Send-telemetry-Node.js-

Quickstart: Send telemetry from a device to an IoT hub and read the telemetry from the hub with a back-end application (Node.js).

This document presents the results of the following hands-on lab about Azure IoT from Microsoft and is available at https://docs.microsoft.com/en-us/azure/iot-hub/quickstart-send-telemetry-node.

Register a device

1. Run the following commands in Azure Cloud Shell to add the IoT Hub CLI extension and to create the device identity.

Note: replace YourIoTHubName by barueri-test-hub which is the IoT Hub created for this experiment.

az extension add --name azure-cli-iot-ext az iot hub device-identity create --hub-name YourIoTHubName --device-id MyNodeDevice

az extension add --name azure-cli-iot-ext
az iot hub device-identity create --hub-name barueri-test-hub --device-id MyNodeDevice         

2. Run the following commands in Azure Cloud Shell to get the device connection string for the device you just registered:

az iot hub device-identity show-connection-string --hub-name barueri-test-hub --device-id MyNodeDevice --output table     

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

HostName=barueri-test-hub.azure-devices.net;DeviceId=MyNodeDevice;SharedAccessKey=1DrstUh8tUnp8ndhobjaMYo4mbN4gYhm5pkdtzg2dms=

3. You also need a service connection string to enable the back-end application to connect to your IoT hub in order to retrieve the messages. The following command retrieves the service connection string for your IoT hub:

az iot hub show-connection-string --hub-name barueri-test-hub --output table       

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

HostName=barueri-test-hub.azure-devices.net;SharedAccessKeyName=iothubowner;SharedAccessKey=6iwF5p2PNqZrBxejs3FZPNlfPkznrUton9Dlnp0Kz/Y=

Send simulated telemetry

1. Open your local terminal window, navigate to the root folder of the sample Node.js project. Then navigate to the iot-hub\Quickstarts\simulated-device folder.

2. Open the SimulatedDevice.js file in a text editor of your choice.

3. In the local terminal window, run the following commands to install the required libraries and run the simulated device application:

npm install
node SimulatedDevice.js

The following screenshot shows the output as the simulated device application sends telemetry to your IoT hub:

Read the telemetry from your hub

1. Open another local terminal window, navigate to the root folder of the sample Node.js project. Then navigate to the iot-hub\Quickstarts\read-d2c-messages folder.

2. Open the ReadDeviceToCloudMessages.js file in a text editor of your choice.

Replace the value of the connectionString variable with the service connection string you made a note of previously. Then save your changes to the ReadDeviceToCloudMessages.js file.

3. In the local terminal window, run the following commands to install the required libraries and run the back-end application:

npm install
node ReadDeviceToCloudMessages.js

The following screenshot shows the output as the back-end application receives telemetry sent by the simulated device to the hub:

Summary

The hands-on activity was successfully complete.