My plan for my next keyboard is to wire it directly into a DIY micro I'm planning, so there won't be any fancy microcontrollers getting in the way. Fortunately, 7bit's group buy hasn't arrived yet, so I have an excuse not to think about that one yet...Code: Select all
Building a Phantom keyboard
===========================
Back in the mid-90's, I got myself a Cherry keyboard with MX blues. It
was great. I used it a lot. I never took it in to work, though, and at
the start of this year, after my KVM broke, they replaced my cheap and
flimsy rubber dome with something far, far worse. Something that might
have cost 2 quid to make. I looked at it in horror, and decided
something must be done.
I wanted a mechanical keyboard for work, and something based off my
old Cherry seemed perfect. Why not use the Cherry itself?
* It didn't do USB. It didn't actually do PS/2, either, having an AT
plug and an adapater
* It lacks Windows keys, which are convenient
* Actually, a couple of keys had started to flake out. That
definitely needs fixing
* It didn't have a metal plate, which seemed a shame
* It wasn't tenkeyless and, well, I never use the number pad and do
use a mouse on the right, so that's a bit sub-optimal
So, I decided to take the old Cherry, and reuse the switches and
keycaps. This project has taken rather longer than I expected (and
been more expensive!), so I should probably have just bought a nice
new mechanical, rather than wait so long, using the horrible work
keyboard, but it's certainly been a fun project.
As I'd never done any custom keyboard stuff before, I just followed a
very simple variation of the Phantom design.
More details in the sections below, but the basic steps ran something
like this:
1. Got customised plate lasered
2. Soldered the Teensy microcontroller to the Phantom PCB
3. Installed diodes
4. Painted plates
5. Installed switches and stabilisers
6. Soldered up the switches
7. Made case
The instructions at
http://deskthority.net/wiki/Phantom_instruction_guide are very good
and should give you everything you need, but I thought I'd just share
my thoughts and experiences.
An image of the final results is included as "Keyboard.jpg"
Plates
======
Edited original file (probably the same as
http://deskthority.net/resources/file/1507) in Inkscape. On importing,
scaled up by 25.4 to get appropriate inch sizes. All I did was remove
the plate holes for keys I'm not using (since I'm not adding a
cosmetic top layer), and add a larger surround with screw holes (since
I'm not using the standard cases). Result is "tkl-rim.dxf".
After a few quotes, and recommendations on the web, the plates were
then laser cut by Yorkshire Profiles. This plate was cut with a couple
of others to get the price down a bit. Would still be a lot better in
a big group buy. The finishing was pretty raw (as expected).
My original plan was to leave it raw, but then I decided to go for a
painted surface. Rubbed with fine grades of steel wool, then sprayed
with etching primer and plain white spray paint.
Used Autotek AT000EP500 500ml Etch Primer and Hammerite Smooth White
Metal Paint. Important things I learnt were:
* If steel wooling with the keyboard on cardboard and a dust sheet,
don't just clean the bits off the keyboard and get on with
spraying. The spray can will blow the bits everywhere. Clear off
the surface too, duh!
* Make sure you wear a mask if you don't want funny-coloured snot
(previously learnt sandpapering a painted surface).
The surface coating wasn't absolutely perfect, but it's good enough,
and the bits without the tiny blemishes do look kinda awesome.
PCB
===
Bought from MechanicalKeyboards website.
Microcontroller
===============
Bought in a group buy from Deskthority.
Downloading
-----------
Got the teensy software from
http://www.pjrc.com/teensy/loader_mac.html
Firmware
--------
https://github.com/tmk/tmk_keyboard looks awesome, but needs the tools
to build
Ended up using phantom_ansi_iso.hex from
https://github.com/BathroomEpiphanies/AVR-Keyboard
Installing
----------
It's very important to solder the Teensy in correctly. Solder the
Teensy as low onto the main PCB as you can, since the Teensy sticking
out the back is the limiting factor on the the depth of your keyboard,
which you probably want to make quite thin. At the very least, take
any plastic blocks off the headers. Ideally, solder the thing flat
against the main board.
Once soldered in, you need to really trim the soldered connections as
flat as possible on the switch side, since they control how low you
can put the switches that overlap the Teensy. You want as near as
possible to flat.
Testing
-------
Flashed it, and it came up as a keyboard. Once the Teensy was soldered
to the main board, bridging the appropriate pads produced the expected
keystroke. Hurrah!
Diodes etc.
===========
Bought in bulk off ebay. Soldered on, and then the keys tested.
Also installed a couple of 5mm LEDs with 220 ohm resistors for the
locks.
Stabilisers
===========
Bought some plate-mounted Cherry stabilisers. Royal Mail lost them.
