In this article I will gather all the information of my Symmetric Stagger Keyboard. The information was starting to become spread out into several threads.
[H=2]PCB[/H]
Front
The PCB supports a few different layout options, there are layout sketches further down. The board takes any Cherry MX switches and PCB mount stabilizers, I suggest 1N4148 or LL4148 diodes (through hole or surface mounted), They are the exact same that Filco uses. The surface mounted ones just barely reach between the pads. There are three different LED "channels" (i.e. Num Lock, Caps Lock, and Scroll Lock, or whatever you want). They are connected to output pins with PWM (pulse width modulation) to make it possible to dim the diodes. There are also surface mount pads in conjecture to the diode mounts to take resistors for non-5v LEDs. LED locations can be found in the picture of the back.
Back
A lot of text, mostly correct English...
[H=2]Controller[/H]
Powered by a Teensy++2.0 the board is fully programmable. You could probably have it mine Bitcoins or whatever (you won't get rich though). I have a working firmware (tested on Ubuntu and Windows, comes without guarantees though). It is possible to piggyback the accompanying Micro-SD card reader. (The necessary pins on the controller board are unused. I haven't even looked into interfacing it though).
[H=2]Case[/H]
The board fits into a full size Filco case. The case needs to be slightly modified to accept PCB mounted stabilizer. They protrude on the back of the PCB where there is a plastic ridge in the case bottom. This ridge needs to be trimmed slightly, It was a quick job using a sharp chisel. Plate mounted stabilizers don't pose the same problem. A few of the diode legs also end up right on the ridge, these diodes can be surface mounted on the front without any trouble, or the ridge can be chiseled.
[H=2]Mounting Plate[/H]
I had a few mounting plates made at a local water cutting company. They are not the highest quality steel and they didn't come de-burred. I have sanded them and spray painted them black. The result was awesome. Next time I would probably go for stainless steel though. I have no idea how well the paint will stick or protect the plate in the long run. As long as they are not subjected to any salt water I guess they will be fine. A sanded and clear coated stainless plate would probably look wicked.
Plates for Cherry or Costar stabilizers, slightly different layouts.
[H=2]Keycaps[/H]
A full set of standard QWERTY keycaps will cover most keys depending on desired layout, probably not all though if you don't already have a hefty private stash.
The "Caps Lock" position requires a 1.25 width keycap.
The left "Shift" requires a 1.00 or 2.00 width keycap.
The right "Shift" requires a 2.00 width keycap.
Other than that you may only need an extra 1.00 width keycap for the "zxcv"-row, and up to 3 extra for the "1234"-row, depending on the chosen layout.
The "Return" key can be either a ANSI, ISO, or a custom 1,25 width keycap.
[H=2]Layouts[/H]
This part really is up to anyone to design on their own, but here are some ideas. The ISO and ANSI version have the Filco type space bar row. The three 2x wide keys in the bottom row of the SYM layout can be replaced with one 6x wide space bar. In general all non-overlapping options can be combined any way desired (for example the ANSI enter with the ISO left Shift). All 2x wide keys on the numpad can be replaced with two 1x wide keys. The gap in the home row have two different options like in the layout suggestions.
[H=2]Quirks with the 2001-05-17 revision[/H]
The Filco case has three pegs holding the PCB in place. I got the middle one dead on, the other two need some modification for the PCB to fit. I tried doing it by machine but I got the best result just filing by hand.
The Filco case bottom has some plastic ridges the PCB rests upon. In some locations the PCB mounted stabilizers interfere with them. The "Spacebar"-row is the biggest problem. There the PCB rest directly on the case bottom, which cannot be easily chiseled away. Plate mounting solves this of course. Some diode pads also interfere with the ridges. This can be solved either by modifying the ridges or surface mounting the diodes.
This is the messy area... The stabilizer holes and switch center holes of the ANSI and ISO return interfere with each other. Drilling holes will work well only for one of the setups. The optional 1.25x wide return is compatible with both ISO and ANSI return since it requires no stabilizer. Plate mounted stabilizers if course do not require drilled holes. I put 1mm holes in the board for easy centering when drilling.
This is the same drilled for an ISO return setup.
Both the left and right "Control" switch locations do not have drilled center holes. They need to be drilled in the desired location. There are centering holes provided.
On to the only real design issues. See that diode location. It is needed for both placements of the right shift key, the stabilizer interferes in both cases. This is not quite as bad as it may look. There is plenty of room for the diode to be mounted on the back of the board. With Costar stabilizers this also is not an issue, since they leave plenty of room down to the PCB.
More stabilizer interferences. That pad is for mounting a resistor (yeah I know that is a diode, but it's for illustrative purposes) in series with that diode in put into the left shift key. This solution works albeit a bit tedious.
This however is not a problem at all. Those two diodes aren't used in conjecture with the double height '+' and 'enter'-keys.
[H=2]Pictures and Videos[/H]
A board of blue switches. I had put high force gray switch springs into them just to try it. That was insane... so I did a no solder spring swap back to blue spring, on most switches. I totally didn't think of this when I de-soldered them to put the plate in. It was a quite easy task identifying the stiff ones though. Counted them all up and decided I had them sorted out. Re-soldered everything with the plate in between. Then it hit me I probably had put a black spring into the spacebar... So there is a switch somewhere with a black spring within =)
Some close-ups.
Another brown/clear board in the ISO layout.
A higher res desktop shot of the symmetric layout board. All keys will have legends when I get the next batch of keycaps from SP.
A really crappy video showing the costar stabilizers in action.
[video=vimeo;26059753]http://vimeo.com/26059753[/video]
And finally, an almost as crappy video of the board in action. Showing the firmware working fine.
[video=vimeo;26059879]http://vimeo.com/26059879[/video]
A brand new release from Bathroom Epiphanies Inc!! Due to public demand we proudly present:
The Symmetric Tenkeyless =)[/SIZE]
Pretty on the outside
Not so pretty on the inside...
