AdaFruit IO basic Netduino HTTP client

I use Netduino devices for teaching and my students often build projects which need a cloud based service like AdaFruit.IO to capture, store and display their sensor data.

My Proof of Concept (PoC) which uses a slightly modified version of the AdaFruit.IO basic desktop HTTP client code has been running on several Netduino 2 Plus, Netduino 3 Ethernet and Netduino 3 Wifi devices for the last couple of days and looks pretty robust.

The Netduino 3 Wifi device also supports https for improved security and privacy. They also make great field gateways as they can run off solar/battery power.

N2PN3WDashBoard

The devices have been uploading temperature and humidity measurements from a Silicon labs Si7005 sensor. (Outside sensor suffering from sunstrike)

N3WifiTemperatureAndHumiditySensor

program.cs

*

Copyright ® 2017 December devMobile Software, All Rights Reserved

THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
PURPOSE.

http://www.devmobile.co.nz

*/
using System;
using System.Net;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using Microsoft.SPOT.Net.NetworkInformation;
using SecretLabs.NETMF.Hardware.Netduino;
using devMobile.NetMF.Sensor;
using devMobile.IoT.NetMF;

namespace devMobile.IoT.AdaFruitIO.NetMF.Client
{
   public class Program
   {
      private const string adaFruitIOApiBaseUrl = @"https://IO.adafruit.com/api/v2/";
      private const string group = "netduino3";
      private const string temperatureFeedKey = "t";
      private const string humidityFeedKey = "h";
      private const string adaFruitUserName = "YourUserName";
      private const string adaFruitIOApiKey = "YourAPIKey";
      private static readonly TimeSpan timerDueAfter = new TimeSpan(0, 0, 15);
      private static readonly TimeSpan timerPeriod = new TimeSpan(0, 0, 30);
      private static OutputPort led = new OutputPort(Pins.ONBOARD_LED, false);
      private static SiliconLabsSI7005 sensor = new SiliconLabsSI7005();
      private static AdaFruitIoClient adaFruitIoClient = new AdaFruitIoClient(adaFruitUserName, adaFruitIOApiKey, adaFruitIOApiBaseUrl);

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

            while (NetworkInterface.GetAllNetworkInterfaces()[0].IPAddress == IPAddress.Any.ToString())
            {
               Debug.Print(" .");
               led.Write(!led.Read());
               Thread.Sleep(250);
            }
            led.Write(false);
         }

         // 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());
         }

         Timer humidityAndtemperatureUpdates = new Timer(HumidityAndTemperatureTimerProc, null, timerDueAfter, timerPeriod);

         Thread.Sleep(Timeout.Infinite);
      }

      static private void HumidityAndTemperatureTimerProc(object state)
      {
         led.Write(true);

         try
         {
            double humidity = sensor.Humidity();

            Debug.Print(" Humidity " + humidity.ToString("F0") + "%");
            adaFruitIoClient.FeedUpdate(group, humidityFeedKey, humidity.ToString("F0"));
         }
         catch (Exception ex)
         {
            Debug.Print("Humidifty read+update failed " + ex.Message);

            return;
         }

         try
         {
            double temperature = sensor.Temperature();

            Debug.Print(" Temperature " + temperature.ToString("F1") + "°C");
            adaFruitIoClient.FeedUpdate(group, temperatureFeedKey, temperature.ToString("F1"));
         }
         catch (Exception ex)
         {
            Debug.Print("Temperature read+update failed " + ex.Message);

            return;
         }

         led.Write(false);
      }

      private static string BytesToHexString(byte[] bytes)
      {
         string hexString = string.Empty;

         // Create a character array for hexidecimal conversion.
         const string hexChars = "0123456789ABCDEF";

         // Loop through the bytes.
         for (byte b = 0; b < bytes.Length; b++)          {             if (b > 0)
               hexString += "-";

            // Grab the top 4 bits and append the hex equivalent to the return string.
            hexString += hexChars[bytes[b] >> 4];

