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Thread: Universal Retro Keyboard project

  1. #1
    Join Date
    Dec 2011
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    Default Universal Retro Keyboard project

    I have been working on a pet project in my (rare) spare time over the past few months, and figured it's a good time to share it. I would like to create a family of keyboard matrices and interfaces that can snap together and drop in place for various vintage computers.

    Sometimes original keyboards for old computers are hard to come by. Interfacing a USB or PS/2 keyboard is just not the same experience as the real thing.

    To start, I have put together a keyboard matrix and that will mechanically drop right into an Apple II or OSI system, and can also be populated with additional keys to produce a fuller version of a classic ASCII keyboard, based on the ADM-3A layout.

    So far, I have working ASCII controller board with Apple I and Apple II compatible interfaces, plus an optional serial port. I also have an OSI-compatible interface designed but not yet fabricated.

    The key scanning controller firmware is mostly platform independent, with all the controller-specific code in a single platform specific module. That means features can be added and tested and then will work on all platforms. As of now, the key scanner implements parallel ASCII output. Creating specialized interfaces such as DEC VT100 and WYSE protocols would just entail modifying the controller PCB to be electrically compatible (in case of DEC), adding the I/O routines in the platform-specific module, and filling in the right codes in the key maps.

    Some features:

    • Mix and match keyboards and controllers. For example, a SOL-20 keyboard layout can be used with the ASCII controller.
    • The keyboard matrix supports Cherry MX and compatible keys, or Futaba MD-4PCS (George Risk KBM-01-01) keys
    • Multiple keymaps supported. Right now these are selected by modifier keys, but DIP switches or special control sequences can also be used. So, for example, supporting APL or special character sets is trivial.
    • Auto repeat (which can be enabled or disabled), and repeat key
    • True N-key rollover
    • Simultaneous software debouncing on every key
    • DIP switches, if desired, can be supported by hooking into the key matrix, so no special DIP switch code is required, and no extra I/O is needed.


    I still need to extend either the stabilizers or the main keyboard PCB to permit mounting on Apple and OSI systems. I also need to make 3D models for a spacebar stabilizer for the futaba keys.

    I am looking for what features might be desirable to make a truly universal keyboard for retrocomputers (including vintage machines, reproductions, and retro-themed modern creations). Also, any suggestions for the keyboard layout, and specific keycaps would be welcome. For example, for the Apple II, is it important to have the "Bel - G" and "^ - N" keycaps instead of regular "G" and "N" keyscaps?

    All the hardware and software will be up on GitHub, once it's reasonably stable. That way, anyone can play with it on their own schedule.

    Any and all suggestions welcome. The goal is for nobody to have to go without a perfectly matched keyboard for their favorite machine.

    Dave
    Last edited by dfnr2; December 7th, 2019 at 01:01 PM.

  2. #2
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    Default

    Here are some (slightly earlier) PCB's for the keyboard, including stabilizers for the futaba (George Risk) keys and for MX keys. The stabilizers are pretty much necessary for the futaba keys and MX compatible keys without posts, and do add some rigidity even for MX keys with posts.
    boards.jpg


    This photo shows an MX Red key with posts, a Futaba key, and an MX brown key without posts:
    switch-types.jpg

    The keyboard layout. I'm aware that the lamp is on the wrong position for the Apple II. It has been moved in a newer rev. I still need to fix the size of the cutout to match the original plastic cover.
    loaded.jpg

    ASCII interface board with Apple 1 and Apple 2 connectors. (the 74154 will be replaced with a pair of more readily sourced 74LS138's, and a serial connector will be added.)
    ascii_adapter.jpg

    The working keyboard, connected to a Replica I via the Apple 2 connector. The interface board is mounted underneath the right side of the keyboard:
    keyboard_test.jpg
    Last edited by dfnr2; December 7th, 2019 at 12:52 PM.

  3. #3

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    Nicely done!

    g.
    Proud owner of 80-0007
    http://www.f15sim.com - The only one of its kind.

  4. #4
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    Default

    Thanks! I have put the project up on GitHub, if anyone cares to check it out.

    https://github.com/osiweb/unified_retro_keyboard

  5. #5
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    Default

    Do you have an estimate on selling price?

  6. #6
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    The PCBs and firmware are open and hosted on GitHub (but I'd wait a bit until I have a chance to test the latest hardware revs). Anyone can order the parts themselves, but I will have some kits of PCBs and keycaps for convenience.

    I've been ordering PCBs from JLCPCB, and the whole set of PCBs and aligners (in qty of 5) with shipping to US is about $90, so that's less than $20 per set.

    Cherry keys run about $1/key, but clones can be had cheaper so perhaps $30-60 for the keys, depending on your taste. The keys caps are about $50-60 in quantities of 20, but there's a bigger price break at $100. If I thought more than 40 people might be interested, I'd just order 100.

    So, it could be possible for the whole thing to be under $100, possibly even in the $70-80 range.

    I'm also working on a SOL-20 compatible version of the keyboard that would probably be about $40-50 more for the keycaps.

  7. #7
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    do you have a square hole bench punch, or is there some place that will do short run stiffener plates?

  8. #8
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    The aligners that you see in the above photos also serve as fairly effective stiffeners, and seem to work well enough. They are just FR4 fiberglass PCB substrate without any traces, ordered from the PCB manufacturer, and work out to less than $4 each (not including shipping, which is about another $4 per piece) in small quantities.

    If the keyboards are not stiff enough, I can add some extra holes along the top and bottom of the keyboard and aligner, to use aluminum (or even wood) bars as spacers. Those could be drilled by CNC or with a drill press. But I'm trying to keep things as simple and inexpensive as possible at first.

    I welcome any and all suggestions.

  9. #9
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    May 2018
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    Melbourne, Australia
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    Default

    So at this point you are not getting any custom keycaps made that much the legends and colours of vintage keys but you are leveraging keys that have already been created for the (modern) keyboard builder/enthusiast market?

  10. #10
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    The keycaps in the photo are custom ordered for the OSI keyboard, with a few extra keys in anticipation of a more generic ASCII keyboard.

    When I finally got around to doing the ASCII encoder, I did add a couple of extra keys. So, the next order will include the keys you see in the photo, but in a medium-dark gray, plus a couple of extra keys unique to the Apple II and OSI, to leverage the volumes. And of course, anyone can mix and match as desired.

    If you want to configure the keyboard with a Selectric-style key map, then you could get one of the enthusiast key sets out there, or cannibalize an old Cherry MX keyboard.

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