Metal Dome Keyboard

I found a tiny keyboard at Apex Electronics in LA.

Similar projects worth following
A while ago, I saw this project: and liked the tiny keyboards jaromir was using. He got those in Czech, so any thoughts of me finding one of these keyboards in real life was out of the question.

Last week, I was poking around Apex Electronics and found the exact same keyboard. The connections in the matrix were dead, so I figured I'd tear it apart. It's actually pretty interesting as far as keyboards go - doubleshot keycaps and a weird metal dome switch I've never seen before.

I'm turning this keyboard into something useful.

  • I keep running into this keyboard

    Benchoff12/14/2014 at 02:26 1 comment

    The only reason I dug these keyboards out of a box at Apex electronics is because I've seen them before in another project here on {Jaromir] found a few of these keyboards salvaged from old Czech equipment, I somehow found them in LA, and now we have another exemplar:

    That's an Ondra, a 'student/school' computer produced by the Czech electronics consortium Tesla. Looks kinda familiar, right? There's a link on the wiki that shows the mechanical design of the keyboard is pretty much identical between [Jaromir]'s and mine.

    At the very least, this is interesting. I do actually prefer the key labels from the Ondra - arrow keys, stuff that's properly labeled, and an '@' symbol would make the Ondra's input much more useful than either mine or [Jaromir]'s keyboards.

  • 3D Printed Case

    Benchoff12/01/2014 at 17:19 0 comments

    Next update will be a tutorial for the TMK firmware, then it's done.

  • Designed a case

    Benchoff10/26/2014 at 21:03 0 comments

    Threw together a quick case. The standoffs for the keyboard and USB/Teensy adapter PCB should be reasonably correct, I make no guarantee about the USB through hole.

    Files added to the github.

  • Preparing to add USB

    Benchoff10/26/2014 at 05:42 0 comments

    Since Todd is a great friend to have, I now have in my possession four or five of these keyboards. They work. I've tested one of them with my LED/Matrix piece of crap, and yes, being sealed in a bag is much more conducive to proper storage than sitting in 0% humidity for a few years.

    The ultimate goal for this project is to have a 'front of house' twitter machine for the hackaspace. Now that I have a few of these keyboards, I can start experimenting with them, starting off by converting one of them to USB. I'll be using the TMK firmware and a Teensy 2.0 (since we're adding those to the Hackaday store, anyway). This means most of the work is done, I just need to design a Teensy -> keyboard matrix adapter and modify the firmware.

    Here's the PCB I designed:

    And the corresponding switch to pin diagram/schematic:

    According to the datasheet (translated from Czech by Jaromir), here's the button mapping:

    This can be verified with my matrix tester, and I'll start modifying the firmware later. Just need the boards delivered, and I can start working on the 3D printed or machined enclosure for this thing.

  • A Teardown of a metal dome keyboard

    Benchoff10/26/2014 at 05:27 0 comments

    I'll start off with the money shot. It's a 35-key keyboard, probably originally intended for handheld inventory computers or something else used in an industrial setting. Pretty normal and what you'd expect, but check it out, doubleshot caps.

    Now for the matrix:

    This isn't a mechanical keyboard, and it's not really a rubber dome either. The best way to describe this would be 'metal dome', where a small disc of metal acts as both the spring force in the key and the contact. Very odd.

    Above is the best evidence of where this keyboard came from. It's from AMP Inc., part number (maybe?) 26051. No, that pic isn't mirrored, it's just the text is on the 'inside' of two folded pieces of plastic.

    Here's the progression of how the keyboard was assembled:

    The back was attached by a dozen or so plastic rivets. This makes the keyboard pretty much un-disassemblable. If it's broken, tough luck.

    The broken part of the keyboard. You can already see a few of the traces on the ribbon cable were borked. It's even worse where the ribbon cable attaches to the matrix. I could fix it with glue and conductive ink, but it's seriously not worth my time or trouble.

    Finally, keycaps. Yes, doubleshot. I have yet to do the full-on keyboard science to figure out what they're made of, but my guess would be ABS.

    I might be getting a few more of these keyboards, so I made a matrix tester:

    Just some LEDs and a few resistors. As far as I can tell, this keyboard is pretty much the same asthe Czech keyboard from this project. The matrix seems to be the same, at the very least.

View all 5 project logs

Enjoy this project?



pdrift86 wrote 01/05/2016 at 08:07 point

Looking forward to updates! I'm trying to use a keyboard from a HP Jornada in my project. I have a teensy 2.0 and I’m waiting for the connector I ordered from china. Tried soldering onto the ribbon but it melts too easily so I ordered the fine pitch connector.

  Are you sure? yes | no

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates