Send custom Message to gw
I would like to send some Info like node ID to the gw and from there to my Controller which is openhab. How can I achieve that?
Have a look at the "download and api" page here on mysensors (link).
Read through the section API (link) to see how you can send a message to the gateway and if you need some in-dept info go through the section SERIAL PROTOCOL (link). You'll notice that everytime a message is send to the gateway it contains the node-id.
How this is then relayed to your controller is explained in the section "Controller". I guess you can find this for yourself in the menu on top of the homepage.