Azure IoT Hub Tutorial

Introduction

Azure IoT Hub is a managed service that acts as a central message hub for bi-directional communication between your IoT application and the devices it manages. It provides device-to-cloud and cloud-to-device communication, ensuring reliable and secure data transfer.

Prerequisites

Before you start using Azure IoT Hub, you need to have the following:

• An active Azure subscription
• Basic knowledge of Azure portal
• Some familiarity with IoT concepts

Step 1: Create an IoT Hub

To create an IoT Hub in Azure, follow these steps:

1. Go to the Azure portal.
2. Click on "Create a resource" and then select "IoT Hub".
3. Fill in the necessary details such as Subscription, Resource Group, Region, and IoT Hub Name.
4. Click "Review + Create" and then "Create".

Step 2: Register a Device

Once the IoT Hub is created, you need to register a device:

1. Navigate to your IoT Hub in the Azure portal.
2. Click on "IoT devices" under the "Explorers" section.
3. Click on "New" to add a new device.
4. Enter a Device ID and click "Save".

Step 3: Connect a Device

To connect a device to your IoT Hub, you need the connection string:

1. Go to the registered device in the IoT Hub.
2. Copy the "Primary Connection String".
3. Use this connection string in your device code to establish a connection.

Step 4: Send Device-to-Cloud Messages

Use the following code snippet to send messages from your device to the cloud:

const iothub = require('azure-iot-device');
const Message = iothub.Message;
const client = iothub.Client.fromConnectionString(connectionString, iothub.Mqtt);

function sendMessage() {
    const message = new Message(JSON.stringify({ temperature: 22.5, humidity: 60 }));
    client.sendEvent(message, (err, res) => {
        if (err) console.log('Send error: ' + err.toString());
        if (res) console.log('Send status: ' + res.constructor.name);
    });
}

sendMessage();
                

Step 5: Receive Cloud-to-Device Messages

Use the following code snippet to receive messages from the cloud:

client.on('message', (msg) => {
    console.log('Message received: ' + msg.getData().toString());
    client.complete(msg, () => {
        console.log('Message processed');
    });
});
                

Step 6: Monitor IoT Hub

You can monitor the activity in your IoT Hub using Azure Monitor:

1. Go to your IoT Hub in the Azure portal.
2. Click on "Metrics" under the "Monitoring" section.
3. Select the metrics you want to monitor, such as "Total messages sent" or "Total messages received".
4. Set the time range and view the metrics.

Conclusion

Azure IoT Hub provides a robust platform for managing IoT devices and ensuring secure, reliable communication between devices and the cloud. By following this tutorial, you should now have a basic understanding of how to create an IoT Hub, register devices, and send and receive messages.