ML.Net YoloV5 + Camera on ARM64 Raspberry PI

Building on my previous post I modified the code to support capturing images with a security camera(Unv ADZK-10) or a Raspberry PI Camera V2.

namespace devMobile.IoT.MachineLearning.ObjectDetectionCamera
{
	class Program
	{
		private static Model.ApplicationSettings _applicationSettings;
		private static YoloScorer<YoloCocoP5Model> _scorer = null;
		private static bool _cameraBusy = false;

		static async Task Main(string[] args)
		{
			Console.WriteLine($"{DateTime.UtcNow:yy-MM-dd HH:mm:ss} ObjectDetectionCamera starting");

			try
			{
				// load the app settings into configuration
				var configuration = new ConfigurationBuilder()
					 .AddJsonFile("appsettings.json", false, true)
					 .Build();

				_applicationSettings = configuration.GetSection("ApplicationSettings").Get<Model.ApplicationSettings>();

				_scorer = new YoloScorer<YoloCocoP5Model>(_applicationSettings.YoloV5ModelPath);

				Timer imageUpdatetimer = new Timer(ImageUpdateTimerCallback, null, _applicationSettings.ImageImageTimerDue, _applicationSettings.ImageTimerPeriod);

				Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss} press <ctrl^c> to exit");

				try
				{
					await Task.Delay(Timeout.Infinite);
				}
				catch (TaskCanceledException)
				{
					Console.WriteLine($"{DateTime.UtcNow:yy-MM-dd HH:mm:ss} Application shutown requested");
				}
			}
			catch (Exception ex)
			{
				Console.WriteLine($"{DateTime.UtcNow:yy-MM-dd HH:mm:ss} Application shutown failure {ex.Message}", ex);
			}
		}

		private static async void ImageUpdateTimerCallback(object state)
		{
			DateTime requestAtUtc = DateTime.UtcNow;

			// Just incase - stop code being called while photo already in progress
			if (_cameraBusy)
			{
				return;
			}
			_cameraBusy = true;

			try
			{
#if SECURITY_CAMERA
				Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss} Security Camera Image download start");

				NetworkCredential networkCredential = new NetworkCredential()
				{
					UserName = _applicationSettings.CameraUserName,
					Password = _applicationSettings.CameraUserPassword,
				};

				using (WebClient client = new WebClient())
				{
					client.Credentials = networkCredential;

					client.DownloadFile(_applicationSettings.CameraUrl, _applicationSettings.InputImageFilenameLocal);
				}
				Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss} Security Camera Image download done");
#endif

#if RASPBERRY_PI_CAMERA
				Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss} Raspberry PI Image capture start");

				using (Process process = new Process())
				{
					process.StartInfo.FileName = @"libcamera-jpeg";
					process.StartInfo.Arguments = $"-o {_applicationSettings.InputImageFilenameLocal} --nopreview -t1 --rotation 180";
					process.StartInfo.RedirectStandardError = true;

					process.Start();

					if (!process.WaitForExit(_applicationSettings.ProcessWaitForExit) || (process.ExitCode != 0))
					{
						Console.WriteLine($"{DateTime.UtcNow:yy-MM-dd HH:mm:ss} Image update failure {process.ExitCode}");
					}
				}

				Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss} Raspberry PI Image capture done");
#endif

				// Process the image on local file system
				using (Image image = Image.FromFile(_applicationSettings.InputImageFilenameLocal))
				{
					Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss} YoloV5 inferencing start");
					System.Collections.Generic.List<YoloPrediction> predictions = _scorer.Predict(image);
					Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss} YoloV5 inferencing done");

					using (Graphics graphics = Graphics.FromImage(image))
					{
						foreach (var prediction in predictions) // iterate predictions to draw results
						{
							double score = Math.Round(prediction.Score, 2);

							graphics.DrawRectangles(new Pen(prediction.Label.Color, 1), new[] { prediction.Rectangle });

							var (x, y) = (prediction.Rectangle.X - 3, prediction.Rectangle.Y - 23);

							graphics.DrawString($"{prediction.Label.Name} ({score})", new Font("Consolas", 16, GraphicsUnit.Pixel), new SolidBrush(prediction.Label.Color), new PointF(x, y));

							Console.WriteLine($"  {prediction.Label.Name} {score:f1}");

						}

						image.Save(_applicationSettings.OutputImageFilenameLocal);
					}
				}
				Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss} YoloV5 inferencing done");
			}
			catch (Exception ex)
			{
				Console.WriteLine($"{DateTime.UtcNow:yy-MM-dd HH:mm:ss} Camera image download, upload or post procesing failed {ex.Message}");
			}
			finally
			{
				_cameraBusy = false;
			}

			TimeSpan duration = DateTime.UtcNow - requestAtUtc;

			Console.WriteLine($"{DateTime.UtcNow:yy-MM-dd HH:mm:ss} Image Update done {duration.TotalSeconds:f1} sec");
		}
	}
}

The name of the input image, output image and yoloV5 model file names are configured in the appsettings.json file.

Raspberry PI Camera V2 Results

Raspberry PI Camera V2 source image
ObjectDectionCamera application running on my RaspberryPI4
Raspberry PI Camera V2 image with MBRs

Security camera Results

Security Camera source image
ObjectDetectionCamera application running on RaspberryPI 8G 4B
Security Camera image with MBRs

Summary

The RaspberryPI Camera V2 images were 3280×2464 2.04M and the security camera images were 1920 x1080 464K so there was a significant quality and size difference.

When I ran the YoloV5s model application on my development box (Intel(R) Core(TM) i7-8700T CPU @ 2.40GHz) a security camera image took less than a second to process.

ObjectDetectionCamera application running on my development box

On the RaspberryPI V4b 8G the Raspberry PI Camera V2 images took roughly 1.52 seconds and security camera images roughly 1.47 seconds.

I was “standing on the shoulders of giants” the Mentalstack code just worked. With a pretrained yoloV5 model, the ML.Net Open Neural Network Exchange(ONNX) plumbing I had a working solution in a couple of hours.

