Can you get resistance from Optical interruptor wheels?

[Trooperuss]

First a little background with what I have in mind and why.

I use the original XB controller for flight simulators on my PC, (because of the size, durability, cost, and availability, and I'm not a big fan of joysticks)
I was having troubles with one aspect and that was controlling the throttle while still trying to control weapons and firing.

I got the idea to add a throttle controller by adding a POT wrapped in a mouse wheel.
I cut a whole in the controller and shaved enough room for it to turn. I then wired the POT in place of one of the POT's used for the right thumbstick axis.

It works fantastic, especially when trying to fly the appache helo when chasing down enemies.
The control much finer with the POT as opposed to the button that I was trying to use previous.
Also because the mouse wheel is not spring loaded (like the thumbsticks) I can set the throttle where ever I wish and leave it, which is much better for hovering in helo's and dogfights in mustangs/spitfires.

In continuing with the xb controllers (I'm really drawn to these for some reason, maybe because I have large hands), I recently aquired an original XB from a friend who upgraded to the 360.
I am a PC gamer through and through, and find controlling first person shooters very difficult with 2 thumb sticks. (I'm very used to mouse)
Controlling movement with the thumb stick works great, but looking around with any precision is very difficult, when compared to PC gaming.

In an attempt to highten the experience I attempted to add a trackball in place of the right thumbstick.
The problem is that trackballs use the old mouse technology of Optical interruptor wheels.
I thought I would attempt to replace the 2 POT's connected to the right thumbstick with a signal from the trackball.
Try as I may I have not found a way to translate the signal sent from trackball into a resistance measurement.

There are devices on the market (SmartJoy FRAG) that can translate the mouse movement to an xbox, so I know it's possible, I just have no Idea how.

Another project I am working on is my Interact V4 Racing Wheel.
It also uses the old style Optical interruptor wheel.
Since the release of windows XP, support for such devices was discontinued and therefore this device no longer functions.
Again I have taken it apart and have attempted to translate the Optical interruptor wheels signal to a resistance measurement, so that I can wire it into another device (lets say xb controller for argument) and continue to use the wheel.
I know that getting the force feedback working again, will be a large feat, but even just being able to used the wheel again would be awesome, as it was very well constructed.

Does anyone know how to accomplish what I am trying to do?

Your advice would be greatly appreciated.
I have only basic electronic knowledge, so any sites your could recomend would be helpful as well.

Thank you for your time.

[myersn024]

I've recently been looking into the same thing, and here's what I know. The microcontrollers in ball mice count pluses of light to determine how far it has traveled in any direction, and then sends the data to the computer in a serial transmission. I was looking into trying to find a way to connect a mouse to a PS2 controller for use in first person shooter games, but since the pots in controllers (like the DualShock 2 and the Xbox controller) use resistance to measure deflection, there's no way to directly wire one to the other. You have to have an intermediary device that reads the signals from one device and translates it into signals that the other device can understand.

If you're wanting some mouse and keyboard action on your Xbox, I whole-heartedly recommend the Smartjoy Frag. They work great, and it'll be easier and cheaper to buy one then it will be to make something on your own (unless your an electrical engineer and/or computer science major). The Smartjoy Frag won't be much help with the racing wheel, though.