Friday, August 4, 2017

Microsoft Azure IoT platform (3): visualizing real-time sensor data with Azure Web Apps


- Layout for this exercise:

* This exercise is based in the previous one

1 - Creating the Web App

- The goal of this exercise is to visualize real-time sensor data received by an IoT hub by running a web application that is hosted on a Web App. 

- Starting from the Azure portal, clicking New -> Web + Mobile -> Web App:

- Filling the required data, like App name, Resource Group, etc .. and pinning to the Dashboard:

- The Web App starts the deployment process:

- An URL is generated that later will be used to visualize real-time sensor data:

2 - Adding a consumer group to the IoT hub

- Consumer groups are used by applications to pull data from an Azure IoT Hub.

- Going back to the Azure portal and opening the IoT Hub:

- Clicking Endpoints -> Events:

- Entering a Consumer group name and saving:

3 - Configuring the Web App to read data from an IoT hub

- Opening the Web App:

- Clicking Settings -> Application settings:

- Entering two key/value pairs. The first one corresponds to the Connection String obtained in previous exercises, the second one refers to the Consumer group name:

- Saving:

- Enabling Web sockets:

- Going to Deployment option -> Choose Source -> Local Git Repository:

- Setting up authentication with username + password:

- The Web App is eventually successfully deployed:

- From Overview, let's copy the Git clone URL that will be used later:

4 - Uploading a web application to be hosted by the Web App

- Now, let's go to the Raspberry Pi device and open a terminal window.

- Entering these commands using:

a) Git clone URL from the previous point
b) appropriate authentication credentials (username + passwords) from the previous point

- Running the simulated Temperature/Humidity sensor device:

- Browsing the URL generated before:

- Finally, the Temperature/Humidity real-time data generated by the simulated device is visualized:

Thursday, August 3, 2017

Microsoft Azure IoT platform (2): connecting a simulated device to an IoT Hub using Node.js


* This exercise is based on the previous one

1 - Creating a device identity

CreateDeviceIdentity.js creates a device identity and associated security key to connect a simulated device app.

- Running this console app generates a unique device ID and key that the device can use to identify itself when it sends device-to-cloud messages to IoT Hub.

- New folder:

- Checking that node and npm are correctly installed:

- npm creates a json package, just accepting the default options:

- Installing the azure-iothub service SDK package:

- Writing the CreateDeviceIdentity.js file:

- It is important to notice that the variable connection string holds the "connection string - primary key" obtained in the previous exercise:

- Also, the deviceID must be entered:

- Running the program, a new Device key is generated:

- The Device key is written down or copied and added to the document with all the parameters and keys:

2 - Receive device to cloud messages

ReadDeviceToCloudMessages.js displays the telemetry sent by the simulated device app, reading device-to-cloud messages from IoT Hub using the AMQP protocol.

- New folder:

- Creating a new json package file and accepting all the default options:

- Installing azure-event-hubs package and saving it:

- Writing the program ReadDeviceToCloudMessages.js:

- As before, it is important to notice that the connection string key must be introduced in the variable connectionString.

3 - Simulated Device

SimulatedDevice.js connects the IoT hub with the device identity created earlier, and sends a telemetry message every second using the MQTT protocol.

- New folder:

- json package:

- Installing azure-iot-device and azure-iot-device-mqtt:

- Writing the program, and using the connectionString variable with the Device key value originated at the section Create a device identity (point 1 of this exercise):

- All of these parameters must be carefully entered:

4 - Running the application

- To run the two applications a separate console must be used, so that the communication between the simulated device and the IoT hub can be displayed.

- Running SimulatedDevice.js to send telemetry data to the IoT hub:

- Running ReadDeviceToCloudMessages.js to monitor the IoT hub: