Arduino Home Automation

A web-based home automation system built with Arduino that allows you to control multiple electrical appliances remotely through a responsive web interface. The system includes real-time temperature monitoring and control of up to 5 relay channels for managing various home devices.

Table of Contents

• Features
• Hardware Requirements
• Software Requirements
• System Architecture
• Installation
• Configuration
• How It Works
• Project Structure
• API Endpoints
• Troubleshooting
• Version History
• Contributing
• Credits
• License

Features

• Web-based Control: Access and control your home appliances from any web browser
• Real-time Temperature Monitoring: Displays current temperature in Celsius
• 5-Channel Relay Control: Independently control up to 5 different appliances
• Responsive Design: Mobile-friendly interface that works on smartphones, tablets, and desktops
• AJAX Communication: Real-time updates without page refresh
• SD Card Storage: Web interface stored on microSD card for easy customization
• Low Power: Efficient Arduino-based implementation
• Room-specific Control: Pre-configured for different rooms (Living Room, Master Bed, Guest Room, Kitchen, Wash Room)

Hardware Requirements

Essential Components

Component	Specification	Notes
Arduino Board	Arduino Uno	Other Arduino boards may work with minor modifications
Ethernet Shield	Official Arduino Ethernet Shield	Compatible shields should work
MicroSD Card	2GB, FAT16 formatted	Stores the web interface (index.htm)
Thermistor	NTC Thermistor	For temperature sensing (connected to pin 2)
Relay Module	5-channel relay board	For controlling AC appliances
Power Supply	9V-12V DC	Adequate current rating for relays

Pin Configuration

Pin 2  : Thermistor (Temperature Sensor)
Pin 4  : SD Card CS (Chip Select)
Pin 5  : Relay 1 - Living Room
Pin 6  : Relay 2 - Master Bed
Pin 7  : Relay 5 - Wash Room
Pin 8  : Relay 4 - Kitchen
Pin 9  : Relay 3 - Guest Room
Pin 10 : Ethernet CS (Chip Select)
Pin 11 : SPI MOSI
Pin 12 : SPI MISO
Pin 13 : SPI SCK

Software Requirements

• Arduino IDE: Version 1.0.5 or higher (tested up to 1.0.5)
• Required Libraries:
  • Ethernet.h - For network communication
  • SD.h - For SD card file operations
  • SPI.h - For SPI communication
  • Thermistor.h - For temperature sensor reading

System Architecture

Overview

The system follows a client-server architecture:

┌─────────────┐         ┌──────────────────┐         ┌─────────────┐
│   Client    │◄───────►│   Arduino Web    │◄───────►│   Relays    │
│ (Browser)   │  HTTP   │     Server       │  GPIO   │  (Devices)  │
└─────────────┘         └──────────────────┘         └─────────────┘
                               │
                               │ SPI
                               ▼
                        ┌──────────────┐
                        │   SD Card    │
                        │ (index.htm)  │
                        └──────────────┘
                               │
                        ┌──────────────┐
                        │ Thermistor   │
                        │   (Pin 2)    │
                        └──────────────┘

Communication Flow

1. Initial Request: Browser requests the main page
2. HTML Delivery: Arduino serves index.htm from SD card
3. AJAX Polling: JavaScript polls server every 1 second
4. State Update: Server responds with XML containing relay states and temperature
5. User Interaction: Button clicks send state change requests
6. Relay Control: Arduino updates GPIO pins based on requests

Installation

Step 1: Hardware Setup

1. Assemble the Stack:

   • Mount the Ethernet Shield on top of the Arduino Uno
   • Ensure proper alignment of pins

2. Connect Relays:

   Arduino Pin 5 → Relay 1 IN (Living Room)
   Arduino Pin 6 → Relay 2 IN (Master Bed)
   Arduino Pin 7 → Relay 5 IN (Wash Room)
   Arduino Pin 8 → Relay 4 IN (Kitchen)
   Arduino Pin 9 → Relay 3 IN (Guest Room)
   

3. Connect Temperature Sensor:

   • Connect thermistor to Pin 2 with appropriate pull-up resistor

4. Prepare SD Card:

   • Format microSD card as FAT16
   • Copy website_on_SD/index.htm to the root of the SD card
   • Insert SD card into the Ethernet Shield

Step 2: Software Setup

1. Install Arduino IDE:

   • Download from arduino.cc

2. Install Required Libraries:

   • Ethernet library (usually pre-installed)
   • SD library (usually pre-installed)
   • Thermistor library (install via Library Manager)

3. Upload the Sketch:

   • Open webserver_sketch/webserver_sketch.ino
   • Configure network settings (see Configuration section)
   • Upload to Arduino board

Step 3: Network Configuration

Edit these lines in the sketch before uploading:

// MAC address from Ethernet shield sticker under board
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

// IP address - change to match your network
IPAddress ip(192, 168, 0, 120);

Configuration

Network Settings

Static IP Configuration (default):

• IP Address: 192.168.0.120
• Server Port: 80 (HTTP)
• MAC Address: Check sticker on your Ethernet shield

Important: Ensure the IP address is:

• Within your network's subnet
• Not already in use by another device
• Accessible from your client devices

Customizing the Web Interface

1. Modify website_on_SD/index.htm on your computer
2. Copy the updated file to the SD card
3. Restart the Arduino to load changes

Relay Assignments

To change room assignments, edit the SetRELAYs() function in the sketch:

// Example: Change Living Room to Bedroom
if (StrContains(HTTP_req, "RELAY1=1")) {
    RELAY_state[0] = 1;
    digitalWrite(5, HIGH);  // Pin 5 controls this relay
}

