Mikrobus.Net Quail, Weather & nRF-C clicks and xively

My next proof of concept uses a Weather click and nRF C click to upload temperature and humidity data to a Xively gateway running on a spare Netduino 2 Plus. I have a couple of Azure Event hub gateways (direct & queued) which require a Netduino 3 Wifi (for TLS/AMQPS support) and I’ll build a client for them in a coming post.

I initially purchased an nRF T click but something wasn’t quite right with its interrupt output. The interrupt line wasn’t getting pulled low at all so there were no send success/failure events. If I disabled the pull up resistor and strobed the interrupt pin on start-up the device would work for a while.


using (OutputPort Int = new OutputPort(socket.Int, true))
{
 Int.Write(true);
};

...

_irqPin = new InterruptPort(socket.Int, false, Port.ResistorMode.Disabled, Port.InterruptMode.InterruptEdgeLow);

The code sends a reading every 10 seconds and has been running for a couple of days. It strobes Led1 for each successful send and turns on Led2 when a send fails.

private static readonly byte[] deviceAddress = Encoding.UTF8.GetBytes("Quail");
private static readonly byte[] gatewayAddress = Encoding.UTF8.GetBytes("12345");
private const byte gatewayChannel = 10;
private const NRFC.DataRate gatewayDataRate = NRFC.DataRate.DR1Mbps;
private const int XivelyUpdateDelay = 10000;
private const char XivelyGatewayChannelIdTemperature = 'J';
private const char XivelyGatewayChannelIdHumidity = 'K';

public static void Main()
{
   NRFC nRF24Click = new NRFC(Hardware.SocketFour);
   nRF24Click.Configure(deviceAddress, gatewayChannel, gatewayDataRate);
   nRF24Click.OnTransmitFailed += nRF24Click_OnTransmitFailed;
   nRF24Click.OnTransmitSuccess += nRF24Click_OnTransmitSuccess;
   nRF24Click.Enable();

   // Configure the weather click
   WeatherClick weatherClick = new WeatherClick(Hardware.SocketOne, WeatherClick.I2CAddresses.Address0);
   weatherClick.SetRecommendedMode(WeatherClick.RecommendedModes.WeatherMonitoring);

   Thread.Sleep(XivelyUpdateDelay);

   while (true)
   {
      string temperatureMessage = XivelyGatewayChannelIdTemperature + weatherClick.ReadTemperature().ToString("F1");
      Debug.Print(temperatureMessage);
      MBN.Hardware.Led1.Write(true);
      nRF24Click.SendTo(gatewayAddress, Encoding.UTF8.GetBytes(temperatureMessage));

      Thread.Sleep(XivelyUpdateDelay);

      string humidityMessage = XivelyGatewayChannelIdHumidity + weatherClick.ReadHumidity().ToString("F1");
      Debug.Print(humidityMessage);
      MBN.Hardware.Led1.Write(true);
      nRF24Click.SendTo(gatewayAddress, Encoding.UTF8.GetBytes(humidityMessage));

      Thread.Sleep(XivelyUpdateDelay);
   }
}

static void nRF24Click_OnTransmitSuccess()
{
   MBN.Hardware.Led1.Write(false);
   if (MBN.Hardware.Led2.Read())
   {
      MBN.Hardware.Led2.Write(false);
   }

   Debug.Print("nRF24Click_OnTransmitSuccess");
}

static void nRF24Click_OnTransmitFailed()
{
   MBN.Hardware.Led2.Write(true);

   Debug.Print("nRF24Click_OnTransmitFailed");
}

I need to have a look at interfacing some more sensors and soak testing the solution.

The MikroBus.Net team have done a great job with the number & quality of the drivers they have available.

Netduino 3 Wifi Queued Azure Event Hub Field Gateway V1.0

My ADSL connection had been a bit flaky which had meant I had lost some sensor data with my initial Azure Event Hub gateway. In attempt make the solution more robust this version of the gateway queues unsent messages using the on-board MicroSD card support.

The code assumes that a file move is an “atomic operation”, so it streams the events received from the devices into a temporary directory (configurable) then moves them to the upload directory (configurable).

This code is proof of concept and needs to be soak tested, improved error handling and some additional multi threading locking added plus the magic constants refactored.

This code is called in the nRF24 receive messages handler

private void OnReceive(byte[] data)
{
   activityLed.Write(!activityLed.Read());

   // Ensure that we have a payload
   if (data.Length < 1 )
   {
      Debug.Print( "ERROR - Message has no payload" ) ;
      return ;
   }

   string message = new String(Encoding.UTF8.GetChars(data));
   Debug.Print("+" + DateTime.UtcNow.ToString("HH:mm:ss") + " L=" + data.Length + " M=" + message);

   string filename = DateTime.UtcNow.ToString("yyyyMMddhhmmssff") + ".txt";

   string tempDirectory = Path.Combine("\\sd", "temp");
   string tempFilePath = Path.Combine(tempDirectory, filename);

   string queueDirectory = Path.Combine("\\sd", "data");
   string queueFilePath = Path.Combine(queueDirectory, filename);

   File.WriteAllBytes(tempFilePath, data);

   File.Move(tempFilePath, queueFilePath);

   new Microsoft.SPOT.IO.VolumeInfo("\\sd").FlushAll();
}

A timer initiates the upload process which uses the AMQPNetlite library

bool UploadInProgress = false;

      
void uploaderCallback(object state)
{
   Debug.Print("uploaderCallback - start");

   if (UploadInProgress)
   {
      return;
   }
   UploadInProgress = true;

   string[] eventFilesToSend = Directory.GetFiles(Path.Combine("\\sd", "data")) ;

   if ( eventFilesToSend.Length == 0 )
   {
      Debug.Print("uploaderCallback - no files");
      UploadInProgress = false;
      return ;
   }

   try
   {
      Debug.Print("uploaderCallback - Connect");
      Connection connection = new Connection(new Address(serviceBusHost, serviceBusPort, serviceBusSasKeyName, serviceBusSasKey));

      Session session = new Session(connection);

      SenderLink sender = new SenderLink(session, "send-link", eventHubName);

      for (int index = 0; index < System.Math.Min(eventUploadBatchSizeMaximum, eventFilesToSend.Length); index++)
      {
         string eventFile = eventFilesToSend[ index ] ;

         Debug.Print("-" + DateTime.UtcNow.ToString("HH:mm:ss") + " " + eventFile ); ;

         Message message = new Message()
         {
            BodySection = new Data()
            {
               Binary = File.ReadAllBytes(eventFile),
            },
         ApplicationProperties = new Amqp.Framing.ApplicationProperties(),
         };

         FileInfo fileInfo = new FileInfo(eventFile);

         message.ApplicationProperties["AcquiredAtUtc"] = fileInfo.CreationTimeUtc;
         message.ApplicationProperties["UploadedAtUtc"] = DateTime.UtcNow;
         message.ApplicationProperties["GatewayId"] = gatewayId;
         message.ApplicationProperties["DeviceId"] = deviceId;
         message.ApplicationProperties["EventId"] = Guid.NewGuid();

         sender.Send(message);

         File.Delete(eventFile);

         new Microsoft.SPOT.IO.VolumeInfo("\\sd").FlushAll();
      }

      sender.Close();
      session.Close();
      connection.Close();
   }
   catch (Exception ex)
   {
      Debug.Print("ERROR: Upload failed with error: " + ex.Message);
   }
   finally
   {
      Debug.Print("uploaderCallback - finally");
      UploadInProgress = false;
   }
}

The timer period and number of files uploaded in each batch is configurable. I need to test the application to see how it handles power outages and MicroSD card corruption. The source is Netduino NRF24L01 AMQPNetLite Queued Azure EventHub Gatewaywith all the usual caveats.