ML.Net YoloV5 Object Detection on ARM64 Raspberry PI

For the last month I have been using preview releases of ML.Net with a focus on Open Neural Network Exchange(ONNX) support. A company I work with has a YoloV5 based solution for tracking the cattle in stockyards so I figured I would try getting YoloV5 working with .Net Core and ML.Net on ARM64.

After some searching I found a repository created by Github user Mentalstack for an ONNX based YoloV5 implementation which I cloned and started hacking. I stared by updating the NuGet packages for the scorer and sample application and fixing what broke.

Yolo V5 Scorer NuGet packages

I didn’t update the System.Drawing.Common Nuget as my Raspberry PI V4 has got .Net Core V5 installed.

Yolo V5 Sample application NuGet Packages

The sample application only had one dependency Microsoft.ML.OnnxRuntime which I was able to drop as it was referenced by the YoloV5Net.Scorer.

I then modified the sample application to process all the images in an “input” folder and save the processed images with Minimum Bounding Boxes(MBRs) to the output folder.

using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using Yolov5Net.Scorer;
using Yolov5Net.Scorer.Models;

namespace Yolov5Net.App
{
	class Program
	{
		static void Main(string[] args)
		{
			var scorer = new YoloScorer<YoloCocoP5Model>("Assets/Weights/yolov5s.onnx");

			DateTime startedAtUtc = DateTime.UtcNow;

			Console.WriteLine($"{startedAtUtc:yyyy:MM:dd HH:mm:ss} Start");

			string[] imageFilesPaths = Directory.GetFiles("Assets/inputs");

			foreach (string imageFilePath in imageFilesPaths)
			{
				using (Image image = Image.FromFile(imageFilePath))
				using (Graphics graphics = Graphics.FromImage(image))
				{
					List<YoloPrediction> predictions = scorer.Predict(image);

					foreach (var prediction in predictions) // iterate predictions to draw results
					{
						double score = Math.Round(prediction.Score, 2);

						graphics.DrawRectangles(new Pen(prediction.Label.Color, 1), new[] { prediction.Rectangle });

						var (x, y) = (prediction.Rectangle.X - 3, prediction.Rectangle.Y - 23);

						graphics.DrawString($"{prediction.Label.Name} ({score})", new Font("Consolas", 16, GraphicsUnit.Pixel), new SolidBrush(prediction.Label.Color), new PointF(x, y));
					}

					image.Save($"Assets/outputs/{Path.GetFileName(imageFilePath)}");
				}
			}

			DateTime finishedAtUtc = DateTime.UtcNow;
			TimeSpan duration = finishedAtUtc - startedAtUtc;

			Console.WriteLine($"{finishedAtUtc:yyyy:MM:dd HH:mm:ss} Finish Duration:{duration.TotalMilliseconds}mSec");
		}
	}
}

The sample images are from wikimedia commons site. Go to Wikimediacommon.md to refer to the image urls and their licenses.

YoloV5Net Solution with sample images

The next step of my Proof of Concept(PoC) was to get the YoloV5 Object Detection sample application working on my Intel(R) Core(TM) i7-8700T CPU @ 2.40GHz 2.40 GHz desktop development system. After debugging the software with Visual Studio I “published” the application to a folder.

Visual Studio 2019 Publish to folder
Desktop YoloV5 Sample application output

The application took roughly 0.9 seconds to process each of my 5 sample images. The next task was to get the YoloV5 sample application working on a Raspberry Pi 4 running Bullseye.

Copying application to RPI4 with Winscp

To deploy applications I often copy the contents of the “publish” directory to the device with WinSCP. Getting the Object sample application running on my Raspberry Pi4 took a couple of attempts…

Input image folder path invalid

I had forgotten then Unix paths are case sensitive inputs vs. Inputs

ONNX Runtime native binary missing exception
pi@raspberrypi4a:~/vsdbg/Yolov5Net.App $ dotnet Yolov5Net.App.dll
Unhandled exception. System.TypeInitializationException: The type initializer for 'Microsoft.ML.OnnxRuntime.NativeMethods' threw an exception.
 ---> System.DllNotFoundException: Unable to load shared library 'onnxruntime' or one of its dependencies. In order to help diagnose loading problems, consider setting the LD_DEBUG environment variable: libonnxruntime: cannot open shared object file: No such file or directory
   at Microsoft.ML.OnnxRuntime.NativeMethods.OrtGetApiBase()
   at Microsoft.ML.OnnxRuntime.NativeMethods..cctor()
   --- End of inner exception stack trace ---
   at Microsoft.ML.OnnxRuntime.SessionOptions..ctor()
   at Yolov5Net.Scorer.YoloScorer`1..ctor(String weights, SessionOptions opts) in C:\Users\BrynLewis\source\repos\yolov5-net\src\Yolov5Net.Scorer\YoloScorer.cs:line 326
   at Yolov5Net.App.Program.Main(String[] args) in C:\Users\BrynLewis\source\repos\yolov5-net\src\Yolov5Net.App\Program.cs:line 14
Aborted
pi@raspberrypi4a:~/vsdbg/Yolov5Net.App $
\

The ONNX runtime was missing so I confirmed the processor architecture with uname then copied the platform specific file to the application folder with Winscp.

Copying platform specific runtime to application folder with WInscp

I then checked Yolo V4 Sample application was generating output images with WinSCP.

Image output folder with marked up images
Sample image with YoloV5 generated MBRs

On the Raspberry PI4B the application took roughly 8.3 seconds to process each of my 5 sample images.

RPI4 Device YoloV5 Sample application output

I was “standing on the shoulders of giants” the Mentalstack code just worked, my changes were minimal and largely so I could collect some basic performance metrics. I need to spend some more time figuring out how the implementation works.

.NET Core RAK811 LoRaWAN library Part3

The massive refactor

After refactoring my RAK3172 device library I have applied a similar approach to code on my RAK811 device library. My test-rig is a RaspberryPI 3B with a PI Supply RAK811 pHat and external antenna.

PI Supply RAK811 LoRaWAN pHat

In the new code a Thread reads lines of text from the SerialPort and processes them, checking for command responses, failures and downlink messages.

