I found a solution to move the TTN data from my airquality sensor (a sensebox) to luftdaten.info.
It boils down to use a node-red server where a function node parses the json object for the x-pins and sensordatavalues as the luftdaten api requires.
The results in our Leuven area can be found here and look for L-38035 and L-38036.
In this experimental phase the lora data transfer is currently done with ABP, later on with OTAA as it should security wise.
@arjanvanb
A great many thanks Arjan for the pull request on github to the author of the sensebox code. It works fine now after Felix from the uni in Münster changed his Arduino code for his SAMD board and also the appropriate payload format for TTN (that was new for him). And indeed, he admitted, the ‘% 255’ was a mistake in its shifting.
The results can be seen for now on https://opensensemap.org/explore/5e10d6b0b0c088001bf22393 (with one little mistake though on the lux values).
I will publish it soon in the right topic: Payload format for the sensebox