.Net Meadow RFM95/96/97/98 LoRa library Part3

Register Read and Write

Now that I could reliably dump all the Arduino shield registers I wanted to be able to configure the Semtech 1276/7/8/9 device and reset it back to factory settings.

A factory reset is done by strobing the reset pin on the device. To support this my Rfm9XDevice class constructor gained an additional parameter, the reset GPIO pin.

Arduino shield connected to Meadow with jumper wires

To configure the RFM9X I wrote some wrapper functions for the Meadow SPI API to read/write byte values, word values and arrays of bytes. The Meadow APIs (Dec 2019) return an additional byte at the start of each reply (unlike the .NetMF and Windows 10 IoT Core APIs) which has to be removed.

Each method was tested by read/writing suitable register(s) in the device configuration (Needed to set it into LoRa mode first).

//---------------------------------------------------------------------------------
// Copyright (c) December 2019, 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.Rfm9x.ReadAndWrite
{
   using System;
    using System.Diagnostics;
    using System.Runtime.InteropServices.WindowsRuntime;
    using System.Threading.Tasks;

   using Meadow;
   using Meadow.Devices;
   using Meadow.Hardware;

   public sealed class Rfm9XDevice
   {
      private SpiPeripheral Rfm9XLoraModem;
      private IDigitalOutputPort ChipSelectGpioPin;
		private const byte RegisterAddressReadMask = 0X7f;
		private const byte RegisterAddressWriteMask = 0x80;

		public Rfm9XDevice(IIODevice device, ISpiBus spiBus, IPin chipSelectPin, IPin resetPin)
      {
         // Chip select pin configuration
         ChipSelectGpioPin = device.CreateDigitalOutputPort(chipSelectPin, initialState: true);
         if (ChipSelectGpioPin == null)
         {
            Console.WriteLine("ChipSelectGpioPin == null");
         }

         // Factory reset pin configuration
         IDigitalOutputPort resetGpioPin = device.CreateDigitalOutputPort(resetPin);
         if (resetGpioPin == null)
         {
            Console.WriteLine("resetGpioPin == null");
         }
         resetGpioPin.State = false;
         Task.Delay(10);
         resetGpioPin.State = true;
         Task.Delay(10);

			Rfm9XLoraModem = new SpiPeripheral(spiBus, ChipSelectGpioPin);
         if (Rfm9XLoraModem == null)
         {
            Console.WriteLine("Rfm9XLoraModem == null");
         }
      }

      public Byte RegisterReadByte(byte address)
      {
         byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
			Debug.Assert(Rfm9XLoraModem != null);

			byte[] readBuffer = Rfm9XLoraModem.WriteRead(writeBuffer, 2);

         return readBuffer[1];
      }

		public ushort RegisterReadWord(byte address)
		{
			byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
			Debug.Assert(Rfm9XLoraModem != null);

			byte[] readBuffer = Rfm9XLoraModem.WriteRead(writeBuffer, 3);

			return (ushort)(readBuffer[2] + (readBuffer[1] << 8));
		}

		public byte[] RegisterRead(byte address, int length)
		{
			byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
			byte[] repyBuffer = new byte[length + 1];
			Debug.Assert(Rfm9XLoraModem != null);

			byte[] readBuffer = Rfm9XLoraModem.WriteRead(writeBuffer, (ushort)repyBuffer.Length);

			Array.Copy(readBuffer, 1, repyBuffer, 0, length);

			return repyBuffer;
		}

		public void RegisterWriteByte(byte address, byte value)
		{
			byte[] writeBuffer = new byte[] { address |= RegisterAddressWriteMask, value };
			Debug.Assert(Rfm9XLoraModem != null);

			Rfm9XLoraModem.WriteBytes(writeBuffer);
		}

		public void RegisterWriteWord(byte address, ushort value)
		{
			byte[] valueBytes = BitConverter.GetBytes(value);
			byte[] writeBuffer = new byte[] { address |= RegisterAddressWriteMask, valueBytes[0], valueBytes[1] };
			Debug.Assert(Rfm9XLoraModem != null);

			Rfm9XLoraModem.WriteBytes(writeBuffer);
		}
		public void RegisterWrite(byte address, [ReadOnlyArray()] byte[] bytes)
		{
			byte[] writeBuffer = new byte[1 + bytes.Length];
			Debug.Assert(Rfm9XLoraModem != null);

			Array.Copy(bytes, 0, writeBuffer, 1, bytes.Length);
			writeBuffer[0] = address |= RegisterAddressWriteMask;

			Rfm9XLoraModem.WriteBytes(writeBuffer);
		}

		public void RegisterDump()
		{
			Console.WriteLine("Register dump");
			for (byte registerIndex = 0; registerIndex <= 0x42; registerIndex++)
			{
				byte registerValue = this.RegisterReadByte(registerIndex);

				Console.WriteLine("Register 0x{0:x2} - Value 0X{1:x2} - Bits {2}", registerIndex, registerValue, Convert.ToString(registerValue, 2).PadLeft(8, '0'));
			}
		}
	}

	public class MeadowApp : App<F7Micro, MeadowApp>
   {
      private Rfm9XDevice rfm9XDevice;

      public MeadowApp()
      {
			ISpiBus spiBus = Device.CreateSpiBus(500);
         if (spiBus == null)
         {
            Console.WriteLine("spiBus == null");
         }

			rfm9XDevice = new Rfm9XDevice(Device, spiBus, Device.Pins.D09, Device.Pins.D11);

			while (true)
         {
				rfm9XDevice.RegisterDump();

				Byte regOpMode = rfm9XDevice.RegisterReadByte(0x1);

				Console.WriteLine("Set LoRa mode and sleep mode (write byte)");
				rfm9XDevice.RegisterWriteByte(0x01, 0b10000000); // 

				Console.WriteLine("Read the preamble (read word)");
				ushort preamble = rfm9XDevice.RegisterReadWord(0x20);
				Console.WriteLine("Preamble 0x{0:x2} - Bits {1}", preamble, Convert.ToString(preamble, 2).PadLeft(16, '0'));

				Console.WriteLine("Set the preamble to 0x80 (write word)");
				rfm9XDevice.RegisterWriteWord(0x20, 0x80);

				Console.WriteLine("Read the centre frequency (read byte array)");
				byte[] frequencyReadBytes = rfm9XDevice.RegisterRead(0x06, 3);
				Console.WriteLine("Frequency Msb 0x{0:x2} Mid 0x{1:x2} Lsb 0x{2:x2}", frequencyReadBytes[0], frequencyReadBytes[1], frequencyReadBytes[2]);

