- 6
- Cyprus
hi has anyone opened a DFP and found the O button wiring connections on the circuit board ? I want to solder in parallel some wires for external handbrake
handbrake wiring DFP
- Thread starter Trevor Lewis
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- 9,256
- United Kingdom
- neema_t
I've done it before, but I don't have my DFP any more. The wiring is a matrix, I can't remember which is which but going from memory there are 8 wires from the main circuit board in the base to the wheel's circuit board, four of them are 'rows' and four are 'columns' to give 4*4=16 buttons. The four 'rows' are the D-pad, X/O/Tri./Sq., Start/Select/L3/R3 and L1/L2/R1/R2 then the four 'columns' correspond to one of the buttons in each group. I'll have to admit that I don't know how the LEDs are illuminated but - If I remember correctly - looking at the connector on the PCB, you can safely short any one of the four pins on the left-hand side to any one of the four pins on the right-hand side with a piece of wire and it'll 'push' a button, but be careful to not accidentally short any of the row or column pins to other rows or columns, that's probably a bad thing. You can also read the circuit board in the wheel quite easily to figure out exactly which row and column you need for a O button, it's a very straightforward layout.
I'll have a look and see if I still have a DFP wheel faceplate later so I can be more specific.
I'll have a look and see if I still have a DFP wheel faceplate later so I can be more specific.
- 6
- Cyprus
Thanks thats really quite helpful. I'll pull it to pieces at the weekend, once I've picked up some supplies like a microswitch etc
- 9,256
- United Kingdom
- neema_t
Before I start: I don't know how much you know about this stuff so I'm assuming nothing, no offence! You might be a professional electronic engineer for all I know...
You'll also need a few different screwdrivers. The disassembly process goes roughly like this:
1. Turn the wheel 90 degrees to the left or right so you can get access to the screws on the back of the wheel, I think there are four (two on the left side, two on the right), they're small Philips screws and you'll need either a very thin or very long screwdriver to be able to reach them (I found a no.0 Philips precision screwdriver, the sort you'd use to repair sunglasses with, the best option). Undo the screws, turn the wheel 180 degrees the other way, undo the other screws. Now you can pull the button panel on the wheel off.
2. Carefully unplug the cable that runs through the steering column and put the panel somewhere safe with the screws.
3. Now you should see - I think - four fairly large domed Philips screws, they're quite tightly torqued too so you'll want a more substantial screwdriver for these.
4. Now you can pull the wheel itself off, but be careful to feed the cable through the hole in the wheel before you remove the wheel, if you drop the wheel with the cable still through the hole you might cause problems...
5. You should be left with four small screws, four large screws, the button panel, the wheel rim and the wheel base with the cable protruding from the now-bare steering column. Flip the base over and start removing the screws from the perimeter. These are quite deeply recessed in parts so you need a screwdriver with a long, thin shank (shaft, whatever), I think a no.0 or 1 Philips should do it. You're looking for silver self-tapping screws - if you find any black screws with a fine thread, leave those alone. I can't remember exactly but I think there are four of those visible on the bottom, they hold the DFP's gearbox in so it's best to leave those in place.
6. With all the screws out you can now remove the top cover of the base. I think the cable coming from the steering wheel is visible so you'll have no trouble tracing it to the wheel's main PCB (PCB = printed circuit board, of course).
So, yeah, you just need three different sizes of screwdriver and maybe a pair of needle-nosed pliers. And, of course, a soldering iron and preferably also a hot glue gun.
As for identifying the pins you need, read the PCB you pulled out of the wheel. It's double-sided so you'll need to unscrew it from the plastic. Look for the pad that was under the circle button, follow the two traces that it's connected to and Bob's your mum's brother, those are the two pins you need. Then hold the cable against the connector (it's keyed so you can only plug it in one way, make sure you have it the right way around!), find the colours that correspond to the pins, then look at the pins those colours are connected to on the wheel base PCB. Solder your switch on the underside of the PCB and that's that.
When it comes to soldering, don't try to just reheat the solder that's already there. First strip the ends of the wire you're soldering on then melt some solder onto the exposed ends (this will likely melt the ends of the insulation slightly, don't overdo the heat because the fumes are toxic, a tiny amount won't kill you, though). Then add a tiny bit more solder to the solder that's already on the PCB - the stuff that's already there is silver and there's no flux, so it won't flow well at all. Adding fluxed lead solder to it (and the wire) will make it much, much easier to make the new joint but you don't need much at all. Don't hold the iron against the connector for too long, maybe 2-3 seconds should be enough to make the new joint, or you'll melt the shroud and then the pin you're soldering will probably move. Consider clipping any excess bare wire (I'd aim for about 5mm of exposed wire at the very, very most) before you solder just to reduce the chance of shorting something accidentally, then use some hot glue (if you have a hot glue gun) to glue the wires somewhere on the PCB. I'd also advise drilling or cutting a small hole in the back of the DFP's case for the wires and then tying a knot or adding some glue to the wire itself to make a strain relief inside the case (i.e. physically restrict how far the wire can be pulled out of the case). Using a wire with two conductors would be better than two separately insulated wires just for tidiness, maybe you can find some scrap low-power speaker wire or something...
