2 systems, 1 control panel - Potential Power issues???

[fibreoptix]

OKay as brief as I can.

Cab build with Xbox360 and PC.
2 hacked MadCatz SFIV pads PCB's (they use common ground),
1 iPac encoder.

Obviously iPac to PC and MadCatz to Xbox360.

Ground (Player 1 controls) From madcatz controller daisy chained to all buttons and the joy stick then to the ground of the iPac.
Then 2 wires from each button. One goes to ipac the other goes to madcatz PCB. Repeated for player 2.

That is the potential set up I have in my mind. My question is this. I assume if both systems are on, this will feed too much voltage and fry everything. I have no idea what will happen if both systems are on at the same time. I'm just assuming there is added voltage to devices that are design to deal with a certain amount of votage.

So is there a 3 way switch I can use that will guarantee power will be served to either or?

Example: Switch in mid position neither receives power, Right position delivers power to PC and Left to Xbox. I am by no means not electronic engineer

[Donkbaca]

you don't need the ipac. just get a KVM switch that has USB, you are going to need a way to switch out the video anyway.  The pads work fine in mame.

THe way you have it set up won't work since you will probably have ground issues, its best to seperate out the grounds, you can do this with a switch, or find the appropriate resistor and wire it up to the SMD power on the xbox pads, but that is PITA and more complicated.

Just use the pads.