I would like to know if there is a pattern to name switches board pinout, at least, for these boards.

The boards are parts of a piano toy. First one for some effects buttons and second one is the piano keyboard.

The pins are named as P10, P11,P12, P13, P20, P22, P23, P40, P43 for a 10 switches board.

Switch board

At the reverse it's easy to see how switches are connected to pinout.

enter image description here

The reason because I ask for the labeling pattern is because I would like to connect the piano keyboard to an Arduino with Midi and, the keyboard, looks with the same labeling pattern:

Piano keyboard pinout

Here the reverse:

3 octaves toy piano

Here schematic pinout for 10 switchesschematic pinout


1 Answer 1


They all start with "P" other than that no obvious pattern.

they seem to be different at each end of the cable, this suggests that they are just net names allocated automatically by the design software used to design the device.

  • \$\begingroup\$ Omg. That means I should to disassemble keyboard and follow all cables. :( Any case, thanks about your answer. \$\endgroup\$
    – danihp
    Aug 8, 2020 at 13:24

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