Quick DC -> Arcade controls ?

[NaTSuMi]

I have my cab already built and set up but I would like to support DC controllers.  My CP is a standard fighter type. 2 players 6 buttons each.  I have the entire set up wired up to a single ground.  Now my questoin is, If i wired up a DC controller up to the same CP, can i just tap into my CPs gorund and run one wire going into the DC controller 1, and another ground wire going into DC controller 2 (they'll be sharing the same ground now)  is that possible? or will i have to seperate them somehow even though my entire controller set up shares a ground.

[SNAAAKE]

gotta be seperate..there is high risk of blowing out dreamcast controller port so dont risk it.besides i think all ports are different ground so it might not register...again.....dont risk it..besides i dont see the point to begin with..its only ground...seperate them

[SirPoonga]

I don't know what snaaake is smoking.  Ground is ground.  You don't need seperate grounds, you can daisy chain your button grounds and hook yo a ground on the dc controller.  I just openned up my DC controller.  All the grounds are common.  Note the very large green areas  that have connect to one side of each of the button circles, that's ground.

[SNAAAKE]

i probley did not understand what he was talking about it...

i thought he was asking that if you can dasiy chain control port 1 and 2 ground all together.sorry if i got em wrong..

[SirPoonga]

I just re-read the question.  Actually snaaake.  It's a combo of both answers.  He has one ground, in his CP, he's thinking of splitting the ground and running the two wires to each controller port.  THAT is bad.  Double grounding soming tends to make problems occur.  Technically speaking it should work, BUT electricity always takes the easiest path.

In audio equipment if you double gorund the equiopment you get a ground loop interference.

Yes, you will need to run player 1 grounds to DC1 and player 2 to DC port 2.

BUt, I have to ask, will the ground also be going to your IPAC, or whatever you use to hook up to a computer?  That'd be bad too.  You'll need to switch from the computer to the DC grounds.  A relay solves that, but I don't know much about relays.

[SNAAAKE]

see thats what i am talkiing about...first time i made a panel..i f__ked my dreamcast up..i was trying to use 2 same ground...psx and dreamcast..so just my warning..

[SNAAAKE]

I  Technically speaking it should work,

still wrong..because when you do that then the whole thing might register as only controller 1 if he uses 1 players ground.but i am about 90% sure that doin so would blow out the controller ports..just make 2 different ground and you be aight..

[CthulhuLuke]

Alright, I think I understand this conversation because I had my setup similar to this.  Here's an answer if you're using an I-pac and two dreamcast controllers.
 Because the two grounds on the I-pac are actually seperate grounds, this is how you want to wire your CP.  Wire one half of the CP, (aka: player 1's side) to the first ground of the I-pac and the Dreamcast Player 1 side, and vice verca with the player 2 side.  Just make sure that none of the grounds connect from the player one side to the player two side, and you're golden.  That's how I did mine, no fused controllers or unhappy gameports, just DO NOT have the keyboards and Dreamcast plugged in at the same time, or else it will draw too much power from the boards and you have a really great chance of blowing something out.
    -CthulhuLuke

[BombProofPlane]

ive got a controller (1 player) with a psx interface and a sidewinder gameport and it grounds only to the sidewinder no explosions no heat no smoke

[NaTSuMi]

My problem is combination of all your guys responses.  I am using a CP with only 1 common ground all going into the IPAC.  I figured that you couldnt' wire the DC controller 1 ground and DC controller 2 ground together and link w/ the CP ground but I was hoping you can because that would make it easier for me.  I think the best solution is what Cthulhuluke said.  I'm probably going to half to split half my CP for player 1 and the other half for player 2 on differnt grounds (going to the 2 grounds on the IPAC) and then from there wire up the 1st DC controller and the 2nd DC controller.  Thanks for all the replies and suggestions everyone!

[Dave_K.]

What the heck! You all need to go back and take Electronics 101! :-)

Ground is used as a REFERENCE value for voltages in a CIRCUIT.  Grounds from two seperate circuits are NOT necessarily the same!!  The Dreamcast (with its own power supply) is one circuit.  The IPAC connected to a computer (using the computers power supply) is a different circuit.  You cannot share grounds between these two circuits!  

I guess you all are to young to remember when old stereo components (using two prong cords) had their metal chasis as ground.  Touching the metal on the front of the stereo to the metal on a seperate component (like a turntable) usually gave you a shock.  This is because the chasis' grounds are both at different potentials (voltages).

As Sirpoonga suggested (in his second post) you will need a relay or just a simple toggle switch between your control panel and your ipac or Dreamcast grounds to keep them isolated.