				Console.WriteLine("Set the centre frequency to 916MHz ( write byte array)");
				byte[] frequencyWriteBytes = { 0xE4, 0xC0, 0x00 };
				rfm9XDevice.RegisterWrite(0x06, frequencyWriteBytes);

				rfm9XDevice.RegisterDump();

				Task.Delay(30000).Wait();
			}
		}
   }
}

The output of the application looked like this

'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll'. 
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\RegisterReadAndWrite\bin\Debug\net472\App.exe'. Symbols loaded.
'App.exe' (CLR v4.0.30319: App.exe): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\RegisterReadAndWrite\bin\Debug\net472\Meadow.dll'. 
The program '[31296] App.exe: Program Trace' has exited with code 0 (0x0).
The program '[31296] App.exe' has exited with code 0 (0x0).
.
.
DirectRegisterAccess = True
==========================================================
Ignore the exceptions generated by the DateTime call here.
==========================================================
.
Register dump
.
Register 0x00 - Value 0X00 - Bits 00000000
Register 0x01 - Value 0X09 - Bits 00001001
Register 0x02 - Value 0X1a - Bits 00011010
Register 0x03 - Value 0X0b - Bits 00001011
Register 0x04 - Value 0X00 - Bits 00000000
Register 0x05 - Value 0X52 - Bits 01010010
Register 0x06 - Value 0X6c - Bits 01101100
Register 0x07 - Value 0X80 - Bits 10000000
Register 0x08 - Value 0X00 - Bits 00000000
Register 0x09 - Value 0X4f - Bits 01001111
Register 0x0a - Value 0X09 - Bits 00001001
Register 0x0b - Value 0X2b - Bits 00101011
Register 0x0c - Value 0X20 - Bits 00100000
Register 0x0d - Value 0X08 - Bits 00001000
Register 0x0e - Value 0X02 - Bits 00000010
Register 0x0f - Value 0X0a - Bits 00001010
Register 0x10 - Value 0Xff - Bits 11111111
Register 0x11 - Value 0X70 - Bits 01110000
Register 0x12 - Value 0X15 - Bits 00010101
Register 0x13 - Value 0X0b - Bits 00001011
Register 0x14 - Value 0X28 - Bits 00101000
Register 0x15 - Value 0X0c - Bits 00001100
Register 0x16 - Value 0X12 - Bits 00010010
Register 0x17 - Value 0X47 - Bits 01000111
Register 0x18 - Value 0X32 - Bits 00110010
Register 0x19 - Value 0X3e - Bits 00111110
Register 0x1a - Value 0X00 - Bits 00000000
Register 0x1b - Value 0X00 - Bits 00000000
Register 0x1c - Value 0X00 - Bits 00000000
Register 0x1d - Value 0X00 - Bits 00000000
Register 0x1e - Value 0X00 - Bits 00000000
Register 0x1f - Value 0X40 - Bits 01000000
Register 0x20 - Value 0X00 - Bits 00000000
Register 0x21 - Value 0X00 - Bits 00000000
Register 0x22 - Value 0X00 - Bits 00000000
Register 0x23 - Value 0X00 - Bits 00000000
Register 0x24 - Value 0X05 - Bits 00000101
Register 0x25 - Value 0X00 - Bits 00000000
Register 0x26 - Value 0X03 - Bits 00000011
Register 0x27 - Value 0X93 - Bits 10010011
Register 0x28 - Value 0X55 - Bits 01010101
Register 0x29 - Value 0X55 - Bits 01010101
Register 0x2a - Value 0X55 - Bits 01010101
Register 0x2b - Value 0X55 - Bits 01010101
Register 0x2c - Value 0X55 - Bits 01010101
Register 0x2d - Value 0X55 - Bits 01010101
Register 0x2e - Value 0X55 - Bits 01010101
Register 0x2f - Value 0X55 - Bits 01010101
Register 0x30 - Value 0X90 - Bits 10010000
Register 0x31 - Value 0X40 - Bits 01000000
Register 0x32 - Value 0X40 - Bits 01000000
Register 0x33 - Value 0X00 - Bits 00000000
Register 0x34 - Value 0X00 - Bits 00000000
Register 0x35 - Value 0X0f - Bits 00001111
Register 0x36 - Value 0X00 - Bits 00000000
Register 0x37 - Value 0X00 - Bits 00000000
Register 0x38 - Value 0X00 - Bits 00000000
Register 0x39 - Value 0Xf5 - Bits 11110101
Register 0x3a - Value 0X20 - Bits 00100000
Register 0x3b - Value 0X82 - Bits 10000010
Register 0x3c - Value 0X00 - Bits 00000000
Register 0x3d - Value 0X02 - Bits 00000010
Register 0x3e - Value 0X80 - Bits 10000000
Register 0x3f - Value 0X40 - Bits 01000000
Register 0x40 - Value 0X00 - Bits 00000000
Register 0x41 - Value 0X00 - Bits 00000000
Register 0x42 - Value 0X12 - Bits 00010010
Set LoRa mode and sleep mode (write byte)
Read the preamble (read word)
Preamble 0x08 - Bits 0000000000001000
Set the preamble to 0x80 (write word)
Read the centre frequency (read byte array)
Frequency Msb 0x6c Mid 0x80 Lsb 0x00
Set the centre frequency to 916MHz ( write byte array)
Register dump
Register 0x00 - Value 0Xf4 - Bits 11110100
Register 0x01 - Value 0X80 - Bits 10000000
Register 0x02 - Value 0X1a - Bits 00011010
Register 0x03 - Value 0X0b - Bits 00001011
Register 0x04 - Value 0X00 - Bits 00000000
Register 0x05 - Value 0X52 - Bits 01010010
Register 0x06 - Value 0Xe4 - Bits 11100100
Register 0x07 - Value 0Xc0 - Bits 11000000
Register 0x08 - Value 0X00 - Bits 00000000
Register 0x09 - Value 0X4f - Bits 01001111
Register 0x0a - Value 0X09 - Bits 00001001
Register 0x0b - Value 0X2b - Bits 00101011
Register 0x0c - Value 0X20 - Bits 00100000
Register 0x0d - Value 0X02 - Bits 00000010
Register 0x0e - Value 0X80 - Bits 10000000
Register 0x0f - Value 0X00 - Bits 00000000
Register 0x10 - Value 0X00 - Bits 00000000
Register 0x11 - Value 0X00 - Bits 00000000
Register 0x12 - Value 0X00 - Bits 00000000
Register 0x13 - Value 0X00 - Bits 00000000
Register 0x14 - Value 0X00 - Bits 00000000
Register 0x15 - Value 0X00 - Bits 00000000
Register 0x16 - Value 0X00 - Bits 00000000
Register 0x17 - Value 0X00 - Bits 00000000
Register 0x18 - Value 0X10 - Bits 00010000
Register 0x19 - Value 0X00 - Bits 00000000
Register 0x1a - Value 0X00 - Bits 00000000
Register 0x1b - Value 0X00 - Bits 00000000
Register 0x1c - Value 0X00 - Bits 00000000
Register 0x1d - Value 0X72 - Bits 01110010
Register 0x1e - Value 0X70 - Bits 01110000
Register 0x1f - Value 0X64 - Bits 01100100
Register 0x20 - Value 0X80 - Bits 10000000
Register 0x21 - Value 0X00 - Bits 00000000
Register 0x22 - Value 0X01 - Bits 00000001
Register 0x23 - Value 0Xff - Bits 11111111
Register 0x24 - Value 0X00 - Bits 00000000
Register 0x25 - Value 0X00 - Bits 00000000
Register 0x26 - Value 0X04 - Bits 00000100
Register 0x27 - Value 0X00 - Bits 00000000
Register 0x28 - Value 0X00 - Bits 00000000
Register 0x29 - Value 0X00 - Bits 00000000
Register 0x2a - Value 0X00 - Bits 00000000
Register 0x2b - Value 0X00 - Bits 00000000
Register 0x2c - Value 0X00 - Bits 00000000
Register 0x2d - Value 0X50 - Bits 01010000
Register 0x2e - Value 0X14 - Bits 00010100
Register 0x2f - Value 0X45 - Bits 01000101
Register 0x30 - Value 0X55 - Bits 01010101
Register 0x31 - Value 0Xc3 - Bits 11000011
Register 0x32 - Value 0X05 - Bits 00000101
Register 0x33 - Value 0X27 - Bits 00100111
Register 0x34 - Value 0X1c - Bits 00011100
Register 0x35 - Value 0X0a - Bits 00001010
Register 0x36 - Value 0X03 - Bits 00000011
Register 0x37 - Value 0X0a - Bits 00001010
Register 0x38 - Value 0X42 - Bits 01000010
Register 0x39 - Value 0X12 - Bits 00010010
Register 0x3a - Value 0X49 - Bits 01001001
Register 0x3b - Value 0X1d - Bits 00011101
Register 0x3c - Value 0X00 - Bits 00000000
Register 0x3d - Value 0Xaf - Bits 10101111
Register 0x3e - Value 0X00 - Bits 00000000
Register 0x3f - Value 0X00 - Bits 00000000
Register 0x40 - Value 0X00 - Bits 00000000
Register 0x41 - Value 0X00 - Bits 00000000
Register 0x42 - Value 0X12 - Bits 00010010

