Getting messages from device to Azure IoT hub

Hi muhammad Alli,

You can try below code, may be useful to you.

public sealed partial class MainPage : Page
{
const string DeviceId = "device1";
const string DeviceKey = "";
const string HubEndpoint = "";
const int LEDPinNumber = 5;
GpioPin LEDPin;
bool LEDPinState;
Brush StatusNormalBrush;
DeviceClient deviceClient;
public MainPage()
{
this.InitializeComponent();
if (!TryInitGPIO().Result)
{
WriteMessage("GPIO initialization failed");
}
deviceClient = DeviceClient.Create(HubEndpoint,
AuthenticationMethodFactory.CreateAuthenticationWithRegistrySymmetricKey(DeviceId, DeviceKey), TransportType.Mqtt_WebSocket_Only);
deviceClient.SetMethodHandlerAsync("ToggleLED", new MethodCallback(ToggleLEDMethod), null);
}
private Task ToggleLEDMethod(MethodRequest methodRequest, object userContext)
{
WriteMessage("Recieved Direct Request to toggle LED");
LEDPinState = !LEDPinState;
UpdateLight();
return Task.FromResult(new MethodResponse(Encoding.UTF8.GetBytes("{\"LightIs\":\"" + (LEDPinState ? "On" : "Off") + "\"}"), 200));
}
public async Task<bool> TryInitGPIO()
{
GpioController gpioController = GpioController.GetDefault();
if (gpioController == null)
{
WriteMessage("This Device is not IoT friendly! (No GPIO Controller found)", true);
return false;
}
if (gpioController.TryOpenPin(LEDPinNumber, GpioSharingMode.Exclusive, out LEDPin, out GpioOpenStatus openStatus))
{
WriteMessage($"Output Pin ({LEDPinNumber}) Opened Successfully!!");
}
else
{
WriteMessage($"Output Pin ({LEDPinNumber}) Failed to Open", true);
return false;
}
LEDPin.SetDriveMode(GpioPinDriveMode.Output);
LEDPin.Write(GpioPinValue.High);
LEDPinState = true;
UpdateLight();
WriteMessage("Output Pin initialized and on");
return true;
}
private async void WriteMessage(string message, bool isError = false)
{
await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
{
StringBuilder sb = new StringBuilder(OutputBox.Text);
if (isError)
{
sb.AppendLine();
sb.AppendLine("*************ERROR**************");
}
sb.AppendLine(message);
if (isError)
{
sb.AppendLine("*************END ERROR**************");
sb.AppendLine();
}
OutputBox.Text = sb.ToString(); //Upon reviewing my code before posting it here, I noticed that this line of code directly modifies a UI element, and yet no errors are thrown (that I can see), whereas changing the color of my little light indicator circle below threw a threading error when I attempted to change the UI from another thread. This function can be called synchronously from async methods, that run on different threads... does that not mean this function would be called on the different thread it was called from?
});
}
private async void ManualToggle_Click(object sender, RoutedEventArgs e)
{
WriteMessage("Recieved Manual Toggle");
LEDPinState = !LEDPinState;
UpdateLight();
}
private async void UpdateLight()
{
LEDPin.Write(LEDPinState ? GpioPinValue.High : GpioPinValue.Low);
await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
{
//StatusIndicator.Fill = LEDPinState ? new SolidColorBrush(Colors.Red) : StatusNormalBrush;
OutputBox.Text = "UpdateLight\r\n";
});
}

References:

https://geektechstuff.com/2019/02/07/azure-iot-hub-raspberry-pi-iot-project-connecting-pi-and-azure-raspberry-pi-python/
https://github.com/MicrosoftDocs/azure-docs/blob/master/articles/iot-hub/iot-hub-raspberry-pi-kit-node-get-started.md
https://github.com/Azure-Samples/iot-hub-python-raspberrypi-client-app
https://azure.microsoft.com/en-in/resources/samples/iot-hub-c-raspberrypi-getstartedkit/
https://brentonc.com/2015/05/03/how-to-send-events-from-a-raspberry-pi-to-microsoft-azure-event-hubs/

video:

https://www.youtube.com/watch?v=HwC3sCvife0

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Elavarasan R7y ago
Hi muhammad Alli,
You can try below code, may be useful to you.
public sealed partial class MainPage : Page
{
    const string DeviceId = "device1";
    const string DeviceKey = "";
    const string HubEndpoint = "";
    const int LEDPinNumber = 5;
    GpioPin LEDPin;
    bool LEDPinState;
    Brush StatusNormalBrush;
    DeviceClient deviceClient;