            // Mask off the upper 4 bits to get the rest of it.
            hexString += hexChars[bytes[b] & 0x0F];
         }

         return hexString;
      }
   }
}

AdaFruit.IO client.cs, handles feed groups and individual feeds

/*

Copyright ® 2017 December devMobile Software, All Rights Reserved

THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
PURPOSE.

http://www.devmobile.co.nz

*/
using System;
using System.IO;
using System.Net;
using System.Text;
using Microsoft.SPOT;

namespace devMobile.IoT.NetMF
{
   public class AdaFruitIoClient
   {
      private const string apiBaseUrlDefault = @"http://IO.adafruit.com/api/v2/";
      private string apiBaseUrl = "";
      private string userName = "";
      private string apiKey = "";
      private int httpRequestTimeoutmSec;
      private int httpRequestReadWriteTimeoutmSec;

      public AdaFruitIoClient(string userName, string apiKey, string apiBaseUrl = apiBaseUrlDefault, int httpRequestTimeoutmSec = 2500, int httpRequestReadWriteTimeoutmSec = 5000)
      {
         this.apiBaseUrl = apiBaseUrl;
         this.userName = userName;
         this.apiKey = apiKey;
         this.httpRequestReadWriteTimeoutmSec = httpRequestReadWriteTimeoutmSec;
         this.httpRequestTimeoutmSec = httpRequestTimeoutmSec;
      }

      public void FeedUpdate(string group, string feedKey, string value)
      {
         string feedUrl;

         if (group.Trim() == string.Empty)
         {
            feedUrl = apiBaseUrl + userName + @"/feeds/" + feedKey + @"/data";
         }
         else
         {
            feedUrl = apiBaseUrl + userName + @"/feeds/" + group.Trim() + "." + feedKey + @"/data";
         }

         HttpWebRequest request = (HttpWebRequest)WebRequest.Create(feedUrl);
         {
            string payload = @"{""value"": """ + value + @"""}";
            byte[] buffer = Encoding.UTF8.GetBytes(payload);

            DateTime httpRequestedStartedAtUtc = DateTime.UtcNow;

            request.Method = "POST";
            request.ContentLength = buffer.Length;
            request.ContentType = @"application/json";
            request.Headers.Add("X-AIO-Key", apiKey);
            request.KeepAlive = false;
            request.Timeout = this.httpRequestTimeoutmSec;
            request.ReadWriteTimeout = this.httpRequestReadWriteTimeoutmSec;

            using (Stream stream = request.GetRequestStream())
            {
               stream.Write(buffer, 0, buffer.Length);
            }

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

            TimeSpan duration = DateTime.UtcNow - httpRequestedStartedAtUtc;
            Debug.Print(" Duration: " + duration.ToString());
         }
      }
   }
}

Bill of materials for PoC

nRF24 Windows 10 IoT Core reboot

My first live deployment of the nRF24L01 Windows 10 IoT Core field gateway is now scheduled for mid Q1 2018 so time for a reboot. After digging out my Raspbery PI 2/3 devices and the nRF24L01+ shield (with modifications detailed here) I have a basic plan with some milestones.

My aim is to be able to wirelessly acquire data from several dozen Arduino, devduino, seeeduino, and Netduino devices, Then, using a field gateway on a Raspberry PI running Windows 10 IoT Core upload it to Microsoft IoT Central

First bit of code – Bleepy a simple background application to test the piezo beeper on the RPI NRF24 Shield

namespace devmobile.IoTCore.Bleepy
{
   public sealed class StartupTask : IBackgroundTask
   {
      private BackgroundTaskDeferral deferral;
      private const int ledPinNumber = 4;
      private GpioPin ledGpioPin;
      private ThreadPoolTimer timer;

      public void Run(IBackgroundTaskInstance taskInstance)
      {
         var gpioController = GpioController.GetDefault();
         if (gpioController == null)
         {
            Debug.WriteLine("GpioController.GetDefault failed");
            return;
         }

         ledGpioPin = gpioController.OpenPin(ledPinNumber);
         if (ledGpioPin == null)
         {
            Debug.WriteLine("gpioController.OpenPin failed");
            return;
         }

         ledGpioPin.SetDriveMode(GpioPinDriveMode.Output);

         this.timer = ThreadPoolTimer.CreatePeriodicTimer(Timer_Tick, TimeSpan.FromMilliseconds(500));

         deferral = taskInstance.GetDeferral();

         Debug.WriteLine("Rum completed");
      }

      private void Timer_Tick(ThreadPoolTimer timer)
      {
         GpioPinValue currentPinValue = ledGpioPin.Read();

         if (currentPinValue == GpioPinValue.High)
         {
            ledGpioPin.Write(GpioPinValue.Low);
         }
         else
         {
            ledGpioPin.Write(GpioPinValue.High);
         }
      }
   }
}

Note the blob of blu tack over the piezo beeper to mute noise
nRF24ShieldMuted

Mikrobus.Net Quail, EthClick and xively

My second proof of concept application for the Mikrobus.Net Quail and EthClick uploads temperature and humidity data to Xively every 30 seconds for display and analysis.

Temperature and humidity Xively data stream

Temperature and humidity Xively data stream

The Xively REST API uses an HTTP PUT which initially didn’t work because the payload was not getting attached.

I patched the AssembleRequest method in the EtherClick driver to fix this issue.

private byte[] AssembleRequest()
{
   var a = RequestType;
   a += " " + Path + " " + Protocol + "\r\nHost: ";
   a += Host + "\r\n";

   foreach (object aHeader in Headers.Keys)
      a += (string)aHeader + ": " + (string)Headers[aHeader] + "\r\n";

   a += "\r\n"; // Cache-Control: no-cache\r\n  //Accept-Charset: utf-8;\r\n

   if (Content != null && Content != string.Empty && (RequestType == "POST" || RequestType == "PUT")) a += Content;

   return Encoding.UTF8.GetBytes(a);
}

The code reads the WeatherClick temperature and humidity values then assembles a CSV payload which it uploads with an HTTP PUT

</pre>
public class Program
{
   private const string xivelyHost = @"api.xively.com";
   private const string xivelyApiKey = @"YourAPIKey";
   private const string xivelyFeedId = @"YourFeedID";

   public static void Main()
   {
      WeatherClick weatherClick = new WeatherClick(Hardware.SocketOne, WeatherClick.I2CAddresses.Address0);
      weatherClick.SetRecommendedMode(WeatherClick.RecommendedModes.WeatherMonitoring);

      EthClick ethClick = new EthClick(Hardware.SocketTwo);
      ethClick.Start(ethClick.GenerateUniqueMacAddress("devMobileSoftware"), "QuailDevice");

      // Wait for an internet connection
      while (true)
      {
         if (ethClick.ConnectedToInternet)
         {
            Debug.Print("Connected to Internet");
            break;
         }
         Debug.Print("Waiting on Internet connection");
      }

      while (true)
      {
         Debug.Print("T " + weatherClick.ReadTemperature().ToString("F1") + " H " + weatherClick.ReadHumidity().ToString("F1") + " P " + weatherClick.ReadPressure(PressureCompensationModes.Uncompensated).ToString("F1"));

         HttpRequest request = new HttpRequest(@"http://" + xivelyHost + @"/v2/feeds/" + xivelyFeedId + @".csv");
         request.Host = xivelyHost;
         request.RequestType = "PUT";
         request.Headers.Add("Content-Type", "text/csv");
         request.Headers.Add("X-ApiKey", xivelyApiKey );

         request.Content = "OfficeT," + weatherClick.ReadTemperature().ToString("F1") + "\r\n" + "OfficeH," + weatherClick.ReadHumidity().ToString("F1") ;
         request.Headers.Add("Content-Length", request.Content.Length.ToString());

         var response = request.Send();
         if (response != null)
         {
            Debug.Print("Response: " + response.Message);
         }
         else
         {
            Debug.Print("No response");
         }
      Thread.Sleep(30000);
      }
   }
}
MikrobustNet Quail with Eth and Weather Clicks

MikrobustNet Quail with Eth and Weather Clicks

This proof of concept code appears to be reliable and has run for days at a time. The IP stack looks like it needs a bit more work.

