Custom 40% Model F Keyboard Is 100% Awesome

Look closely at this beauty. No, that’s not a chopped IBM Model M or anything — it’s a custom 40% capacitive buckling spring keyboard with an ortholinear layout made by [durken]. Makes it easy to imagine an alternate reality where IBM still exists as IBM and has strong keyboard game, or one where Unicomp are making dreams come true for those who don’t need anywhere near 101 or 104 keys.

Buckling what now? This lovely board uses capacitive buckling spring switches from an old IBM Model F. Basically, every time you press a key, a little spring is bent over (or buckled) in the name of connectivity. In the capacitive version, the spring pushes a hammer onto a pair of plates, causing a change in capacitance that gets recognized as a key press. In this case, those key presses are read by a TH-XWhatsit controller.

Using a Model F XT’s PCB as a guide, [durken] made a field of capacitive pads on one PCB, and made a second, ground plane PCB to avoid interference. In a true homage to these keyboards, [durken] decided to curve the PCB slightly, which naturally complicated almost everything, especially the barrel plate.

The solution was to make a separate barrel plate that slides into the case and gets screwed to the top via mounting bracket. For an extra bit of fun, [durken] mounted an SKCL lock switch under the IBM logo which enables solenoid mode. Be sure to check that out in the (updated!) video after the break.

One of the best things about a buckling spring keyboard is that each key sounds slightly different. Not so in solenoid mode, unless you were to use multiple solenoids.

41 thoughts on “Custom 40% Model F Keyboard Is 100% Awesome

  1. > One of the best things about a buckling spring keyboard is that each key sounds slightly different.

    I’m sure the household assistant recording your keystrokes and working out your password from them is duly appreciative of this.

      1. I’d say that the Venn diagram for HOUSEHOLDS that have both Model M keyboards and audio cloud-based assistants has considerably more overlap.

        In the 1980s, we were not allowed to use electric typewriters to prepare classified documents, because it had been shown that the power line transients produced by each key on a given machine were unique and discernible. I once asked if the audio signature of a mechanical typewriter couldn’t be similarly analyzed, but was told to shut the f up, unless I wanted us to be restricted to longhand. And of course, if you DID write anything classified on a pad of paper, you had to burn the rest of the pad. Which just led me to wonder why we could write documents on soft linoleum-topped desks, but at that point I knew better than to ask. As it was, typewriter ribbons (even fabric ones that got reused for months) had to be treated as classified documents, which meant locking them up in a safe whenever you left the office, and burning them for disposal. I got a chuckle out of Richard Feynman’s book, in which he describes how in the Manhattan Project days he would go into other people’s offices and crack their safes, leaving them open and causing widespread panic. Which SHOULD have convinced the security people that these safes were ridiculously NOT, but we were still using the same ones thirty years later.

        1. Some models of IBM Selectric could be converted into a keyboard and printer for a computer by installing 5 or 6 switches for the levers that controlled the ball to hit. Running wires out from the control solenoids were used to operate it as a printer. The same switch trick could be used to bug the typewriter, sending every keystroke out via a wire or radio with a hidden transmitter. It was an article in the 1980’s on spying technology where I first read about that. It was mentioned the CIA regularly inspected all their Selectrics for such additions.

          That would have been of more concern than measuring the power line transients. Powerline noise should have been slightly different for each typewriter. With enough difference someone would have to first test each typewriter to record the changes for each key.

          A whole bunch of typewriters used together on the same electric circuit would make unreadable noise. Each one would require a decoder and transmitter at or in the outlet it was plugged into, or added inside the typewriter. A tap at a breaker panel wouldn’t be able to sort it out.

          A good defense against electric transient decoding would be a big inductor-capacitor filter where the line cord connected to the power supply. No interference in, no noise out.

          One very 1980’s possibility for electric data exfiltration could be X-10 hacking. Modify some outlets with built in X-10 to look like normal ones to covertly (and slowly, given the limitations of the era) send out data via the electric wiring. These days it could be done at up to 54 megabits per second, plenty good enough to hide a microphone inside the ground pin hole and stream audio out.

