I needed a way to experiment with various keypad arrangments for a PIC microprocessor experimenter board. I have the PIC 16/32 explorer board but an available experimenter's keypad does not seem to be available that plugs directly into the board's interconnection connector. The design is to provide five rows by seven columns of switches in an array so that any specific switch unique row column address (i.e. 11 to 57) can be connected using 12 pins. One end (rows) could be an output and other end (columns) to be input pin. Then specific switch address keypress can be sensed by strobing a specific row (1 of the 5) and reading returned high level on one of the (1-7) column pins. This provides a unique row/column address for specific switch. Alternatively the rows and columns might be switched.
revision - removed the header component from top layer because OSH Park cutout slots in the copper board where these were located.