.NET Core SX127X library Arduino LoRaSender & LoRaReceiver

The arduino-LoRa library comes with a number of samples showing how to use its functionality. The LoRaSender and LoRaReceiver samples show the bare minimum of code required to send and receive messages.

LoRaSender

This sample uses all default settings except for frequency

#include <SPI.h>
#include <LoRa.h>

int counter = 0;

void setup() {
  Serial.begin(9600);
  while (!Serial);

  Serial.println("LoRa Sender");

  if (!LoRa.begin(915E6)) {
    Serial.println("Starting LoRa failed!");
    while (1);
  }
  
  delay(5000);  
}

void loop() {
  Serial.print("Sending packet: ");
  Serial.println(counter);

  // send packet
  LoRa.beginPacket();
  LoRa.print("hello ");
  LoRa.print(counter);
  LoRa.endPacket();

  counter++;

  delay(5000);
}

Arduino-LoRa library LoRaSender monitor output

In the Visual Studio output window I could see the received messages including a “corrupted” one which was displayed because the SX127XLoRaDeviceClient couldn’t force Cyclic Redundancy Check(CRC)s.

Loaded '/usr/lib/dotnet/shared/Microsoft.NETCore.App/5.0.4/Microsoft.Win32.Primitives.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
17:08:14-RX length 108 "hello 7" snr 9.3 packet rssi -63dBm rssi -102dBm 
17:08:24-RX length 108 "hello 0" snr 9.5 packet rssi -64dBm rssi -104dBm 
17:08:29-RX length 108 "hello 1" snr 9.3 packet rssi -64dBm rssi -102dBm 
17:08:34-RX length 108 "hello 2" snr 9.5 packet rssi -64dBm rssi -102dBm 
17:08:39-RX length 108 "hello 3" snr 8.5 packet rssi -61dBm rssi -104dBm 
17:08:44-RX length 108 "hello 4" snr 8.5 packet rssi -62dBm rssi -104dBm 
17:08:49-RX length 108 "hello 5" snr 9.3 packet rssi -64dBm rssi -104dBm 
17:08:54-RX length 108 "hello 6" snr 9.3 packet rssi -64dBm rssi -102dBm 
17:08:59-RX length 108 "hello 7" snr 9.3 packet rssi -64dBm rssi -102dBm 
17:09:04-RX length 108 "hello 8" snr 9.3 packet rssi -64dBm rssi -100dBm 
17:09:09-RX length 108 "hello 9" snr 9.3 packet rssi -64dBm rssi -102dBm 
17:09:14-RX length 108 "hello 10" snr 8.8 packet rssi -58dBm rssi -102dBm 
17:09:19-RX length 108 "hello 11" snr 9.3 packet rssi -60dBm rssi -104dBm 
17:09:24-RX length 108 "hello 12" snr 9.5 packet rssi -59dBm rssi -104dBm 
17:09:29-RX length 108 "hello 13" snr 9.0 packet rssi -60dBm rssi -102dBm 
17:09:34-RX length 108 "hello 14" snr 9.5 packet rssi -59dBm rssi -105dBm 
17:09:39-RX length 108 "hello 15" snr 9.0 packet rssi -57dBm rssi -102dBm 
17:09:44-RX length 108 "hello 16" snr 9.3 packet rssi -61dBm rssi -104dBm 
17:09:49-RX length 108 "hello 17" snr 9.5 packet rssi -61dBm rssi -104dBm 
17:09:54-RX length 108 "hello 18" snr 9.0 packet rssi -59dBm rssi -104dBm 
17:09:59-RX length 108 "hello 19" snr 9.3 packet rssi -61dBm rssi -102dBm 
17:10:04-RX length 108 "hello 20" snr 9.0 packet rssi -59dBm rssi -104dBm 
17:10:09-RX length 108 "hello 21" snr 9.3 packet rssi -61dBm rssi -102dBm 
17:10:14-RX length 108 "hello 22" snr 9.5 packet rssi -60dBm rssi -102dBm 
17:10:19-RX length 108 "hello 23" snr 9.3 packet rssi -60dBm rssi -104dBm 
17:10:24-RX length 108 "hello 24" snr 9.3 packet rssi -60dBm rssi -103dBm 
17:10:26-RX length 212 "�Q�Ԕv&G=����[9Y���
2S��ᒵ��O*�Ϥ��X��p쏊��" snr 50.8 packet rssi -104dBm rssi -102dBm 
17:10:30-RX length 108 "hello 25" snr 9.5 packet rssi -60dBm rssi -102dBm 
17:10:35-RX length 108 "hello 26" snr 9.3 packet rssi -60dBm rssi -104dBm 

LoRaReceiver

This sample also uses all default settings except of the frequency

#include <SPI.h>
#include <LoRa.h>

void setup() {
  Serial.begin(9600);
  while (!Serial);

  Serial.println("LoRa Receiver");

  if (!LoRa.begin(915E6)) {
    Serial.println("Starting LoRa failed!");
    while (1);
  }
}

void loop() {
  // try to parse packet
  int packetSize = LoRa.parsePacket();
  if (packetSize) {
    // received a packet
    Serial.print("Received packet '");

    // read packet
    while (LoRa.available()) {
      Serial.print((char)LoRa.read());
    }

    // print RSSI of packet
    Serial.print("' with RSSI ");
    Serial.println(LoRa.packetRssi());
  }
}
Arduino-LoRa library LoRaReceiver monitor output

In the Visual Studio output window I could see messages getting transmitted with sent confirmations.

