[Help] Modifying a typewriter into a computer keyboard

[tinco]

I bought an IBM ActionWriter at a thrift shop because the keyboard is just awesome. I took it apart and the keyboard just begs to be modded into a case.







I've researched a bit, and it seems that I need some sort of a controller. There's 2 bands of wires going out of the PCB. One has 13 wires, the other has 8.

From this topic http://geekhack.org/index.php?topic=29483.0 I learned that it can be achieved by soldering the wires to an Atmel and then use https://github.com/tmk/tmk_keyboard to program the atmel to make sense of the input and put it on a USB bus somehow.

That sounds like a plan, but I'm not sure on any of the details yet. If anyone has any extra information, pointers or advice I'd be very glad to hear it.

edit: Just found this, the schema looks super simple: http://mg8.org/rump/. It does mention that it "wouldn't pass a USB specification test", but it seems like that doesn't matter much for this purpose. Anyone have experience with this controller?

[Findecanor]

That sounds like a plan. The biggest difficult seems to be to decipher the matrix. Doing that by hand with a multimeter would take some time. When you have the matrix, you have to write support for your keyboard in your firmware.
It is important that you enable blocking in the firmware (#define MATRIX_HAS_GHOST), or you will get ghosting. No Model M series keyboard has diodes in the matrix.

Do save the plastic top of the typewriter for "plastic surgery" later, if you opt for that.

[tinco]

Could I just first select one of the standard IBM schemas, and then use keypresses to find out what the actual matrix layout is?

Also a noob question: Do I need a separate device to flash the Atmega? what would you recommend?

[dorkvader]

If you need, I have pictures of the membranes from when I boltmodded my wheelwriter

[tinco]

That would be great

[dorkvader]

grr, looks like they used different membranes for the actionwriters, so (sadly) there's a good chance that this is completely different from yours, but here's some of the many pictures I took of my wheelwriter KB when I boltmodded it. As you can see, they only changed the barrel frame between most of the wheelwriter revisions.


edit:album of my wheelwriter bolt mod photos
http://imgur.com/a/FOu89

[tinco]

Thanks!

I learn from this that they use all the space under the black plastic for the membranes. Mine has quite a bit of excess on the left side, but from your images I gather I can't just saw the left side off.

p.s.: I just realized there's a separate board for geekhack projects, if this thread would fit better there, then please do move it