Code found at http://crumpspot.blogspot.com/2013/05/using-3x4-matrix-keypad-with-raspberry.html
Adapted to fix some formatting errors and updated pin numbers to match photos.
Code found at http://crumpspot.blogspot.com/2013/05/using-3x4-matrix-keypad-with-raspberry.html
Adapted to fix some formatting errors and updated pin numbers to match photos.