Create a Reliable Bluetooth Door Lock

Introduction

If you’re looking for a practical, beginner-friendly Arduino project with real-world applications, a Bluetooth-controlled door lock is an excellent choice. It introduces you to basic security concepts while teaching you how to control actuators like a servo motor remotely. This project is perfect for beginners because it uses simple, accessible components, and thanks to the BluetooIno app, you can easily trigger commands wirelessly without writing a complex interface yourself.

How it works

The idea behind this Bluetooth door lock is straightforward. You’ll use your phone to open BluetooIno, connect to your HC-05 Bluetooth module, and select the Buttons Controller. Each button inside the app sends a specific command over Bluetooth to the HC-05. The Arduino reads these serial commands and activates a servo motor attached to the locking mechanism. For example, pressing the Unlock button sends the command "U", prompting the servo to rotate and release the latch, while pressing Lock sends "L", rotating it back into the locked position.

Wiring the project

1.Connect the HC-05 module’s TX pin to Arduino RX (pin 0) and RX pin to Arduino TX (pin 1).

2.Connect the HC-05’s VCC and GND to the Arduino’s 5V and GND.

3.Attach the servo motor’s control wire to Arduino pin 9.

4.Connect the servo motor’s power (VCC) and ground (GND) to the Arduino’s 5V and GND.

5.Ensure all connections are secure and not sharing too much current from the Arduino’s 5V line.

For extra stability, it’s a good idea to power the servo with an external 5V supply, connecting the ground lines together.

Once you’ve made all your connections, upload a simple Arduino sketch to read Bluetooth serial commands and rotate the servo based on received values. Use basic if-else statements to trigger the servo’s position.

To physically lock and unlock, mount the servo so its arm controls a latch mechanism or bolt. You can even use a simple rotating stick or pin for testing before setting up a real lock.

Conclusion

This simple Bluetooth door lock project is a great way to combine basic security concepts with wireless control, and it’s beginner-friendly thanks to BluetooIno’s intuitive button interface. It’s quick to build, easy to customize, and a solid starting point for more advanced home automation ideas. Download BluetooIno and take full control of your projects with your phone.