Hack anolog controls for psx

[reighty]

I am creating a racing cabinet and have created a steering wheel and want to be able to hook it up to the analog contols of a psx controller and want to know if anyone has ever done this before or if there is a faq out there somewhere.  I am using 100k pots and do not want to hack up psx wheel because I am also using it for my pc.

[Dave_K.]

Trust me, its cheaper and easier to just hack the psx wheel.  Other wise you are only going to re-invent "the wheel" (pun intended).

[hotboy_92]

Well, I've hacked a pot directly into the PSX analog controller. It does work, but the thing that confused me is the PSX joystick almost acts as two pots on each axis due to the centering. If you put a multimeter on the pins of the sticks to measure the resistance you'll see what I mean - instead of getting a smooth sweep from 0 ohms up to max ohms, it goes from max ohms to 0 and back up to max again!!

So once you get your head around that you can get the calibration to work. I tested it with my analogue pedals (hacked an extra pair of wires from the gas pedal pot so the thing still worked as a PSX controller).

I did it more as an exercise to see if I could build a break out box for each button and axis so I can plug in and button or pot that I want to in a modular way. I did this for the standard soundcard joystick port a few years ago, using RCA phono connectors as the interface - worked a charm.

[Dave_K.]

Well, I've hacked a pot directly into the PSX analog controller. It does work, but the thing that confused me is the PSX joystick almost acts as two pots on each axis due to the centering. If you put a multimeter on the pins of the sticks to measure the resistance you'll see what I mean - instead of getting a smooth sweep from 0 ohms up to max ohms, it goes from max ohms to 0 and back up to max again!!

The reason why you are seeing this is because the 2 axis pots of the analog stick are wired together in paralell.  If you try to take resistance measurements on one pot, the other pots ground is eventually going to look closer that the one you are measuring.  If you removed the pot from the circuit it will sweep normally.

What this means is if you are wanting to hack a gas pedal (single axis) to an analog joystick, you will have to wire it up in parallel to the joysticks other axis (even though you aren't using it).

[hotboy_92]

Thanks for that Dave. A lot of games expect y-axis up to be accelerate and y-axis down to be brake. Do you know how I should wire up the gas and brake pots to the single axis on the PSX controller?

Cheers

[Dave_K.]

Ahh, now I see what you were wanting to do.  My guess is that you would wire the gas/brake pots in series (but the wipers are wired together).  What you have out of that assembly is 3 wires which is then wired in parallel to the joysticks' other axis as before.  This is really just off the top of my head, and I don't know if it would actually work (so don't blame me if you burn down your house).  

[reighty]

I am using the 100k pots so that I can easily hook it up to my PC.  I was hoping that I could some how take out the pots on the psx pad and hook these up (I also want to possibly hook it up so I could possible connect other system up to it also).  I did something similar for my arcade stick, where in the back I had a hatch where I had a removable box containg hack up controller pads (think of it like a removable hard drive bay).  This way I could just make a new removable box and hook it up to practically any system.

[u_rebelscum]

Here's one nice page with info on combined (Y axis) vs dual pedal wiring to a PC with normal POTs: http://www.gunpowder.freeserve.co.uk/wheels/wiring.htm

[AGarv]

Any idea as to what the pot voltage is for the small pots contained within the dual shock controllers?

I'd very much like to be able to wire the left dual shock joy up to an analog stick...

[Dave_K.]

The voltage shouldn't be your concern...the resistance of the pot should be (since thats whats dividing the input voltage) to make sure its smooth from gnd to input voltage.

BTW: I believe its +5v (I've measured 2.5v when centered).  This is on the original Dual Shock 2.