So I got a Falcon 8, and want to use it as a dedicated macro trigger device. However, I'm not quite sure what the best keys are to map the 8 keys to so that I can make macros with them, presumably using a USB Device Key trigger.
People have mentioned xk24 keyboards are perfect for this, as their keystrokes can be captured uniquely, but don't do anything otherwise... but I've looked around and am not sure if it's possible to make other programmable keyboards (like the Falcon 8) emit the same sorts of signals that the xk24 keyboards do.
Just add a USB Device Key trigger and press the button on the Falcon 8. If Keyboard Maestro can recognise the button press, it will be recorded in the keystroke and you're good to go. If not, then you are probably out of luck.
If you do a USB Device Key trigger, it doesn't swallow the keypress. So for example, if the default is start, strop, increase brightness, decrease brightness, those will still happen... I ended up finding a way to map the keys to f16-f23 and then I used the USB Device Key trigger as you said!