Quickstart: Send IoT telemetry from an Android device

IoT Hub is an Azure service that enables you to ingest high volumes of telemetry from your IoT devices into the cloud for storage or processing. In this quickstart, you send telemetry to an IoT Hub from an Android application running on a physical or simulated device.

The quickstart uses a pre-written Android application to send the telemetry. The telemetry will be read from the IoT Hub using the Azure Cloud Shell. Before you run the application, you create an IoT hub and register a device with the hub.

Use Azure Cloud Shell

Azure hosts Azure Cloud Shell, an interactive shell environment that you can use through your browser. You can use either Bash or PowerShell with Cloud Shell to work with Azure services. You can use the Cloud Shell preinstalled commands to run the code in this article without having to install anything on your local environment.

To start Azure Cloud Shell:

Option Example/Link
Select Try It in the upper-right corner of a code block. Selecting Try It doesn't automatically copy the code to Cloud Shell. Example of Try It for Azure Cloud Shell
Go to https://shell.azure.com, or select the Launch Cloud Shell button to open Cloud Shell in your browser. Launch Cloud Shell in a new window
Select the Cloud Shell button on the top-right menu bar in the Azure portal. Cloud Shell button in the Azure portal

To run the code in this article in Azure Cloud Shell:

  1. Start Cloud Shell.

  2. Select the Copy button on a code block to copy the code.

  3. Paste the code into the Cloud Shell session by selecting Ctrl+Shift+V on Windows and Linux or by selecting Cmd+Shift+V on macOS.

  4. Select Enter to run the code.

If you don’t have an Azure subscription, create a free account before you begin.

Prerequisites

  • Android studio from https://developer.android.com/studio/. For more information on Android Studio installation, see android-installation.

  • Android SDK 27 is used by the sample in this article.

  • Run the following command to add the Microsoft Azure IoT Extension for Azure CLI to your Cloud Shell instance. The IOT Extension adds IoT Hub, IoT Edge, and IoT Device Provisioning Service (DPS) specific commands to Azure CLI.

    az extension add --name azure-cli-iot-ext
    
  • The sample Android application you run in this quickstart is part of the azure-iot-samples-java repository on GitHub. Download or clone the azure-iot-samples-java repository.

Create an IoT hub

This section describes how to create an IoT hub using the Azure portal.

  1. Sign in to the Azure portal.

  2. From the Azure homepage, select the + Create a resource button, and then enter IoT Hub in the Search the Marketplace field.

  3. Select IoT Hub from the search results, and then select Create.

  4. On the Basics tab, complete the fields as follows:

    • Subscription: Select the subscription to use for your hub.

    • Resource Group: Select a resource group or create a new one. To create a new one, select Create new and fill in the name you want to use. To use an existing resource group, select that resource group. For more information, see Manage Azure Resource Manager resource groups.

    • Region: Select the region in which you want your hub to be located. Select the location closest to you.

    • IoT Hub Name: Enter a name for your hub. This name must be globally unique. If the name you enter is available, a green check mark appears.

    Important

    Because the IoT hub will be publicly discoverable as a DNS endpoint, be sure to avoid entering any sensitive or personally identifiable information when you name it.

    Create a hub in the Azure portal

  5. Select Next: Size and scale to continue creating your hub.

    Set the size and scale for a new hub using the Azure portal

    This screen allows you to set the following values:

    • Pricing and scale tier: Your selected tier. You can choose from several tiers, depending on how many features you want and how many messages you send through your solution per day. The free tier is intended for testing and evaluation. It allows 500 devices to be connected to the hub and up to 8,000 messages per day. Each Azure subscription can create one IoT hub in the free tier.

    • IoT Hub units: The number of messages allowed per unit per day depends on your hub's pricing tier. For example, if you want the hub to support ingress of 700,000 messages, you choose two S1 tier units. For details about the other tier options, see Choosing the right IoT Hub tier.

    • Advanced Settings > Device-to-cloud partitions: This property relates the device-to-cloud messages to the number of simultaneous readers of the messages. Most hubs need only four partitions.

  6. For this article, accept the default choices, and then select Review + create to review your choices. You see something similar to this screen.

