Hacking a keyboard - have a few questions

[leapinlew]

I have an old compaq keyboard that I want to use for a driving cabinet that needs about 10 connections. The keyboard has a full sized circuit board in it and looks like this:



I can cross two points behind each letter and pull up that letter in notepad. What I wanted to do is solder on about 20 wires and connect them to a terminal block and wire my switches to the terminal block.

My questions are:

Do you see any problems with this?
What size wire should I use? Can I use maybe network cable, speaker or phone cable?
Am I correct in assuming this isn't a matrix style setup and I shouldn't have problems with ghosting?
I've read up on soldering and never actually done any... will I be able to solder this from the back where the solder points are now? I'm thinking heat it up and stick my wire in?

What I need for buttons are:
gas
brake
shift hi
shift low
turbo
credit
1 player
fire button
quit
and an additional button to exit the front end and shut down the machine

Thanks!

[Tiger-Heli]

I have an old compaq keyboard that I want to use for a driving cabinet that needs about 10 connections. The keyboard has a full sized circuit board in it and looks like this:

Actually, that fullsized circuit board looks like it is just connected to a ribbon-cable to the small circuit board on the right.  You could either solder to the full circuit board, solder to the small circuit board, or you MIGHT be able to cut and strip the ribbon cable and run that to a terminal strip with no soldering required.

I can cross two points behind each letter and pull up that letter in notepad. What I wanted to do is solder on about 20 wires and connect them to a terminal block and wire my switches to the terminal block.

That should work also.

Do you see any problems with this?

You will POSSIBLY have problems with ghosting and or blocking.  However, keep in mind that these problems will only occur when three inputs are pressed simultaneously.  Looking at your chart, you could have problems with shift, gas or brake, and turbo being pressed simultaneously, but with only ten inputs it's unlikely.

What size wire should I use? Can I use maybe network cable, speaker or phone cable?

You are dealing with low current and voltage, so wire gauge isn't an issue, you should base your decision on what gauge wire you are comfortable soldering with.  I suck at soldering, so I can't answer that.

Am I correct in assuming this isn't a matrix style setup and I shouldn't have problems with ghosting?

No, that would most likely be an incorrect assumption.

I've read up on soldering and never actually done any... will I be able to solder this from the back where the solder points are now? I'm thinking heat it up and stick my wire in?

Sounds right, but see my comments above.

BTW, see http://www.mameworld.net/emuadvice/keyhack2.html for more info (shameless plug).

[Zakk]

Just get one of groovygamegear's  little encoders if you're willing to do the soldering anyway.  You will save yourself TONS of aggravation.  I mean, they're what, $20?  What's that expense compared with hours of driving enjoyment?

[Chris]

My first KB hack was a similar Compaq keyboard.  The response wasn't great; I don't know if it's the Compaq firmware or what.  But I was using it for games like Track and Field and Joust where a sluggish button is a killer.

If you really want to do a KB hack just for the joy of doing it I would probably pick a different KB... but the GGG encoder is really the better solution. 

[leapinlew]

Damn...

I'm wondering now if I should commit the time to this or just order an encoder. I've already wasted lots of time trying to get a X-arcade solo to work.

Whats driving this is the fact we are having people over this weekend and I wanted to show it off. I think the best bet is to just miss this weekend and do it right.

[Chris]

Well, if you want to push forward, I'll bet the controller is on that little daughterboard and the two ribbon cables represents the two sides of the matrix.   Might be an easier way to attack the problem.  It'll still be several hours worth of work, and you may want to consider it "temporary" to get through the weekend... up to you if it's worth the effort.

[Tiger-Heli]

Damn...

I'm wondering now if I should commit the time to this or just order an encoder. I've already wasted lots of time trying to get a X-arcade solo to work.

Whats driving this is the fact we are having people over this weekend and I wanted to show it off. I think the best bet is to just miss this weekend and do it right.

I made my comments based on the fact that I understood the theory of the keyboard hack.

All the other comments are correct.

Order the KeyWiz Eco (better yet, the pin header one and a ribbon cable so you can forget soldering) and PM RandyT and see if he can FedEx it to you.  (for a little additional shipping, of course).  You will be much happier in the long run.

[leapinlew]

Right... ok, so I've decided to go with the ipac and talked to Divemaster who is going to ship out quickly (thank you thank you!).

I'm going to prep all the wiring, get the computer mounted, marquee mounted, and power supply.