Tests forked Keypad library.
No extra hardware is needed besides the wires and switches. The columns are outputs configured with open drain. The rows are inputs configured with pull up resistors. A key press pulls down its row. With scanning the column is determined thereafter.
See keypad for the forked library used in this project.
|Multiple keys added
|Added polling support.
|- clean up ; - added led code from Rene Greiner's IRQKeypad1.
|Tests forked Keypad library