    Review information for creating the new hub

  7. Select Create to create your new hub. Creating the hub takes a few minutes.

Register a device

A device must be registered with your IoT hub before it can connect. In this quickstart, you use the Azure Cloud Shell to register a simulated device.

  1. Run the following command in Azure Cloud Shell to create the device identity.

    YourIoTHubName: Replace this placeholder below with the name you chose for your IoT hub.

    MyAndroidDevice: This is the name of the device you're registering. It's recommended to use MyAndroidDevice as shown. If you choose a different name for your device, you'll also need to use that name throughout this article, and update the device name in the sample applications before you run them.

    az iot hub device-identity create --hub-name {YourIoTHubName} --device-id MyAndroidDevice
    
  2. Run the following command in Azure Cloud Shell to get the device connection string for the device you just registered:

    YourIoTHubName: Replace this placeholder below with the name you chose for your IoT hub.

    az iot hub device-identity show-connection-string --hub-name {YourIoTHubName} --device-id MyAndroidDevice --output table
    

    Make a note of the device connection string, which looks like:

    HostName={YourIoTHubName}.azure-devices.net;DeviceId=MyAndroidDevice;SharedAccessKey={YourSharedAccessKey}

    You'll use this value later in this quickstart to send telemetry.

Send simulated telemetry

  1. Open the GitHub sample Android project in Android Studio. The project is located in the following directory of your cloned or downloaded copy of azure-iot-sample-java repository.

     \azure-iot-samples-java\iot-hub\Samples\device\AndroidSample
    
  2. In Android Studio, open gradle.properties for the sample project and replace the Device_Connection_String placeholder with the device connection string you made a note of earlier.

    DeviceConnectionString=HostName={YourIoTHubName}.azure-devices.net;DeviceId=MyAndroidDevice;SharedAccessKey={YourSharedAccessKey}
    
  3. In Android Studio, click File > Sync Project with Gradle Files. Verify the build completes.

    Note

    If the project sync fails, it may be for one of the following reasons:

    • The versions of the Android Gradle plugin and Gradle referenced in the project are out of date for your version of Android Studio. Follow these instructions to reference and install the correct versions of the plugin and Gradle for your installation.
    • The license agreement for the Android SDK has not been signed. Follow the instructions in the Build output to sign the license agreement and download the SDK.
  4. Once the build has completed, click Run > Run 'app'. Configure the app to run on a physical Android device or an Android emulator. For more information on running an Android app on a physical device or emulator, see Run your app.

  5. Once the app loads, click the Start button to start sending telemetry to your IoT Hub:

    Application

Read the telemetry from your hub

In this section, you will use the Azure Cloud Shell with the IoT extension to monitor the device messages that are sent by the Android device.

  1. Using the Azure Cloud Shell, run the following command to connect and read messages from your IoT hub:

    YourIoTHubName: Replace this placeholder below with the name you chose for your IoT hub.

    az iot hub monitor-events --hub-name {YourIoTHubName} --output table
    

    The following screenshot shows the output as the IoT hub receives telemetry sent by the Android device:

    Read the device messages using the Azure CLI

Clean up resources

If you will be continuing to the next recommended article, you can keep the resources you've already created and reuse them.

Otherwise, you can delete the Azure resources created in this article to avoid charges.

Important

Deleting a resource group is irreversible. The resource group and all the resources contained in it are permanently deleted. Make sure that you do not accidentally delete the wrong resource group or resources. If you created the IoT Hub inside an existing resource group that contains resources you want to keep, only delete the IoT Hub resource itself instead of deleting the resource group.

To delete a resource group by name:

  1. Sign in to the Azure portal and select Resource groups.

  2. In the Filter by name textbox, type the name of the resource group containing your IoT Hub.

  3. To the right of your resource group in the result list, select ... then Delete resource group.

    Delete

  4. You will be asked to confirm the deletion of the resource group. Type the name of your resource group again to confirm, and then select Delete. After a few moments, the resource group and all of its contained resources are deleted.

Next steps

In this quickstart, you set up an IoT hub, registered a device, sent simulated telemetry to the hub using an Android application, and read the telemetry from the hub using the Azure Cloud Shell.

To learn how to control your simulated device from a back-end application, continue to the next quickstart.