Feasibility of adding more buttons + profile switching about ocreeb-12

[sb-ocr]

Thank you for checking out the project.

1- As you said the footprint of the board you chose isn't compatible with this PCB. So if you're going to design a new one for it to fit, it should be fine. The other thing is the castellated pads, this board doesn't have them and to solder it directly to a PCB you would need to use use some shortened headers for example.

2- Yes you need more pins to add more switches in your matrix but usually it's in a grid configuration. If we take the example you provided 4 x 5. You can setup this as 4 columns and 5 rows (or the other way around) for a total of 9 pins to detect 20 keys, the diodes will prevents the current to go backwards (and causing ghost keystrokes). After you initialize the keyboard class in KMK you supply the row pins, the columns pins and the diodes orientation. The matrix scanner isn't the only one available in KMK you can checkout this part of the documentation for more options on how to add other hardware.

3- Yes, this concept is called Layers in keyboard firmware. You can jump between them in different ways: Toggle, Momentary hold or even Tap dance (that's what I used to toggle the midi layer in this project)

I hope this answered all your questions. Best of luck!

[ItaloKnox]

Thanks for taking the time to explain it. The whole thing is a lot clearer now that I can reference the parts I didn't understand directly from the KMK firmware. Going to give it a try once all pieces needed are here. Thanks again!