As I mentioned in the previous log, I am going to use an NC (normally closed) circuit for the treble keyboard of the accordion.

The idea is to have something like this:

I kept the other wires out of this diagram for the sake of simplicity (the 74HC165 shift register needs to be connected to the ESP32 too).

So, when the key is idle, the circuit is CLOSED, hence NC. When you press a key, that circuit is OPEN.

To test this I found a very ingenious approach based on https://www.instructables.com/simple-normally-closed-switch/. It uses wooden pegs as NC switches, amazing! Right?

Piece of advice: those drawing pins are sharp and can hurt you, that is why I have inverted their position in the wooden peg.

For the copper strip, I am using the melodica reeds, since it is made of metal and was in hand. As I am not a good solderer I decided to connect the keys' resistors mechanically only (a.k.a. twisting the wires together).

And here is the result (I found it amazing :D)

Next step: make the real keyboard!