[Coco] Convert Passive Matrix Keyboard to USB...

[Frank Swygert]

Date: Sat, 30 Mar 2013 13:35:45 -0500
From: Allen Huffman<alsplace at pobox.com>

On Mar 30, 2013, at 10:38 AM, Frank Swygert<farna at amc-mag.com>  wrote:

Found this searching for some Raspberry PI projects on Instructables. The keyboard part sounds like it will work with a CoCo keyboard.  Uses a Teensy++ 2.0 microcontroller<http://www.pjrc.com/teensy/index.html>  for the keyboard interface.
-------------------------------------------------

And yes, this is exactly the same thing I am doing for the CoCo keyboard. The Teensy 2.0 has enough I/O pins that it can be done simply by running the keyboard matrix wires to I/O pins on the Teensy and writing a bit of code to handle translating the matrix to USB keyboard codes. Very cool.

John Strong sent me a few PCBs he made that will plug in to the CoCo keyboard connectors and then let me solder in wires, which is good for an experiment, but I will have to find something more off-the-shelf so others can build them (or I can make them for them) easier.
==========================================================

When I made a remote keyboard cable for my CoCo repack I just used a straight header connector. Instead of soldering onto a board I soldered a ribbon cable directly to the pins. The pins push nicely into the CoCo keyboard connector. If there is room in the CoCo case over the connector (I forget!!) you could mount a Teensy on a small PCB with a header on the bottom and plug directly in. Might need some sort of additional support, but a piece of styrofoam glued to the board would work fine.

-- 
Frank Swygert
Editor - American Motors Cars Magazine
www.amc-mag.com