Wiring Gas/Brake Pedals, for AndyWarne, UncleT, others?

[Tiger-Heli]

As most of you are probably aware, I believe MAME typicaly wants dual-axis control for Gas/Brake Pedals -  i.e. separate pots control each axis, and the pots can be pressed independently - you can mash the brake with the accelerator floored - would appear in Windows Calibration as gas pedal moves up and down, and brake pedal moves side to side.  But some PC games and most PC pedals are configured in a single-axis mode with the pots feeding into each other - i.e. pressing the brake is the same as releasing the gas - Would appear in Windows Calibration as gas moves cursor up, brake moves cursor down, both pedals up or depressed the same amount leaves cursor centered.

http://www.gunpowder.freeserve.co.uk/wheels/wiring.htm has a simple circuit for switching between the two using a single DPDT switch, but it is set-up for connection to the gameport.

http://dave.bit2000.com/AKIdoc.html has a similar (more complicated) circuit for doing this with the AKI, but it requires an 8-pole dual throw switch, along with two 500-ohm resistors.

I know UncleT was asking about this, and it sounds like he got it working with a Microsoft Dual Strike Hack, but I never saw the circuit posted anywhere.

And I would think it could be done with the A-PAC, but I can't tell from the diagrams on the A-PAC page how you would connect this.

If someone could post diagrams for how to connect this to a dual strike or A-PAC, it would be appreciated.

Thanks!!!

[AndyWarne]

There are two ways to do this on the A-PAC. I have tested both. The first way is to use a double-pole changeover switch. I can draw a diagram of this if interested but this second way is better I think:

Wire the pots as normal to the P1 side of the board.
Then connect the following wire links:
1 Right to 2 Up
1 Down to 2 Down
1D to 2D

Then, the P1 side behaves as two independent gas/brake pedals and the P2 side behaves as combined pedals on a single axis. So no switch needed. The other advantage of this method is that you can calibrate each variant independently. This will almost certainly be necessary because pedal pots don't normally go right to the end of the travel.
Andy

[Tiger-Heli]

Andy,

That second way is pretty slick

Could you also post (or put on the A-PAC page and link to) the method with the double-pole changeover switch.  (I think some users might want to use that and have another set of pots left over for steering wheel and clutch without having to buy two A-PAC's.

Thanks again!

[Flinkly]

or someone could always make an eight axis analog interface board...

you could call it the 8-pac too!

[Tiger-Heli]

or someone could always make an eight axis analog interface board...

^
^
^
 |
  - - - Or that  !!!

[Tiger-Heli]

Andy,

With the simplified method, if I understand correctly, movement of either pedal will be seen as activity on BOTH joysticks.  I know you can filter this out by how you map the joystick to the emulator, but does it make any noticeable impact on performance?

Also - is a matching capacitor required on the P2 side of the board with your method.

Thanks in advance!

[unclet]

Unfortunately I can not add anything to this topic since I never ended up using a switch to flip between single and dual axis pedals via a Dual Strike hack.

[Tiger-Heli]

Unfortunately I can not add anything to this topic since I never ended up using a switch to flip between single and dual axis pedals via a Dual Strike hack.   I simply have 2 sets of gas/brake pedals and one set is hacked to a Dual Strike (using the two pots) for dual axis support and the other pedal set is connected to another Dual Strike hack (using one pot) for single-axis. 

Okay, thanks!

BTW, are there any games that require single-axis?  I thought most MAME games wanted dual axis, and I expected most high-end PC racing games to expect this also.

[unclet]

I thought most older Mame racing games were all single-axis and only a few used dual-axis.

[Tiger-Heli]

I thought most older Mame racing games were all single-axis and only a few used dual-axis.   Many of the older racing games only had one pedal ... right?  Dual-axis pedals are required in case you wanted to slam your foot on the brake pedal while your gas pedal was floored so you could cause your  car to "spin out" or "burn rubber".    You could not do this on single-axis pedals since it would be impossible to have the brake and gas pedals both register high input levels at the same time.

BTW: I never really use my dual-axis pedals at all, but included them on my cabinet in case I wanted to use them eventually ... maybe with PC games in the future ... just never got around to playing any of those type games.    I got an Xbox instead of playing on the PC      I use my driving cabinet for the older Mame racing games (Pole Position, Bump-n-Jump, etc...)

Okay, now I'm a bit confused.

I agree some games (Outrun - for example) either used separate pots for both the gas and brake or maybe pots for the gas and a microswitch for the brake.  These games need dual axis pedals.

Some games (Pole Position?) had only a gas pedal and no brake pedal, but I would think these would play better with dual axis (the gas controls a single pot and uses full travel) but would work with single-axis pedals.

Is there any game that works with single-axis pedals (or requires single-axis pedals) that would NOT work with a dual-axis setup.

[u_rebelscum]

are there any games that require single-axis?  I thought most MAME games wanted dual axis, and I expected most high-end PC racing games to expect this also.

Any game in mame can use a single-axis setup.  But for those games that expect seperate axes, if you use a single, you'll miss some of the game play as mentioned above.

As for if a game needs single axis, that depends on how the game is emulated.  If the game driver has "Pedal 1" & "Pedal 2" listed in the inputs, you can use seperate, whether of not the original game did.  However, if the game driver uses "stick Y" for both gas & brake, you need single axis.

I don't know if any are stick Y, OTTOMH.  And the listinfo/listxml isn't detailed enough to easily search for them.

FYI, when I first got into mame (~0.36b14), most drivers used stick Y.  Since then, slowly many have moved over to pedel 1 & 2.  However, if mame really wants to document properly, if the original game used a single axis, mame should too, IMO, even with the can't-use-seperate-axes problem it would cause.  OTOH, inputs is one of the few areas mame is "loose" (and in some cases has to be if people want to play them).  [shrug]

[lkench]

I ended up wiring my gas and brake pedal combo as a single axis.  Whenever I hooked them up as dual axis, I had trouble getting it to register that I wasn't pushing the pedal.  I was using Mame32, so maybe that was part of the problem.  Once I wired them up as a single axis, when I wasn't pushing any pedals, nothing moved.  Anyway, that's what worked for me.