Hi. There are two reasons to create this project: 1. sorry for wasting a lot of contacts to the matrix keyboard. 2. I had many PC2 keyboards with tiny boards inside. I decided to create a keyboard using only 1 contact (Data) and cheap matrix keyboard 4x4 keybboard AK-1604-N-WWB. For this keyboard is not difficult to create an arbitrary code table. Unfortunately I have not found examples of using the keyboard in the projects. Such as data entry or menu selection. I hope this can someone come in handy.