[function_seven]

I use a QMK keyboard, and wrote some code for the firmware that would enforce this in the keyboard itself. "Naughty" combinations like you listed would just NO_OP instead of emitting a scan code.

It was frustrating as hell. Which, I guess is the point at first. But I got tired of it faster than I learned to balance the key presses.

I wonder if just a small beep or other subtle signal would work? Allow the wrong combo, but give the typist some feedback.

[Ambroisie]

Do you have a hosted version of that source code somewhere? I have been thinking about doing this with my own keyboard at some point.

[function_seven]

Okay this is wild. I went looking to see if I could find the file, and came up empty. I don’t know what I did with it. Then I started wondering if I really did do this or if I had done it in autohotkey instead.

So then I searched to see if somebody else had created one, and found this[1]

I wrote that!

So there’s my file. I don’t know if I made any improvements to it since posting that, since I can’t find it anymore. Let me know if you encounter any bugs.

[1] https://www.reddit.com/r/olkb/comments/8mxpdp/qmk_code_to_en...