This project wouldn’t have been possible without

Netduino 3 Wifi Azure Event Hub Field Gateway V2.0

After some testing I have improved the error handling and robustness of my Netduino 3 wifi based Azure Eventhub field gateway.

private void OnReceive(byte[] data)
{
   activityLed.Write(!activityLed.Read());

   // Ensure that we have a payload
   if (data.Length < 1 ) { Debug.Print( "ERROR - Message has no payload" ) ; return ; } string message = new String(Encoding.UTF8.GetChars(data)); Debug.Print(DateTime.UtcNow.ToString("HH:mm:ss") + " L=" + data.Length + " M=" + message); Thread thread = new Thread(() => EventHubSendMessage( data));
   thread.Start();
}

private void EventHubSendMessage( byte[] messageBody)
{
   #region Diagnostic assertions
   Debug.Assert(eventHubName != null);
   Debug.Assert(deviceId != null);
   Debug.Assert(gatewayId != null);
   Debug.Assert(messageBody != null);
   Debug.Assert(messageBody.Length > 0);
   #endregion

   if ((connection == null) || (session == null ) || (senderLink == null ))
   {
      lock (lockThis)
      {
         if (connection == null)
         {
            Debug.Print("AMQP Establish connection");
            try
            {
               connection = new Connection(new Address(serviceBusHost, serviceBusPort, serviceBusSasKeyName, serviceBusSasKey));

               connection.Closed = ConnectionClosedCallback;

               Debug.Print("AMQP Establish connection done");
            }
            catch (Exception ex)
            {
               Debug.Print("ERROR: AMQP Establish connection: " + ex.Message);
            }
         }

         if (connection == null)
         {
            return;
         }

         if (session == null)
         {
            Debug.Print("AMQP Establish session");
            try
            {
               session = new Session(connection);

               session.Closed = SessionClosedCallback;

               Debug.Print("AMQP Establish session done");
            }
            catch (Exception ex)
            {
               Debug.Print("ERROR: AMQP Establish session: " + ex.Message);
            }
         }

         if (session == null)
         {
            return;
         }

         if (senderLink == null)
         {
            Debug.Print("AMQP Establish SenderLink");
            try
            {
               senderLink = new SenderLink(session, "send-link", eventHubName);

               senderLink.Closed = SenderLinkClosedCallback;

               Debug.Print("AMQP Establish SenderLink done");
            }
            catch (Exception ex)
            {
               Debug.Print("ERROR: AMQP Establish SenderLink: " + ex.Message);
            }
         }

         if (senderLink == null)
         {
            return;
         }
      }
   }

         
   try
   {
      Debug.Print("AMQP Send start");
      DateTime startAtUtc = DateTime.UtcNow;

      Message message = new Message()
      {
         BodySection = new Data()
         {
            Binary = messageBody
         },
         ApplicationProperties = new Amqp.Framing.ApplicationProperties(),
      };

      message.ApplicationProperties["UploadedAtUtc"] = DateTime.UtcNow;
      message.ApplicationProperties["GatewayId"] = gatewayId;
      message.ApplicationProperties["DeviceId"] = deviceId;
      message.ApplicationProperties["EventId"] = Guid.NewGuid();

      senderLink.Send(message);
      DateTime finishAtUtc = DateTime.UtcNow;
      TimeSpan duration = finishAtUtc - startAtUtc;
      Debug.Print("AMQP Send done duration " + duration.ToString());
   }
   catch (Exception ex)
   {
      Debug.Print("ERROR: Publish failed with error: " + ex.Message);
   }
}

The software is quite reliable, when my internet connection fails it recovers gracefully and resumes uploading events when connectivity is restored.

The only issue is when the wireless access point is restarted, when the device reconnects it locks up and doesn’t recover. I have posted in the Netduino forums and logged at issue at the Github Netduino wifi repository.

I have been exploring rebooting the device in the NetworkChange_NetworkAvailabilityChanged handler when connectivity is restored.

Based on my logging the sending of events is pretty quick and the threads are interleaved

03:20:59 L=25 M={“D”:2,”H”:63.0,”T”:18.8}
AMQP Send start
03:20:59 L=25 M={“D”:1,”H”:54.5,”T”:18.7}
AMQP Send start
03:20:59 L=17 M={“D”:10,”P”:27.9}
AMQP Send start
AMQP Send done duration 00:00:00.2738220
AMQP Send done duration 00:00:00.4709960
AMQP Send done duration 00:00:01.0813910
03:21:01 L=17 M={“D”:10,”P”:27.4}
AMQP Send start
AMQP Send done duration 00:00:00.2820090
03:21:03 L=17 M={“D”:10,”P”:26.9}

Here is the code with usual caveats.