The next step is to extract the SPI register access functionality into a module and configure the bare minimum of settings required to get the RFM9X to transmit.

.Net Meadow RFM95/96/97/98 LoRa library Part2

Register Dump

Next step was to dump all registers (0x00 thru 0x42) of the SX1276/7/8/9 device

//---------------------------------------------------------------------------------
// Copyright (c) December 2019, 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.Rfm9x.RegisterScan
{
   using System;
   using System.Threading.Tasks;

   using Meadow;
   using Meadow.Devices;
   using Meadow.Hardware;

   public sealed class Rfm9XDevice
   {
      private SpiPeripheral sx127xDevice;
      private IDigitalOutputPort spiPeriphChipSelect;

      public Rfm9XDevice(IIODevice device, ISpiBus spiBus, IPin chipSelectPin)
      {
         spiPeriphChipSelect = device.CreateDigitalOutputPort(chipSelectPin, initialState: true);
         if (spiPeriphChipSelect == null)
         {
            Console.WriteLine("spiPeriphChipSelect == null");
         }

         sx127xDevice = new SpiPeripheral(spiBus, spiPeriphChipSelect);
         if (sx127xDevice == null)
         {
            Console.WriteLine("sx127xDevice == null");
         }
      }

      public Byte RegisterReadByte(byte registerAddress)
      {
         byte[] txBuffer = new byte[] { registerAddress };

         byte[] rxBuffer = sx127xDevice.WriteRead(txBuffer, 2);

         return rxBuffer[1];
      }
   }

   public class MeadowApp : App<F7Micro, MeadowApp>
   {
      private Rfm9XDevice rfm9XDevice;

      public MeadowApp()
      {
         ISpiBus spiBus = Device.CreateSpiBus(500);
         if (spiBus == null)
         {
            Console.WriteLine("spiBus == null");
         }

         rfm9XDevice = new Rfm9XDevice(Device, spiBus, Device.Pins.D09);

         while (true)
         {
            for (byte registerIndex = 0; registerIndex <= 0x42; registerIndex++)
            {
               byte registerValue = rfm9XDevice.RegisterReadByte(registerIndex);

               Console.WriteLine("Register 0x{0:x2} - Value 0X{1:x2} - Bits {2}", registerIndex, registerValue, Convert.ToString(registerValue, 2).PadLeft(8, '0'));
            }

