First of all - big thanks to nougad for reverse engineering how the velux api works.
It was the basis of this module.
https://github.com/nougad/velux-cli/blob/master/velux-protocol.md
I know that you can directly add the Velux Active to Apple homekit, but at some point I was so fed up with Homekit since sometimes automations wouldn't work for some stupid reason - therefore I decided to integrate everything in node-red and so I needed this plugin to control the velux devices I have.
Maybe it is also useful for some of you too :)