Next steps queuing messages in memory and then on the MicroSD card.

Netduino 3 Wifi Azure Event Hub Field Gateway V1.0

The Netduino 3 Wifi device supports TLS connectivity and looked like it could provide a low power consumption field gateway to an Azure EventHub for my nRF24L01 equipped Netduino, Arduino & devDuino 1.3, 2.0 & 3.0 devices.

Netduino 3 Wifi Azure Event Hub Field Gateway

Netduino 3 Wifi Azure Field Gateway and a selection of arduino & devDuino devices

Bill of materials for field gateway prices as at (Sept 2015)

  • Netduino 3 Wifi USD69.95
  • SeeedStudio Solar Shield USD13.95
  • Lithium Ion 3000mAH battery USD15.00
  • Embedded coolness nRF24L01 shield with high power module USD17.85

The software uses AMQPNetLite which provides a lightweight implementation of the AMQP protocol (on the .Net framework, .Net Compact Framework, .Net Micro Framework, and WindowsPhone platforms) and the Nordic nRF24L01 Net Micro Framework Driver.The first version of the software is a proof of concept and over time I will add functionality and improve the reliability.

On application start up the nRF24L01, Azure Event Hub and network settings are loaded from the built in MicroSD card.

// Write empty template of the configuration settings to the SD card if pin D0 is high
if (!File.Exists(Path.Combine("\\sd", "app.config")))
{
   Debug.Print("Writing template configuration file then stopping");

   ConfigurationFileGenerate();

   Thread.Sleep(Timeout.Infinite);
}
appSettings.Load();

If there is no configuration file on the MicroSD card an empty template is created.

private void ConfigurationFileGenerate()
{
   // Write empty configuration file
   appSettings.SetString(nRF2L01AddressSetting, "Base1");
   appSettings.SetString(nRF2L01ChannelSetting, "10");
   appSettings.SetString(nRF2L01DataRateSetting, "0");

   appSettings.SetString(serviceBusHostSetting, "serviceBusHost");
   appSettings.SetString(serviceBusPortSetting, "5671");
   appSettings.SetString(serviceBusSasKeyNameSetting, "serviceBusSasKeyName");
   appSettings.SetString(serviceBusSasKeySetting, "serviceBusSasKey");
   appSettings.SetString(eventHubNameSetting, "eventHubName");

   appSettings.Save();
}

Once the Wifi connection has been established the device connects to a specified NTP server so any messages have an accurate timestamp and then initiates an AMQP connection.

Debug.Print("Network time");
try
{
   DateTime networkTime = NtpClient.GetNetworkTime(ntpServerHostname);
   Microsoft.SPOT.Hardware.Utility.SetLocalTime(networkTime);
   Debug.Print(networkTime.ToString(" dd-MM-yy HH:mm:ss"));
}
catch (Exception ex)
{
   Debug.Print("ERROR: NtpClient.GetNetworkTime: " + ex.Message);
   Thread.Sleep(Timeout.Infinite);
}
Debug.Print("Network time done");

// Connect to AMQP gateway
Debug.Print("AMQP Establish connection");
try
{
   Address address = new Address(serviceBusHost, serviceBusPort, serviceBusSasKeyName, serviceBusSasKey);
   connection = new Connection(address);
}
catch (Exception ex)
{
   Debug.Print("ERROR: AMQP Establish connection: " + ex.Message);
   Thread.Sleep(Timeout.Infinite);
}
Debug.Print("AMQP Establish connection done");

After the device has network connectivity, downloaded the correct time and connected to AMQP hub the nRF241L01 device is initialised.

