Driving Force GT - Potentiometer Output Values

Hey folks,

is there a chance anyone of you has disassembled the Driving Force GT Pedals?

I am currently in the making of my own pedals and want to use potnetiometers that are compatible to the Driving Force GT (a/d)controller inside the wheel so that I just need to buy a set of 2 sliding potentiometers (easier to assamble) and a plug/cord to plug them into my DFGT. (I'll use the a/d from my old and broken M$ FF Wheel for the clutch)

I already got the pinout to the plug straight - but I just have no Idea which potentiometers I'd have to use without voiding the guarantee of my DF GT as it is only 2 weeks old...

Can anyone help me with that matter?

regards,
Bernhard

Hi Bernhard,
I did the same kind of mod to my DFGT, but I used the original potentiometers. Anyway, they are both 10kOhm. Since I'm using original cable, I didn't have to do any wirings to 9pin plug either. I could measure the resistant between the pot wires and the plug pins to assist you with the correct wirings with the plug. I'll get back to you by this weekend when I'm done with measurements.

-Esa

You've got any pictures on how you used the original pots? I'm not really sure how I should mount that gear-construction on my DIY pedals.. =)

You will probably void your warranty by taking it apart anyways.

You can use any 10kOhm potentiometer basically. Make sure to get a linear pot and NOT logarithmic (unless that is what you want).
Connect the two outer connections to Gnd (0v) and +5V respectively (reverse the two to reverse the direction if needed). The middle connection will go to the A/D and give you the position.

Yah, but as I read that the DFGT uses a gear-mounted pod I might like an example solution as I wanted to mount the pod via a gear anyways (I think it may be more reliable than an 1mm thin r/c-car steering-axe solution (I've got a [relatively fat] cat which might enjoy 1 sticks standing out somewhere..

Okay, here are the pictures of my pedals. Instead of using original gearing, I used plastic gears that I found from a local electronic shop. In the gearing picture you see original ones. It doesn't matter which to use as long as pedal-pot ratio is suitable so the pedal travel is adequate. Original larger gear (pedal) diameter is 34mm and smaller (pot) is 13mm. They give ratio 13/34=0,38 and my gearing is 12/40=0,3. As you can see, my pedals are quite long in their arm, so I need a bit thigter ratio so the travel isn't too long. If you are planning to do pedals with quite similar lenght as the original, original gearing will do just fine.





But instead of using original pots and gearing, you mentioned using sliding pots. As you have still warranty, I think it's better idea to try not to dissassemble the logitech pedals. And with sliding pots it would be quite easy to arrenge some sort of adjustment to pot ratio. If you decide to go with sliding pots (or any other similar solution) wiring the 7pin plug (it's a basic 9 pin plug with 2 pins removed) goes like this:

brake pedal pot:
middle - green wire
outer two - red and black wires

throttle pedal pot:
middle - white wire
outer two - red and black wires
As Frakk mentioned, you can switch outer wirings to get desired direction of pots.

9 pin plug:
(1 doesn't exist)
2 - white wire
3 - green
4 - red
(5 doesn't exist)
6 - black
7 - white
8 - green
9 - red
You can see location of the pin numbers in original plug as they are marked. I have no idea why they are cross linked in pots as I have no knowledge in electronics :

One option which I tried was to use regular 270 degree pots. Problem was that it required lots of gears to get sufficient travel to pedal. With lots of gears, gearing turned out to be very tacky in operation. Original pots have only about 70-80 deg of rotation. As I don't have warranty any longer, simple solution was to dismantle the logitech pedals.

When you get your pedal project started, please post some pictures of them. It's a shame DFGT has those not-so-good soft plastic pedals, compared to the wheel which is a very good one. With proper DIY pedals it's a good budget friendly alternative to G25/27. The last picture goes a bit off topic, as it shows my H-shifter which is made of logitech wingman force 3D joystick which operates also the clutch.

Anyway, good luck with those pedals! :thbup:

Oh hell, I think I just fell in love with your post... Thanks for that much information!! I really appriciate your effort!

I will post pictures as soon as I am statisfied with the pedal's mechanics, still experimenting on them

curious.. I only have 1 white wire.. frankly I am a little confused which pedal should be wired to which port..

I'm glad to help! And to your question, do you mean you disassembled the pedals and there is only one white wire connected to the throttle pot? If so, then it's the same way as I have, the white wire only splits up to pin 2 and 7 in the plug. So you can't see more than one white wire. Is that what you mean?

Yah, I decided to take a look inside after all..

That's exactly what I mean, thanks for your quick reply, I think I figured it out now