Re: Keyboard conversion project? IIGS portable ideas

[et472@FreeNet.Carleton.CA (Michael Black)]

Michael J. Mahon (mjmahon@aol.com) writes:
> In article <a2c2f792.0303250857.4227f8d8@posting.google.com>, jon@i-manila.com
> (Jon Co) writes:
> 
>>Just came by a computer-junk shop and found a pile of laptop
>>keyboards.  under the pile was 2 //c+ keyboards but some of the keys
>>are missing.  I think a //c+ keyboard will make a good base for the
>>//e connector, just have to get the correct wires from the matrix into
>>the right pins.
> 
> I'd be surprised if the //c+ keyboard was the same matrix as
> the //e.  Keyboards tend to be unique--look at the "funny" key
> placement for hints.  And, of course, there are many possible
> matrix wiring diagrams for each geometrical layout.
> 
> -michael
> 
I once added an external, and better, keyboard to my Radio Shack
Color Computer.  But that was in the days when there were plenty of
surplus keyboards, in various states of assembly.  I found one
at the local surplus store that just had keyswitches (and their keytops)
mounted on a piece of metal.  I merely had to wire it up myself to
get it to work, which meant that I could wire it to the same matrix
layout as the original.

Another level might be doable, but more complicated.  Something like
the original Mac keyboard used the same sort of keyswitches, though
from memory I think the switches were merely mounted on a piece
of circuit board.  To work those, you'd have to either create a new
piece of circuit board, to mount the keyswitches, or cut all
the traces and then wire up the keyswitches manually, merely using
the circuit board to physically hold the keyswitches.  How difficult
that might be would depend on whether it was a single or double sided
circuit board.  If the latter, one would have to remove the board from
the keyswitches, and at that point, it likely isn't worth the trouble.

And of course, a lot of more recent keyboards don't have mechanical 
keyswitches, but some scheme where the parts are built up over the
board, and which may not even work unless the proper circuitry is
there.  Forget whether the matrix layout matches; if they operate
on some capacitance method, they won't work with decoders that are
set up for old keyswitch type keyboards.

If the IIC used the same keyboard encoder as the IIe (or some
better integrated clone of it) then likely the matrix would have
to be the same.  But of course, the layout is fairly arbitrary,
and if Apple went to their own decoder, rather than an off the
shelf IC that was used in the original II, then they could set
things for easiest layout or whatever.  

  Michael