Help with wiring Steering Wheel Pots: A-Pac

[esoteric_rt]

Hi there,

Anybody got any tips?

I am trying to wire Virtua Racing steering wheel pots to an A-Pac, I have located the right wires and connected - although when I play the likes of Daytona USA the car jerks to the right or left.

When I calibrate the A-Pac in 'game controllers', the only Pot values I get are (X-Axis) -2048, 0, 2047 (full wheel turns).

There seems to be no in between numbers- is this right? I.e. when I move the wheel slightly to the right I get 2047, and slightly to the left I get -2048.

Hope this makes sense....

Thanks!  

[BadMouth]

Can't help you, but it might help to change the title to include something about it being an A-Pac issue.
It would get the attention of other A-Pac users who might know what the issue is, whether they're using it with a steering wheel or something else.

Check out the driving cab info link in my signature.  You might find something useful.  (for after you get the pots sorted.)

[DeLuSioNal29]

Can't help you, but it might help to change the title to include something about it being an A-Pac issue.

I agree.  I clicked on it thinking that you needed help with wiring the Virtua Racing game itself (no A-pac) since my buddy owns one of these.

D

[BadMouth]

I'm hoping this gets some replies and leads to a discussion of wiring pots.  I'm trying to wire the pots in a positional gun to a usb gameport adapter and having no luck.

Guess I'll go ahead, hijack the thread and throw my problem out there:

I'm trying to wire some 100k pots to a "Super Joy 7" usb gameport adapter.
I know they're 100k pots because I tested them, I tried different pots I had laying around that said 100k on the back,
and I went and bought a pair of new 100k pots just in case something was wrong with all 4 of the other pots I tried.
I've wired them using three wires per pot (5v, analogue pin, Ground).
I've wired them using 2 wires per pot and a 100k resistor (analogue pin+100k resistor+Ground, 5v, unused).

Always the same result in the gamepad calibration screen.....
It tracks fine until it gets to 255, then it jumps back to the beginning, then it loops through a second time, then it gets almost halfway through a third trip, then freezes at the midpoint (128).

I wired the pots to an Act Labs pedal box and they work 100% right with it, but I want to use a gameport so I don't have to use a different interface for the trigger and aux buttons.

I know some guru on here probably knows what the problem is.
Please don't make me have to figure this out for myself. 

I got two evenings tied up in it already.

[esoteric_rt]

Thanks fellas, good call - have changed the name.

This is strange issue I am having, to explain it further - when the wheel is turned to the left slightly it goes straight to the full value of the pot, the same when turning right.

There doesn't appear to be any gradual movement and is quite jerky (if you know what I mean).

Could this be due to the value of the pots? Does anybody know what value Virtua Racing pots are? Should I replace them?

Thanks for your help!

Luke

[Marsupial]

Always the same result in the gamepad calibration screen.....
It tracks fine until it gets to 255, then it jumps back to the beginning, then it loops through a second time, then it gets almost halfway through a third trip, then freezes at the midpoint (128).

that's called rollover - you overpass the bit limit (255 decimal is 11111111 - if you have only 8 bits of data, 255 + 1 = 0!)
Maybe the 100k isn't all used by the joystick? if the values are too big for this controller, it'll send too high data for the driver to understand.

 try a 30k pot or a 10k pot.

[BadMouth]

This is strange issue I am having, to explain it further - when the wheel is turned to the left slightly it goes straight to the full value of the pot, the same when turning right.

Do you have pots wired up besides the wheel? (pedals?)
Are they behaving the same way?

that's called rollover - you overpass the bit limit (255 decimal is 11111111 - if you have only 8 bits of data, 255 + 1 = 0!)
Maybe the 100k isn't all used by the joystick? if the values are too big for this controller, it'll send too high data for the driver to understand.
 try a 30k pot or a 10k pot.

Thanks for the reply.  I appreciate it.  
 I probably never would have come accross the rollover thing on my own.  
I thought about trying a 30k pot though (hey, if it only works 1/3 of the way, only use 1/3)
I'll probably pick up one tomorrow and tinker with it for the learning experience.
Doubt I'll swap out the ones in the gun as it looks like it would be a PITA.
Everything I came across in researching this said the old joysticks were 100k though.
Seems odd to be off by more than 3x.  I'm wondering if there is some other step that I'm missing.
I have a couple old joysticks that I bought to play Virtual On with, but I'm not liking the analogue feel.
Maybe I'll tear one apart and wire these pots to it and see what happens.

[BadMouth]

Was doing a little research at work and might have figured out a few things.

I found an article where someone hacked one of the joysticks I have.
There are no components inside it but the buttons and two variable linear resistors...100k  
There are only two wires going to each resistor.
The joystick works fine with the gameport adapter, so it has to be something in my wiring.

Then I found this diagram:


It doesn't appear that there is any ground whatsoever on the pot circuit.
Is this the right way to wire it?

I thought I had tried it this way once and it behaved like a digital joystick.
Maybe I just went by the gamepad screen and didn't bother trying to calibrate it.

(I'm sure I'll find out when I get home from work, but it would be nice to know that I'm on the right track)


EDIT:  Got home and wired it like the above diagram.  Works fine now.  There is a little dead zone toward the end of the pot, but the guns don't have a real wide range, so hopefully it won't affect anything.

  my newbness!