Bluetooth-Based Smart Home Automation - Electronic Engineering Guide
1. Introduction
The Bluetooth-Based Smart Home Automation system enables users to wirelessly control household appliances using Bluetooth technology and a microcontroller, typically an Arduino. The system offers a cost-effective and efficient solution for modernizing home control systems without internet dependence.
2. Objectives
• Control home appliances remotely using Bluetooth.
• Ensure secure and responsive control through a mobile app.
• Provide feedback to the user regarding device status.
• Develop a low-cost, DIY home automation prototype.
3. Components Required
• Arduino Uno / Nano
• HC-05 Bluetooth Module
• Relay Module (4-channel or more)
• Light Bulbs / Fan / Devices (as load)
• Android Smartphone (with Bluetooth app)
• Jumper Wires and Breadboard
• Power Supply (5V/12V for relays and Arduino)
4. System Overview
The system connects an Arduino microcontroller to an HC-05 Bluetooth module. A user sends commands via a smartphone app to the Bluetooth module, which forwards them to the Arduino. The Arduino then activates or deactivates relays connected to electrical appliances.
5. Bluetooth Communication
• The HC-05 Bluetooth module operates over serial
communication (TX/RX).
• It pairs with Android devices to receive ON/OFF commands.
• The module communicates at 9600 baud rate with Arduino.
6. Arduino-Based Control Logic
• Arduino listens for Bluetooth serial input.
• It parses characters (e.g., 'A' to turn ON light1, 'a' to turn OFF).
• Based on the command, it switches the appropriate relay HIGH or LOW.
7. Mobile App Interface
• Apps like 'Bluetooth Terminal' or custom apps built on MIT
App Inventor can be used.
• Buttons are assigned specific characters that trigger appliance states.
• App provides manual control with on-screen toggles.
8. Circuit Design and Connections
• HC-05 TX to Arduino RX (pin 0), HC-05 RX to Arduino TX
(pin 1) via voltage divider.
• Relay IN pins connected to Arduino digital outputs (e.g., D2–D5).
• Relay VCC/GND to 5V and GND.
• Load devices connected to relay outputs with proper isolation.
9. Arduino Code Explanation
Sample Code Snippet:
char data = 0;
void setup() {
Serial.begin(9600);
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
}
void loop() {
if (Serial.available()) {
data = Serial.read();
if (data == 'A') digitalWrite(2,
HIGH);
if (data == 'a') digitalWrite(2,
LOW);
if (data == 'B') digitalWrite(3,
HIGH);
if (data == 'b') digitalWrite(3,
LOW);
}
}
10. Applications
• Remote light and fan control
• Smart office control systems
• Elderly assistance automation
• Security lighting and alarms
11. Limitations and Future Enhancements
• Limited range (~10 meters for Bluetooth).
• No internet-based remote control.
• Can be enhanced with Wi-Fi for IoT functionality or integrated with voice
assistants.
• Add sensors for automation triggers (e.g., motion sensors).
12. Conclusion
The Bluetooth-Based Smart Home Automation system is an accessible and practical project for electronic engineering students. It demonstrates control system design, serial communication, and embedded software integration to enhance everyday living spaces.