@Dominic-Bonneau In 2.0 it was just called getConfig. Change this float temperature = static_cast<float>(static_cast<int>((getControllerConfig().isMetric?sensors.getTempCByIndex(i):sensors.getTempFByIndex(i)) * 10.)) / 10.; to this float temperature = static_cast<float>(static_cast<int>((getConfig().isMetric?sensors.getTempCByIndex(i):sensors.getTempFByIndex(i)) * 10.)) / 10.; and you shouldn't get that error. Can't say for sure you wont get others though.

I saw few videos about bed occupancy sensors, maybe you could take some ideas from those

Yeah ! could do the trick ... i don't have time to check right now but is he explained every detail and hardware of his process ? Thanks

@Dominic-Bonneau - You mean a Pro Mini 5v? As i said I would change the usb charger to another and see what happens. Also I would make sure i have capacitors on the radio and the wiring/soldering is good. Sounds to me like power issue (long shot without more info) and somethings crash the radio. Please report with logs and sketches if possible.

@sincze I've got some buck converters that regulate 12V to 3.3V without any pain. I use it for my gesture controlled lamp. Works like a charm. Well I'm by far any export on this field. But I'm working on a node which I couldn't get stable. The Node crashed after 6, 8 sometimes 12 hours. I've added a watchdog, which works great, but after the watchdog did it's work some sensors on the node just couldn't work. Although I've powered them externally. To make this story shorter ;-). I found out that it's better to always power the radio externally. For some kind of reason it consumes more power than my ProMini 3.3V can provide. This symptom occurs when you add multiple sensors to an Arduino. It took me a long time to investigate what the problem was. But my conclusion is, just don't power anything from the Arduino and use an external power adapter if possible. Except for dedicated Arduino's that can be found on openhardware. My sensebender has been running for 4 month on the same batteries without any problems.

@Dominic-Bonneau Have a look at this thread https://forum.mysensors.org/topic/4415/my-final-setup-to-get-mysensors-and-openhab-communicating-via-mqtt it might provide you with the answers you seek.

OMG I think I found my problem .... Is it possible to put code into Arduino mini pro with this : https://cdn-shop.adafruit.com/1200x900/954-02.jpg Because I check tuto on the web and they all use this : https://abra-electronics.com/images/thumbnails/280/217/detailed/134/ARD-FTDI-F(1).jpg Thanks

It look like the issue come from the dev branch : https://forum.mysensors.org/topic/1728/uno-ethernet-shield-radio-init-fail-solved/2 Is there something i can do ?

@Dominic-Bonneau Hi! Most examples on the mysensors build pages use components suitable for 5 V which is not optimal for a battery driven device. The most common PIR component can be modified to use 3.3 V though. There are lots of advice for building battery driven sensors in the forum and one page on the mysensors web dedicated to this. Many DIY openhardware build PCBs that specialize in battery power can be found on the openhardware site linked in the forum. But I suggest you follow @mfalkvidd 's advice and don't go for too much or too hard in your first build. Just get your first simple sensor together, and take it from there.