            Task.Delay(10000).Wait();
         }
      }
   }
}

The output of the application looked like this

'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll'. 
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\RegisterScan\bin\Debug\net472\App.exe'. Symbols loaded.
'App.exe' (CLR v4.0.30319: App.exe): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\RegisterScan\bin\Debug\net472\Meadow.dll'. 
The program '[3148] App.exe: Program Trace' has exited with code 0 (0x0).
The program '[3148] App.exe' has exited with code 0 (0x0).
.
.
DirectRegisterAccess = True
==========================================================
Ignore the exceptions generated by the DateTime call here.
==========================================================
.
Register 0x00 - Value 0X00 - Bits 00000000
Register 0x01 - Value 0X09 - Bits 00001001
Register 0x02 - Value 0X1a - Bits 00011010
Register 0x03 - Value 0X0b - Bits 00001011
Register 0x04 - Value 0X00 - Bits 00000000
Register 0x05 - Value 0X52 - Bits 01010010
Register 0x06 - Value 0X6c - Bits 01101100
Register 0x07 - Value 0X80 - Bits 10000000
Register 0x08 - Value 0X00 - Bits 00000000
Register 0x09 - Value 0X4f - Bits 01001111
Register 0x0a - Value 0X09 - Bits 00001001
Register 0x0b - Value 0X2b - Bits 00101011
Register 0x0c - Value 0X20 - Bits 00100000
Register 0x0d - Value 0X08 - Bits 00001000
Register 0x0e - Value 0X02 - Bits 00000010
Register 0x0f - Value 0X0a - Bits 00001010
Register 0x10 - Value 0Xff - Bits 11111111
Register 0x11 - Value 0X71 - Bits 01110001
Register 0x12 - Value 0X15 - Bits 00010101
Register 0x13 - Value 0X0b - Bits 00001011
Register 0x14 - Value 0X28 - Bits 00101000
Register 0x15 - Value 0X0c - Bits 00001100
Register 0x16 - Value 0X12 - Bits 00010010
Register 0x17 - Value 0X47 - Bits 01000111
Register 0x18 - Value 0X32 - Bits 00110010
Register 0x19 - Value 0X3e - Bits 00111110
Register 0x1a - Value 0X00 - Bits 00000000
Register 0x1b - Value 0X00 - Bits 00000000
Register 0x1c - Value 0X00 - Bits 00000000
Register 0x1d - Value 0X00 - Bits 00000000
Register 0x1e - Value 0X00 - Bits 00000000
Register 0x1f - Value 0X40 - Bits 01000000
Register 0x20 - Value 0X00 - Bits 00000000
Register 0x21 - Value 0X00 - Bits 00000000
Register 0x22 - Value 0X00 - Bits 00000000
Register 0x23 - Value 0X00 - Bits 00000000
Register 0x24 - Value 0X05 - Bits 00000101
Register 0x25 - Value 0X00 - Bits 00000000
Register 0x26 - Value 0X03 - Bits 00000011
Register 0x27 - Value 0X93 - Bits 10010011
Register 0x28 - Value 0X55 - Bits 01010101
Register 0x29 - Value 0X55 - Bits 01010101
Register 0x2a - Value 0X55 - Bits 01010101
Register 0x2b - Value 0X55 - Bits 01010101
Register 0x2c - Value 0X55 - Bits 01010101
Register 0x2d - Value 0X55 - Bits 01010101
Register 0x2e - Value 0X55 - Bits 01010101
Register 0x2f - Value 0X55 - Bits 01010101
Register 0x30 - Value 0X90 - Bits 10010000
Register 0x31 - Value 0X40 - Bits 01000000
Register 0x32 - Value 0X40 - Bits 01000000
Register 0x33 - Value 0X00 - Bits 00000000
Register 0x34 - Value 0X00 - Bits 00000000
Register 0x35 - Value 0X0f - Bits 00001111
Register 0x36 - Value 0X00 - Bits 00000000
Register 0x37 - Value 0X00 - Bits 00000000
Register 0x38 - Value 0X00 - Bits 00000000
Register 0x39 - Value 0Xf5 - Bits 11110101
Register 0x3a - Value 0X20 - Bits 00100000
Register 0x3b - Value 0X82 - Bits 10000010
Register 0x3c - Value 0Xfd - Bits 11111101
Register 0x3d - Value 0X02 - Bits 00000010
Register 0x3e - Value 0X80 - Bits 10000000
Register 0x3f - Value 0X40 - Bits 01000000
Register 0x40 - Value 0X00 - Bits 00000000
Register 0x41 - Value 0X00 - Bits 00000000
Register 0x42 - Value 0X12 - Bits 00010010

I also started to refactor the code, passing the Meadow IIODevice & ISpiBus into the constructor, and extracting the Read functionality.

The device was not in LoRa mode (Bit 7 of RegOpMode 0x01) so the next step was to read and write registers so I could change its configuration.

.Net Meadow RFM95/96/97/98 LoRa library Part1

After writing Windows 10 IoT Core & .NetMF RFM9X libraries I figured a port to a Wilderness Labs Meadow device shouldn’t be “rocket science”.

To get started I used a Dragino LoRa shield for Arduino which looked compatible with my Meadow device.

Dragino shield schematic

The shield ships with the SPI lines configured for ICSP so the three jumpers diagonally across the shield from the antenna connector need to be swapped to the side closest to the edge of the shield.

Dragino Arduino shield based test harness
//---------------------------------------------------------------------------------
// Copyright (c) Dec 2019, 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.Rfm9x
{
   using System;
   using System.Threading.Tasks;
   using Meadow;
   using Meadow.Devices;
   using Meadow.Hardware;

   public class MeadowApp : App<F7Micro, MeadowApp>
   {
      const byte RegVersion = 0x42;
      ISpiBus spiBus;
      SpiPeripheral sx127xDevice;
      IDigitalOutputPort spiPeriphChipSelect;

      public MeadowApp()
      {
         ConfigureSpiPort();
         //ReadDeviceID();
         ReadDeviceIDDiy();
      }

      public void ConfigureSpiPort()
      {
         try
         {
            spiBus = Device.CreateSpiBus(500);
            if (spiBus == null)
            {
               Console.WriteLine("spiBus == null");
            }

            Console.WriteLine("Creating SPI NSS Port...");
            spiPeriphChipSelect = Device.CreateDigitalOutputPort(Device.Pins.D09);
            if (spiPeriphChipSelect == null)
            {
               Console.WriteLine("spiPeriphChipSelect == null");
            }
   
            Console.WriteLine("sx127xDevice Device...");
            sx127xDevice = new SpiPeripheral(spiBus, spiPeriphChipSelect);
            if (sx127xDevice == null)
            {
               Console.WriteLine("sx127xDevice == null");
            }

            Console.WriteLine("ConfigureSpiPort Done...");
         }
         catch (Exception ex)
         {
            Console.WriteLine("ConfigureSpiPort " + ex.Message);
         }
      }

      
      public void ReadDeviceID()
      {
         Task.Delay(500).Wait();

         while (true)
         {
            try
            {
               Console.WriteLine("sx127xDevice.ReadRegister...1");

               byte registerValue = sx127xDevice.ReadRegister(RegVersion);

               Console.WriteLine("sx127xDevice.ReadRegister...2");

               Console.WriteLine("Register 0x{0:x2} - Value 0X{1:x2} - Bits {2}", RegVersion, registerValue, Convert.ToString(registerValue, 2).PadLeft(8, '0'));
            }
            catch (Exception ex)
            {
               Console.WriteLine("ReadDeviceID " + ex.Message);
            }

            Task.Delay(10000).Wait();
         }
      }

      public void ReadDeviceIDDiy()
      {
         var txBuffer = new byte[2];
         var rxBuffer = new byte[2];

         Task.Delay(500).Wait();

         while (true)
         {
            try
            {
               Console.WriteLine("spiBus.ExchangeData...1");

               txBuffer[0] = RegVersion;

               spiBus.ExchangeData(spiPeriphChipSelect, ChipSelectMode.ActiveLow, txBuffer, rxBuffer, 2);

               Console.WriteLine("spiBus.ExchangeData...2");

               byte registerValue = rxBuffer[1];

               Console.WriteLine("Register 0x{0:x2} - Value 0X{1:x2} - Bits {2}", RegVersion, registerValue, Convert.ToString(registerValue, 2).PadLeft(8, '0'));
            }
            catch (Exception ex)
            {
               Console.WriteLine("ReadDeviceIDDiy " + ex.Message);
            }

            Task.Delay(10000).Wait();
         }
      }
   }
}

After some trial and error (using beta 3.6) I found that the ReadRegister method didn’t work as expected (possibly related to this issue) and I had to manually assemble the request to read the SX127X RegVersion register.

