IoT Live Demo with LavinMQ

This project demonstrates using LavinMQ for an IoT live demo at conferences. It contains two main parts:

• esp32_c6/ → Arduino sketches (C/C++ code for the IoT device). Needs to be uploaded to the ESP32 microcontroller.
• landingpage/ → A simple landing page built with Bootstrap, CSS, JavaScript, and HTML.

Project Structure

iot-demo-page/
├── esp32_c6/ # Arduino sketches (C/C++ code for IoT device)
├── landingpage/ # Landing page (Bootstrap, CSS, JS, HTML)
├── subscribers/ # MQTT subscribers in different languages
└── README.md # Project documentation

Consumers

• Python
• C#
• JS
• Ruby

Hardware

• ESP32-C6 microcontroller
• DHT temperature & humidity sensor
• USB-C cable
• Jumper wires (red = power, black = ground, yellow = data)

Software

• Arduino IDE
• Python 3.x
• Node.js
• .NET
• Ruby

Step 1: Setup the IoT Device

1. Connect the DHT sensor to the Arduino board with jumper wires:

   • Red → Power
   • Black → Ground
   • Yellow → Data

2. Connect the Arduino to your PC with a USB-C cable.

3. Open the Arduino sketch from the esp32_c6/ folder in Arduino IDE.

   • Make sure to open and upload the entire sketch folder (not just a single .ino file).
   • Ensure you have the following libraries installed:
     • DHT sensor library by Adafruit
     • PubSubClient by Nick O'Leary
   • Select the correct board from the Board menu.
   • Upload the sketch to the board.

4. Open Serial Monitor from Arduino IDE.

   • Unplug and replug the USB-C cable.
   • The IP address of the board will appear.

Step 2: Configure Wi-Fi and MQTT

1. On your PC, connect to the IoT access point (demowifi-<deviceid>).

2. Open a browser and go to: http://192.168.4.1

3. A mini portal will open:

• Enter your MQTT details and press Save.
• Enter your Wi-Fi credentials and press Save.

4. Close the portal and wait 1 minute for the IoT device to connect to your Wi-Fi.

• Once connected, demowifi-<deviceid> will disappear from available networks.
• The device will start publishing sensor data to LavinMQ.

👉 Wi-Fi and MQTT credentials are stored on the board, so next time you just need to power it on.

Step 3: Consume the Data

You can consume the messages in two ways.

Option 1: Terminal Subscriber

1. Navigate to the subscribers/ directory.
2. Choose your preferred language and edit the corresponding file:
   • JavaScript: MQTT_subscriber.js
   • Python: MQTT_subscriber.py
   • Ruby: MQTT_subscriber.rb
   • C#: Program.cs
3. Replace the placeholder values with your LavinMQ instance credentials:
   • <broker-name> → Your LavinMQ broker URL
   • <username> → Your LavinMQ username
   • <password> → Your LavinMQ password
4. Run the appropriate command for your chosen language.

Python

python3 MQTT_subscriber.py

C#

dotnet run

Node.js

node MQTT_subscriber.js

Ruby

ruby MQTT_subscriber.rb

This will print temperature and humidity readings directly in your terminal.

Option 2: Web Dashboard

1. Start a local HTTP server from the landingpage/ folder:

cd landingpage
python3 -m http.server 8000

2. Open a browser and go to: http://localhost:8000/index.html

3. View temperature, humidity, and trend charts on the page.