    public MainPage()
    {
        this.InitializeComponent();

        if (!TryInitGPIO().Result)
        {
            WriteMessage("GPIO initialization failed");
        }

        deviceClient = DeviceClient.Create(HubEndpoint,
            AuthenticationMethodFactory.CreateAuthenticationWithRegistrySymmetricKey(DeviceId, DeviceKey), TransportType.Mqtt_WebSocket_Only);
        deviceClient.SetMethodHandlerAsync("ToggleLED", new MethodCallback(ToggleLEDMethod), null);
    }

    private Task ToggleLEDMethod(MethodRequest methodRequest, object userContext)
    {
        WriteMessage("Recieved Direct Request to toggle LED");
        LEDPinState = !LEDPinState;
        UpdateLight();
        return Task.FromResult(new MethodResponse(Encoding.UTF8.GetBytes("{\"LightIs\":\"" + (LEDPinState ? "On" : "Off") + "\"}"), 200));
    }

    public async Task<bool> TryInitGPIO()
    {
        GpioController gpioController = GpioController.GetDefault();
        if (gpioController == null)
        {
            WriteMessage("This Device is not IoT friendly!  (No GPIO Controller found)", true);
            return false;
        }
        if (gpioController.TryOpenPin(LEDPinNumber, GpioSharingMode.Exclusive, out LEDPin, out GpioOpenStatus openStatus))
        {
            WriteMessage($"Output Pin ({LEDPinNumber}) Opened Successfully!!");
        }
        else
        {
            WriteMessage($"Output Pin ({LEDPinNumber}) Failed to Open", true);
            return false;
        }

        LEDPin.SetDriveMode(GpioPinDriveMode.Output);
        LEDPin.Write(GpioPinValue.High);
        LEDPinState = true;
        UpdateLight();
        WriteMessage("Output Pin initialized and on");
        return true;
    }

    private async void WriteMessage(string message, bool isError = false)
    {
        await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
        {

            StringBuilder sb = new StringBuilder(OutputBox.Text);
            if (isError)
            {
                sb.AppendLine();
                sb.AppendLine("*************ERROR**************");
            }
            sb.AppendLine(message);
            if (isError)
            {
                sb.AppendLine("*************END ERROR**************");
                sb.AppendLine();
            }
            OutputBox.Text = sb.ToString();  //Upon reviewing my code before posting it here, I noticed that this line of code directly modifies a UI element, and yet no errors are thrown (that I can see), whereas changing the color of my little light indicator circle below threw a threading error when I attempted to change the UI from another thread.  This function can be called synchronously from async methods, that run on different threads... does that not mean this function would be called on the different thread it was called from?
        });
    }

    private async void ManualToggle_Click(object sender, RoutedEventArgs e)
    {
        WriteMessage("Recieved Manual Toggle");
        LEDPinState = !LEDPinState;
        UpdateLight();
    }

    private async void UpdateLight()
    {

        LEDPin.Write(LEDPinState ? GpioPinValue.High : GpioPinValue.Low);

        await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
        {
            //StatusIndicator.Fill = LEDPinState ? new SolidColorBrush(Colors.Red) : StatusNormalBrush;
            OutputBox.Text = "UpdateLight\r\n";
        });
    }
References:
https://geektechstuff.com/2019/02/07/azure-iot-hub-raspberry-pi-iot-project-connecting-pi-and-azure-raspberry-pi-python/
https://github.com/MicrosoftDocs/azure-docs/blob/master/articles/iot-hub/iot-hub-raspberry-pi-kit-node-get-started.md
https://github.com/Azure-Samples/iot-hub-python-raspberrypi-client-app
https://azure.microsoft.com/en-in/resources/samples/iot-hub-c-raspberrypi-getstartedkit/
https://brentonc.com/2015/05/03/how-to-send-events-from-a-raspberry-pi-to-microsoft-azure-event-hubs/

video:
https://www.youtube.com/watch?v=HwC3sCvife0
Logesh Palani8y ago
First understand the full message API working module

https://docs.microsoft.com/en-us/azure/iot-hub/iot-hub-devguide-messages-c2d