanding! The content is well-structured, and the writing style is engaging. It's evident that the author has a deep understanding of the subject matter and a knack for making complex ideas accessible. I can't wait to see what other exciting projects they have in store.


Can a locksmith learn these prototypes to deal with such smart door locks?

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