LoRa Simple Communication with Nemeus XM001

Hi everyone,

I am currently working on a project in school. I have to create a LoRa communication between two arduino.

To do this I have the following elements :

  • 2 Arduino uno board
  • 2 NEMEUS RF module (PRODUCT ID: XM001-EU)
  • 2 Antenna

The problem is that I have no technical skills in LoRa nor in Radio Communication and no tutorials or similar project (using the Nemeus XM001) exists.

Based on the tutorial : Mobilefish.com - Build Lora node using Arduino Uno and HopeRF RFM95 LoRa transceiver module.

I realized this wiring:
![](https://forum.arduino.cc/Users/baptiste/Desktop/Capture d’écran 2019-01-14 à 11.36.23.png)

Using the "Lora.h" library, I do the equivalence with the Nemeus board :
![](https://forum.arduino.cc/Users/baptiste/Desktop/Corres table.png)

But when I run the "LoraSender" example code from the LoRa library,
I get the "Starting LoRa failed!" error message.

Can you please help me to find the errors ?
I am totaly unskilled so this project is hard for me.

Thank you.

Do post a schematic drawing of your actual circuit, and links to the specific libraries you run.

Another thing: don't mix up LoRa with LoRaWAN. Two different things.

And a direct linhk to the actual module you are using.

If the LoRa module is 3.3V, and most are, you did use logic level conversion between Arduino Uno and LoRa module ?

Finally, I don't use SPI communication but UART communication.

Here is the schematic (for the sender):
![](https://forum.arduino.cc/Users/baptiste/Desktop/Capture d’écran 2019-01-14 à 15.53.39.png)

I read that maybe I have to use the "WakeUp" Port.

The module is this one :

(I linked the wiring table)

The UART communication seems to be very Easy but I think I am missing an important point.
I think the module that I work on has a lot of features compared to the features that I need to use.

I've used RFM95 modules; very easy to get going over SPI using the RadioHead library.

Works fine with both a NodeMCU and a 3.3V Pro Mini. The latter works great on 2xAA batteries.

Cyclotron2:
The UART communication seems to be very Easy but I think I am missing an important point.

I think you will find the Library you are using is for the SPI based LoRa module, not a UART one.

There is no data on your module at the page you linked to.

srnet:
There is no data on your module at the page you linked to.

Sorry, you will find data on this page :

Yes after some research, I found out that the "LoRa.h" library is for the SPI but I also found out that the UART communication is probably easier to build and code.

So I choose to do it as simple as it can be and to do it using UART communication.

But if you can help me with the SPI method, I also can do it this way.

Thanks a lot for your support !

Cyclotron2:
I also found out that the UART communication is probably easier to build and code.
So I choose to do it as simple as it can be and to do it using UART communication.

It might be easier to build and code, but only if you can find the data on how to drive it and\or a library.

So your choice is now a "more complicated" 4-wire instead of 2-wire connection, or going through the effort of writing your own library.

I'd go for the two extra wires.

Don't forget the level shifters.

wvmarle:
So your choice is now a "more complicated" 4-wire instead of 2-wire connection, or going through the effort of writing your own library.

I'd go for the two extra wires.

Don't forget the level shifters.

I am quite lost right now ...

So what would you do in my shoes ?

Cyclotron2:
I am quite lost right now ...

So what would you do in my shoes ?

The choice is clear;

Use a standard SPI based LoRa module, RFM96/8, DRF1276/8 etc, with a standard Arduino library and known working examples.

or

Find the data on your UART module and write your own library and examples, there probably is not one already.

Using a 3.3V Arduino, Pro Mini for instance, is a lot easier than using level shifters.

The problem is that I have to use this module.

I thought that this kind of module was "generic" and that some librairies can work also on all of them. Am I wrong?

The pin table you attached to #0 shows SPI connections. Pin 6, 7 and 9 (plus pin 10, GND, which of course you have connected alraedy). So what's keeping you from using that?

Actually I realise the extra wiring of SPI over UART is just one wire... You need three for UART (TX, RX, GND) vs. four for SPI (MISO, MOSI, CS, GND).

Cyclotron2:
I thought that this kind of module was "generic" and that some librairies can work also on all of them. Am I wrong?

Have you found a library or even the full data on the module ?

Okay,
Here is a little update of my wiring to get input in my module in 3.3V :
![](https://forum.arduino.cc/Users/baptiste/Desktop/New Wiring.png)

My code is this very simple one (in joined documents).

I used this code in Case of a direct communication between two arduino(RX/TX communication).

It doesn't seems to work with this wiring.(Or if it works the software of Radio visualization that I use doesn't work well, if you know another one?)

srnet:
Have you found a library or even the full data on the module ?

I think that using UART communication (RX/TX), I don't need any library.

Concerning the Data about the module I can't find anything intersting. I called the supplier yesterday to get the data sheet, they will send it to me within today.

Thanks you for your comments guys ! Your help is really appreciated :slight_smile:

Code_emmeteur.ino (188 Bytes)

A library is never a strict necessity, but it can make life a lot easier.

If you can get it working with e.g. the RadioHead library you get all the goodies that come with it - such as encryption, addressed messages, automatic resends, etc.