Artonn:
Ahh alright yeah that makes sense, since it's some kind of one way vavle as far as I understood. So the grey little band should be connected like this. The black wire is ground wire.
I'm guessing I might have burned my diode, since it emitted some smoke? Should I fetch a new one?
Would 8.4V maybe be too strong for a IN4001 diode? Should I maybe have a resistor for the diode gate perhaps? So far it works now. It seems like everything is perfect now.
I think I'm going to start a new thread about the Switch that probably burned out my last Ardunio, so I can get it working.