Wow, that was a much longer post than I'd expected, sorry! I hope that helps.
You'll also need a few different screwdrivers. The disassembly process goes roughly like this:
1. Turn the wheel 90 degrees to the left or right so you can get access to the screws on the back of the wheel, I think there are four (two on the left side, two on the right), they're small Philips screws and you'll need either a very thin or very long screwdriver to be able to reach them (I found a no.0 Philips precision screwdriver, the sort you'd use to repair sunglasses with, the best option). Undo the screws, turn the wheel 180 degrees the other way, undo the other screws. Now you can pull the button panel on the wheel off.
2. Carefully unplug the cable that runs through the steering column and put the panel somewhere safe with the screws.
3. Now you should see - I think - four fairly large domed Philips screws, they're quite tightly torqued too so you'll want a more substantial screwdriver for these.
4. Now you can pull the wheel itself off, but be careful to feed the cable through the hole in the wheel before you remove the wheel, if you drop the wheel with the cable still through the hole you might cause problems...
5. You should be left with four small screws, four large screws, the button panel, the wheel rim and the wheel base with the cable protruding from the now-bare steering column. Flip the base over and start removing the screws from the perimeter. These are quite deeply recessed in parts so you need a screwdriver with a long, thin shank (shaft, whatever), I think a no.0 or 1 Philips should do it. You're looking for silver self-tapping screws - if you find any black screws with a fine thread, leave those alone. I can't remember exactly but I think there are four of those visible on the bottom, they hold the DFP's gearbox in so it's best to leave those in place.
6. With all the screws out you can now remove the top cover of the base. I think the cable coming from the steering wheel is visible so you'll have no trouble tracing it to the wheel's main PCB (PCB = printed circuit board, of course).
So, yeah, you just need three different sizes of screwdriver and maybe a pair of needle-nosed pliers. And, of course, a soldering iron and preferably also a hot glue gun.
As for identifying the pins you need, read the PCB you pulled out of the wheel. It's double-sided so you'll need to unscrew it from the plastic. Look for the pad that was under the circle button, follow the two traces that it's connected to and Bob's your mum's brother, those are the two pins you need. Then hold the cable against the connector (it's keyed so you can only plug it in one way, make sure you have it the right way around!), find the colours that correspond to the pins, then look at the pins those colours are connected to on the wheel base PCB. Solder your switch on the underside of the PCB and that's that.
When it comes to soldering, don't try to just reheat the solder that's already there. First strip the ends of the wire you're soldering on then melt some solder onto the exposed ends (this will likely melt the ends of the insulation slightly, don't overdo the heat because the fumes are toxic, a tiny amount won't kill you, though). Then add a tiny bit more solder to the solder that's already on the PCB - the stuff that's already there is silver and there's no flux, so it won't flow well at all. Adding fluxed lead solder to it (and the wire) will make it much, much easier to make the new joint but you don't need much at all. Don't hold the iron against the connector for too long, maybe 2-3 seconds should be enough to make the new joint, or you'll melt the shroud and then the pin you're soldering will probably move. Consider clipping any excess bare wire (I'd aim for about 5mm of exposed wire at the very, very most) before you solder just to reduce the chance of shorting something accidentally, then use some hot glue (if you have a hot glue gun) to glue the wires somewhere on the PCB. I'd also advise drilling or cutting a small hole in the back of the DFP's case for the wires and then tying a knot or adding some glue to the wire itself to make a strain relief inside the case (i.e. physically restrict how far the wire can be pulled out of the case). Using a wire with two conductors would be better than two separately insulated wires just for tidiness, maybe you can find some scrap low-power speaker wire or something...
Wow, that was a much longer post than I'd expected, sorry! I hope that helps.
- 6
- Cyprus
that's absolutely brilliant, thanks very much, very concise and well described, like I was doing it already in my head. I am actually an engineer, mechanic and composites specialist I build and restore cars, had a rally parts business and almost 50, but have gamed rally since the first McRae games and done real rallying for a few years. But I'm also wise enough to know that internet forums are a melting pot of info and no need to delve into something like taking these things apart without finding out if someone did it first. So I very much appreciate your input. Cheers.
- 9,256
- United Kingdom
- neema_t
Well then! This is extremely off-topic, but maybe you can help me out with something... How would you go about mechanically stopping a shaft from rotating more than 900 degrees/2.5 turns? I'm modifying my G27 wheel to belt drive instead of gears (because they're loud, notchy and generally not as good as belts for this application), but I can't for the life of me work out how I can stop the shaft at either end of the rotation range.
