Alright 🙂 Had the time to try again and it seems to be working now.
But it was mirrored vertically so I adjusted the function getIndex function. There is now a bool you can put to true if it is mirrored.
I also adjusted the LED type to APA102. you can find the ino here and the HEX here.
I also created a quick protoboard that already incorporates the WiFi-adapter. Use at your own risk and double check the connections. You can use BlackBoard designer to open the file. Otherwise see here: top wires, bottom wires, parts (the two switches are on the underside), altogether. Just imagine that the pin headers are actually pin sockets…