Mikrobus.Net Quail and Weather Click

In my second batch of MikroElektronika Mikrobus sensors I had purchased a Weather click because I was interested to see how the temperature and humidity values it returned compared with the Silicon labs Si7005 devices I use with my Arduino and Netduino devices. (I was a bit suspicious of the Si7005 humidity values)

I downloaded the Mikrobus.Net driver for the BME280 and created a simple console application to see how well the sensor and driver worked

public class Program
{
   public static void Main()
   {
      WeatherClick weatherClick = new WeatherClick(Hardware.SocketOne, WeatherClick.I2CAddresses.Address0);

      weatherClick.SetRecommendedMode(WeatherClick.RecommendedModes.WeatherMonitoring);

      while (true)
      {
         Debug.Print("T " + weatherClick.ReadTemperature().ToString(" F1 ") +
" H " + weatherClick.ReadHumidity().ToString("F1") +
" P " + weatherClick.ReadPressure(PressureCompensationModes.Uncompensated).ToString("F1"));

         Thread.Sleep(30000);
      }
   }
}

The temperature values looked pretty good but the humidity values were rough half of what I was getting from the SI7005 connected to a devDuino V2 on the desk next to my Quail board

The thread ‘<No Name>’ (0x2) has exited with code 0 (0x0).
T 24.9 H 49.3 P 1014.8
T 25.0 H 49.4 P 1014.9
T 25.0 H 49.1 P 1014.8
T 25.0 H 49.9 P 1014.8
T 24.9 H 49.1 P 1014.9
T 25.0 H 50.8 P 1014.9
T 25.0 H 49.2 P 1015.0

The code for doing the conversions looked pretty complex so I modified a Netduino BME280 driver (uses a different approach for conversions) I have used on another projects to work on the Quail/Mikrobus architecture.

The modified driver returned roughly the same values so it looks like the problem is most probably with the SI7005 code.(or my understand of the humidity values it returns)

Netduino Silicon Labs Si7005 Device Driver

A while back I wrote a post about some problems I was having with a Silicon Labs Si7005 device and now I have had some time to package up the code.

My code strobes the I2C SDA line and then initiates a request that will always fail, from there on everything works as expected.

public SiliconLabsSI7005(byte deviceId = DeviceIdDefault, int clockRateKHz = ClockRateKHzDefault, int transactionTimeoutmSec = TransactionTimeoutmSecDefault)
{
   this.deviceId = deviceId;
   this.clockRateKHz = clockRateKHz;
   this.transactionTimeoutmSec = transactionTimeoutmSec;

   using (OutputPort i2cPort = new OutputPort(Pins.GPIO_PIN_SDA, true))
   {
      i2cPort.Write(false);
      Thread.Sleep(250);
   }

   using (I2CDevice device = new I2CDevice(new I2CDevice.Configuration(deviceId, clockRateKHz)))
   {
      byte[] writeBuffer = { RegisterIdDeviceId };
      byte[] readBuffer = new byte[1];

      // The first request always fails
      I2CDevice.I2CTransaction[] action = new I2CDevice.I2CTransaction[] 
      { 
         I2CDevice.CreateWriteTransaction(writeBuffer),
         I2CDevice.CreateReadTransaction(readBuffer)
      };

      if( device.Execute(action, transactionTimeoutmSec) == 0 )
      {
         //   throw new ApplicationException("Unable to send get device id command");
      }
   }
}

This is how the driver should be used in an application

public static void Main()
{
   SiliconLabsSI7005 sensor = new SiliconLabsSI7005();

   while (true)
   {
      double temperature = sensor.Temperature();

      double humidity = sensor.Humidity();

      Debug.Print("T:" + temperature.ToString("F1") + " H:" + humidity.ToString("F1"));

      Thread.Sleep(5000);
      }
   }

I have added code to catch failures and there is a sample application in the project. For a project I’m working on I will modify the code to use one of the I2C sharing libraries so I can have a number of devices on the bus

Silicon Labs Si7005 Device Driver oddness

I have been working on a Netduino I2C driver for the Silicon Labs Si7005 Digital I2C Humidity & Temperature Sensor for weather station and building monitoring applications as it looks like a reasonably priced device which is not to complex to interface with.I’m using a SeeedStudio Grove – Temperature&Humidity Sensor (High-Accuracy & Mini) for development.

