C128D keyboard modification

[MIRKOSOFT]

Hi!


Look at picture in attachment...
is possible to create that modification?


Thanks for comments.


Miro

[BigDumbDinosaur]

Which modification?

[MIRKOSOFT]

Please look at picture in attachment.


Thanks.


Miro

[Steve Gray]

So, lets see...

* top row... moving function keys and special keys.... some are "lock" keys that protrude through the circuit board...

* move the entire keypad down to add an extra row, reducing the wrist-rest area.. lots of plastic work needed.

* major shifting of SHIFT,CONTROL, ESC, RUNSTOP, CAPS LOCK, C= keys etc... lots of rewiring of the circuit board plus moving keys where none exist (and likely where circuit traces are)... major work

* separate cursor keys... possible with additional chip (like the C65 does)

Overall.. extremely hard, but then not impossible. The main problem is that the keyboard matrix is optimized for the normal placement of each key, so moving them is not trivial, plus each key is not soldered on separately but integrated with the plastic.

Steve

[Steve Gray]

  I've been doing some thinking about this recently. I guess the questions are... how much work do you want to do? Do you want it to look like an "authentic" C128 keyboard, or are you just looking for something that works?

  One option would be to use a standard PC keyboard and a converter circuit, like the "C=key" from Jim Brain. Perhaps there is a way without needing any electronics?...

  I thought about what would be the best layout for the C128 (and C64) and it occurs to me that the standard PC keyboard layout is pretty efficient. I have been opening up some of my keyboards to look at them (both Commodore and PC ones). Today's keyboards are much different than the typical commodore keyboard. In fact commodore keyboards have quite the variety themselves.

  Most modern keyboards use a membrane consisting of two sheets with traces (much like a circuit board) and pads separated by a third sheet with holes. When you press on a key the rubber part presses down on the top sheet, through the hole in the middle sheet and makes contact with the bottom sheet completing the circuit. I am wondering if it would be possible to modify these sheets to "re-wire" the keyboard matrix to be compatible with commodore machines? You can buy silver contact pens that let you draw conductive traces. Perhaps that might be easier than hacking up your Commodore 128 keyboard?

  I have a bunch of SX-64s with missing keyboards. If I could find some cheap PC keyboards that could be modified easily/cheaply they would be much more useful ;-)

It would also be possible to wire up the numeric keypad or make 8 separate function keys etc.

SX-64 and C128D keyboards are in demand.

Thoughts?

Steve

[MIRKOSOFT]

Hi Steve!


It's only layout modification. Not hardware, but I'll look at Jim Brain's webpage, thank you very much.


Miro

[Hydrophilic]

Interesting idea.  I'd also like to point out it is not clear which keys, if any, would activate CRSR left/right and CRSR up/down.  Some programs depend on these specific keys. 

Also the left-arrow symbol (normally at the top left where you placed ESC) has been mapped to a SHIFT function of the number 0.  Again some programs check specifically for that key.  If the user presses Shift-0 this will, at least momemtarily, send SHIFT key in addition to left-arrow key.  This can cause problems if the software also does special things when SHIFT is pressed.  Several flight simulator games would have this problem for sure.

Also, maybe I missed it, but I didn't see RUN/STOP.  That is a very important key!

Like Steve said, it is possible but would require considerable effort.  And then you would still have software problems.

I had an idea.  You have two sets of cursor keys.  Leave the one at bottom as it is.  The ones at top could be left-arrow, CRSR left/right, CRSR up/down, and RUN/STOP.

[bacon]

I am wondering if it would be possible to modify these sheets to "re-wire" the keyboard matrix to be compatible with commodore machines? You can buy silver contact pens that let you draw conductive traces. Perhaps that might be easier than hacking up your Commodore 128 keyboard?

I tried this a few years ago. It doesn't work; the "ink" won't stick to the sheets.

[Steve Gray]

I am wondering if it would be possible to modify these sheets to "re-wire" the keyboard matrix to be compatible with commodore machines? You can buy silver contact pens that let you draw conductive traces. Perhaps that might be easier than hacking up your Commodore 128 keyboard?

I tried this a few years ago. It doesn't work; the "ink" won't stick to the sheets.

What about trying the silver tape used for duct work. Cut it into thin strips. Should be flat and conductive and fairly cheap...

Steve