'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll'. 
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\Users\BrynLewis\source\repos\RFX9X.Meadow\FeatherWingSPI\bin\Debug\net472\App.exe'. Symbols loaded.
'App.exe' (CLR v4.0.30319: App.exe): Loaded 'C:\Users\BrynLewis\source\repos\RFX9X.Meadow\FeatherWingSPI\bin\Debug\net472\Meadow.dll'. 
The program '[22324] App.exe: Program Trace' has exited with code 0 (0x0).
The program '[22324] App.exe' has exited with code 0 (0x0).
.
.
DirectRegisterAccess = True
==========================================================
Ignore the exceptions generated by the DateTime call here.
==========================================================
.
Creating SPI NSS Port...
sx127xDevice Device...
ConfigureSpiPort Done...
spiBus.ExchangeData...1
spiBus.ExchangeData...2
Register 0x42 - Value 0X12 - Bits 00010010
spiBus.ExchangeData...1
spiBus.ExchangeData...2
Register 0x42 - Value 0X12 - Bits 00010010
spiBus.ExchangeData...1
spiBus.ExchangeData...2
Register 0x42 - Value 0X12 - Bits 00010010
spiBus.ExchangeData...1
spiBus.ExchangeData...2

Bosch IoT Suite with MQTTnet

As I’m testing my Message Queue Telemetry Transport(MQTT) LoRa gateway I’m building a proof of concept(PoC) .Net core console application for each IoT platform I would like to support.

This PoC was to confirm that I could connect to the Bosch IoT Suite MQTT API then format topics and payloads correctly.

MQTTNet Console Client

The Bosch IoT Hub MQTT broker, username, password, and clientID are the required command line parameters. For this PoC I ran out of time to get cloud to device (C2D) messaging or any presentation functionality working.

/*
    Copyright ® 2019 December devMobile Software, All Rights Reserved
 
    MIT License

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE

	 A quick and dirty test client to explore how BoschIoT Suite MQTT connectivity works
 */
namespace devMobile.Mqtt.TestClient.BoschIoTSuite
{
   using System;
   using System.Diagnostics;
   using System.Threading;
   using System.Threading.Tasks;

   using MQTTnet;
   using MQTTnet.Client;
   using MQTTnet.Client.Disconnecting;
   using MQTTnet.Client.Options;
   using MQTTnet.Client.Receiving;
   using Newtonsoft.Json;
   using Newtonsoft.Json.Linq;

   class Program
   {
      private static IMqttClient mqttClient = null;
      private static IMqttClientOptions mqttOptions = null;
      private static string server;
      private static string username;
      private static string password;
      private static string clientId;

      static void Main(string[] args)
      {
         MqttFactory factory = new MqttFactory();
         mqttClient = factory.CreateMqttClient();

         if (args.Length != 4) 
         {
            Console.WriteLine("[MQTT Server] [UserName] [Password] [ClientID]");
            Console.WriteLine("Press <enter> to exit");
            Console.ReadLine();
            return;
         }

         server = args[0];
         username = args[1];
         password = args[2];
         clientId = args[3];

         mqttOptions = new MqttClientOptionsBuilder()
            .WithTcpServer(server)
            .WithCredentials(username, password)
            .WithClientId(clientId)
            .WithTls()
            .Build();

         mqttClient.UseDisconnectedHandler(new MqttClientDisconnectedHandlerDelegate(e => MqttClient_Disconnected(e)));
         mqttClient.UseApplicationMessageReceivedHandler(new MqttApplicationMessageReceivedHandlerDelegate(e => MqttClient_ApplicationMessageReceived(e)));
         mqttClient.ConnectAsync(mqttOptions).Wait();

         string topicD2C = "telemetry";

         while (true)
         {
            JObject payloadJObject = new JObject();

            payloadJObject.Add("OfficeTemperature", "22." + DateTime.UtcNow.Millisecond.ToString());
            payloadJObject.Add("OfficeHumidity", (DateTime.UtcNow.Second + 40).ToString());

            string payload = JsonConvert.SerializeObject(payloadJObject);
            Console.WriteLine($"Topic:{topicD2C} Payload:{payload}");

            var message = new MqttApplicationMessageBuilder()
               .WithTopic(topicD2C)
               .WithPayload(payload)
               .WithAtMostOnceQoS() // Anthing but this causes timeout
               .WithRetainFlag()
            .Build();

            Console.WriteLine("PublishAsync start");
            mqttClient.PublishAsync(message).Wait();
            Console.WriteLine("PublishAsync finish");

            Thread.Sleep(30100);
         }
      }

      private static void MqttClient_ApplicationMessageReceived(MqttApplicationMessageReceivedEventArgs e)
      {
         Console.WriteLine($"ClientId:{e.ClientId} Topic:{e.ApplicationMessage.Topic} Payload:{e.ApplicationMessage.ConvertPayloadToString()}");
      }

      private static async void MqttClient_Disconnected(MqttClientDisconnectedEventArgs e)
      {
         Debug.WriteLine("Disconnected");
         await Task.Delay(TimeSpan.FromSeconds(5));

         try
         {
            await mqttClient.ConnectAsync(mqttOptions);
         }
         catch (Exception ex)
         {
            Debug.WriteLine("Reconnect failed {0}", ex.Message);
         }
      }
   }
}

The bosch IoT Hub device configuration was via a swagger API but I need to spend some more time figuring out how to configure the data analysis and presentation tools.

I adapted the steps in the IoT Hub Documentation for Sending Device Data using MQTT. The first step was to create a free Hub subscription.

IoT Hub Subscription

Then using the device registry swagger UI page to add a new device.

Device Registry Swagger UI

After a couple of failed attempts I worked out the format of the Authorisation details (I think the username format in the online documentation might be wrong)

Swagger UI Authorisation form
Querying the available devices

Of the 10+ SaaS IoT services I have setup the Bosch IoT Suite was the hardest to get working. I think this was becuase it is meant to be managed via the API from a in-house application. In a future post I’ll get configure the cloud to device messaging, plus analysis and display functionality.

Armtronix IA005 SX1276 loRa node

A month ago I ordered a pair of IA005: SX1276 Lora node STM32F103 devices from the Armtronix shop on Tindie for evaluation. At USD18 each these devices were competitively priced and I was interested in trialling another maple like device.