The first time I try and read anything from the device it fails. Otherwise my driver works as expected.

Netduino 2 Plus & Silicon Labs Si7005

Bill of materials (prices as at April 2015)

  • Netduino Plus 2 USD60 NZD108
  • Grove – Temperature&Humidity Sensor (High-Accuracy & Mini) USD11.50
  • Grove – Base Shield USD8.90

This code just shows the flow, I’ll package into a driver shortly

I strobe the I2C line which seems to help

using (OutputPort i2cPort = new OutputPort(Pins.GPIO_PIN_SDA, true))
{
   i2cPort.Write(false);
   Thread.Sleep(1000);
}

I then try and read the Device ID (0x50) from register 0X11 but this (and any other read fails)

byte[] writeBuffer = { RegisterIdDeviceId };
byte[] readBuffer = new byte[1];

I2CDevice.I2CTransaction[] action = new I2CDevice.I2CTransaction[] 
{ 
   I2CDevice.CreateWriteTransaction(writeBuffer),
   I2CDevice.CreateReadTransaction(readBuffer)
};

int length = device.Execute(action, TransactionTimeoutMilliseconds);
Debug.Print(&quot;Byte count &quot; + length.ToString());
foreach (byte Byte in readBuffer)
{
   Debug.Print(Byte.ToString(&quot;X2&quot;));
}

I can read the temperature and humidity by writing to the command register

byte[] writeBuffer = { RegisterIdConiguration, CMD_MEASURE_TEMP };

I2CDevice.I2CTransaction[] action = new I2CDevice.I2CTransaction[] 
{ 
   I2CDevice.CreateWriteTransaction(writeBuffer),
};

int length = device.Execute(action, TransactionTimeoutMilliseconds);
Debug.Print(&quot;Byte count&quot; + length.ToString());

Then poll for measurement process to finish

conversionInProgress = true
do
{
   byte[] writeBuffer = { RegisterIdStatus };
   byte[] readBuffer = new byte[1];

   I2CDevice.I2CTransaction[] action = new I2CDevice.I2CTransaction[] 
   { 
      I2CDevice.CreateWriteTransaction(writeBuffer4),
      I2CDevice.CreateReadTransaction(readBuffer4)
   };

   int length = device.Execute(action, TransactionTimeoutMilliseconds);
   Debug.Print(&quot;Byte count &quot; + length.ToString());
   foreach (byte Byte in readBuffer)
   {
      Debug.Print(Byte.ToString());
   }

   if ((readBuffer[RegisterIdStatus] &amp;&amp; STATUS_RDY_MASK) != STATUS_RDY_MASK)
   {
      conversionInProgress = false;
   }
} while (conversionInProgress);

Then finally read and convert the value

byte[] writeBuffer = { REG_DATA_H };
byte[] readBuffer = new byte[2];

I2CDevice.I2CTransaction[] action = new I2CDevice.I2CTransaction[] 
{ 
   I2CDevice.CreateWriteTransaction(writeBuffer),
   I2CDevice.CreateReadTransaction(readBuffer)
};

int length = device.Execute(action, TransactionTimeoutMilliseconds);
Debug.Print(&quot;Byte count &quot; + length.ToString());
foreach (byte Byte in readBuffer)
{
   Debug.Print(Byte.ToString());
}

int temp = readBuffer[0];

temp = temp &lt;&lt; 8;
temp = temp + readBuffer[1];
temp = temp &gt;&gt; 2;

double temperature = (temp / 32.0) - 50.0;

Debug.Print(&quot; Temp &quot; + temperature.ToString(&quot;F1&quot;));