I have finished the add on module which is a separate project which can be found here:

https://hackaday.io/project/7464-cyclistic

It works quite well it is a circuit which allows you to power the development board and control a 12V RGB LED Strip via Bluetooth

I am quite happy with the prototype and gained some experience with soldering and building circuits on protoboard.

I will draw a schematic of the project soon and add some build instructions to the project page.