Keyboard hack... help needed

[RoboG2]

Considering the fact that im low on money, I decided on using a keyboard hack to run my controls.  I attained an old IBM keyboard with a 16 x 8 matrix which I thought would be perfect for my project.  I tested it and I will be able to press 19 keys at once without being blocked.  My question is how do I wire up the pcb to my buttons and joysticks?  There are 2 groups on the pcb to wire together but also the ground and there is only positive and negative on my microswitches.  Feel free to speak technically.
Thanks in advance.  

[RandyT]

Microswitches don't have a + or -, they just close a circuit.

The keys on your keybord do exactly the same thing.  You just need to identify all the keys that you can press simultaneously and trace all the connections back to the pins on the CPU (or fingers on the board).

Keep careful notes about what 2 lines make what key so you know which 2 lines to connect to your switches for that key.

Should take about 2 hours to trace and document the controller.  A decent multimeter will help things along quite a bit.

The "ground" doesn't have anything to do with your switches when dealing with a matrixed encoder.

Hope that helps some.

RandyT

[RoboG2]

Thanks a lot.  That really helped.  I already have the matrix... got it online.  ... Where to I trace the ground to?

[spystyle]

Cool !
I'm not the only one poor enough to make keyboard hacks !

I've made 3 using this tutorial :
http://dragonsden.emuunlim.com/ddkeytutl.htm

Instead of movie cases I put them into radio shack project enclosures

They work well

To map out the buttons I use the program "keyhook"

If you use keyhook note that mame 1 player movement keys are "grey left, grey right, grey up, grey down"

not "left, right, up, down" (I learned the hard way)

Dig it?
Craig


PS
For those of you reading this thread who have never hacked and mapped a keyboard:

It's a *real* pain in the butt, it takes an entire evening, and it requires *accurate* small scale soldering skills.

A great alternative would be to buy the KeyWiz Eco encoder from www.groovygamegear.com, it's only $26.95 USD, and made by a fellow BYOAC message board poster RandyT.

not to mention it's groovy

[Tiger-Heli]

Considering the fact that im low on money, I decided on using a keyboard hack to run my controls.  I attained an old IBM keyboard with a 16 x 8 matrix which I thought would be perfect for my project.  I tested it and I will be able to press 19 keys at once without being blocked.  My question is how do I wire up the pcb to my buttons and joysticks?  There are 2 groups on the pcb to wire together but also the ground and there is only positive and negative on my microswitches.  Feel free to speak technically.
Thanks in advance.  

I have a long tutorial on keyboard hacking here: http://www.mameworld.net/emuadvice/keyhack2.html

That said, I recommend you spend the extra $$$ on a KeyWiz ECO from www.groovygamegear.com.  You won't regret it.

If you are set on doing the hack, I wouldn't trust a matrix downloaded on-line unless you have personally verified it yourself.

BTW, no way that I know of that you get 19 keys at once from a 16x8 matrix, unless you mean by allowing blocking on the joystick up and down inputs there are 19 useable inputs, but I won't argue with you.

To wire it up, Say you want a button connected to "A" and "A" is row 5 and column 13.  You connect the Row 5 wire to NO on the pushbutton and the column 13 wire to COM, or vice versa.

[Tahnok]

I'm working on a keyboard hack as well (and a mouse hack). I am mounting everything on an old piece of plexi.

I must say that mapping the matrix out was no big deal and that the diodes are dirt cheap. I don't understand why someone who could use a keyboard hack wouldn't and buy an expensive encoder. The encoders are cool for things like shift keys, but I don't think it is worth the money.

[FractalWalk]

"I don't understand why someone who could use a keyboard hack wouldn't and buy an expensive encoder."

For me it was an issue of time and quality. I mapped out everything easy enough. But I was limited on the number of inputs and reliant upon soldering leads that were less than 1/8" apart. I managed to do it, but my leads kept breaking or shorting to its neighbor.

After spending more than a few hours on it I decided that my time was more valuable then the minimal cost of an IPAC. Plus the I-PAC is much better quality, reliability and functionality than I could have ever produced with a hack.

After trying the hack, it really was a no-brainer for me to go
with the IPAC.

[Tiger-Heli]

I'm working on a keyboard hack as well (and a mouse hack). I am mounting everything on an old piece of plexi.

I must say that mapping the matrix out was no big deal and that the diodes are dirt cheap. I don't understand why someone who could use a keyboard hack wouldn't and buy an expensive encoder. The encoders are cool for things like shift keys, but I don't think it is worth the money.

As Fractalwalk said, there are time and quality issues.  An encoder will also outperform a keyboard hack as well.

Beyond this, if all you want is MAME and a basic SF layout, you can make a keyboard hack work.  But you will be limited to fixed key assignments and a fixed key layout.

The biggest drawback is if you ever run a program that doesn't allow re-mapping of inputs, you probably can't have your keyboard hack work with it.

And expensive is a relative thing - For $26.95 (plus shipping), you can get a KeyWiz Eco.  You can find a keyboard for free (after rebates), but then you will want terminal blocks and wiring, so there is at least a $5 cost to the keyboard hack.

For most users, the additional $20 is well worth the time saved and greater functionality.

[brained]

Well I've successfully built my keyboard hack on saturday and sunday. It takes a lot of time and stuff, but hey what's the pressure. Nobody is pointing you with a gun and saying "I WANT MY ARCADE NOW".

I think keyboard hacks are nice for a limited number of inputs. The cool thing about keyboard hacks is that it's a true DIY . Also most of us have old keyboards, so gutting them out it's the way to go!!

It's a little painfull but it's fun.

*edit*
use a terminal block for the rows and the columns... and IDE CABLE