Unlike most of the devices I have worked with the RAK811 Join and Send commands are synchronous so return once the process has completed. The RAK811 responses also have quite a few empty, null prefixed or null suffixed lines which is a bit odd.

public void SerialPortProcessor()
{
	string line;

	while (CommandProcessResponses)
	{
		try
		{
#if DIAGNOSTICS
			Debug.WriteLine($" {DateTime.UtcNow:hh:mm:ss} ReadLine before");
#endif
			line = SerialDevice.ReadLine().Trim('\0').Trim();
#if DIAGNOSTICS
			Debug.WriteLine($" {DateTime.UtcNow:hh:mm:ss} ReadLine after:{line}");
#endif
			// consume empty lines
			if (String.IsNullOrWhiteSpace(line))
			{
				continue;
			}

			// Consume the response from set work mode
			if (line.StartsWith("?LoRa (R)") || line.StartsWith("RAK811 ") || line.StartsWith("UART1 ") || line.StartsWith("UART3 ") || line.StartsWith("LoRa work mode"))
			{
				continue;
			}

			// See if device successfully joined network
			if (line.StartsWith("OK Join Success"))
			{
				OnJoinCompletion?.Invoke(true);

				CommandResponseExpectedEvent.Set();

				continue;
			}

			if (line.StartsWith("at+recv="))
			{
				string[] payloadFields = line.Split("=,:".ToCharArray());

				byte port = byte.Parse(payloadFields[1]);
				int rssi = int.Parse(payloadFields[2]);
				int snr = int.Parse(payloadFields[3]);
				int length = int.Parse(payloadFields[4]);

				if (this.OnMessageConfirmation != null)
				{
					OnMessageConfirmation?.Invoke(rssi, snr);
				}
				if (length > 0)
				{
					string payload = payloadFields[5];

					if (this.OnReceiveMessage != null)
					{
						OnReceiveMessage.Invoke(port, rssi, snr, payload);
					}
				}
				continue;
			}

			switch (line)
			{
				case "OK":
				case "Initialization OK":
				case "OK Wake Up":
				case "OK Sleep":
					CommandResult = Result.Success;
					break;

				case "ERROR: 1":
					CommandResult = Result.ATCommandUnsuported;
					break;
				case "ERROR: 2":
					CommandResult = Result.ATCommandInvalidParameter;
					break;
				case "ERROR: 3": //There is an error when reading or writing flash.
				case "ERROR: 4": //There is an error when reading or writing through IIC.
					CommandResult = Result.ErrorReadingOrWritingFlash;
					break;
				case "ERROR: 5": //There is an error when sending through UART
					CommandResult = Result.ATCommandInvalidParameter;
					break;
				case "ERROR: 41": //The BLE works in an invalid state, so that it can’t be operated.
					CommandResult = Result.ResponseInvalid;
					break;
				case "ERROR: 80":
					CommandResult = Result.LoRaBusy;
					break;
				case "ERROR: 81":
					CommandResult = Result.LoRaServiceIsUnknown;
					break;
				case "ERROR: 82":
					CommandResult = Result.LoRaParameterInvalid;
					break;
				case "ERROR: 83":
					CommandResult = Result.LoRaFrequencyInvalid;
					break;
				case "ERROR: 84":
					CommandResult = Result.LoRaDataRateInvalid;
					break;
				case "ERROR: 85":
					CommandResult = Result.LoRaFrequencyAndDataRateInvalid;
					break;
				case "ERROR: 86":
					CommandResult = Result.LoRaDeviceNotJoinedNetwork;
					break;
				case "ERROR: 87":
					CommandResult = Result.LoRaPacketToLong;
					break;
				case "ERROR: 88":
					CommandResult = Result.LoRaServiceIsClosedByServer;
					break;
				case "ERROR: 89":
					CommandResult = Result.LoRaRegionUnsupported;
					break;
				case "ERROR: 90":
					CommandResult = Result.LoRaDutyCycleRestricted;
					break;
				case "ERROR: 91":
					CommandResult = Result.LoRaNoValidChannelFound;
					break;
				case "ERROR: 92":
					CommandResult = Result.LoRaNoFreeChannelFound;
					break;
				case "ERROR: 93":
					CommandResult = Result.StatusIsError;
					break;
				case "ERROR: 94":
					CommandResult = Result.LoRaTransmitTimeout;
					break;
				case "ERROR: 95":
					CommandResult = Result.LoRaRX1Timeout;
					break;
				case "ERROR: 96":
					CommandResult = Result.LoRaRX2Timeout;
					break;
				case "ERROR: 97":
					CommandResult = Result.LoRaRX1ReceiveError;
					break;
				case "ERROR: 98":
					CommandResult = Result.LoRaRX2ReceiveError;
					break;
				case "ERROR: 99":
					CommandResult = Result.LoRaJoinFailed;
					break;
				case "ERROR: 100":
					CommandResult = Result.LoRaDownlinkRepeated;
					break;
				case "ERROR: 101":
					CommandResult = Result.LoRaPayloadSizeNotValidForDataRate;
					break;
				case "ERROR: 102":
					CommandResult = Result.LoRaTooManyDownlinkFramesLost;
					break;
				case "ERROR: 103":
					CommandResult = Result.LoRaAddressFail;
					break;
				case "ERROR: 104":
					CommandResult = Result.LoRaMicVerifyError;
					break;
				default:
					CommandResult = Result.ResponseInvalid;
					break;
			}
		}
		catch (TimeoutException)
		{
			// Intentionally ignored, not certain this is a good idea
		}

		CommandResponseExpectedEvent.Set();
	}
}

After a lot of testing I think my thread based approach works reliably. Initially, I was having some signal strength issues because I had forgotten to configure the external antenna. I need to add some validation to the metrics and payload field unpacking (though I’m not certain what todo if they are the wrong format).

.NET Core RAK3172 LoRaWAN library Part5

The massive refactor

After getting Activation By Personalisation(ABP) and Over The Air Activation(OTAA) working on my RAK3172 test rig I was looking at the code and SerialDataReceivedEventHandler was really ugly.

