I’m trying to write some keyboard drivers for OS X (and a logitech keyboard to begin with). I’ve looked at a lot of code - especially with emulating keypresses using user-space code.

What I want to do is to interpret keypresses in the keyboard and then based on the frontmost application do different things. Before I start coding, I want to get a general idea what I should be doing, so I’ll try to explain my thoughts here.

1) write a kernel extension that a particular application (daemon) will take a hold of 2) write a daemon that talks to that kernel extension and then based on keypress X, will simulate the appropriate keypress.

Also, besides USBProber and IORegistryExplorer, what are some good (software only - free preferably) utilities for USB debugging, etc.

Any pointers and ideas would help greatly.

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Hello! Apparently, no one answered your question! But maybe you�re able now to tell us how you did it? I�m very interested in this subject.

Here�s my question: Is it possible to intercept the text input from one and only one keyboard and modify it before passing it to the text system? And if so, can/should it be made in a driver?

I�m trying to make a CueCat driver for OS X. Of course, a modified CueCat outputs regular digits and letters but

1) It swaps upper- and lowercase (in code128, for example, David would become dAVID)

and 2) if you regularly use a non-qwerty physical keyboard or keyboard layout, the output will be dQVID, and 12345 would become &�”’( with a French keyboard layout.

You�ll say I just have to switch to the American keyboard layout, but:

• it�s very painful,
• you always forget about it, then enter bad text with your regular keyboard,
• you always forget about it, then quit the program (cmd-Q) instead of selecting all (cdm-A) :-((
• Anyway, the upper/lowercase swapping remains�

I hope you�ll understand my question and give me some clues. Thanks, Wdyp.