Eject key on Logitech K750 doesn't work

[Sebastien]

Hello,
I would like to add a shortcut to the Eject key from my K750 keyboard but it does not seem to be detected as "Hot Key Trigger". FN key is also in the same case.
Is there a solution?
Thanks in advance.

[Airy]

Those keys are (almost certainly) not USB keys. In the case of the FN key, its processing is handled 100% inside the keyboard, and your computer has no possible way of detecting its usage. I'm not certain about the Eject key, but it's likely a similar case.

[kevinb]

Welcome to the forum, @Sebastien.

Straightforward answer: those keys are for internal use, so forget about them and use other key combinations instead.

@Airy is correct about the fn key and indeed this subject is covered in the FAQ:

The Fn key is not a modifier, it is a hardware toggle that toggles whether the physical key behaves as a function key (eg F3) or a hardware key (eg increase brightness).

That said, some people have reported that success using other software, including BetterTouchTool, and then using that to trigger Keyboard Maestro. In order for that to work, the keyboard in question would need to be sending some kind of signal when fn were pressed (it would certainly not be one that is supported by Apple’s public APIs, and the policy with KM is to use only those).

Excerpts from an old thread:

@AlanRalph

@peternlewis

The Fn key is not supported by the system Hot Key API.

However, if you're using a non-Apple keyboard (I'm typing this on a Microsoft Natural Ergonomic 4000 keyboard) you might have more luck. I'm using the F-Lock key as a toggle for my microphone.

@lapel

I just figured out that BetterTouchTool handles the fn key as a key modifier.
So you can create any shortcut with the FN key. Pretty handy !
And from BetterTouchTool, you can easily call any macro in keyboardmaestro.
Hope that helps !

And surprisingly, @Airy, you said there that you had had some success too?!

@Airy

It (the Fn Key, also called Globe) works for me, as a KM hotkey, using Sonoma. But in order to make it work I had to go into the System Settings / Keyboard page and switch "Press Globe key" to "do nothing." In fact, I've been using it for months without knowing that it wasn't supposed to work.

So anyway, no, Keyboard Maestro cannot directly support fn or esc... so choose other hot keys.

[kevinb]

For completeness only... If you are already a user of Karabiner Elements, here is one interesting idea regarding low-level remapping of the fn key:

@B_Vasconcelos

I don't know the reason, but if you want to change this, I recommend Karabiner .

However, from a very quick Web search, I get the impression that the results in this case would not be guaranteed.

[Nige_S]

@kevinb

For completeness only...

For more completeness... on an Apple Magic Keyboard, both Fn and the Eject key work with the "USB Device Key" trigger -- so that may work for the Logitech too.

@Sebastien

Is there a solution?

So using the "USB Device Key" trigger may work for you.

Usual caveat for the Device Key trigger -- keystrokes are passed through to the frontmost app (unlike hot keys, which KM swallows), so be careful of unintended consequences. You'll probably be OK with the bare Eject key, but beware of any modifiers -- ⌥⌘ + Eject might run your macro but will put your Mac to sleep!

[skillet]

@Nige_S

For more completeness... on an Apple Magic Keyboard, both Fn and the Eject key work with the "USB Device Key" trigger

Also the fn key also works works as a hot key trigger and shows up as Globe, the Eject key does not for me on an Apple Magic Keyboard 2.

[Sebastien]

Thanks for your answers ! It helped me a lot.

I managed to work as I wanted the Eject button.
On the other hand, the FN key I can't do it. But it does not matter, I managed to make all the shortcuts I needed thanks to KM, BTT and Karabiner.
The only touch that still resists me (apart from FN) it is the F4 touch that increase the sound like the F12 touch which is dedicated to that (icon on this touch).
With Karabiner, these 2 keys are recognized as identical, I cannot differentiate them.