ESP32 Relay Control System

A Django web application that controls an ESP32-based relay system through AWS IoT Core MQTT messaging. This system provides a secure and reliable way to remotely control relay operations through a web interface.

🔧 System Architecture

Web Interface (Django) <-> AWS IoT Core <-> ESP32 Relay
      [MQTT Publish]       [MQTT Subscribe]

🚀 Features

• Secure relay control through AWS IoT Core
• Real-time MQTT messaging
• Web-based control interface
• SSL/TLS security with certificate-based authentication
• Error handling and status feedback
• Secure certificate management

📋 Prerequisites

• Python 3.8+
• Django 4.2+
• AWS IoT Core account
• ESP32 device with relay module
• AWS IoT certificates
• paho-mqtt library

🛠️ Installation

1. Clone the repository

git clone [your-repository-url]
cd esp32-relay-control

2. Create and activate virtual environment

python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

3. Install dependencies

pip install -r requirements.txt

4. Set up environment variables

cp .env.example .env

Edit .env with your AWS IoT Core settings:

AWS_IOT_ENDPOINT=your-endpoint.iot.region.amazonaws.com
AWS_IOT_PORT=Your Port
AWS_IOT_TOPIC= Your Topic
AWS_IOT_CLIENT_ID= Your Client ID
DJANGO_SECRET_KEY=your-secret-key

🔒 AWS IoT Core Setup

1. Create an AWS IoT Core Thing

   • Go to AWS IoT Core Console
   • Create a Thing for your ESP32
   • Create and download certificates

2. Certificate Setup

   • Create a certificates directory in project root
   • Add your AWS IoT certificates:
     • Root CA certificate (AWS_ROOT_CA_FILENAME)
     • Device certificate (AWS_DEVICE_CERT_FILENAME)
     • Private key (AWS_PRIVATE_KEY_FILENAME)
   • Update certificate filenames in .env

3. Configure IoT Policy

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "iot:Connect",
                "iot:Publish",
                "iot:Subscribe",
                "iot:Receive"
            ],
            "Resource": [
                "arn:aws:iot:your-region:your-account:client/${iot:Connection.Thing.ThingName}",
                "arn:aws:iot:your-region:your-account:topic/relaycontrol"
            ]
        }
    ]
}

🏃‍♂️ Running the Application

1. Apply migrations

python manage.py migrate

2. Start the development server

python manage.py runserver

3. Access the control panel at http://localhost:8000

🔐 Security Considerations

• Keep certificates secure and never commit them to version control
• Use proper file permissions for certificate files
• Regularly rotate certificates
• Monitor AWS IoT Core logs for unauthorized access attempts
• Use HTTPS in production
• Implement user authentication for the web interface

🌐 MQTT Communication

The system uses the following MQTT topic and message format

💻 Development

Project Structure

esp32-relay-control/
├── certificates/          # AWS IoT certificates (not in version control)
├── relay_control/        # Django app
│   ├── views.py         # Main control logic
│   └── urls.py          # URL routing
├── templates/           # HTML templates
├── manage.py           # Django management script
└── requirements.txt    # Python dependencies

Key Components

1. RelayController Class

   • Handles MQTT communication
   • Manages SSL/TLS certificates
   • Processes relay commands

2. Web Interface

   • Simple control panel
   • Status feedback
   • Error handling

📝 License

MIT

🤝 Contributing

1. Fork the repository
2. Create your feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request

🙏 Acknowledgments

• AWS IoT Core documentation
• Django documentation
• Paho MQTT library