Skip to main content

[IoT Home Project] Part 5 - Send data to Azure IoT Hub, control time interval and refac the configuration information

In this post we will discover how we can:
  • Send all device sensor data that are read from GrovePI to Azure IoT Hub
  • Read sensor data at a specific time interval
  • Extract all configuration data in a separate file

Send all device sensor data that are read from GrovePI to Azure IoT Hub
This is a simple task. The function that reads sensor data from GrovePI already returns all the sensor data. The only thing that we need to do is to put this information in the message that is send to Azure IoT Hub.
In the future it is pretty clear that we will have different type of messages that we send over IoT Hub. Because of this we shall add a property to the message that is send to IoT Hub that specifies the message type - in our case we'll call the message that contains sensor data 'sensorData'.
var dataToSend = JSON.stringify({
    deviceId: "vunvulearaspberry",
    msgType: "sensorData",
    sensorInf: {
        temp: sensorsData.temp,
        humidity: sensorsData.humidity,
        distance: sensorsData.distance,
        light: sensorsData.light
    }
});
deviceCommunication.sendMessage(dataToSend);

Read sensor data at a specific time interval
In this moment we have a 'while(true)' that reads sensor information and send data to IoT Hub. This works great, but what if we want to control how often data is read.
To be able to do this, we can use 'setInterval' function from node.js. This function allows us to specify a time interval when a function is called. The time interval is specified in milliseconds. 
The nice thing is that the functions will not be executed in parallel if the first call didn't finished yet. This is important when we specify a small time interval like 100 ms and the read sensor information and send data operations takes more than 100 ms.
function collectSensorData(grovePiSensors, deviceCommunication) {
    var timeIntervalInMilisec = 5000;  // 5s
    setInterval((grovePiSensors, deviceCommunication) => {
        var sensorsData = grovePiSensors.getAllSensorsData();

        var dataToSend = JSON.stringify({
            deviceId: "vunvulearaspberry",
            msgType: "sensorData",
            sensorInf: {
                temp: sensorsData.temp,
                humidity: sensorsData.humidity,
                distance: sensorsData.distance,
                light: sensorsData.light
            }

        });
        deviceCommunication.sendMessage(dataToSend);
    }, timeIntervalInMilisec, grovePiSensors, deviceCommunication);
}

Extract all configuration data in a separate file
In this moment we have configuration data in multiple modules. If we want to change something, we need to search where the configuration is stored, some information like device id string is duplicated.
The code is not so nice and a change can be buggy and time consuming.
To avoid all this problems, we ca create a config.json file in our application where all configuration data is added. For each module I prefer to create a section where I group specific configuration for that that module ('deviceCommunicationConfig' and 'grovePiConfig').
{
    "debug" : true,
    "sensorDataTimeSampleInSec" : 5,
    "deviceCommunicationConfig":
    {
        "deviceId" : "vunvulearaspberry",
        "azureIoTHubMasterConnectionString" : "HostName=vunvulear-iot-hub.azure-devices.net;SharedAccessKeyName=iothubowner;SharedAccessKey=+whKMyd08PLDNoaR+yEmToJcHL6wsFo36tAyDBU8Qr0=",
        "azureIoTHubHostName" : "vunvulear-iot-hub.azure-devices.net"
    },
    "grovePiConfig":
    {
        "dhtDigitalSensorPin" : 2,
        "ultrasonicDigitalSensorPin" : 4,
        "lightAnalogSensorPin" : 2,
        "soundAnalogSensorPin" : 0
    }
}

Once we have all this configuration, we will need to access it. For this we can load the JSON in our application and access the properties of the configuration file.
var Config = require('./config.json');
...
var grovePiSensors = new GrovePiSensors(Config.grovePiConfig);
...
this.debug = debug;
this.registry = AzureIoTHub.Registry.fromConnectionString(Config.deviceCommunicationConfig.azureIoTHubMasterConnectionString);
this.deviceId = Config.deviceCommunicationConfig.deviceId;
this.azureIoTHubHostName = Config.deviceCommunicationConfig.azureIoTHubHostName;

In each module we don't need to specify all the configuration file. We can only specify the section that is specific to that module ('Config.deviceCommunicationConfig'). For this you can take a look in the source file.

Conclusion
Mission complete for now. See push all sensor data to Azure IoT Hub and we have the flexibility to change configuration more easily. Additional to this we have control on how often data is pushed to Azure IoT Hub.

Next Step
In the next post we will start to store the data that is pushed to Azure IoT Hub to blobs. On top of this we will take a look on how we can calculate the average values for read data.

Next post: [IoT Home Project] Part 6 - Stream Analytics and Power BI

Comments

Popular posts from this blog

How to check in AngularJS if a service was register or not

There are cases when you need to check in a service or a controller was register in AngularJS.
For example a valid use case is when you have the same implementation running on multiple application. In this case, you may want to intercept the HTTP provider and add a custom step there. This step don’t needs to run on all the application, only in the one where the service exist and register.
A solution for this case would be to have a flag in the configuration that specify this. In the core you would have an IF that would check the value of this flag.
Another solution is to check if a specific service was register in AngularJS or not. If the service was register that you would execute your own logic.
To check if a service was register or not in AngularJS container you need to call the ‘has’ method of ‘inhector’. It will return TRUE if the service was register.
if ($injector.has('httpInterceptorService')) { $httpProvider.interceptors.push('httpInterceptorService&#…

ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded

Today blog post will be started with the following error when running DB tests on the CI machine:
threw exception: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information. at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName) This error happened only on the Continuous Integration machine. On the devs machines, everything has fine. The classic problem – on my machine it’s working. The CI has the following configuration:

TeamCity.NET 4.51EF 6.0.2VS2013
It seems that there …

Run native .NET application in Docker (.NET Framework 4.6.2)

Scope
The main scope of this post is to see how we can run a legacy application written in .NET Framework in Docker.

Context
First of all, let’s define what is a legacy application in our context. By a legacy application we understand an application that runs .NET Framework 3.5 or higher in a production environment where we don’t have any more the people or documentation that would help us to understand what is happening behind the scene.
In this scenarios, you might want to migrate the current solution from a standard environment to Docker. There are many advantages for such a migration, like:

Continuous DeploymentTestingIsolationSecurity at container levelVersioning ControlEnvironment Standardization
Until now, we didn’t had the possibility to run a .NET application in Docker. With .NET Core, there was support for .NET Core in Docker, but migration from a full .NET framework to .NET Core can be costly and even impossible. Not only because of lack of features, but also because once you…