Thank you both for your answers.

With so many parameters to play with, it was not easy to understand what was wrong.. But I think I finally got a way do get my hardware working

Here are my findings :

• I thought I got RFM73 version of NRF24-like radios. They look like like here and here.
• After checking and connecting all VCC and GND together, switch radios and arduinos... I got them suddenly working with Mysensors development librairies, then back to silence without apparent reason...
• Indeed like @mark_venn suggested, I went back to stable librairies and try so set a static ID. Worked well... until it went back to silence again !
• Then, following @mfalkvidd advice, I realised that flashing the eeprom_clear sketch solved my all my problems !

My summary :

• Ensure that your 3.3V power supply is strong enough.
• Ensure that your arduino, radios and sensors are sharing the same GND and VCC.
• Use development librairies from github
• Flash eeprom_clear before flashing your mysensor sketches
• Then gatewaySerial and relayActuator should be able to communicate "out of box", mean you'll monitor some lines like this on the gateway serial : 0;255;3;0;9;read: 0-0-0 s=255,c=3,t=15,pt=0,l=2,sg=0:

Thanks again for your help, now I can start to play

Good to know, indeed my setup is working now with stable libraries thanks to this helpful community.
I'll go back later to development libraries to see if I'm able to work with it as well.

Finally I got it !
In the stable version, baud-rate is at 115200, I changed it to 38400 in MyConfig.h and now it is working !
A question still need to be solved : why it is not working with the development libraries since 38400 is default baud-rate ?

With my node-id=1, my child-sensor-id would be 1 as well, I should send 1;1;1;0;2;1(without ack) or 1;1;1;1;2;1(with ack). Am I right ?
I've tried to send it through arduino IDE with a new line at the end, but the gateway is still not responding...
Am I missing something ?

Great idea. I'll dig in that way.
Is there same kind of tool for linux ?
If not, maybe could I send some serial messages through arduino IDE's serial monitor ?
That probably means I'll need to learn a bit more about mysensor API...

@AWI I did get error messages (Error sending switch command, check device/hardware !) in the past and did played with the ack option in domoticz hardware menu.
In fact, I've just checked and ack was enabled without getting error messages... So I've disabled and re-enabled it, and I got error message back... How to know what happens in the gateway while receiving messages from Domoticz ?

@AWI Yes, I'm using examples "Serial Gateway" and "relayActuator". I've just changed gw.begin(incomingMessage, AUTO, true); to gw.begin(incomingMessage, 1, true); otherwise my node was not detected.

So, to answer to your first question, I guess I should read "Incoming change for sensor: ... , New status: ...." and state of pin 3 should change...

You're right, that the deal while moving between different libraries versions, I forgot to put back the debug mode on development version...
Anyway, I had a drop in my voltage regulator last night, I guess that explains that my serial reads were not complete...
So now I'm back with with MySensor 1.5.4, debug active, and Domoticz 3.5143, but with no more luck.

Here is an entire sequence :

• I run Domoticz, go to hardware and configure a Mysensors Gateway USB, Domoticz report :

MySensors: Using serial port: /dev/ttyUSB3

• I reset the gateway, Domoticz report :

MySensors: Gateway Ready...

And here is serial output of the gateway :

0;0;3;0;9;gateway started, id=0, parent=0, distance=0
0;0;3;0;14;Gateway startup complete.

• I reset the relay node.

Domoticz :

MySensors: Node: 1, Sketch Name: Relay
MySensors: Node: 1, Sketch Version: 1.0
(Mysensors) Lighting 2 (Light)

Gateway :

t=15,pt=2,l=2,sg=0:0
1;255;3;0;15;0
0;0;3;0;9;read: 1-1-0 s=255,c=0,t=18,pt=0,l=5,sg=0:1.5.4
1;255;0;0;18;1.5.4
0;0;3;0;9;read: 1-1-0 s=255,c=3,t=6,pt=1,l=1,sg=0:0
1;255;3;0;6;0
0;0;3;0;9;read: 1-1-0 s=255,c=3,t=11,pt=0,l=5,sg=0:Relay
1;255;3;0;11;Relay
0;0;3;0;9;read: 1-1-0 s=255,c=3,t=12,pt=0,l=3,sg=0:1.0
1;255;3;0;12;1.0
0;0;3;0;9;read: 1-1-0 s=1,c=0,t=3,pt=0,l=0,sg=0:
1;1;0;0;3;

Relay node :

send: 1-1-0-0 s=255,c=3,t=15,pt=2,l=2,sg=0,st=ok:0
send: 1-1-0-0 s=255,c=0,t=18,pt=0,l=5,sg=0,st=ok:1.5.4
send: 1-1-0-0 s=255,c=3,t=6,pt=1,l=1,sg=0,st=ok:0
repeater started, id=1, parent=0, distance=0
send: 1-1-0-0 s=255,c=3,t=11,pt=0,l=5,sg=0,st=ok:Relay
send: 1-1-0-0 s=255,c=3,t=12,pt=0,l=3,sg=0,st=ok:1.0
send: 1-1-0-0 s=1,c=0,t=3,pt=0,l=0,sg=0,st=ok:

• Then, the switch appears in domoticz devices so I add it to the panel and try to switch on/off

Domoticz :

Admin initiated a switch command
(Mysensors) Lighting 2 (Light)

Gateway and Node : nothing but the gateway serial led is shortly blinking...

