Ah I had added it just for completeness. But thanks for the effort!!
Oh, could you please double check if your setup is the same as my diagram above?
I had drawn that diagram quickly during my short lunch break today, to get some feedback.
But in my hurry it seems I have drawn it incorrectly 
My setup looks currently like this:
So I would REALLY appreciate if you could double check my drawing with your setup.
I have done it like that, because in our other discussion on Discourse it was adviced to do it that way. Although now I see that in that drawing the pull-up resistor was connected to 5V while mine is connected to 3V3. Perhaps that is my issue?