Raspberry Pi3 with Grove Base Hat and RAK3172 Breakout (using UART2)

After some experimentation in the BreakOutSerial project I decided to reimplement the RAK3172 command processing. In the new code a Thread reads lines of text from the SerialPort and processes them. I have replaced the Join and Send(Confirmed) methods with ones that block only while the command are sent to the RAK3172. Then, when completed the OnJoinCompletion or OnMessagesConfirmation event handlers are called.

private Result SendCommand(string command)
{
	if (command == null)
	{
		throw new ArgumentNullException(nameof(command));
	}

	if (command == string.Empty)
	{
		throw new ArgumentException($"command cannot be empty", nameof(command));
	}

	serialDevice.WriteLine(command);

	this.CommandResponseExpectedEvent.Reset();

	if (!this.CommandResponseExpectedEvent.WaitOne(CommandTimeoutDefaultmSec, false))
	{
		return Result.Timeout;
	}

	return CommandResult;
}

private void SerialPortProcessor()
{
	string line;

	while (CommandProcessResponses)
	{
		try
		{
#if DIAGNOSTICS
			Debug.WriteLine($" {DateTime.UtcNow:hh:mm:ss} ReadLine before");
#endif
			line = serialDevice.ReadLine();
#if DIAGNOSTICS
			Debug.WriteLine($" {DateTime.UtcNow:hh:mm:ss} ReadLine after:{line}");
#endif

			// See if device successfully joined network
			if (line.StartsWith("+EVT:JOINED"))
			{
				OnJoinCompletion?.Invoke(true);

				continue;
			}

			// See if device failed ot join network
			if (line.StartsWith("+EVT:JOIN FAILED"))
			{
				OnJoinCompletion?.Invoke(false);

				continue;
			}

			// Applicable only if confirmed messages enabled 
			if (line.StartsWith("+EVT:SEND CONFIRMED OK"))
			{
				OnMessageConfirmation?.Invoke();

				continue;
			}

			// Check for A/B/C downlink message
			if (line.StartsWith("+EVT:RX_1") || line.StartsWith("+EVT:RX_2") || line.StartsWith("+EVT:RX_3") || line.StartsWith("+EVT:RX_C"))
			{
				// TODO beef up validation, nto certain what todo if borked
				string[] metricsFields= line.Split(' ', ',');

				int rssi = int.Parse(metricsFields[3]);
				int snr = int.Parse(metricsFields[6]);

				line = serialDevice.ReadLine();

#if DIAGNOSTICS
				Debug.WriteLine($" {DateTime.UtcNow:HH:mm:ss} UNICAST :{line}");
#endif
				line = serialDevice.ReadLine();
#if DIAGNOSTICS
				Debug.WriteLine($" {DateTime.UtcNow:HH:mm:ss} Payload:{line}");
#endif
				// TODO beef up validation, nto certain what todo if borked
				string[] payloadFields = line.Split(':');

				byte port = byte.Parse(payloadFields[1]);
				string payload = payloadFields[2];

				OnReceiveMessage?.Invoke(port, rssi, snr, payload);

				continue;
			}

#if DIAGNOSTICS
           Debug.WriteLine($" {DateTime.UtcNow:hh:mm:ss} ReadLine Result");
#endif
			line = serialDevice.ReadLine();
#if DIAGNOSTICS
             Debug.WriteLine($" {DateTime.UtcNow:hh:mm:ss} ReadLine Result:{line}");
#endif
			switch (line)
			{
				case "OK":
					CommandResult = Result.Success;
					break;
				case "AT_ERROR":
					CommandResult = Result.AtError;
					break;
				case "AT_PARAM_ERROR":
					CommandResult = Result.ParameterError;
					break;
				case "AT_BUSY_ERROR":
					CommandResult = Result.BusyError;
					break;
				case "AT_TEST_PARAM_OVERFLOW":
					CommandResult = Result.ParameterOverflow;
					break;
				case "AT_NO_NETWORK_JOINED":
					CommandResult = Result.NotJoined;
					break;
				case "AT_RX_ERROR":
					CommandResult = Result.ReceiveError;
					break;
				case "AT_DUTYCYLE_RESTRICTED":
					CommandResult = Result.DutyCycleRestricted;
					break;
				default:
					CommandResult = Result.Undefined;
					break;
			}

			CommandResponseExpectedEvent.Set();
		}
		catch (TimeoutException)
		{
			// Intentionally ignored, not certain this is a good idea
		}
	}
}

After a lot of testing I think my thread based approach works reliably. I also had to modify the code to shutdown the command processor thread and free any non managed resources.

/// <summary>
/// Ensures unmanaged serial port and thread resources are released in a "responsible" manner.
/// </summary>
public void Dispose()
{
	CommandProcessResponses = false;

	if (CommandResponsesProcessorThread != null)
	{
		CommandResponsesProcessorThread.Join();
		CommandResponsesProcessorThread = null;
	}

	if (serialDevice != null)
	{
		serialDevice.Dispose();
		serialDevice = null;
	}
}

I need to add some validation to the metrics and payload field unpacking (though I’m not certain what todo if they are the wrong format) and review the handling of multi-line event messages.

.NET Core RAK3172 LoRaWAN library Part4

Starting again with Threads

After getting Activation By Personalisation(ABP) and Over The Air Activation(OTAA) working on my RAK3172 test rig I was looking at the code and SerialDataReceivedEventHandler was really ugly.