What wrong did I do ?

Thanks for your answer.
In my case, there is nothing on serial monitoring for both node (relayActuator) and gateway when switching the relay from domoticz.
However the gateway RX led is blinking, so I guess it is receiving something from Domoticz. That's why I was wandering if there is some code to add to the gateway for it to be more talkative.

I just tried to give you some logs from the initialisation sequence (from arduino IDE) and I found that some times lines are not complete. Is that some common artefacts of arduino IDE or should I be worried about it ? Maybe have I a problem of serial transmission reliability ?

NGA-, 2.0.0-beta)
0;255;3;0;9;Radio init successful.
0;255;3;0;14;Gateway startup complete.
0;255;0;0;18;2.0.0-beta
0;255;3;0;9;Init complete, id=0, parent=0, distance=0
0;255;3;0;9;read: 0-0-0 s=255,c=3,t=15,pt=0,l=2,sg=0:

0;255;3;0;15;

0;255;3;0;9;read: 0-0-0 s=255,c=0,t=18,pt=0,l=10,sg=0:2.0.0-beta
0;255;0;0;18;2.0.0-beta
0;255;3;0;9;read: 0-0-0 s=255,c=3,t=6,pt=1,l=1,sg=0:0
0;255;3;0;9;read: 0-0-0 s=255,c=3,t=11,pt=0,l=5,sg=0:Relay
0;255;3;0;9;read: 0-0-0 s=255,c=3,t=12,pt=0,l=3,sg=0:1.0
0;255;3;0;9;read: 0-0-0 s=1,c=0,t=3,pt=0,l=0,sg=0:
0;1;0;0;3;
a
0;255;3;0;9;Init complete, id=0, parent=0, distance=0

Hi,
I'm a beginner with MySensors and Domoticz. I did configure some nodes last days and I'm able to monitor temperature, humidity, pressure, air quality, distance... and until now I was happy with it !
But, I'm actually trying to control an RGB strip LED and I discovered that although my nodes were sending their data, they cannot receive messages from Domoticz. So I did some simple tests with relayActuator node, and no way to control it...

My config

• Arduino IDE 1.6.9 on Linux Mint
• Arduino mini pro 3.3V 8MHz
• CH340G USB to TTL
• 1.5A power supply
• NRF24L01+ Radios close to each-other with 47uF capacitors (maybe RFM73?)
• Try with both stable (1.5.4) and development branch (2.0 beta from github) of MySensors libraries
• Try with Domoticz 3.4834, 3.5143 and master from github

What happens
Almost nothing... that's the problem. Message is not received by node, however the gateway serial led blink a bit when I turn off and on the relay switch on Domoticz interface. But nothing appears when monitoring serial communication with arduino IDE.
Logs of domoticz :

User: Admin initiated a switch command
(mysensor) Lighting 2 (Light)

Is there a way to debug it better ? Like some commands to put on gateway sketch to know if it receives something...
Could it be related to ack (I didn't really understand what it is...) and some supposed RFM73 radios ?
Could someone give me its working combination of version of MySensor and Domoticz ?
Any other suggestions ?

Thanks for your help.

Thank you both for your answers.

With so many parameters to play with, it was not easy to understand what was wrong.. But I think I finally got a way do get my hardware working

Here are my findings :

• I thought I got RFM73 version of NRF24-like radios. They look like like here and here.
• After checking and connecting all VCC and GND together, switch radios and arduinos... I got them suddenly working with Mysensors development librairies, then back to silence without apparent reason...
• Indeed like @mark_venn suggested, I went back to stable librairies and try so set a static ID. Worked well... until it went back to silence again !
• Then, following @mfalkvidd advice, I realised that flashing the eeprom_clear sketch solved my all my problems !

My summary :

• Ensure that your 3.3V power supply is strong enough.
• Ensure that your arduino, radios and sensors are sharing the same GND and VCC.
• Use development librairies from github
• Flash eeprom_clear before flashing your mysensor sketches
• Then gatewaySerial and relayActuator should be able to communicate "out of box", mean you'll monitor some lines like this on the gateway serial : 0;255;3;0;9;read: 0-0-0 s=255,c=3,t=15,pt=0,l=2,sg=0:

Thanks again for your help, now I can start to play