The first version of the software starts a new thread to handle each message and handles connectivity failures badly. These issues and features like local queuing of messages will be added in future iterations.

private void OnReceive(byte[] data)
{
   activityLed.Write(!activityLed.Read());

   // Ensure that we have a payload
   if (data.Length < 1 ) { Debug.Print( "ERROR - Message has no payload" ) ; return ; } string message = new String(Encoding.UTF8.GetChars(data)); Debug.Print(DateTime.UtcNow.ToString("HH:mm:ss") + " " + gatewayId + " " + data.Length + " " + message); Thread thread = new Thread(() => EventHubSendMessage(connection, eventHubName, deviceId, gatewayId, data));
   thread.Start();
}



private void EventHubSendMessage(Connection connection, string eventHubName, string deviceId, string gatewayId, byte[] messageBody)
{
   try
   {
      Session session = new Session(connection);
      SenderLink sender = new SenderLink(session, "send-link", eventHubName);

      Message message = new Message()
      {
         BodySection = new Data()
         {
            Binary = messageBody
         },
         ApplicationProperties = new Amqp.Framing.ApplicationProperties(),
      };

      message.ApplicationProperties["UploadedAtUtc"] = DateTime.UtcNow;
      message.ApplicationProperties["GatewayId"] = gatewayId;
      message.ApplicationProperties["DeviceId"] = deviceId;
      message.ApplicationProperties["EventId"] = Guid.NewGuid().ToString();

      sender.Send(message);

      sender.Close();
      session.Close();
      }
   catch (Exception ex)
   {
      Debug.Print("ERROR: Publish failed with error: " + ex.Message);
   }
}

Initially the devices send events with a JSON payload.

ServiceBus Explorer

JSON Event messages displayed in ServiceBus Explorer

The code is available NetduinoNRF24L01AMQPNetLiteAzureEventHubGatewayV1.0 and when I have a spare afternoon I will upload to github.

My first AzureSBLite program

Extending on the theme for my previous post I decided to take a look at Azure ServiceBus Lite by Paolo Patierno. Same objective as last time, a minimalist application running on my Netduino 3 Wifi which connects to my home wifi, waits for an IP address then uploads an event to an Azure EventHub.

public class Program
{
   private const string connectionString = "Endpoint=sb://[YourNamespace].servicebus.windows.net/;SharedAccessKeyName=[YourKeyName];SharedAccessKey=[YourSaSKey]";
   private const string eventHub = "[YourEventHub]";

...

// Wait for Network address if DHCP
NetworkInterface networkInterface = NetworkInterface.GetAllNetworkInterfaces()[0];
if (networkInterface.IsDhcpEnabled)
{
   Debug.Print(" Waiting for IP address ");

   while (NetworkInterface.GetAllNetworkInterfaces()[0].IPAddress == IPAddress.Any.ToString())
   {
      Debug.Print(".");
   }
}

// Display network config for debugging
Debug.Print("Network configuration");
Debug.Print(" Network interface type: " + networkInterface.NetworkInterfaceType.ToString());
Debug.Print(" MAC Address: " + BytesToHexString(networkInterface.PhysicalAddress));
Debug.Print(" DHCP enabled: " + networkInterface.IsDhcpEnabled.ToString());
Debug.Print(" Dynamic DNS enabled: " + networkInterface.IsDynamicDnsEnabled.ToString());
Debug.Print(" IP Address: " + networkInterface.IPAddress.ToString());
Debug.Print(" Subnet Mask: " + networkInterface.SubnetMask.ToString());
Debug.Print(" Gateway: " + networkInterface.GatewayAddress.ToString());

foreach (string dnsAddress in networkInterface.DnsAddresses)
{
   Debug.Print(" DNS Server: " + dnsAddress.ToString());
}

string deviceId = BytesToHexString(networkInterface.PhysicalAddress);
Debug.Print("DeviceId " + deviceId.ToString());

A bit less code is required to send an event using AzureSBLite

try
{
   MessagingFactory factory = MessagingFactory.CreateFromConnectionString(connectionString);

   EventHubClient client = factory.CreateEventHubClient(eventHub);

   string messageBody = @"{""DeviceId"":""" + deviceId + @""",""Time"":""" + DateTime.Now.ToString("yy-MM-dd hh:mm:ss") + @"""}";
   EventData data = new EventData(Encoding.UTF8.GetBytes(messageBody));

   //EventData data = new EventData();
   //data.Properties.Add("Time", DateTime.Now);
   //data.Properties.Add("DeviceId", deviceId);

   client.Send(data);
   client.Close();

   factory.Close();
}
catch (Exception ex)
{
   Debug.Print("ERROR: Send failed with error: " + ex.Message);
}

Over all, a very similar experience to “MyFirst AMQPNetLite” program, after a couple of typos, and fixing a copy ‘n’ paste issue with the connection string my application worked, with the bonus of less code. Both AMQPNetLite and AzureSBLite look suitable for my application so I’ll need to evaluate them in more detail.

