Re: Homebrew pi400

Daniel <me@sc1f1dan.com> wrote:

This past summer was a good time to lower the power bill and overall
temperature of the den by transitioning to rpi's for my computing
needs. The main pc was replaced by a pi400. Lovely, silent, low
power. Lovely. 
 
Well, mostly so. I really don't like the keyboard and question why they
went with it. The full sized keyboard is something I miss, you know,
with the full row of function keys, dedicated number pad, full sized
arrows, the pageup.down,insert,delete cluster. The keys themselves suck
- where they often fail to register key presses and I have to fix
spelling quite often. I had hoped that the keys would wear in and solve
the problem, but it really just seems to be bad design. Hopes are it's
simply bad luck and a bad keyboard. 
 
The problem is easy to solve by plugging in a usb keyboard, but it
defeats the appeal and purpose of the all-in-one design. 
 
How hard would it be to rig the mobo into a full size keyboard shell?
Design a new lower shell of a chosen keyboard to accomodate the mobo and
port holes for 3d printing. A search online didn't yield evidence that
it has been done yet. But if this thing with it's massive heat sync can
fit in this small keyboard, it shouldn't have issues fitting in  full
sized keybord.

https://forum.diyperks.com/user-projects/raspberry-pi-400-x-mechanical-keyboard/
https://www.printables.com/model/318803-raspberry-pi-400-mechanical-keyboard-upgrade
https://hackaday.io/project/175844-the-mechanical-pi-400
https://www.tomshardware.com/news/orthopi-raspberry-pi-400-ortholinear-mod

are a few examples I found by searching 'rpi 400 mechanical keyboard'.
There are no doubt others.

Found a teardown video and saw a custom ribbon cable utilized to connect
the keyboard to the mobo - so that's a complication. After a bit of
searching, they utilized one of the four usb ports in the hub for the
keyboard logic.

The keyboard has a Holtek HT45R0072 (one time programmed) microcontroller to
convert the matrix to USB.  Your options are either to repurpose this
microcontroller, at which point you need to match the keyboard matrix of the
Pi400 (hard):
https://www.40percent.club/2020/12/orthopi.html

or just ignore it and use a USB port.  Another alternative is to cut the
traces to the Holtek (or unsolder it) and use its USB lines:
https://www.40percent.club/2020/11/raspberry-pi-400-keyboard-controller.html

Theo