Bill of materials (Prices as at December 2019)

  • IA005 SX1276 loRa node USD36 (USD18 each)
  • Grove – Temperature&Humidity Sensor USD11.5
  • Grove – 4 pin Female Jumper to Grove 4 pin Conversion Cable USD3.90
Armtronix device with Seeedstudio temperature & humidity sensor

I used a modified version of my Arduino client code which worked after I got the pins sorted and the female jumper sockets in the right order.

/*
  Copyright ® 2019 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.

  You can do what you want with this code, acknowledgment would be nice.

  http://www.devmobile.co.nz

*/
#include <stdlib.h>
#include <LoRa.h>
#include <TH02_dev.h>

//#define DEBUG
//#define DEBUG_TELEMETRY
//#define DEBUG_LORA

// LoRa field gateway configuration (these settings must match your field gateway)
const char FieldGatewayAddress[] = {"LoRaIoT1"};
const char DeviceAddress[] = {"ArmTronix01"};
const float FieldGatewayFrequency =  915000000.0;
const byte FieldGatewaySyncWord = 0x12 ;

// Payload configuration
const int ChipSelectPin = PA4;
const int InterruptPin = PA11;
const int ResetPin = PC13;

// LoRa radio payload configuration
const byte SensorIdValueSeperator = ' ' ;
const byte SensorReadingSeperator = ',' ;
const int LoopSleepDelaySeconds = 30 ;

const byte PayloadSizeMaximum = 64 ;
byte payload[PayloadSizeMaximum];
byte payloadLength = 0 ;


void setup()
{
  Serial.begin(9600);
#ifdef DEBUG
  while (!Serial);
#endif
  Serial.println("Setup called");

  Serial.println("LoRa setup start");
  
  // override the default chip select and reset pins
  LoRa.setPins(ChipSelectPin, ResetPin, InterruptPin); 
  if (!LoRa.begin(FieldGatewayFrequency))
  {
    Serial.println("LoRa begin failed");
    while (true); // Drop into endless loop requiring restart
  }

  // Need to do this so field gateways pays attention to messsages from this device
  LoRa.enableCrc();
  LoRa.setSyncWord(FieldGatewaySyncWord);

#ifdef DEBUG_LORA
  LoRa.dumpRegisters(Serial);
#endif
  Serial.println("LoRa Setup done.");

  // Configure the Seeedstudio TH02 temperature & humidity sensor
  Serial.println("TH02 setup start");
  TH02.begin();
  delay(100);
  Serial.println("TH02 setup done");

  PayloadHeader((byte*)FieldGatewayAddress,strlen(FieldGatewayAddress), (byte*)DeviceAddress, strlen(DeviceAddress));

  Serial.println("Setup done");
  Serial.println();
}


void loop()
{
  float temperature ;
  float humidity ;

  Serial.println("Loop called");

  PayloadReset();

  // Read the temperature & humidity & battery voltage values then display nicely
  temperature = TH02.ReadTemperature();
  Serial.print("T:");
  Serial.print( temperature, 1 ) ;
  Serial.println( "C " ) ;

  PayloadAdd( "T", temperature, 1);

  humidity = TH02.ReadHumidity();
  Serial.print("H:");
  Serial.print( humidity, 0 ) ;
  Serial.println( "% " ) ;

  PayloadAdd( "H", humidity, 0) ;

#ifdef DEBUG_TELEMETRY
  Serial.print( "RFM9X/SX127X Payload len:");
  Serial.print( payloadLength );
  Serial.println( " bytes" );
#endif

  LoRa.beginPacket();
  LoRa.write( payload, payloadLength );
  LoRa.endPacket();

  Serial.println("Loop done");
  Serial.println();
  delay(LoopSleepDelaySeconds * 1000l);
}


void PayloadHeader( byte *to, byte toAddressLength, byte *from, byte fromAddressLength)
{
  byte addressesLength = toAddressLength + fromAddressLength ;

#ifdef DEBUG_TELEMETRY
  Serial.print("PayloadHeader- ");
  Serial.print( "To len:");
  Serial.print( toAddressLength );
  Serial.print( " From len:");
  Serial.print( fromAddressLength );
  Serial.print( " Header len:");
  Serial.print( addressesLength );
  Serial.println( );
#endif

  payloadLength = 0 ;

  // prepare the payload header with "To" Address length (top nibble) and "From" address length (bottom nibble)
  payload[payloadLength] = (toAddressLength << 4) | fromAddressLength ;
  payloadLength += 1;

  // Copy the "To" address into payload
  memcpy(&payload[payloadLength], to, toAddressLength);
  payloadLength += toAddressLength ;

  // Copy the "From" into payload
  memcpy(&payload[payloadLength], from, fromAddressLength);
  payloadLength += fromAddressLength ;
}


void PayloadAdd( const char *sensorId, float value, byte decimalPlaces)
{
  byte sensorIdLength = strlen( sensorId ) ;

#ifdef DEBUG_TELEMETRY
  Serial.print("PayloadAdd-float ");
  Serial.print( "SensorId:");
  Serial.print( sensorId );
  Serial.print( " Len:");
  Serial.print( sensorIdLength );
  Serial.print( " Value:");
  Serial.print( value, decimalPlaces );
  Serial.print( " payloadLen:");
  Serial.print( payloadLength);
#endif

  memcpy( &payload[payloadLength], sensorId,  sensorIdLength) ;
  payloadLength += sensorIdLength ;
  payload[ payloadLength] = SensorIdValueSeperator;
  payloadLength += 1 ;
  payloadLength += strlen( dtostrf(value, -1, decimalPlaces, (char *)&payload[payloadLength]));
  payload[ payloadLength] = SensorReadingSeperator;
  payloadLength += 1 ;
  
#ifdef DEBUG_TELEMETRY
  Serial.print( " payloadLen:");
  Serial.println( payloadLength);
#endif
}


void PayloadAdd( const char *sensorId, int value )
{
  byte sensorIdLength = strlen( sensorId ) ;

#ifdef DEBUG_TELEMETRY
  Serial.print("PayloadAdd-int ");
  Serial.print( "SensorId:");
  Serial.print( sensorId );
  Serial.print( " Len:");
  Serial.print( sensorIdLength );
  Serial.print( " Value:");
  Serial.print( value );
  Serial.print( " payloadLen:");
  Serial.print( payloadLength);
#endif  

  memcpy( &payload[payloadLength], sensorId,  sensorIdLength) ;
  payloadLength += sensorIdLength ;
  payload[ payloadLength] = SensorIdValueSeperator;
  payloadLength += 1 ;
  payloadLength += strlen( itoa( value,(char *)&payload[payloadLength],10));
  payload[ payloadLength] = SensorReadingSeperator;
  payloadLength += 1 ;
  
