I you have already a Raspberry Pi, you can install Node-RED. Then you can make "a flow" that reads MQTT messages, manipulates them, and sends them out with another topic.

Edit : I got it to build by moving those methods to the top of the _P105_RGBW.ino file, but that's obviously a hack. If someone could explain what simple thing I must be missing here, I'd really appreciate it. It also works if we just declare these functions before the Plugin_105() function: void P...

Yes, it might work. I had better luck with the _P144_RC-Switch-TX.ino , though. To use it, copy it to the src directory, then compile it. If you get an error message that it can't find the rc-switch library, download the rc-switch library and put it in the lib directory. If you get an error message ...

You can upload files using curl: