This tip may already be known.

I have an Arduino uno and an breadbord to make tests of new projects but got tired
of to have the radio "nRF24L01+" hanging loose in the wires.
I then find that there was an adapter to the ESP8266-01, "WiFi Module", to be used
on an breadboard. The pin configuration is wrong so I put a label on the adapter
and numbered the pins in accordance with nRF24L01+, pic 1. I also have to desolder the
capacitor on the adapter, pic 2, this could be of diiferent kinds and other places.
And now the radio fits on the breadboard!

@dbemowsk I'm have just started with mysensors and have configured a soil moisture sensor together with openHAB.
To get it to work I used the sketch for soil moisture but present the child as S_HUM and send the reading as V_HUM.

Hello,
This work for me on OH3.2.

@vores8 said in https://forum.mysensors.org/post/110626:
i've managed to build new version from the sources found here https://github.com/nikolac/openhab-addons/tree/mysensors-oh3-migration

So far, so good - working with the latest OH 3.1.0

please download from https://disk.yandex.ru/d/Yq3gn8N7tXSQxA

@Yveaux Thanks, it helped me.

Hello,
This work for me on OH3.2.

@vores8 said in https://forum.mysensors.org/post/110626:
i've managed to build new version from the sources found here https://github.com/nikolac/openhab-addons/tree/mysensors-oh3-migration

So far, so good - working with the latest OH 3.1.0

please download from https://disk.yandex.ru/d/Yq3gn8N7tXSQxA

At first I'm no expert of MySensors or openHAB.
Perhaps I had luck but got the connection between MySensors and OH to work from
the beginning with only minor problems. The system has now been working for almost 2 years and I did it this way.
OH is installed on a RPi 3B, have a serial gateway on an Arduino Nano with nrf24L01 pa+lna the nodes (5 pcs) are built on Arduino pro mini.
The nodes are 3 Door/Window sensors, one relay and one tempereture/humidity sensor.
Since the gateway is placed in the basement and the nodes are on first floor one of the nodes is using nrf24L01 pa+lna and the other nrf24L01+.
The nrf24L01+ are chines and I bought about 15 of them and tested them at a distance of 12m through 2 wooden walls and have to scrap 3 of them.
The gateway and nodes have all standard sketches according to MySensors examples with minor changes. All nodes have fixed node_id.
Installation:
Downloaded "openHABianPi" SD card image file.
Wrote the image to a SD card and put it in the RPi.
Started the RPi and after some minutes OH was up and running.
Complete insructions can be found at https://www.openhab.org/v2.4/docs/installation/openhabian.html.
Connected the gateway to OH via a USB cable.
Went to MySensors/Controller/openHAB and followed the "Install instructions" at https://github.com/tobof/openhab2-addons/wiki.
Used Paper UI to configure the thing "MySensors serial gateway" and not .things file.
Now the nodes (things) pop up in the Inbox. Don't remember if I had to restart the RPi, gateway and nodes.
I hope this can help someone.

@masmat No it's not necessary to put the "Contact" in a sitemap, your arduino shall send boolean (0/1).

@gohan Thanks for your reply, you can show me how the code should look.

I am a newbie and have some thoughts about the battery level that I did not find in this forum.
The 8MHz 3.3V Arduino Pro Mini can handle down to roughly 2.8V.
If I have understood the calculations in the sketch correctly then the analog value of A0 is 1023 at 3.44V and 0 at 0V.
This means that at 2.8V the value is about 830 = 83% and under this, the Arduino stops working. Is this right?
If this is correct, I wonder if someone has changed the calculation in the sketch so that the battery percentage becomes 0 at 2.8V?
This would mean that the battery percentage becomes a more real value on the battery level.

@Yveaux Thanks, it helped me.

I have a battery operated node with a door switch using sleep and no debouncer.
The node seem to work well but I have some thoughts about reliably in my sketch.
The first 2 lines in the "void loop()" is:
wait(50); // Short delay to allow switch to properly settle
value = digitalRead(BUTTON_PIN);
and the last is:
sleep(digitalPinToInterrupt(BUTTON_PIN), CHANGE, SLEEP_TIME);.
As I have understand, when the door e.g. is opened during sleep time the arduino wakes up and starts the loop from the beginning, is this correct?
If so, will "wait (50)" prevent "bouncing"?

Perhaps not the best solution but easy for a beginner.
It's possible to use "Win32 Disk Imager" to make an image of the a RPi SD card and save on e.g. Windows PC. Explained here: https://computers.tutsplus.com/articles/how-to-clone-your-raspberry-pi-sd-cards-with-windows--mac-59294
If you make an image, e.g. after changes in openHAB or at selected times, can't this be used to restore the system?
I'm aware of that data colected since the last made image will be lost and the system is down during the process.

@dbemowsk I'm have just started with mysensors and have configured a soil moisture sensor together with openHAB.
To get it to work I used the sketch for soil moisture but present the child as S_HUM and send the reading as V_HUM.

@rozpruwacz Thanks!

That it could be that simple! Did not see the connection between sending the battery status in the sketch and the thing in openhab.