Raspberry Pi3 with Grove Base Hat and RAK3172 Breakout (using UART2)

After some experimentation in the BreakOutSerial project I decided to reimplement the RAK3172 command processing. In the new code a Thread reads lines of text from the SerialPort and processes them. I have replaced the Join and Send(Confirmed) methods with ones that block only while the command are sent to the RAK3172. Then, when completed the OnJoinCompletion or OnMessagesConfirmation event handlers are called.

private Result SendCommand(string command)
{
   if (command == null)
   {
      throw new ArgumentNullException(nameof(command));
   }

   if (command == string.Empty)
   {
      throw new ArgumentException($"command invalid length cannot be empty", nameof(command));
    }

   serialDevice.ReadTimeout = (int)CommandTimeoutDefault.TotalMilliseconds;
   serialDevice.WriteLine(command);

   this.atExpectedEvent.Reset();

   if (!this.atExpectedEvent.WaitOne((int)CommandTimeoutDefault.TotalMilliseconds, false))
      return Result.Timeout;

   return result;
}

public void SerialPortProcessor()
{
   string line;

   while (true)
   {
      this.serialDevice.ReadTimeout = -1;

      Debug.WriteLine("ReadLine before");
      line = serialDevice.ReadLine();
      Debug.WriteLine($"ReadLine after:{line}");

            // check for +EVT:JOINED
      if (line.StartsWith("+EVT:JOINED"))
      {
            OnJoinCompletion?.Invoke(true);

            continue;
      }

      if (line.StartsWith("+EVT:JOIN FAILED"))
      {
	     OnJoinCompletion?.Invoke(false);

         continue;
      }

      if (line.StartsWith("+EVT:SEND CONFIRMED OK"))
      {
         OnMessageConfirmation?.Invoke();

         continue;
      }

      // Check for A/B/C downlink message
      if (line.StartsWith("+EVT:RX_1") || line.StartsWith("+EVT:RX_2") || line.StartsWith("+EVT:RX_3") || line.StartsWith("+EVT:RX_C"))
      {
         string[] fields1 = line.Split(' ', ',');

         int rssi = int.Parse(fields1[3]);
         int snr = int.Parse(fields1[6]);
 
         line = serialDevice.ReadLine();
         Console.WriteLine($"{DateTime.UtcNow:HH:mm:ss} UNICAST :{line}");

         line = serialDevice.ReadLine();
         Console.WriteLine($"{DateTime.UtcNow:HH:mm:ss} Payload:{line}");

         string[] fields2 = line.Split(':');

         int port = int.Parse(fields2[1]);
         string payload = fields2[2];

         OnReceiveMessage?.Invoke(port, rssi, snr, payload);

         continue;
      }

      try
      {
         this.serialDevice.ReadTimeout = 3000;

         Debug.WriteLine("ReadLine Result");
         line = serialDevice.ReadLine();
         Debug.WriteLine($"ReadLine Result after:{line}");

         switch (line)
         {
            case "OK":
               result = Result.Success;
               break;
         case "AT_ERROR":
               result = Result.Error;
               break;
         case "AT_PARAM_ERROR":
               result = Result.ParameterError;
               break;
         case "AT_BUSY_ERROR":
               result = Result.BusyError;
               break;
         case "AT_TEST_PARAM_OVERFLOW":
               result = Result.ParameterOverflow;
               break;
         case "AT_NO_NETWORK_JOINED":
               result = Result.NotJoined;
               break;
         case "AT_RX_ERROR":
               result = Result.ReceiveError;
               break;
         case "AT_DUTYCYLE_RESTRICTED":
               result = Result.DutyCycleRestricted;
               break;
         default:
               result = Result.Undefined;
               break;
         }
      }
      catch (TimeoutException) 
      {
         result = Result.Timeout;
      }
   atExpectedEvent.Set();
}

The code is not suitable for production but it confirmed my thread based approach works. I need to add code to shutdown the message processing thread in a controlled way, support for Class B & C devices, replace the OnJoinCompletionHandler timer magic numbers and soak test for 5-7 days.

Visual Studio Displaying RAK3172 device joining network then sending messages

In the Visual Studio 2019 debug output I could see messages getting sent and then after a short delay they were visible in the TTN console.

TTN Displaying RAK3172 device joining network then sending messages

.NET Core RAK3172 LoRaWAN library Part3

Nasty ABP connect

After getting basic connectivity for my RAK3172 test rig sorted I wanted to see if I could get the device connected to The Things Network(TTN) via the RAK7246G LPWAN Developer Gateway on my bookcase.

Raspberry Pi3 with Grove Base Hat and RAK3172 Breakout (using UART2)

My Activation By Personalisation (ABP) implementation is very “nasty” (just like the OTAA one) I have assumed that there would be no timeouts or failures and I only send one BCD message “48656c6c6f204c6f526157414e” which is “hello LoRaWAN”.

The code just sequentially steps through the necessary configuration to join the TTN network with a suitable delay after each command is sent.

//---------------------------------------------------------------------------------
// Copyright (c) September 2021, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.NetCore.RAK3172.NetworkJoinABP
{
	using System;
	using System.Diagnostics;
	using System.IO.Ports;
	using System.Threading;

	public class Program
	{
		private const string SerialPortId = "/dev/ttyS0";
		private const string DevAddress = "...";
		private const string NwksKey = "...";
		private const string AppsKey = "...";
		private const byte MessagePort = 1;
		private const string Payload = "A0EEE456D02AFF4AB8BAFD58101D2A2A"; // Hello LoRaWAN

		public static void Main()
		{
			string response;

			Debug.WriteLine("devMobile.IoT.NetCore.Rak3172.NetworkJoinOTAA starting");

			Debug.WriteLine(String.Join(",", SerialPort.GetPortNames()));

			try
			{
				using (SerialPort serialPort = new SerialPort(SerialPortId))
				{
					// set parameters
					serialPort.BaudRate = 9600;
					serialPort.DataBits = 8;
					serialPort.Parity = Parity.None;
					serialPort.StopBits = StopBits.One;
					serialPort.Handshake = Handshake.None;

					serialPort.ReadTimeout = 5000;

					serialPort.NewLine = "\r\n";

					serialPort.Open();

					// clear out the RX buffer
					response = serialPort.ReadExisting();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");
					Thread.Sleep(500);