How It Works

Initialization Process

1. System Boot (setup() function):

   - Disable Ethernet chip
   - Initialize Serial (9600 baud) for debugging
   - Initialize SD card and verify index.htm exists
   - Configure relay pins (5-9) as OUTPUT
   - Initialize Ethernet with MAC and IP
   - Start HTTP server on port 80

2. Ready State: Arduino listens for incoming connections on port 80

Request Handling Loop

The loop() function continuously:

1. Client Detection: Checks for incoming HTTP requests
2. Request Parsing: Buffers incoming data (max 60 bytes)
3. Request Type Identification:
   • AJAX Request (button_state in URL): Returns XML
   • Page Request: Serves HTML from SD card

AJAX/XML Communication

Request Format:

GET /button_state&RELAY1=1&nocache=12345 HTTP/1.1

Response Format:

<?xml version = "1.0" ?>
<inputs>
  <temp>25</temp>
  <BUTTON>on</BUTTON>
  <BUTTON>off</BUTTON>
  <BUTTON>off</BUTTON>
  <BUTTON>on</BUTTON>
  <BUTTON>off</BUTTON>
</inputs>

State Management

The system maintains relay states in a boolean array:

boolean RELAY_state[BTN_NUM] = {0}; // 5 relays, all initially OFF

State Update Flow:

1. Browser sends button click: RELAY1=1
2. Arduino parses request in SetRELAYs()
3. Updates RELAY_state[0] = 1
4. Sets GPIO pin: digitalWrite(5, HIGH)
5. Returns updated state in XML response
6. JavaScript updates button display

Temperature Monitoring

Thermistor temp(2);  // Initialize on pin 2

// In XML_response():
byte celsius = temp.getTemp();  // Read temperature
cl.print("<temp>");
cl.print(celsius);
cl.print("</temp>");

The web interface polls every 1 second and updates the temperature display.

Project Structure

Arduino-Home-Automation/
├── webserver_sketch/
│   └── webserver_sketch.ino    # Main Arduino sketch
├── website_on_SD/
│   └── index.htm                # Web interface (to be copied to SD card)
├── screenshot/
│   ├── HomeAutomation-2.0.png   # Version 2.0 screenshot
│   └── HomeAutomation-4.0.jpg   # Version 4.0 screenshot
├── CHANGELOG.md                 # Detailed version history
└── README.md                    # This file

API Endpoints

GET /

Description: Serves the main HTML interface

Response: index.htm from SD card

Content-Type: text/html

---

GET /button_state

Description: AJAX endpoint for real-time updates and control

Query Parameters:

• RELAYn=0|1 (optional): Set relay n to OFF (0) or ON (1)
• nocache=<random>: Cache-busting parameter

Examples:

GET /button_state&nocache=12345
GET /button_state&RELAY1=1&RELAY2=0&nocache=67890

Response: XML document with current state

Content-Type: text/xml

Troubleshooting

Common Issues

Problem: Arduino doesn't respond on network

• Solution:
  • Verify IP address is correct for your network
  • Check Ethernet cable connection
  • Ensure MAC address is unique on network
  • Try pinging the Arduino IP address

Problem: "ERROR - SD card initialization failed!"

• Solution:
  • Check SD card is properly inserted
  • Verify card is formatted as FAT16
  • Try a different SD card (max 2GB recommended)
  • Check pin 4 connection

Problem: "ERROR - Can't find index.htm file!"

• Solution:
  • Ensure index.htm is in root directory of SD card
  • Verify filename is exactly index.htm (case-sensitive)
  • Check file is not corrupted

Problem: Relays not switching

• Solution:
  • Verify relay module is powered
  • Check GPIO pin connections (5-9)
  • Test relay board independently
  • Check relay trigger level (active HIGH/LOW)

Problem: Temperature shows incorrect value

• Solution:
  • Check thermistor connection to pin 2
  • Verify Thermistor library is installed
  • Calibrate thermistor if needed

Debugging

Enable Serial Monitor (9600 baud) to see diagnostic messages:

Serial.begin(9600);  // Already in setup()

Monitor for:

• SD card initialization status
• File existence checks
• Any custom debug messages you add

Version History

See CHANGELOG.md for detailed version history.

Current Version: 0.4.2 (March 28, 2016)

Major Milestones:

• v0.1.0 (Feb 2016): Initial release with 5-relay control
• v0.2.0 (Feb 2016): Added temperature sensor
• v0.3.0 (Feb 2016): Improved code with DRY principles
• v0.4.0 (Feb 2016): Simplified button functions
• v0.4.2 (Mar 2016): Final refinements

Screenshots

Version 2.0

Version 4.0 (Current)

Contributing

Contributions are welcome! Here's how you can help:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Ideas for Contribution

• Add DHCP support for automatic IP configuration
• Implement authentication for security
• Add scheduling/timer functionality
• Support for more sensors (humidity, motion, etc.)
• Mobile app integration
• MQTT support for IoT platforms
• Energy consumption monitoring

Credits

Original Author

W.A. Smith Website: Starting Electronics

Enhanced Version

Jobayer Arman GitHub: @jobayerarman Twitter: @JobayerArman Email: carbonjha@gmail.com

References

• WebServer example by David A. Mellis and modified by Tom Igoe
• SD card examples by David A. Mellis and Tom Igoe
• Ethernet Library Documentation
• SD Card Library Documentation

License

This project is open source and available for educational and personal use.

Need Help?

Feel free to:

• Create an issue
• Tweet me
• Send an email

I'd be glad to help where I can!

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Note: This project involves working with mains voltage (AC power) through relays. Always follow proper electrical safety procedures and consult with a licensed electrician when necessary. The authors are not responsible for any damage or injury resulting from the use of this project.