travis
(Travis Northcutt)
1
I want to program a key to send the same keycode that my Macbook Air’s built in keyboard sends when I press the fn
key on the built in keyboard.
I’ve looked through what appear to be the available keycodes here and I don’t see any that would make sense.
The screenshot below is what Karabiner EventViewer reports when I press this key.

merlin
(Michael Richters)
2
You can’t, unfortunately. It’s not a USB HID key code of any sort, so external keyboards are not capable of sending it.
travis
(Travis Northcutt)
3
Oh wow, interesting!
Out of curiosity, do you know how Apple’s own external keyboards send it? Some proprietary magic?
james.nvc
(James Cash)
4
There was a big exegesis on that topic a few years ago from QMK: The Apple Fn Key · Issue #2179 · qmk/qmk_firmware · GitHub
This is interesting, because the Nuphy Air75 is able to do it which is a third party keyboard. I wonder how they do it.
Haven’t tried this yet, but it looks promising. QMK Apple Fn
jesse
(Jesse)
6
We have support for the Apple Fn key in Chrysalis these days. (It’s called a ‘Globe’ key), along with Lock Screen, Mission Control and Expose.
travis
(Travis Northcutt)
7
What’s the right way to send this with Kaleidoscope?
travis
(Travis Northcutt)
8
@jesse is it possible to send this key with Kaleidoscope (vs. Chrysalis)?
jesse
(Jesse)
9
Yup. It’s Consumer_AC_NextKeyboardLayoutSelect