deskthority

On second thought, the daisy chaining and microcontroller are optional. Given four connectors rather than two, the single-key PCBs can be arranged in the traditional scanned matrix. The only active component is then a diode. Also, you can skip the mounting holes on the PCB, and use panel-mount Cherr...

The solution to the PCB size problem is this: One PCB per key. This PCB should hold only: one keyswitch. the cheapest available low-pin-count microcontroller (for instance, the PIC10F200, which comes in SOT-23 packaging!) two small connectors for daisy chaining (simple one or two-wire bus) two or mo...