					// Set the Working mode to LoRaWAN
					Console.WriteLine("Set Work mode");
					serialPort.WriteLine("AT+NWM=1");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the Region to AS923
					Console.WriteLine("Set Region");
					serialPort.WriteLine("AT+BAND=8-1");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the JoinMode
					Console.WriteLine("Set Join mode");
					serialPort.WriteLine("AT+NJM=0");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the device address
					Console.WriteLine("Set Device Address");
					serialPort.WriteLine($"AT+DEVADDR={DevAddress}");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the network session key
					Console.WriteLine("Set Network Session Key");
					serialPort.WriteLine($"AT+NWKSKEY={NwksKey}");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the application session key
					Console.WriteLine("Set application Session Key");
					serialPort.WriteLine($"AT+APPSKEY={AppsKey}");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the Confirm flag
					Console.WriteLine("Set Confirm off");
					serialPort.WriteLine("AT+CFM=0");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Join the network
					Console.WriteLine("Start Join");
					serialPort.WriteLine("AT+JOIN=1:0:10:2");

					// Read the blank line
					response = serialPort.ReadLine();

					// Read the Result
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					Thread.Sleep(10000);

					// Read the +EVT:JOINED
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					while (true)
					{
						Console.WriteLine("Sending");
						serialPort.WriteLine($"AT+SEND={MessagePort}:{Payload}");

						// Read the blank line
						response = serialPort.ReadLine();

						// Read the result
						Console.WriteLine("Send result");
						response = serialPort.ReadLine();
						Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

						Thread.Sleep(300000);
					}
				}
			}
			catch (Exception ex)
			{
				Debug.WriteLine(ex.Message);
			}
		}
	}
}

The code is not suitable for production but it confirmed my software and hardware configuration worked.

In the Visual Studio 2019 debug output I could see messages getting sent and then after a short delay they were visible in the TTN console.

The RAK3172 command format is quite different from other modules I have used e.g. Requesting the firmware version information

  • TX- AT+VER=?
  • RX- Blank Line
  • RX- V1.0.2
  • RX- OK

Requesting the APPEUI

  • TX- AT+DEVADDR=?
  • RX- 11223344
  • RX- Blank line
  • RX- OK

I think the RAK3172 module ships with a default DEVEUI so in this code and my library I have assumed it will be configured as part of a “provisioning” process.

.NET Core RAK3172 LoRaWAN library Part2

Nasty OTAA connect

After getting basic connectivity for my RAK3172 test rig sorted I wanted to see if I could get the device connected to The Things Network(TTN) via the RAK7246G LPWAN Developer Gateway on my bookcase.

Raspberry Pi3 with Grove Base Hat and RAK3172 Breakout (using UART2)

My Over the Air Activation (OTAA) implementation is very “nasty” I have assumed that there would be no timeouts or failures and I only send one BCD message “48656c6c6f204c6f526157414e” which is “hello LoRaWAN”.

The code just sequentially steps through the necessary configuration to join the TTN network with a suitable delay after each command is sent.

//---------------------------------------------------------------------------------
// Copyright (c) September 2021, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.NetCore.RAK3172.NetworkJoinOTAA
{
	using System;
	using System.Diagnostics;
	using System.IO.Ports;
	using System.Threading;

	public class Program
	{
		private const string SerialPortId = "/dev/ttyS0";
		private const string AppEui = "...";
		private const string AppKey = "...";
		private const byte MessagePort = 1;
		private const string Payload = "A0EEE456D02AFF4AB8BAFD58101D2A2A"; // Hello LoRaWAN

		public static void Main()
		{
			string response;

			Debug.WriteLine("devMobile.IoT.NetCore.Rak3172.NetworkJoinOTAA starting");

			Debug.WriteLine(String.Join(",", SerialPort.GetPortNames()));

			try
			{
				using (SerialPort serialPort = new SerialPort(SerialPortId))
				{
					// set parameters
					serialPort.BaudRate = 9600;
					serialPort.DataBits = 8;
					serialPort.Parity = Parity.None;
					serialPort.StopBits = StopBits.One;
					serialPort.Handshake = Handshake.None;

					serialPort.ReadTimeout = 5000;

					serialPort.NewLine = "\r\n";

					serialPort.Open();

					// clear out the RX buffer
					response = serialPort.ReadExisting();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");
					Thread.Sleep(500);


					// Set the Working mode to LoRaWAN
					Console.WriteLine("Set Work mode");
					serialPort.WriteLine("AT+NWM=1");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the Region to AS923
					Console.WriteLine("Set Region");
					serialPort.WriteLine("AT+BAND=8-1");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the JoinMode
					Console.WriteLine("Set Join mode");
					serialPort.WriteLine("AT+NJM=1");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the appEUI
					Console.WriteLine("Set App Eui");
					serialPort.WriteLine($"AT+APPEUI={AppEui}");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the appKey
					Console.WriteLine("Set App Key");
					serialPort.WriteLine($"AT+APPKEY={AppKey}");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Set the Confirm flag
					Console.WriteLine("Set Confirm off");
					serialPort.WriteLine("AT+CFM=0");
					// Read the blank line
					response = serialPort.ReadLine();
					// Read the response
					response = serialPort.ReadLine(); 
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					// Join the network
					Console.WriteLine("Start Join");
					serialPort.WriteLine("AT+JOIN=1:0:10:2");

					// Read the blank line
					response = serialPort.ReadLine();

					// Read the Result
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					Thread.Sleep(10000);

					// Read the +EVT:JOINED
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

					while (true)
					{
						Console.WriteLine("Sending");
						serialPort.WriteLine($"AT+SEND={MessagePort}:{Payload}");

						// Read the blank line
						response = serialPort.ReadLine();

						// Read the result
						Console.WriteLine("Send result");
						response = serialPort.ReadLine();
						Debug.WriteLine($"RX :{response.Trim()} bytes:{response.Length}");

						Thread.Sleep(300000);
					}
				}
			}
			catch (Exception ex)
			{
				Debug.WriteLine(ex.Message);
			}
		}
	}
}

The code is not suitable for production but it confirmed my software and hardware configuration worked.

In the Visual Studio 2019 debug output I could see messages getting sent and then after a short delay they were visible in the TTN console.

The RAK3172 command format is quite different from other modules I have used e.g. Requesting the firmware version information

  • TX- AT+VER=?
  • RX- Blank Line
  • RX- V1.0.2
  • RX- OK

Requesting the APPEUI

  • TX- AT+APPEUI=?
  • RX- 1122334455667788
  • RX- Blank line
  • RX- OK

I think the RAK3172 module ships with a default DEVEUI so in this code and my library I have assumed it will be configured as part of a “provisioning” process.

