deskthority

Would it be feasible to connect a gaming keyboard to a controller (Teensy? Raspberry?) and mangle the keyboards collection of HID devices into a generic USB Keyboard device??

Background:
I really want a QMK (or similar) ready 113+ key custom keyboard with backlighting, but I don't have the skills/patience to craft it from scratch and most custom kits are << 100%.

Gaming keyboards are pretty much the only readily available mainstream keyboards with dedicated macro buttons.

Sadly gaming keyboards rarely work with KMV switches due to issues with the KMV keyboard emulation.

The issue seems to be that gaming keyboards connect as multiple USB HID devices.
EG: A Roccat Ryos MK on Windows 10 (with no Roccat software installed) has:
{2 x HID-compliant device, 2 x USB Input Device, HID-compliant consumer control device, HID-compliant vendor-defined device}

I've seen projects with controllers used to provide macros for standard non-programmable keyboards, but I'm specifically wondering what sort of controller (if any) would recognise several HID devices from the connected keyboard.

I'll direct connect the keyboard to a PC to program the macros, set the backlight etc., and I don't need NKRO or other gaming features - so I hope the controller wouldn't have to do anything other than pass the incoming keystrokes to the output as a generic USB keyboard.

Many thanks for any coments or suggestions.

How about a PS/2 gaming keyboard?

I’m a Mac guy and a vintage keyboard snob, so I’ve no idea if they still are a thing. My Filco NovaTouch is PS2/USB, for instance. I've long heard people claiming (wrongly) that PS/2 is "faster" than USB for keyboard input latency, and assume that's still a draw for PS/2 among some gamers.

PS/2 can be converted to USB quite easily, by a TMK (if not QMK) converter etc. The advantage there being user-defined programmability and the fact PS/2 must drop all those useless "device endpoints" you want gone.

Another option, though pricey, is Hasu's programmable USB to USB "converter", which runs TMK.

My experience with a large custom board, on EasyAVR and possibly QMK, was that the random cheapo KVMs I used didn't like the NKRO modes. They would work, but it wouldn't sniff the "type control-control-2 to switch to the other machine" for example. I wasn't really testing some of the other devices, though. I moved my main PC out of the WFH office and retired the KVMs instead.

One aggressive approach would be to basically brain-transplant the board-- cut off the original controller and wire up an alternative MCU running QMK to engage the same matrix.

@moon: Any functionality which requires a custom keyboard driver on your PC would not work when you connect it through a separate controller.

Thanks everyone. I'll investigate your suggestions further.

Muirium wrote: ↑

14 Jan 2024, 00:39

How about a PS/2 gaming keyboard?

I think I have some in the loft, but it's kind of straying from my mission to modernise my desktop!

Muirium wrote: ↑

14 Jan 2024, 00:39

Another option, though pricey, is Hasu's programmable USB to USB "converter", which runs TMK.

It's got an interesting list of compatible keyboards, but not found many with macro keys yet.

Hak Foo wrote: ↑

14 Jan 2024, 04:37

One aggressive approach would be to basically brain-transplant the board-- cut off the original controller and wire up an alternative MCU running QMK to engage the same matrix.

I was excited reading about a few projects that did this - but when I opened up my keyboards I realised I don't have the dexterity/patience to make it happen. I'm much more software than hardware!

vvp wrote: ↑

14 Jan 2024, 08:08

@moon: Any functionality which requires a custom keyboard driver on your PC would not work when you connect it through a separate controller.

I'm really only interested in the macro keys, and would use a keyboard with on-board memory that doesn't require drivers.

Hasu's USB to USB is open source, and you can build it yourself; or maybe a more hardware-oriented friend could.

https://github.com/tmk/USB2USB_Converter

In your position, I'd give it a shot and buy one. I don't see any good reason why it wouldn't work just great. I've heard rave reviews about that very "converter" here on DT for years. Just never had a need for one myself.

My guess is that the keyboard in question speaks a standards-compliant HID protocol, but one which supports NKRO. And then there are additional virtual devices to support media keys and programmability.

I'm not sure that Hasu's USB-to-USB converter actually supports keyboards that are NKRO over USB, but the protocol it uses to speak with the host is NKRO. So if the KVM does not support NKRO protocols then you're not helped either way.