My first AMQPNetLite program

After having some problems with my Netduino 3 wifi Azure Event Hub client code (which are most probably due to the issues discussed here) I decided to have a look at AMQPNetLite which had been suggested by Paolo Patierno in a response to one of my posts in the Netduino forums.

I usually create a “minimalist” project so I can figure out how a new library works without an domain specific code getting in the way. Overall, my first experience was pretty positive, the code compiled first time, ran second time and worked third time.

The objective for my first AMQPNetLite application running on my Netduino 3 Wifi was to connect to my home wifi, wait for an IP address then upload an event to an Azure EventHub

private const int amqpPortNumber = 5671;
private const string sbNamespace = "ServiceBus Namespace";
private const string keyName = "SaS Key name";
private const string keyValue = "SaS Key value";
private const string eventHub = "EventHub name";

...

// Wait for Network address if DHCP
NetworkInterface networkInterface = NetworkInterface.GetAllNetworkInterfaces()[0];
if (networkInterface.IsDhcpEnabled)
{
   Debug.Print(" Waiting for IP address ");

   while (NetworkInterface.GetAllNetworkInterfaces()[0].IPAddress == IPAddress.Any.ToString())
   {
      Debug.Print(".");
   }
}

// Display network config for debugging
Debug.Print("Network configuration");
Debug.Print(" Network interface type: " + networkInterface.NetworkInterfaceType.ToString());
Debug.Print(" MAC Address: " + BytesToHexString(networkInterface.PhysicalAddress));
Debug.Print(" DHCP enabled: " + networkInterface.IsDhcpEnabled.ToString());
Debug.Print(" Dynamic DNS enabled: " + networkInterface.IsDynamicDnsEnabled.ToString());
Debug.Print(" IP Address: " + networkInterface.IPAddress.ToString());
Debug.Print(" Subnet Mask: " + networkInterface.SubnetMask.ToString());
Debug.Print(" Gateway: " + networkInterface.GatewayAddress.ToString());

foreach (string dnsAddress in networkInterface.DnsAddresses)
{
   Debug.Print(" DNS Server: " + dnsAddress.ToString());
}

string deviceId = BytesToHexString(networkInterface.PhysicalAddress);
Debug.Print("DeviceId " + deviceId.ToString());

Then I constructed the AMQP address for the event hub, started an AMQP session and sent the message. I tried sending a message with a JSON payload and also using the “type safe” application properties.

try
{
   Address address = new Address(sbNamespace, amqpPortNumber, keyName, keyValue);
   Connection connection = new Connection(address);

   Session session = new Session(connection);

   SenderLink sender = new SenderLink(session, "send-link", eventHub);

   string messageBody = @"{""DeviceId"":""" + deviceId + @""",""Time"":""" + DateTime.Now.ToString("yy-MM-dd hh:mm:ss") + @"""}";

   Message message = new Message()
   {
      //BodySection = new Data() { Binary = Encoding.UTF8.GetBytes(messageBody)},
      ApplicationProperties = new Amqp.Framing.ApplicationProperties(),
   };

   message.ApplicationProperties["Time"] = DateTime.Now;
   message.ApplicationProperties["DeviceId"] = deviceId;

   sender.Send(message);

   sender.Close();
   session.Close();
   connection.Close();
}
catch (Exception ex)
{
   Debug.Print("ERROR: Publish failed with error: " + ex.Message);
}

For my scenario I was pleasantly surprised how easy it was to get working.

AMQP has a non TLS option (only for non sensitive data) and if this is supported I could use a device like a Netduino 3 Ethernet which don’t have baked in TLS support.

