@miro i think you're confusing a node id VS a child node id, a device VS a sensor data. typo mistake. for a device you can have only one id. but you can have multiple sensors so multiple child ids in a device. Battery could be one of these sensors. You can't have the battery voltage for a temperature sensor or humidity sensor. that does not mean anything. you're not sensing battery level with the temperature ic/sensor... whereas a battery level for a device makes sense. For more infos i would advise to read the great docs https://www.mysensors.org/download/sensor_api_20 etc.

The library for SI7021 is missing. You'll find it here: https://github.com/mysensors/MySensorsArduinoExamples

The only thing I changed in parts is that I use a NRF24L01+ with antenna. But I don`t think I need to change anything in the code for that? And I use a Arduino Pro mini 3.3V with two AA Batteries.

No I haven't moved to UI7 so I couldn't say.

Now when I tested the sensor in arduino monitor it says just. Req id Also the other sensor have stop working. Something wrong with gateway?

I have now got all my parts and should test this sensor. Now when I connect the serial gateway to my vera edge it says "Lua Startup Failure Can't Detect Device". What can the problem be? I tried to disconnect it and connect it again but nothing happends. Erlier when I haven`t all parts for the sensor all worked okay with the gateway, the only difference now is that I have connected the radio laso. Please help.