Logitech's own system is a tiny pinion at the tip of the steering column which moves a plastic rack, then a lobe on the column itself rests on stops on either end of the rack so you physically can't turn the wheel any further. I wanted to mimic that but the logistics of it when I'm using off-the-shelf parts, a 25mm stainless steel pipe as a steering column and very limited tools and workshop experience kind of put a stop to that.
Then I thought I could use some string or rope, the idea being that it would be slack when the wheel is centered and precisely long enough that it could wrap around the steering column 2.5 times before running out of slack. Great idea, right? Well, so far I've only tried 3mm steel rope and it's far, far too springy when coiled and it can't wrap around a 25mm radius anyway, so it just loads the shaft which will kill the motors or FETs quickly, I guess. I've ordered some 2mm steel rope and some polymer bailing twine to experiment with, but I have absolutely no knowledge of different strings or ropes to try.
Another option could be a sort of solenoid used in conjunction with a rotation sensor, the idea there being the solenoid is triggered when one full rotation from the centre position is made to move a block into place which will then stop the shaft from rotating by engaging with a lug or block on the shaft, basically like an electromechanical version of the Logitech system. But that's expensive, requires external power and just isn't very elegant.
Do you have any ideas please?
On topic: I happened to find an image about an hour ago showing that if you remove the screws from the front of the DFP's wheel, you can pull the Gran Turismo badge off and access the screws that hold the wheel to the base through that but it seems like more effort and you almost certainly have a screwdriver you can use to take the entire front off as I described (which you'll have to do anyway), so. Anyway, photos:
You should be able to see the larger screws through these holes. Unscrewing those leads to:
I actually completely forgot you don't have to feed the cable through the wheel to separate it from the base, there's an intermediate connector in the shaft itself. Handy!
Logitech's own system is a tiny pinion at the tip of the steering column which moves a plastic rack, then a lobe on the column itself rests on stops on either end of the rack so you physically can't turn the wheel any further. I wanted to mimic that but the logistics of it when I'm using off-the-shelf parts, a 25mm stainless steel pipe as a steering column and very limited tools and workshop experience kind of put a stop to that.
Then I thought I could use some string or rope, the idea being that it would be slack when the wheel is centered and precisely long enough that it could wrap around the steering column 2.5 times before running out of slack. Great idea, right? Well, so far I've only tried 3mm steel rope and it's far, far too springy when coiled and it can't wrap around a 25mm radius anyway, so it just loads the shaft which will kill the motors or FETs quickly, I guess. I've ordered some 2mm steel rope and some polymer bailing twine to experiment with, but I have absolutely no knowledge of different strings or ropes to try.
Another option could be a sort of solenoid used in conjunction with a rotation sensor, the idea there being the solenoid is triggered when one full rotation from the centre position is made to move a block into place which will then stop the shaft from rotating by engaging with a lug or block on the shaft, basically like an electromechanical version of the Logitech system. But that's expensive, requires external power and just isn't very elegant.
Do you have any ideas please?
On topic: I happened to find an image about an hour ago showing that if you remove the screws from the front of the DFP's wheel, you can pull the Gran Turismo badge off and access the screws that hold the wheel to the base through that but it seems like more effort and you almost certainly have a screwdriver you can use to take the entire front off as I described (which you'll have to do anyway), so. Anyway, photos:
You should be able to see the larger screws through these holes. Unscrewing those leads to:
I actually completely forgot you don't have to feed the cable through the wheel to separate it from the base, there's an intermediate connector in the shaft itself. Handy!
- 6
- Cyprus
have you downloaded the logitech profiler program? you can limit the degrees of turn with that program if you are PC gaming, the program limits the degrees electronically.
- 9,256
- United Kingdom
- neema_t
Yeah, the problem is if there's no mechanical stop then the wheel won't stop turning during the initial calibration, and because I've binned everything (well, I still have all the parts in unmodified condition, but they're not going to be part of the finished article) from the original wheel except the motors and PCB I need to make something from scratch to stop the shaft from turning so it can calibrate properly in the first place. Right now I have four timing pulleys, two belts, three shafts, the two motors and some shaft couplers and some pieces of wood with holes cut in them to mount stuff to, oh and some bearings - nothing to stop the shaft from turning, though!
- 6
- Cyprus
can you still use a rack like what is in the wheel already (the white flat gear) but only use it as a lockstop like a real car's steering rack. so still have a gear on the shaft (pinion) that moves a rack you could then limit the rotation with something clamped to the rack like small jubilee clip maybe
- 6
- Cyprus
got the wiring done, O button is brown and light blue, made a rudimentary handbrake this afternoon and its working really great
