International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 13 Issue: 08 | Aug 2026
p-ISSN: 2395-0072
www.irjet.net
IoT-Based Keypad Controlled Smart Door Lock System Design and Implementation of a Password-Based Electronic Access Control System Saraswathi R Devadiga1, Jayashri2, Alsha3, Fathima Jazeela4 1,2Department of BCA, Trisha Vidya College of Commerce and Management, Katpady, Karnataka, India.
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Abstract-ecurity is an essential requirement in homes, offices, institutions, laboratories, hostels, and other controlled environments. Conventional door locks depend on physical keys, which may be lost, broken, or copied. This paper presents the design and implementation of a keypad-based electronic door locking system using an Arduino UNO microcontroller, matrix keypad, servo motor, and LCD display. The user enters a predefined password through the keypad, and the Arduino verifies the entered value against the password stored in its memory. When authentication is successful, the servo motor moves the locking mechanism to the unlocked position for a short duration and then returns to the locked position automatically. When authentication fails, access is denied and an appropriate message is displayed. The LCD also provides user prompts while concealing the entered password using asterisks. The proposed system is simple, low-cost, and suitable as a prototype for password-based access control. Although the project is described using IoT concepts, the supplied implementation does not include an active remote-access facility; Wi-Fi, Bluetooth, mobile control, biometrics, alarms, and access logging are identified as future enhancements. Keywords: Smart door lock, IoT, Arduino UNO, keypad, password authentication, servo motor, LCD, embedded system, access control.
1. INTRODUCTION Security has become increasingly important in residential, institutional, and workplace environments. Traditional lock-andkey mechanisms remain widely used, but physical keys can be misplaced, damaged, or duplicated without authorization. These limitations have encouraged the development of electronic access-control systems in which authentication is performed through a digital credential. A keypad-controlled door lock replaces the physical key with a password. In the proposed system, a matrix keypad provides the user interface, while an Arduino UNO processes the entered password. A servo motor performs the physical locking and unlocking operation, and an LCD provides feedback such as access granted, access denied, and password-entry prompts. The supplied project describes the design as an IoT-oriented security system, while also noting that remote access is not present in the current version. The purpose of this work is to develop a simple, affordable, and user-friendly electronic door lock that demonstrates password authentication, automatic unlocking, and automatic relocking.
2. PROBLEM STATEMENT Physical keys introduce risks associated with loss, duplication, and unauthorized use. A secure electronic alternative should provide controlled access without requiring a physical key while remaining simple and affordable. The proposed project addresses this problem through password-based authentication using a keypad and a microcontroller-controlled servo locking mechanism.
3. OBJECTIVES
To design a keypad-based door locking system using password authentication.
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