#ifdef DEBUG_TELEMETRY
  Serial.print( " payloadLen:");
  Serial.println( payloadLength);
#endif
}


void PayloadAdd( const char *sensorId, unsigned int value )
{
  byte sensorIdLength = strlen( sensorId ) ;

#ifdef DEBUG_TELEMETRY
  Serial.print("PayloadAdd-unsigned int ");
  Serial.print( "SensorId:");
  Serial.print( sensorId );
  Serial.print( " Len:");
  Serial.print( sensorIdLength );
  Serial.print( " Value:");
  Serial.print( value );
  Serial.print( " payloadLen:");
  Serial.print( payloadLength);
#endif  

  memcpy( &payload[payloadLength], sensorId,  sensorIdLength) ;
  payloadLength += sensorIdLength ;
  payload[ payloadLength] = SensorIdValueSeperator;
  payloadLength += 1 ;
  payloadLength += strlen( utoa( value,(char *)&payload[payloadLength],10));
  payload[ payloadLength] = SensorReadingSeperator;
  payloadLength += 1 ;

#ifdef DEBUG_TELEMETRY
  Serial.print( " payloadLen:");
  Serial.println( payloadLength);
#endif
}


void PayloadReset()
{
  byte fromAddressLength = payload[0] & 0xf ;
  byte toAddressLength = payload[0] >> 4 ;
  byte addressesLength = toAddressLength + fromAddressLength ;

  payloadLength = addressesLength + 1;

#ifdef DEBUG_TELEMETRY
  Serial.print("PayloadReset- ");
  Serial.print( "To len:");
  Serial.print( toAddressLength );
  Serial.print( " From len:");
  Serial.print( fromAddressLength );
  Serial.print( " Header len:");
  Serial.println( addressesLength );
#endif
}

To get the application to download I had to configure the board in the Arduino IDE

Then change the jumpers

Initially I had some problems deploying my software because I hadn’t followed the instructions (the wiki everyone referred to appeared to be offline) and run the installation batch file (New dev machine since my previous maple based project).

15:40:56.207 -> LoRa Setup done.
15:40:56.207 -> TH02 setup start
15:40:56.307 -> TH02 setup done
15:40:56.307 -> PayloadHeader- To len:8 From len:11 Header len:19
15:40:56.354 -> Setup done
15:40:56.354 -> 
15:40:56.354 -> Loop called
15:40:56.354 -> PayloadReset- To len:8 From len:11 Header len:19
15:40:56.408 -> T:23.9C 
15:40:56.408 -> PayloadAdd-float SensorId:T Len:1 Value:23.9 payloadLen:20 payloadLen:27
15:40:56.508 -> H:70% 
15:40:56.508 -> PayloadAdd-float SensorId:H Len:1 Value:70 payloadLen:27 payloadLen:32
15:40:56.608 -> RFM9X/SX127X Payload len:32 bytes
15:40:56.655 -> Loop done
15:40:56.655 -> 
15:41:26.647 -> Loop called
15:41:26.647 -> PayloadReset- To len:8 From len:11 Header len:19
15:41:26.684 -> T:24.0C 
15:41:26.730 -> PayloadAdd-float SensorId:T Len:1 Value:24.0 payloadLen:20 payloadLen:27
15:41:26.784 -> H:69% 
15:41:26.784 -> PayloadAdd-float SensorId:H Len:1 Value:69 payloadLen:27 payloadLen:32
15:41:26.884 -> RFM9X/SX127X Payload len:32 bytes
15:41:26.931 -> Loop done
15:41:26.931 -> 
15:41:56.904 -> Loop called
15:41:56.904 -> PayloadReset- To len:8 From len:11 Header len:19
15:41:56.948 -> T:24.1C 
15:41:56.982 -> PayloadAdd-float SensorId:T Len:1 Value:24.1 payloadLen:20 payloadLen:27
15:41:57.054 -> H:69% 
15:41:57.054 -> PayloadAdd-float SensorId:H Len:1 Value:69 payloadLen:27 payloadLen:32
15:41:57.157 -> RFM9X/SX127X Payload len:32 bytes
15:41:57.191 -> Loop done
15:41:57.191 -> 
15:42:27.211 -> Loop called
15:42:27.211 -> PayloadReset- To len:8 From len:11 Header len:19
15:42:27.258 -> T:24.1C 
15:42:27.258 -> PayloadAdd-float SensorId:T Len:1 Value:24.1 payloadLen:20 payloadLen:27
15:42:27.343 -> H:69% 
15:42:27.343 -> PayloadAdd-float SensorId:H Len:1 Value:69 payloadLen:27 payloadLen:32
15:42:27.427 -> RFM9X/SX127X Payload len:32 bytes
15:42:27.481 -> Loop done
15:42:27.481 -> 
15:42:57.504 -> Loop called
15:42:57.504 -> PayloadReset- To len:8 From len:11 Header len:19
15:42:57.504 -> T:24.1C 
15:42:57.550 -> PayloadAdd-float SensorId:T Len:1 Value:24.1 payloadLen:20 payloadLen:27
15:42:57.604 -> H:68% 
15:42:57.604 -> PayloadAdd-float SensorId:H Len:1 Value:68 payloadLen:27 payloadLen:32
15:42:57.704 -> RFM9X/SX127X Payload len:32 bytes
15:42:57.755 -> Loop done
15:42:57.755 -> 

I configured the device to upload to my Azure IoT Hub/Azure IoT Central gateway and it has been running reliably for a couple of days.

Azure IoT Central temperature and humidity values

Initially I had some configuration problems but I contacted Armtronix support and they promptly provided a couple of updated links for product and device documentation.

wolkabout with MQTTnet

As I’m testing my Message Queue Telemetry Transport(MQTT) LoRa gateway I’m building a proof of concept(PoC) .Net core console application for each IoT platform I would like to support.

This PoC was to confirm that I could connect to the walkabout MQTT API then format topics and payloads correctly.

