[GTALUG] Hardware Hack - help needed

[Christopher Browne]

On 11 April 2017 at 11:53, Lennart Sorensen via talk <talk at gtalug.org> wrote:
> On Mon, Apr 10, 2017 at 09:41:24PM -0400, Giles Orr via talk wrote:
>> I'd like to do that, but I think there are a few more steps involved.
>> Want to help out?  Can you point me to a detailed HOWTO for doing
>> this?  I'm not an electrical engineer, but I can solder, I have basic
>> programming skills, and I can probably lay hands on a ROM burner if
>> needed.  But it seems translating the output to USB is may also be an
>> added challenging step ...  Any help appreciated.
>
> Well the thinkpad keyboards don't have a rom, or any map.  They have
> a raw matrix apparently, and you need a controller with a lot of input
> puts to read the keyboard state and turn that into key codes.
>
> From looking at what you linked to, it seems you would need some small
> processor that can work as a USB client device to pretend to me a USB
> keyboard, and also has some 35 to 40 inputs that can be connected to
> the keyboard.
>
> It does sound like quite a bit of work to figure out.

There is a chip, and a project, for that sort of thing.

The Atmel processors (recently discussed by Peter Hiscock) include
some quite suitable to the task, notably the Atmega32U4

http://www.microchip.com/wwwproducts/en/ATmega32u4

There's a project for managing keyboard firmware for various keyboards
using that chip, and it includes some "I built my own from scratch"
options...

https://github.com/qmk/qmk_firmware

-- 
When confronted by a difficult problem, solve it by reducing it to the
question, "How would the Lone Ranger handle this?"