Introduction - If you have any usage issues, please Google them yourself
homemade USB keyboard, with the source code, and using the principle of a 4* 4 small keyboard, a 0-9 10 numeric keys, Num Lock key, Caps Lock key, Shift key, Ctrl key and Alt key, the Enter key, and so on. Up to be three keys are pressed together, if the intersection, the most pressing only two keys