MQTTNet Console Client

The walkabout MQTT broker, username, API Key, and device ID are the required command line parameters. For this PoC I couldn’t get cloud to device (C2D) or Transport Layer Security(TLS) working so will have to do some more research.

namespace devmobile.Mqtt.TestClient.WolkAbout
{
   using System;
   using System.Diagnostics;
   using System.Threading;
   using System.Threading.Tasks;

   using MQTTnet;
   using MQTTnet.Client;
   using MQTTnet.Client.Disconnecting;
   using MQTTnet.Client.Options;

   using Newtonsoft.Json;
   using Newtonsoft.Json.Linq;

   class Program
   {
      private static IMqttClient mqttClient = null;
      private static IMqttClientOptions mqttOptions = null;
      private static string server;
      private static string username;
      private static string apiKey;
      private static string clientID;

      static void Main(string[] args)
      {
         MqttFactory factory = new MqttFactory();
         mqttClient = factory.CreateMqttClient();

         if ((args.Length != 4) )
            {
            Console.WriteLine("[MQTT Server] [UserName] [APIKey] [ClientID]");
            Console.WriteLine("Press <enter> to exit");
            Console.ReadLine();
            return;
         }

         server = args[0];
         username = args[1];
         apiKey = args[2];
         clientID = args[3];

         Console.WriteLine($"MQTT Server:{server} Username:{username} ClientID:{clientID}");

         // wolkabout formatted client state update topic
         string topicD2C = $"readings/{username}/";

         mqttOptions = new MqttClientOptionsBuilder()
            .WithTcpServer(server)
            .WithCredentials(username, apiKey)
            .WithClientId(clientID)
            //.WithTls()
            .Build();

         mqttClient.UseDisconnectedHandler(new MqttClientDisconnectedHandlerDelegate(e => MqttClient_Disconnected(e)));
         mqttClient.ConnectAsync(mqttOptions).Wait();

         while (true)
         {
            JObject payloadJObject = new JObject();

            double temperature = 22.0 + (DateTime.UtcNow.Millisecond / 1000.0);
            double humidity = 50 + (DateTime.UtcNow.Millisecond / 100.0);

            payloadJObject.Add("Temperature", temperature);
            payloadJObject.Add("Humidity", humidity);

            string payload = JsonConvert.SerializeObject(payloadJObject);
            Console.WriteLine($"Topic:{topicD2C} Payload:{payload}");

            var message = new MqttApplicationMessageBuilder()
               .WithTopic(topicD2C)
               .WithPayload(payload)
               .WithAtLeastOnceQoS()
               .Build();

            Console.WriteLine("PublishAsync start");
            mqttClient.PublishAsync(message).Wait();
            Console.WriteLine("PublishAsync finish");

            Thread.Sleep(30100);
         }
      }

      private static async void MqttClient_Disconnected(MqttClientDisconnectedEventArgs e)
      {
         Debug.WriteLine("Disconnected");
         await Task.Delay(TimeSpan.FromSeconds(5));

         try
         {
            await mqttClient.ConnectAsync(mqttOptions);
         }
         catch (Exception ex)
         {
            Debug.WriteLine("Reconnect failed {0}", ex.Message);
         }
      }
   }

The walkabout device configuration was relatively easy but I need watch the instructional videos again to better understand the device and data semantics relationship.

Data semantics configuration
Devices setup
Device Setup
My first dashboard

SmartWorks with MQTTnet

As I’m testing my Message Queue Telemetry Transport(MQTT) LoRa gateway I’m building a proof of concept(PoC) .Net core console application for each IoT platform I would like to support.

This PoC was to confirm that I could connect to the SmartWorks (formerly Carriots) MQTT API then format topics and payloads correctly.

MQTTNet Console Client

The SmartWorks MQTT broker, username, and device ID are the required command line parameters. I didn’t notice any configuration options for cloud to device (C2D) messaging which maybe due to my device configuration or the free trial I was using.

namespace devMobile.Mqtt.TestClient.SmartWorks
{
   using System;
   using System.Diagnostics;
   using System.Threading;
   using System.Threading.Tasks;

   using MQTTnet;
   using MQTTnet.Client;
   using MQTTnet.Client.Disconnecting;
   using MQTTnet.Client.Options;
   using MQTTnet.Client.Receiving;
   using Newtonsoft.Json;
   using Newtonsoft.Json.Linq;

   class Program
   {
      private static IMqttClient mqttClient = null;
      private static IMqttClientOptions mqttOptions = null;
      private static string server;
      private static string username;
      private static string clientId;
      private static string commandTopic;
      private static string groupname;
      private static string feedname;

      static void Main(string[] args)
      {
         MqttFactory factory = new MqttFactory();
         mqttClient = factory.CreateMqttClient();

         if (args.Length != 3) 
         {
            Console.WriteLine("[MQTT Server] [UserName] [ClientID]");
            Console.WriteLine("Press <enter> to exit");
            Console.ReadLine();
            return;
         }

         server = args[0];
         username = args[1];
         clientId = args[2];

         mqttOptions = new MqttClientOptionsBuilder()
            .WithTcpServer(server)
            .WithCredentials(username, "")
            .WithClientId(clientId)
            .WithTls()
            .Build();

         mqttClient.UseDisconnectedHandler(new MqttClientDisconnectedHandlerDelegate(e => MqttClient_Disconnected(e)));
         mqttClient.ConnectAsync(mqttOptions).Wait();

         // Adafruit.IO format for topics which are called feeds
         string topicD2C = $"{username}/streams";

         while (true)
         {
            JObject payloadJObject = new JObject();

            payloadJObject.Add("at", "now");
            payloadJObject.Add("device", clientId);
            payloadJObject.Add("protocol", "v2");

            double temperature = 22.0 + (DateTime.UtcNow.Millisecond / 1000.0);
            double humidity = 50 + (DateTime.UtcNow.Millisecond / 100.0);

            JObject dataJObject = new JObject();
            dataJObject.Add("OfficeTemperature", temperature);
            dataJObject.Add("OfficeHumidity", humidity);

            payloadJObject.Add("data", dataJObject);

            string payload = JsonConvert.SerializeObject(payloadJObject);
            Console.WriteLine($"Topic:{topicD2C} Payload:{payload}");

            var message = new MqttApplicationMessageBuilder()
               .WithTopic(topicD2C)
               .WithPayload(payload)
               .WithAtLeastOnceQoS()
            .Build();

            Console.WriteLine("PublishAsync start");
            mqttClient.PublishAsync(message).Wait();
            Console.WriteLine("PublishAsync finish");

            Thread.Sleep(30100);
         }
      }

      private static async void MqttClient_Disconnected(MqttClientDisconnectedEventArgs e)
      {
         Debug.WriteLine("Disconnected");
         await Task.Delay(TimeSpan.FromSeconds(5));

         try
         {
            await mqttClient.ConnectAsync(mqttOptions);
         }
         catch (Exception ex)
         {
            Debug.WriteLine("Reconnect failed {0}", ex.Message);
         }
      }
   }
}

The ThingsBoard device configuration was relatively easy with convenient buttons to copy the Device ID (Client ID in test client) and Access Token (UserName in test client). I need to revisit the Device and Group configuration to see if I can make the automatically generated names more user friendly.

Devices configuration

The Device configuration form has a tab which has a link for the “Data Streams” form which was useful for debugging.

Device configuration

I have emailed SmartWorks support about a free trial of their dashboard product as it is not available in the free trial.

Device data stream query form

Overall the initial configuration went smoothly but the lack of any dashboard functionality in the free trial was quite limiting.