          I have a powerline data gizmo with two modules to connect two computers to a router. Could use more modules if I wanted. I haven’t used it in a while since WiFi is faster now and I also have 5G internet service that’s faster than 54mbps.

  2. Can anyone explain the appeal of minimalist keyboards to me?

    I must admit, I don’t use the numeric keypad very often although once every 2, 3 years or so it does come in handy when I have something that is mostly numbers to type. Left of that though, well.. printscreen, scroll lock and break are probably the only keys I don’t use much of. And what I wouldn’t give for a dedicated compose key! I guess if I had one then I wouldn’t use the menu button much, which I have mapped to compose. I don’t like the menu button’s position though, I think I would like to hack a single regular-sized key width off the left side of the spacebar and put compose between the left alt and space. Or maybe cut the spacebar a bit more and put it on both sides.

    But yeah, these keyboards that are pretty much just alphanumeric.. No way! Do you have some sort of multi-keypress tricks to get to the functions of those missing keys? How is that an advantage? I just don’t get it.

    Where I would think maybe those would make sense is the non-techie, just uses a computer for social media crowd. But it’s usually programmers, hackers and makers that I see with the cut down keyboards.

    What am I missing?

    1. yeah they use chording for extra keys. there’s usually a ‘fn’ key somewhere that accesses the second (or third!) function for each key. i don’t like it either. TKL (no number pad) makes a lot of sense to me. and i can usually get by pretty well with the kind of compromises they make in laptop keyboards (though i always miss page up / down, and appreciate home/end/ins/del too). but this thing doesn’t even have number keys. it seems so pointless. just a lot of learning new habits for a one-off keyboard you’ll never see anywhere else.

      and i’m saying that from the perspective of someone who has switched back and forth between colemak and dvorak a half dozen times just for the novelty.

    2. Sun Microsystems keyboards have a dedicated Compose key. And an extra set of 10 other dedicated keys for cut, copy, paste, undo, redo etc. Search out a Sun Type 7 USB one and make sure the backspace and \ keys are where you expect them (there are traditional Sun non-PC variants). As-new examples are still available (as are worn out and yellowing examples!). I use mine under Kubuntu; Compose just worked once I had chosen a Sun keyboard layout but I had to assign Cut, Copy etc functions to the dedicated keys.

    3. I don’t mind loosing the numpad, as at least for me everything that is on it can be reached from the touch typing home keys very comfortably – so naturally its what I do. But loosing the Home/End Page up and down etc keys noo thanks highly useful keys. Loosing the Function row again wouldn’t mind as its not like shifting the numbers (or one of the rows) to being the FN keys isn’t too bad.

      That said with some decent num-lock type latching or shift keys to shift layer I can see a keyboard like this being very much more convient and useful than a regular after a little learning – every time you want the printscn and beyond parts of the keyboard its take your hands off the default typing position you need for 99% of your keyboard interactions – so putting those functions in an easy and seamless to reach place seems like a winner.

      1. Did the early IBM PC keyboards have a number pad? The generation with the function keys at the side. I’m suddenly.oicturing a keyboard that wasn’t as wide.

        1. Some of the early IBM terminal keyboards certainly did have function keys down the sides, and more than one row across the top with a numberpad and an extra key in the arrow cluster to make it a + shape too (I have one of these ones, and it was for some time my default keyboard running via USB, for ages even, but seems the teensy I was using for scancode-usb HID conversion has let out the magic smoke – not had a chance to really look at it, may be more or less terminal a failure than that).

          But there were many models of their keyboards, some of which didn’t have numberpads or function keys at all even in the ‘early’ days…

    4. In addition to the possibility of chording, if you mainly use a window manager and Vim (maybe EMacs too? never used it myself) then you don’t really need more keys as window managers (for the most part) and Vim are designed for low finger travels and work great with 40% keyboards. Once one gets used to the setup, these setups can have much faster and intuitive workflows than a large keyboard + mouse.

      I think the only time I’ve used a function key on my current Linux setup is for model refresh (F5) on programmatic CAD, and if I had a 40% a remap to FN+something would be easy.

