Common ground controller question (perhaps slightly off topic)


#1

Hi All!

I have a wiring question. Let’s say (hypothetically) that I like to play KOF with a racing wheel, but feel that the face buttons don’t have enough oomph for my punches and kicks and would prefer to use a heavy duty gear shifter for my uber chohissatsushinobibachi action. With me so far? :wink:

Well anyway, I’m using this tutorial here:
http://www.briandorey.com/post/External-Button-Connections.aspx

It states that it’s common ground, but it wants you to use 3 ground points anyway, and I’m not sure why I have to. FYI I’m only planning on wiring up the face buttons, not the shifter paddles. I just want to make it as simple as possible so I don’t screw it up. If anyone’s curious, this is the “stick” I will be using:
http://www.youtube.com/watch?v=HYAS1_Y3Qpk

Please forgive the unusual nature of my request. I just knew you guys were the experts. Just so you guys don’t think I’m some idiot crackpot off the street, I offer you one of my other projects to peruse, so you may know that I am only partially idiotic:

https://www.oratan.com/forum/viewtopic.php?f=3&t=502

Thank you so much for any assistance, or at very least, allowing me escape this thread without a ban. :wink:


#2

hello im looking for a pcb for my hori hrap premuim vlx it seems not to work with my pc any longer can you assist me in this


#3

Grounds aren’t always the same. That said, it looks very much like he’s only using one of the ground lines himself, so I expect you’ll be fine just using one. (In the pic, common 1 and 3 aren’t connected to wires.)


#4

Thanks Rufus!

I know many controllers aren’t common ground (actually my gear shifter has discreet grounds for all the switches for just such an occasion), but him calling the ground points “common” is what confused me. I saw the same thing as you did with the only one ground being attached so I emailed the author to clarify. Thanks for replying back.


#5

Those aren’t always the same, but, for the purposes of modding, they often are.


#6

There are a diffrence between a common and a ground.

Commons is when multiple signals (but not necessarily all signals) return or receives voltage (Plus or Minus) to a same point.
Ground: In electrical engineering, the reference point in an electrical circuit from which other voltages are measured, or a common return path for electric current, or a direct physical connection to the Earth. Hence where the return voltage goes to.

Common ground is a shared return voltage.

Its likely the guy in the video has a PCB that is not a common ground PCB or he is treating it or wiring it as if it is not common ground.


#7

Because I can’t resist pedanticalness: Common need not be the negative side of a circuit, it can be any potential. Witness common-cathode vs. common-anode diode arrays. And common on a relay doesn’t have any inherent polarity, it just means both switches connect to that point, a.k.a. share it in common. If you have a double-ended power supply (+15 and -15 volts, for example) the 0-volt rail is typically referred to as “common.”

His use of common 1, 2, and 3 on the picture with the arrows is confusing and in isolation I probably would have assumed they were actually for different circuits. Maybe I’ve been hanging around relays too much. But then where he solders to the connector and calls them ground points 1, 2, and 3 I would take that, in isolation, to mean “here are three points that are connected to ground.” In the context of a control PCB it probably means what you expect it to mean.

But when in doubt, whip [the multimeter] out.


#8

Thanks for the additional info, your post made me realize I forgot the word* receive* in my definition of common.


#9

Pedantry.

I’ll get me coat… :slight_smile:


#10

:o(
You know, I even looked that up to make sure it was spelled right but missed the “adjective” part.


#11

^^I just couldn’t resist the bad joke, sorry…


#12

Fighting games with a racing wheel?

Blasphemy?
Madness?
TECH TALK!