You could share grounds between the dreamcast joystick ports, but doing so only shows that you are sloppy/lazy.  Its a cleaner implementation to keep each set of player controls on their own set of chained grounds which connect to the joystick port's ground.

-Dave

[CthulhuLuke]

Isn't this why you don't connect the DC and the PC at the same time as mentioned?  lol, yeah I'm lazy though ^_^  I was thinking of installing a switch under my cab for DC/PC so I would never have to worry about these problems, my only problem was what kind of switch could go between (1player DC ground + 2player DC ground  /   1player IPac Ground + 2Player IPac Ground)?  But not have the 1player and 2player DC grounds touching together?  4PDT or something?  I'm still in high school and my school doesn't offer an electronics class so I get all my info from my dad, so help would be nice.  I don't want to start a new thread with this question, so anyone who can respond, that'd be great.
     -CthulhuLuke

[CthulhuLuke]

Oh wait, I think I can do it with a dpdt switch, yesss.....

[SNAAAKE]

no need no class peeps..i am in high school too..aint no eletric class in there.

you can use a printer port switch box....the 25 pin onces..then switch between..you can also leave all connected and they is no way to blow anything out since its a switch box..i have this kind setup..with 3 interface...mame,dreamcast,psx or ps2.and still have 1 more port for x-box or whatever comes out with good games.(why should i even buy x-box?).

make sure you get 4 way switch box for future add ons.

[Howard_Casto]

Actually what CthulhuLuke said is the easiest and most logical approach.  The only way the circuit can be completed i if there is voltage running through it.  (duh) When the pc is on and the dc is off, the natural properties of electricity are going to tend to make it go back to the ipac (or whatever your using)  Any backflow to the ground on the dc pad is going to be minimal and well within the tolerances of the dc.  Vice versa for the dc on and the pc off.  As long as you aren't foolish enough to have the dc and hte pc on at the same time your going to be ok and you might even still be ok if they are still on (although the grounds screwing with each other are going to make controls actu funny) as I THINK the dc and the pc keyboard both pull about 3 volts and some change for the buttons, if that much.

If we were dealing with higher voltages this would be a problem, but with electronics like this it isn't a huge deal.  Both devices are designed to take way more voltage than they generate, so it's not like the littlest bit of stray juice is going to blow them to kingdom come.   Now mind you this isn't the "electrician's approved" method, but it's the practical one.

[Dave_K.]

The only way the circuit can be completed i if there is voltage running through it.  (duh) When the pc is on and the dc is off, the natural properties of electricity are going to tend to make it go back to the ipac (or whatever your using)  

You couldn't be more wrong Howard (which is quite rare).  The properties of electricity are going to make voltages seek the path to greatest ground potential (not whichever power supply you are using).  Because computers use 3 prong outlets, the ground pin is tied to "earth ground".  In most cases this will be lower than circuits which use 2 prong outlets (like the Dreamcast).  So there is the chance to see a better ground from the PC/Ipac (even when the PC is off!).  

If we were to get really technical, you could argue that the ground on the USB or keyboard/mouse (used for the I-Pac) is isolated from the earth ground the pc power supply uses.  This might be the case, but the point is you don't want to leave it up to someone else to make sure things are properly grounded.  Hopefully nobody is tieing the ground of the control panel to the cabinet chasis (like on some Jamme cabs).

So in summary, stop being lazy, and isolate grounds between your different setups/circuits.  I REALLY hate to admit it :-), but Snaaake is right on with his switch box solution.  A simple toggle switch for ground will work also.

-Dave

[SNAAAKE]

I REALLY hate to admit it :-), but Snaaake is right on with his switch box solution.  A simple toggle switch for ground will work also.

-Dave

HAHAHHAAHH ...admit admit admit !!!!

[CthulhuLuke]

A simple toggle switch for ground will work also.

Ok, this is getting annoying.  This is exactly what I said -____-  ANYWAYS, I don't really need anymore info on the matter because I'm pretty sure this will work.
   -CthulhuLuke

[BombProofPlane]

just for the heck of it i hooked up my joystick to both "pc and dreamcast" and played the same game on both machine with all ground to the pc as i mentioned before. no switch boxes no dipswitches just diodes between each connection to stop interference and thats it.

For testing i played garou, Marvel vs Capcom, and Last Blade 2

all the moves identical (yes im a wierdo with a tv right next to my monitor)

no key blocking no smoke no heat and its been working like this connected to both machines for almost a year with no problems  nothing shorted or blew up

go be lazy its fine