    5. For me, it’s about touch typing. I hate-hate-HATE having to look at the keyboard, just to find a key, or having to move my hands from their home positions. I would much rather press two keys than break my connection with the keyboard. This also, by the way, is the ONE excuse for the Trackpoint mouse ever to have existed.

      1. Hey i like the trackpoint, its way better than touchpads tend to be, though they are getting better by default slowly…

        Neither match a trackball or normal mouse though.

    6. It amazes me they get made without burning the house down or any other mishaps because I tend to make the assumption that people who want 40% keebs are intellectually deficient. /s Since they had to spend their own time realizing them I think the sunk cost fallacy basically forces them to keep singing their praises for about 3 years until they are psychologically able to admit they are wrong.

    7. It boils down to a simple principle: move the keys to your hands instead of moving your hands to the keys.
      With some smart layer functionality all the keys of a full sized keyboard is available on a much smaller keyboard.

      For example: the key where I rest my left thumb works as space when tapped, but when I hold it down it activates my numbers layer and I get a numpad under my right hand (456 where jkł is normally) and basic operators under my left home row (+, -, *, /) which means I can input simple calculations with barely moving my fingers from the home row. They key where I rest my right thumb is backspace when tapped and activates a symbol layer when held. F and J are the letters when tapped and Ctrl when held. You get the idea.

      I understand it can seem unusable on a daily basis whith so many keys “missing” but I assure you it’s not :)

    8. I want a cross between a Monterey K104 and a Focus KeyPro FK-9000. From the Monterey take the “Big Three” keys, reverse L Enter, big Backspace, and big right Shift. Put the backslash where it belongs between right Alt and Ctrl. *No useless menu key!* Both of these keyboards have a blank do-nothing key between the left Ctrl and Alt. Make that the WinKey.

      The FK-9000 has two sets of 12 function keys. The AT and later style across the top in three groups of four. At the left end are two columns of six *programmable* function keys. That’s built into the keyboard, no need for software. That’s where the FK-9000 differs from the “Big Three” layout. The right end of right Shift got cut off to make room for backslash and where backslash should be was made the Prog key for programming PF1~PF12. But since I’ve always struck the left end of right Shift that’s not a big problem. What is a problem is I’ve always hit the left end of Backspace and the upper leg of Enter. Along with the left end of right Shift are the usual places any keyboard made since the 1995 introduction of Windows Keys has backslash moved to.

      The FK-9000 also has a built in calculator. The KB/CALC key toggles the numpad between numpad and calculator mode. Unfortunately the calc can’t send what’s on its display to the computer. Then there’s the 8-way cursor keys surrounding a Turbo button. It has a NiCd battery that charges from keyboard power and is used to keep the PF key macros and calculator memory. Lastly, it has a tiltable frame to hold function key note cards with legends in black, blue, red, and green. That RGB matches the color of the labels on Ctrl, Shift, and Alt to do different things with the F keys, black being their defaults. Highly useful for Word, Word Perfect, Excel, Lotus 123 etc.

      A modernized FK-9000 should have all that, with the backslash relocated and Prog moved somewhere out of the way. Replace the card holder with a long LCD or OLED, possibly a touch screen. Replace the simple calculator LCD with an OLED that can show more stuff, and give the calculator the ability to send and receive to and from the computer. All in the keyboard PF macro programming should remain plus it should have the ability to program everything from a computer its connected to with USB. It should also be possible to program F key and PF key info into the top display using the keyboard alone. I’d put a USB port on it to store configurations so that it would be backed up and easy to copy a setup directly to other keyboards.

      I started PC use with a “Big Three” keyboard (probably a Monterey) and all these years later it still feels absolutely perfect for me. Pissed me off ever since that Microsoft essentially pointed to my fave keyb design and ordered its execution, when all they had to do was nip an extra bit more off the spacebar to leave room for backslash right were it was. Right WinKey and Menu should have been crammed in between right Alt and the space bar.

      Currently there’s no #$^^@#^ing reason to not bring back “Big Three” since many recent keyboards, especially on laptops, don’t even have the Right WinKey and Menu.