.NET Core RAK3172 LoRaWAN library Part1

Basic connectivity

Over the weekend I have been working on a .NET Core C# library for the RAKwireless RAK3172 module using a RAK3172S breakout board, Seeedstudio Grove Base Hat for Raspberry PI and a Seeedstudio Grove-4 pin Female Jumper to Grove 4 pin Conversion Cable.

Raspberry Pi3 with Grove Base Hat and RAK3172 Breakout (using UART2)

The RaspberryPI OS is a bit more strict than the other devices I use about port access. To allow my .Net Core application to access a serial port I connected to the device with ExtraPutty, then ran the RaspberyPI configuration tool, from the command prompt with “sudo raspi-config”

RaspberyPI OS Software Configuration tool mains screen
RaspberryPI OS IO Serial Port configuration
Raspberry PI OS disabling remote serial login shell
RaspberryPI OS enabling serial port access

Once serial port access was enabled I could enumerate them with SerialPort.GetPortNames() which is in the System.IO.Ports NuGet package. My sample code has compile time options for synchronous and asynchronous operation.

//---------------------------------------------------------------------------------
// Copyright (c) September 2021, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.NetCore.RAK3172.ShieldSerial
{
	using System;
	using System.Diagnostics;
	using System.IO.Ports;
	using System.Threading;

	public class Program
	{
		private const string SerialPortId = "/dev/ttyS0";

		public static void Main()
		{
			SerialPort serialPort;

			Debug.WriteLine("devMobile.IoT.NetCore.Rak3172.pHatSerial starting");

			Debug.WriteLine(String.Join(",", SerialPort.GetPortNames()));

			try
			{
				serialPort = new SerialPort(SerialPortId);

				// set parameters
				serialPort.BaudRate = 9600;
				serialPort.Parity = Parity.None;
				serialPort.DataBits = 8;
				serialPort.StopBits = StopBits.One;
				serialPort.Handshake = Handshake.None;

				serialPort.ReadTimeout = 1000;

				serialPort.NewLine = "\r\n";

				serialPort.Open();

#if SERIAL_ASYNC_READ
				serialPort.DataReceived += SerialDevice_DataReceived;
#endif

				while (true)
				{
					serialPort.WriteLine("AT+VER=?");

#if SERIAL_SYNC_READ
					// Read the response
					string response = serialPort.ReadLine();
					Debug.WriteLine($"RX:{response.Trim()} bytes:{response.Length}");

					// Read the blank line
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX:{response.Trim()} bytes:{response.Length}");

					// Read the result
					response = serialPort.ReadLine();
					Debug.WriteLine($"RX:{response.Trim()} bytes:{response.Length}");
#endif

					Thread.Sleep(20000);
				}
			}
			catch (Exception ex)
			{
				Debug.WriteLine(ex.Message);
			}
		}

#if SERIAL_ASYNC_READ
		private static void SerialDevice_DataReceived(object sender, SerialDataReceivedEventArgs e)
		{
			SerialPort serialPort = (SerialPort)sender;

			switch (e.EventType)
			{
				case SerialData.Chars:
					string response = serialPort.ReadExisting();

					Debug.WriteLine($"RX:{response.Trim()} bytes:{response.Length}");
					break;

				case SerialData.Eof:
					Debug.WriteLine("RX :EoF");
					break;
				default:
					Debug.Assert(false, $"e.EventType {e.EventType} unknown");
					break;
			}
		}
#endif
	}
}

When I requested the RAK3172 version information with the AT+VER? command the response was three lines, consisting of the version information, a blank line, then the result of the command. If I sent an invalid command the response was two lines, a blank line then “AT_ERROR”

AT+VER? response synchronous

The asynchronous version of the application displays character(s) as they arrive so a response could be split across multiple SerialDataReceived events

AT+VER? response asynchronous

Unlike the RAK811 module the RAK3172 defaults 9600 baud which means there is no need to change the baudrate before using the device. I use the excellent RaspberryDebugger to download application and debug them on my Raspberry PI 3.

.NET Core Seeed LoRaE5 LoRaWAN library Part2

Nasty OTAA connect

After getting basic connectivity for my Seeed LoRa-E5 test rig sorted I used RAK7246G LPWAN Developer Gateway on my bookcase to connect to The Things Network(TTN)

Seeed LoRa-E5 Development kit connected to Gove bas shield on a Raspberry PI3

My Over the Air Activation (OTAA) implementation is very “nasty” I have assumed that there would be no timeouts or failures and I only send one BCD message “48656c6c6f204c6f526157414e” which is “hello LoRaWAN”.

The code just sequentially steps through the necessary configuration to join the TTN network with a suitable delay after each command is sent. There also appeared to be quite a variation in response times, especially for joining the network(most probably network related) and the progress of sending a message.

//---------------------------------------------------------------------------------
// Copyright (c) September 2021, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.NetCore.SeeedLoRaE5.NetworkJoinOTAA
{
	using System;
	using System.Diagnostics;
	using System.IO.Ports;
	using System.Threading;

	class Program
	{
		private const string SerialPortId = "/dev/ttyS0";

		private const string AppKey = "................................";
		private const string AppEui = "................";

		private const byte MessagePort = 15;

		//private const string Payload = "48656c6c6f204c6f526157414e"; // Hello LoRaWAN
		private const string Payload = "01020304"; // AQIDBA==
		//private const string Payload = "04030201"; // BAMCAQ==

		public static void Main()
		{
			string response;

			Debug.WriteLine("devMobile.IoT.SeeedLoRaE5.NetworkJoinOTAA starting");

			Debug.WriteLine(String.Join(",", SerialPort.GetPortNames()));

			try
			{
				using (SerialPort serialDevice = new SerialPort(SerialPortId))
				{
					// set parameters
					serialDevice.BaudRate = 9600;
					serialDevice.Parity = Parity.None;
					serialDevice.StopBits = StopBits.One;
					serialDevice.Handshake = Handshake.None;
					serialDevice.DataBits = 8;

					serialDevice.ReadTimeout = 10000;

					serialDevice.NewLine = "\r\n";

					serialDevice.Open();

