Not being one to shy away from a challenge, I decided to make my own
keyboard hack to use on my
crapmame.
I've never done one before so everything I knew about them was from reading
other people's experiences and write ups, and I've written enough about them
so it was time to walk the walk rather than talk the talk.
Now don't get me wrong, they are not without their problems and if
I was building a new cab for myself I would use an
I-Pac,
but for its limited use in my crapmame running a DOS MAME cab it
would be fine and should be fit for purpose.
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click for full size image |
The keyboard I used was an old Fujitsu Siemens one with a PS/2
connector which worked out really well to be honest. Once I'd
opened it up you can see the controller board and where it comes
into contact with the 2 overlays that make up the inside workings.
The nice small controller makes it ideal for a
keyboard hack for those with a steady soldering hand. |
The 2 overlays really made the
job much easier as it meant I didn't have to try each combination
of inputs on the controller to work out which combo resulted in
which key press. I simply worked out which keys I would need to
run my cab and marked them out on the overlays with a permanent
marker before removing and carefully separating them.
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Once separated I
marked the bottom one up the same as the first so all my required
keys were marked out, then I numbered each trace on the overlays
and controller from 1 to 26, the top overlay from 1 to 8 and the
botom one from 9 to 26, then came the laborious task of tracing
each one back to the controller
interface to see where it went.
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I traced each one back on the top overlay and then each one on the bottom
overlay so that every button I needed now had two numbers associated with
it, one between 1 and 8 and one between 9 and 26.
These sets of numbers I then added into a
spreadsheet so
I could easily see how many contacts I would need to solder onto the board. |
As you can see from the spreadsheet I didn't need every contact from 1
to 26 but some I needed more than once so to make things easier I would
connect
them to a block connector, and any that were needed four times or more I duplicated in the block connector
which meant I needed a total of 24 connections. Here you can see how I've
numbered the block connector points and how I have duplicated
some of them with a simple link.
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Here is the finished article with every necessary contact on the controller
connected to a point on the block connectors, and
here
it is in my crapmame ready to be hooked up to each button and joystick which
just means looking at the spreadsheet to see which two connector points each
control should be connected to, so for example the Player 1 Fire 2 button
should be connected to 5 and 13. |
Now came the laborious, and sometimes fiddly task of connecting all the
controls to the necessary connector block while trying
not to disturb the ones already done. It won't win any awards
for beauty but it is most certainly functional, and cheap too. |
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Here it is in all its glory.
click for full size image