    1. a bit of both. the grid is easier to navigate subconsciously than anything else. it’s like looking at a spreadsheet in the mind. The 15 column design seems to be increasing in popularity among veterans because the numpad mapped in the middle allows hand separation.

        1. I use an ortho keyboard and like it. I am typing this on a diy 3d printed teensy 2.0 based olkb preonic clone, which i have been using for two years. I am a slow typist having never properly learned due to not working in IT. My use case is merely surfing the net from bed so the need to type is minimal. It is paired with a trackball to reduce wrist pain and to remove the need to use a mousepad in bed.

      1. My brain has never worked fast enough that typing is the bottleneck of my workflow… But putting the number pad in the middle if the keyboard is brilliant! Ambidextrous, and as you say, separates the two hands nicely. Thanks for the tip!

    2. Ortho is more ergonomic for the left hand, thought it’s kind-of a middle ground between regular staggered rows and split keyboards. It’s not really easier to construct. PCB fabs don’t care about offsetting button through-holes/pads (in most cases) or capacitive footprints (in this case), it’s all Gerbers to them, and (reasonably-designed) keyboard PCBs don’t have any tight tolerances.

    3. There’s a third reason, which is for a more compact layout, minimizing the footprint of a keyboard. Since it takes practically zero time to get used to an ortho keyboard, why are we still stuck with a key arrangement that itself was a concession to constructability? The whole reason for the offsets was so that the key bars would be evenly spaced in mechanical typewriters. But it’s like the silly 1.27mm offset of that connector on the Arduino – we’re stuck with it just because it’s always been that way.

      1. I tried so hard to love an nice ortho keyboard. After a week of typing non stop gibberish, the novelty quickly wore off and I returned the keyboard. Just couldn’t break 30 years of muscle memory. I was sad. I never had any repetitive injuries or anything from a “normal” keyboard anyway though.

  3. OK I’m going to date myself here as ancient, but the IBM selectric is by far the best keyboard ever made – too bad no one has built a keyboard with that kind of feel – it was silky smooth and very easy on the hands – which you can’t say about any contemporary computer keyboard since the PC revolution in the 80’s – they all suck – even IBM’s old spring loaded ones from their PCs.

    1. There’s no technical reason one can’t be made, but I think one issue is that the Selectric keyboard mechanism requires a lot of space. I loved the feel of the Selectric keyboard too, but I can’t use a keyboard that would be so high.

    2. I worked on the Selectric in the 70’s. The “keyboard feel” was somewhat adjustable. The techs adjusted them to be as light as possible without “flicking” — a condition where the machine would cycle, without selecting a character. Depending on the era of manufacture, a hyphen was usually printed. A keystroke would push an interposer with notches encoding the character and then trip a cycle. Set the last part too easy and flicking would occur, so we couldn’t go any further. If they complained about hyphens, i would have to adjust the cycle latch for a little more bite. They would then complain that I ruined the feel – which I did.

      A lot of secretaries would place a service just to have their keyboard adjusted every few months. After checking for flicking, I would insert a screw driver into the rear vent of the machine, asking them type type as I twisted an imaginary adjustment screw. When the said “that’s it”, I’d withdraw the screw driver and be one my way.

      The Selectric was a great example of you a mechanical monster could feel so good to operate and give great results. Everything was adjustable.

    1. The radius of the barrel plate is 375 mm which should be fairly close to that of the Model F. I can see why you would say that though, since this keyboard only has four rows the curvature is not as obvious as on the originals. Imagine this without the numrow:

      That being said, this is designed by me as a hobbyist and printed at home, obviously it won’t be comparable to the real IBM boards, you should view it more as a tribute.

      I hope that answers your question :)

  4. The radius of the barrel plate is 375 mm which should be fairly close to that of the Model F. I can see why you would say that though, since this keyboard only has four rows the curvature is not as obvious as on the originals. Imagine this without the numrow:

    That being said, this is designed by me as a hobbyist and printed at home, obviously it won’t be comparable to the real IBM boards, you should view it more as a tribute.

    I hope that answers your question :)

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