[geeks] new keyboard goodness

[Nate]

On Apr 20, 2011, at 9:38 PM, der Mouse wrote:

> I suspect most of them were trying to solve the problem with
> off-the-shelf parts in which inhered nontrivial fractions of the
> problem.  That's a recipe for frustration and failure.

Like I said earlier today:

"If I'm remembering correctly, the Microsoft SideWinder X4 keyboard (a
rather unremarkable membrane keyswitch gaming keyboard) can achieve a >6KRO
over USB by sending HID packets that have more data in them, in combination
with an additional USB driver that can interpret those packets.  The other
method of achieving >6KRO over USB is how the Noppoo Choc Mini does it, by
creating multiple virtual 6KRO HID devices, however while that doesn't need
an extra driver, it doesn't work well with all operating systems (and
doesn't work at all with OS X)."

> I could design everything except the USB interface right now - and that
> exception is only because I don't know enough USB;

To create something compliant, a good place to start is with the spec:

http://www.usb.org/developers/devclass_docs/HID1_11.pdf

In particular "Appendix F: Legacy Keyboard Implementation" on page 73.

> let it sit behind a
> USB serial port and take power from an external wallwart (so I can
> ignore the USB aspects) and I could design the whole thing right now.
> I could even build a prototype by cannibalizing a stock keyboard,
> cutting etch runs to get a 100-plus independent buttons, wiring them up
> into a 10x11 (or whatever, depending on the exact key count) matrix
> with diodes and sticking some small CPU-on-a-chip in front of it.

You might want to consider something like this as a starting point if you're
serious:

http://geekhack.org/showwiki.php?title=Island:14618

> I don't know what it would cost to build.  Maybe more than people are
> willing to pay; that's another undiscussed constraint.  But upthread
> said that "[a]lso even with hacks and special drivers, I don't think
> anyone has ever managed NKRO with USB", not "someone did it and it was
> a commercial failure".

You might also want to check this post out:

http://geekhack.org/showthread.php?4078-N-key-rollover-test.&p=205648&viewful
l=1#post205648