Making a custom keyboard with arduino?

Hello everyone,

I want to make a custom keyboard and many of its keys are "keyboard modifiers". By using the "keypad.h" library I have seen that the custom keypad is created from a char matrix. I would like to create a byte matrix where I could include the hexadecimal ASCII keys.

I think I could do this changing the library definition of the custom keypad. Has someone tried this?

Thank you in advance.