Tried sawing off PCB-mounted stabilisers (like you can saw pins off
the PCB-mounted keyswitches to create ones suitable for
plate-mounting). Put them in the board. Looked about right, but when I
stuck a keycap on the alignment was clearly wrong as the keys stuck.
Got some more plate-mounted Cherry stabilisers. These ones arrived,
and did the business. It took a while to work out the best way to
mount them. They are pushed in from the keycap side, having first
passed the metal bar through the cut-out slot from the cap side to the
soldering side.
Keys
====
Vintage MX blues taken from my old Cherry keyboard (bought in
1995). Opened them all up, took them apart got the accumulated fluff
out with a loupe, a pointy stick and Rodico.
Afterwards, tested them all for correct switching and correct feel -
the keyboard had had about a decade of constant use, so some of the
switches didn't feel as nice as the others. Since this is a TKL build,
and the original keyboard was full-size, I could take a few out of
circulation.
Keycaps
=======
Taken from my old Cherry keyboard. (They're doubleshot. This is not
something I'd realised at first, so I was somewhat surprised after the
first few years that there was really no sign of wear to the
labels...).
They were quite grubby after all their usage, but they quicky cleaned
up when I scrubbed them with water and washing-up liquid, using an old
toothbrush.
For the modifiers, I needed to add 1u Cherry profile Windows keys. In
the end, I bought a Qwerkeys end-of-stock set of brightly-coloured
modifiers that include the 1u. The bright colours rather change the
look of the design (not quite so subdued and minimalist any more), but
they are rather fun. The profile's a not-bad but not perfect match
(the Cherry keys modifier row profile is the old profile that's not
done any more).
Case
====
I built a wooden case. The main thing I learnt here is that I'm no
good at woodwork. Wood, without the right tools, is very slow going to
make right. Oh, and it's very easy to get wrong - indelible dents,
things too short/thin/narrow, things gone non-square and difficult to
get back. Splintering when you least expect it.
Appropriate tools help. Experience plus power tools would have made it
a doddle. I bought increasingly non-inappropriate tools, including a
mitre saw, chisel and tiny little files (needed for doing the
connector recess). I bought a Dremel 231 router set-up for my Dremel
tool. This has incredibly bad write-ups on the web as being flimsy as
anything, but was perfect for my needs of creating recessed areas in
small pieces of fairly soft wood. Eventually I got not bad at planing,
too.
The other thing I learnt is that you can take four straight pieces of
wood together and get something non-planar as a result. Argh. A
keyboard that wobbles. So, in between the wooden frame and the base, I
added a shim to correct the wobble. Super ugly.
To put it together, I used appropriate glue. The keyboard top (screwed
into place) and bottom (a metal sheet covered in baize to make it rest
nicely on the work top, held in place with nail) do the real job of
holding it together.
The case is clearly the weakest link, something I'm not terribly proud
of, but I don't have the time (or energy!) to really make it lovely.
USB Socket
----------
I wanted a USB socket on the case, so I ended up creating an extension
for the Teensy by cutting a cable in half and soldering it onto a
socket embedded in the case. It didn't work initially, until I found
out that either the colours in the cable or the socket pin-out or
something was lying. Debugging was aided by comparing a cable that
worked, vs my hacked-up cable, with a continuity tester. In my case,
it appears I swapped D+ and D-, and once these were reversed it worked
fine. The socket was then glued into the case.
The internal plug that plugged into the Teensy needed to have its
plastic cut off in order to fit into the available internal
space. Snip snip snip...
Finishing
---------
I varnished the wood. Protip: A matt clear varnish will make you
wonder why you bothered, since it's basically invisible.
In the end, it looks in no way professional. However, I can live with
the rustic look - I'm quite happy to have a keyboard that makes it
clear I built it myself, and it still does the job for typing upon.
Thoughts on the Phantom design
==============================
The Phantom design tries to be a jack of all trades. It covers ISO and
ANSI, plus a few other custom funky things, with 1u and 1.5 Windows
keys. This does lead to a few ugly things - the wide switch hole for
caps lock, the space bar with multiple stabiliser cut-outs, various
bits on the PCB where the holes are a bit ick, etc.
Overall, it does a pretty good job, but if I were to do this again I'd
probably tidy up the plate a little bit more. I'd not try to redo the
PCB though!
On of the more painful bits is quite how thick the keyboard has to be
because of the Teensy and the way it's mounted. As I'm reasonably
confident with my soldering, /if/ I were to produce my own PCB, I
think I'd directly solder a microcontroller to the board, saving the
depth. If I could find an appropriate easy-to-solder SMT
microcontroller, I guess.