Loaded '/usr/lib/dotnet/shared/Microsoft.NETCore.App/5.0.4/Microsoft.Win32.Primitives.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
17:21:19- Length 28 "Hello LoRa from .NET Core! 1"
17:21:19-TX Done
17:21:29- Length 28 "Hello LoRa from .NET Core! 2"
17:21:29-TX Done
17:21:39- Length 28 "Hello LoRa from .NET Core! 3"
17:21:39-TX Done
17:21:49- Length 28 "Hello LoRa from .NET Core! 4"
17:21:49-TX Done
17:21:59- Length 28 "Hello LoRa from .NET Core! 5"
17:21:59-TX Done
17:22:09- Length 28 "Hello LoRa from .NET Core! 6"
17:22:09-TX Done
17:22:19- Length 28 "Hello LoRa from .NET Core! 7"
17:22:19-TX Done
17:22:29- Length 28 "Hello LoRa from .NET Core! 8"
17:22:29-TX Done
17:22:39- Length 28 "Hello LoRa from .NET Core! 9"
17:22:39-TX Done
17:22:49- Length 29 "Hello LoRa from .NET Core! 10"
17:22:49-TX Done
17:22:59- Length 29 "Hello LoRa from .NET Core! 11"
17:22:59-TX Done
17:23:09- Length 29 "Hello LoRa from .NET Core! 12"
17:23:09-TX Done
17:23:19- Length 29 "Hello LoRa from .NET Core! 13"
17:23:19-TX Done
17:23:29- Length 29 "Hello LoRa from .NET Core! 14"
17:23:29-TX Done
17:23:39- Length 29 "Hello LoRa from .NET Core! 15"
17:23:39-TX Done
17:23:49- Length 29 "Hello LoRa from .NET Core! 16"
17:23:49-TX Done
17:23:59- Length 29 "Hello LoRa from .NET Core! 17"
17:23:59-TX Done
17:24:09- Length 29 "Hello LoRa from .NET Core! 18"
17:24:09-TX Done

I modified the SX127X.NetCore SX127XLoRaDeviceClient adding a conditional compile options for each sample

static void Main(string[] args)	
{
	int messageCount = 1;

	sX127XDevice.Initialise(
			SX127XDevice.RegOpModeMode.ReceiveContinuous,
			915000000.0,
			powerAmplifier: SX127XDevice.PowerAmplifier.PABoost,
#if LORA_SENDER // From the Arduino point of view
			rxDoneignoreIfCrcMissing: false
#endif
#if LORA_RECEIVER // From the Arduino point of view, don't actually need this as already inverted
			invertIQTX: true
#endif

#if LORA_SET_SYNCWORD
			syncWord: 0xF3,
			invertIQTX: true,
			rxDoneignoreIfCrcMissing: false
#endif
#if LORA_SET_SPREAD
			spreadingFactor: SX127XDevice.RegModemConfig2SpreadingFactor._256ChipsPerSymbol,
			invertIQTX: true,
			rxDoneignoreIfCrcMissing: false
#endif
	);

#if DEBUG
	sX127XDevice.RegisterDump();
#endif

#if LORA_SENDER
	sX127XDevice.OnReceive += SX127XDevice_OnReceive;
	sX127XDevice.Receive();
#endif
#if LORA_RECEIVER
	sX127XDevice.OnTransmit += SX127XDevice_OnTransmit;
#endif

#if LORA_SENDER
	Thread.Sleep(-1);
#else
	Thread.Sleep(5000);
#endif

	while (true)
	{
		string messageText = "Hello LoRa from .NET Core! " + messageCount.ToString();

		byte[] messageBytes = UTF8Encoding.UTF8.GetBytes(messageText);

		Console.WriteLine($"{DateTime.Now:HH:mm:ss}- Length {messageBytes.Length} \"{messageText}\""); 

		sX127XDevice.Send(messageBytes);

		messageCount += 1;

		Thread.Sleep(10000);
	}
}

Summary

While testing the LoRaReceiver sample I found a problem with how my code managed the RegOpMode register LoRa status value. In previous versions of the code I used RegOpModeModeDefault to manage status when the ProcessTxDone(byte IrqFlags) method completed and Receive() was called.

I had assumed that that the device would always be set with SetMode(RegOpModeModeDefault) but RegOpModeModeDefault was always RegOpModeMode.Sleep.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.