keyb as interface?

[nils]

hi guys! i'm quite new to this so my question can maybe seem a little stupid.. but i was thinking about this:
i'm planning to build my first mame controller and i checked a little around.. i found out that the I-PAC, which looks perfect to me, is only some kind of "fake keyboard" and that the usb version should work better than the ps/2 one..
so the question is.. could i just take a usb keyboard, open it and patch all the keys (or only the ones i need) to the buttons and the joysticks (and maybe a trackwheel) on my controller?? it sounds logical to me.. and cheaper.. and easier.. but there is maybe something i missed.. so i'm not really sure it's a good solution..
i would be really happy if some of you could give me an answer.. and by the way.. anyone of you knows a european site from where to buy buttons and joysticks? it's really expensive to order from usa..
thanx for the help..
nils.

[Stingray]

Ultimarc, the makers of the IPAC are located in the UK.

Hacking a keyboard, while certainly cheaper isn't anything like easier, it's a royal pain. Attaching wires to an IPAC (I assume the Keywiz is similar, but I've not used one of those) is super easy. Also if you're making a controller with more than a few inputs you'll probably get ghosting issues. I'm sure someone who understands this phenomenon better than I do will be along shortly to explain it. To put it simply when you hit more than one or two keys at once it can sometimes confuse the keyboard into sending the wrong signal. Like I said, I don't understand it, but I have experienced it and it stinks. You don't get this problem with an encoder.

Also the PS2 IPAC and the USB IPAC are the same, you just get the cable for whichever port you need.

-S

[mahuti]

Basically you will make your gameplay experience better if you just use the iPac. Problems that will interfere with game play, especially in a 2 player game, do not exist on the iPac, that WOULD exist on a keyboard hack.

It's much easier to use the iPac as well, as Stingray noted.... no soldering problems, cleaner, programmable. Don't scrimp on the encoder, now that so many good ones exist.

[nils]

ok guys!! thanx a lot for the help..
but as you could exepct.. after an answer there's always another question..
so here it comes:
if i use the "small" i-pac.. the one with 28 inputs, well.. how many buttons can i use then? in other words.. how many inputs do i need for two sticks? i planned to buy 2 switchable 4-8 ways sticks from ultimarc (euro-sticks) but i don't know if they need 8 inputs each or only 4..
and another one..
if i mount a trackball too, do i need then 2 different usb connections to my pc or can i use the same one?

thanx a lot for all the suggestions.. hope i can start soon with my controll-project!

[Thenasty]

Each Joystick takes 4 - inputs
I suggest having 6 butons or 7 for each player 1 and 2
Then start buttons for player 1 and 2
so...

Player 1 Joystcik plus 7 buttons takes    11 inputs
Player 2 Joystcik plus 7 buttons takes    11 inputs
Player 1 and 2 start buttons takes            2 inputs
Player 1 and 2 COIN takes                         2 inputs
MISC ADMIN KEYS
ESC, TAB, F2, F3 etc...you need to decide how many

And if you are thinking about running out of USB port, use the PS2 port for the IPAC.