Netduino 3 Wifi Azure Service Bus client certificate issue

A few months ago I wrote a post about using a Netduino 3 wifi device to push data to an Azure Event Hub. Last week I wanted to reuse some of the code for another gateway I was building but it didn’t appear to work. When my application made an HTTPS request to the service bus endpoint of my Event Hub it failed with an exception. Initially I though it might be a problem with wildcard certificates so I build a small demo program which makes three HTTPS requests to endpoints with different certificate configurations (for more detail see the code below).

using System;
using System.Net;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Net.NetworkInformation;

namespace devMobile.Netduino3WifiCertificateQuery
{
   public class Program
   {
      public static void Main()
      {
         // Wait for Network address if DHCP
         NetworkInterface networkInterface = NetworkInterface.GetAllNetworkInterfaces()[0];
         if (networkInterface.IsDhcpEnabled)
         {
            Debug.Print(" Waiting for IP address ");
            while (NetworkInterface.GetAllNetworkInterfaces()[0].IPAddress == IPAddress.Any.ToString())
            {
               Debug.Print(".");
               Thread.Sleep(250);
            }
         }

         // Baseline check with google
         Debug.Print("https://www.google.co.nz");
         try
         {
            using (HttpWebRequest request = (HttpWebRequest)WebRequest.Create(@"https://www.google.co.nz"))
            {
               request.Method = "GET";
               request.KeepAlive = false;
               request.Timeout = 5000;
               request.ReadWriteTimeout = 5000;
               request.KeepAlive = false;

               using (var response = (HttpWebResponse)request.GetResponse())
               {
                  Debug.Print("HTTP Status:" + response.StatusCode + " : " + response.StatusDescription);
               }
            }
         }
         catch (Exception ex)
         {
            Debug.Print(ex.Message);
         }

         /*
         DNS Name=*.wordpress.com
         DNS Name=wordpress.com
         */
         Debug.Print("https://wordpress.wordpress.com/");
         try
         {
            using (HttpWebRequest request = (HttpWebRequest)WebRequest.Create(@"https://wordpress.wordpress.com/"))
            {
               //request.Proxy = proxy; 
               request.Method = "GET";
               request.KeepAlive = false;
               request.Timeout = 5000;
               request.ReadWriteTimeout = 5000;
               request.KeepAlive = false;


               using (var response = (HttpWebResponse)request.GetResponse())
               {
                  Debug.Print("HTTP Status:" + response.StatusCode + " : " + response.StatusDescription);
               }
            }
         }
         catch (Exception ex)
         {
            Debug.Print(ex.Message);
         }


         /*
         DNS Name=*.servicebus.windows.net
         DNS Name=servicebus.windows.net
         */
         Debug.Print(@"https://myhomemonitor.servicebus.windows.net/");
         try
         {
            using (HttpWebRequest request = (HttpWebRequest)WebRequest.Create(@"https://myhomemonitor.servicebus.windows.net/"))
            {
               //request.Proxy = proxy; 
               request.Method = "GET";
               request.KeepAlive = false;
               request.Timeout = 5000;
               request.ReadWriteTimeout = 5000;
               request.KeepAlive = false;

               using (var response = (HttpWebResponse)request.GetResponse())
               {
                  Debug.Print("HTTP Status:" + response.StatusCode + " : " + response.StatusDescription);
               }
            }
         }
         catch (Exception ex)
         {
            Debug.Print(ex.Message);
         }
      }
   }
}

I then noticed that when I looked at the certificate details of the endpoint where the requests were failing in Google Chrome (only occurred in Chrome) there was a warming about “obsolete cryptography”.

Google Chrome info about ok certificate

Google Chrome info about ok certificate

Google Chrome info about error causing certificate

Google Chrome info about possibly error causing certificate

I have downloaded the Netduino 3 Wifi IP stack code from github and have traced down to the native interop call which appears to be failing at the very bottom of the stack. My post at Netduino.com has additional detail about my debugging efforts.

Now I’m wondering if the crypto required by newish certificate for the service bus endpoint is not supported/needs to be enabled for the TI CC3100 SimpleLink Wifi network processor.