I have plan to use a keyboard on console to play vs fighting games, and, because keyboards are not natively supported in these games on console, there are two options: mod an existing keyboard with a pi pico directly soldered to keys pins (with arcade stick firmware) or using a QMK keyboard (like a Keychron V5) with a gamepad firmware (brentaro QMK_HID_Gamepad_with_SOCD for example).
The point is that the first solution provide something like 1ms of input lag, but I do not have any idea for the second solution. It seems that usually QMK keyboard are around 10ms, but it will be great if some of you can give me some feedback.
It depends on how is coded the QMK firmware but you usually obtain a delay of much less than 10ms.
USB polling rate is usually set at 1000Hz (this gives the same 1ms delay you said for the first solution).
Then the firmware itself adds more delay (because delays always add up).
I’d say for a keyboard with no lighting active (managing RGB adds more CPU cost and adds even more delay) you could expect between 2 and 3ms delay.
Scanning keys of a gamepad is faster than on a keyboard (less keys) but even on your first solution don’t expect to have 1ms delay, it will probably be a bit more.
Hear some people increasing the USB polling rate to reduce delay even more, but really less than 3ms of delay no normal human can tell the difference.
But I forgot the debounce algorithm that usually adds 5ms in QMK.
There are advanced debouncing algorithms in QMK that allow to have no delay when detecting if a key is pressed but you have to modify the firmware for this.
Now I know this is a keyboard forum here but I’d personally make my own arcade stick with arcade buttons (and a pi pico of course as the brain).
Keyboard switches have a long travel of often 4mm, nothing beats a short throw round accade button that you can slam as fast as possible