					// clear out the RX buffer
					serialDevice.ReadExisting();
					response = serialDevice.ReadExisting();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");
					Thread.Sleep(500);

					// Set the Region to AS923
					serialDevice.WriteLine("AT+DR=AS923\r\n");
					response = serialDevice.ReadLine();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

					// Set the Join mode
					serialDevice.WriteLine("AT +MODE=LWOTAA\r\n");
					response = serialDevice.ReadLine();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

					// Set the appEUI
					serialDevice.WriteLine($"AT+ID=AppEui,\"{AppEui}\"\r\n");
					response = serialDevice.ReadLine();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

					// Set the appKey
					serialDevice.WriteLine($"AT+KEY=APPKEY,{AppKey}\r\n");
					response = serialDevice.ReadLine();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

					// Set the port number
					serialDevice.WriteLine($"AT+PORT={MessagePort}\r\n");
					response = serialDevice.ReadLine();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

					// Join the network
					serialDevice.WriteLine("AT+JOIN\r\n");

					// Join start
					response = serialDevice.ReadLine();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

					// JOIN normal
					response = serialDevice.ReadLine();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

					Thread.Sleep(5000);

					// network joined
					response = serialDevice.ReadLine();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

					// Net ID
					response = serialDevice.ReadLine();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

					// Join done
					response = serialDevice.ReadLine();
					Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

					while (true)
					{
						Debug.WriteLine("Sending");

						serialDevice.WriteLine($"AT+MSGHEX=\"{Payload}\"\r\n");

						// Start
						response = serialDevice.ReadLine();
						Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

						// Fpending
						response = serialDevice.ReadLine();
						Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

						//Read metrics
						response = serialDevice.ReadLine();
						Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

						//Done
						response = serialDevice.ReadLine();
						Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");

						Thread.Sleep(30000);
					}
				}
			}
			catch (Exception ex)
			{
				Debug.WriteLine(ex.Message);
			}
		}
	}
}

The code is not suitable for production but it confirmed my software and hardware configuration worked.

Visual Studio debugger output window showing network join and sensing a message

In the Visual Studio 2019 debug output I could see messages getting sent and then after a short delay they were visible in the TTN console.

The Things Industries Live Data view showing network join and sensing a message

Most of the LoRaWAN modems I have worked with reply “OK” when a command is successful. The SeeedLoRa-E5 often returns the payload of the request in the response which makes the code a little bit more complex.

AppEui command structure in AT Command documentation

For example the AppEui can be passed in as “00:00:00:00:00:00:00:00” or “0000000000000000” but in the response the format is always “00:00:00:00:00:00:00:00”

.NET Core Seeed LoRaE5 LoRaWAN library Part1

Basic connectivity

Over the weekend I started building a .Net Core C# library for a Seeedstudio LoRa-E5 Development Kit which was connected to a Raspberry PI 3 with a Grove Base Hat for Raspberry Pi

The RaspberryPI OS is a bit more strict than the other devices I use about port access. To allow my .Net Core application to access a serial port I connected to the device with ExtraPutty, then ran the RaspberyPI configuration tool, from the command prompt with “sudo raspi-config”

RaspberyPI OS Software Configuration tool mains screen
RaspberryPI OS IO Serial Port configuration
Raspberry PI OS disabling remote serial login shell
RaspberryPI OS enabling serial port access

Once serial port access was enabled I could enumerate them with SerialPort.GetPortNames() which is in the System.IO.Ports NuGet package. The code has compile time options for synchronous and asynchronous operation.

//---------------------------------------------------------------------------------
// Copyright (c) September 2021, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.NetCore.SeeedLoRaE5.ShieldSerial
{
	using System;
	using System.Diagnostics;
	using System.IO.Ports;
	using System.Threading;

	public class Program
	{
		private const string SerialPortId = "/dev/ttyS0";

		public static void Main()
		{
			SerialPort serialPort;

			Debug.WriteLine("devMobile.IoT.NetCore.SeeedLoRaE5.ShieldSerial starting");

			Debug.WriteLine(String.Join(",", SerialPort.GetPortNames()));

			try
			{
				serialPort = new SerialPort(SerialPortId);

				// set parameters
				serialPort.BaudRate = 9600;
				serialPort.Parity = Parity.None;
				serialPort.DataBits = 8;
				serialPort.StopBits = StopBits.One;
				serialPort.Handshake = Handshake.None;

				serialPort.ReadTimeout = 1000;

				serialPort.NewLine = "\r\n";

				serialPort.Open();

#if SERIAL_ASYNC_READ
				serialPort.DataReceived += SerialDevice_DataReceived;
#endif

				while (true)
				{
					serialPort.WriteLine("AT+VER");

#if SERIAL_SYNC_READ
					string response = serialPort.ReadLine();

					Debug.WriteLine($"RX:{response.Trim()} bytes:{response.Length}");
#endif

					Thread.Sleep(20000);
				}
			}
			catch (Exception ex)
			{
				Debug.WriteLine(ex.Message);
			}
		}

#if SERIAL_ASYNC_READ
		private static void SerialDevice_DataReceived(object sender, SerialDataReceivedEventArgs e)
		{
			SerialPort serialPort = (SerialPort)sender;

			switch (e.EventType)
			{
				case SerialData.Chars:
					string response = serialPort.ReadExisting();

					Debug.WriteLine($"RX:{response.Trim()} bytes:{response.Length}");
					break;

				case SerialData.Eof:
					Debug.WriteLine("RX :EoF");
					break;
				default:
					Debug.Assert(false, $"e.EventType {e.EventType} unknown");
					break;
			}
		}
#endif
	}
}

The synchronous version of the test client requests the Seeeduino LoRa-E5 version information with the AT+VER command.

Synchronously reading characters from the Seeeduino LoRa-E5

The asynchronous version of the application displays character(s) as they arrive so a response can be split across multiple SerialDataReceived events.

Asynchronous versions displaying partial responses

I use the excellent RaspberryDebugger to download the application and debug it on my Raspberry PI 3.