Project Hub /Robotics & Autonomous Systems/Motor Drivers & Motion Control/OTP-Based Smart Wireless Locking System Using Arduino

Intermediate

ARDUINO

₹1,500 – ₹5,000

3 – 6 Hours

Partial Kit

OTP-Based Smart Wireless Locking System Using Arduino

Build a secure OTP-based smart wireless locking system using an Arduino and Bluetooth module that generates a new password every time you unlock it.

Originally published on ElectronicsForU

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

Arduino UNO R3 Board (Compatible) – ATmega328P Microcontroller with USB Cable Rs. 999.00
ESP32 WiFi+Bluetooth CP2102 Development Board Rs. 858.00
10pcs 5mm RED Diffused Light Emitting Diodes - LEDs Set Rs. 39.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
TowerPro SG90 Mini Servo – 180 degree Rotation – Standard Quality Rs. 179.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

We don't carry yet: Battery (generic / unspecified)

Browse all components

How It Works

The OTP-Based Smart Wireless Locking System coordinates hardware and software to provide dynamic security via an Arduino Uno. At the center of the system is the Arduino Uno, which executes the core logic loaded onto it through the Arduino IDE and connected via a USB Type B Cable. Wireless communication is handled by the Bluetooth HC-05 module, allowing the microcontroller to pair with a custom mobile interface designed using MIT App Inventor. When a user requests access, the software generates a One-Time Password (OTP) that changes with every unlock cycle, mitigating the risk of credential interception. Once the correct code is transmitted wirelessly from the smartphone to the Bluetooth HC-05, the Arduino processes the incoming string and verifies it against the generated value. Upon successful validation, the microcontroller sends a control signal to the Servo Motor. The servo physically rotates to disengage the lock mechanism, while an LED provides a visual confirmation of the status change. Power is supplied reliably to the entire circuit via a 5V Battery or Power Bank, with all components interconnected securely using Jumper Wires.

Why Build This

Design and deploy a dynamic access control mechanism for smart home door locks and secure storage cabinets.

Integrate wireless serial communication protocols with microcontroller firmware for embedded security applications.

Program custom Android user interfaces using visual blocks to interface directly with physical hardware.

Real-World Application

Smart home door locks, secure storage cabinets, office access control, and anti-theft physical security enclosures.

Skills You'll Learn

Microcontroller serial communication

servo motor pulse-width modulation control

mobile app UI design

dynamic password generation algorithms

power distribution management

Safety Precautions

Ensure correct voltage supply to avoid damaging the Arduino and Bluetooth module. Secure all wiring properly to prevent short circuits.

Technology Tags

ARDUINO

BLUETOOTH HC-05

SERVO MOTOR

MIT APP INVENTOR

ANDROID

OTP

WIRELESS LOCKING

Frequently Asked Questions

How does the system ensure a new password is used every time?

The logic programmed into the Arduino (or the companion app built in MIT App Inventor) generates a fresh random numerical string upon each successful unlock event, requiring the user to reference the new code for subsequent access.

Can I use a standard wall adapter instead of a 5V battery?

Yes, as long as the power source delivers a stable 5V output that matches the requirements of both the Arduino Uno and the connected peripherals without introducing voltage spikes.

Do I need prior experience with MIT App Inventor?

Basic familiarity helps, but MIT App Inventor uses a visual block-based programming environment that makes it straightforward to set up the Bluetooth pairing and text display elements needed for this project.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

PRJ-00069