Interface custom shifter to hacked G27 shifter?

[BadMouth]

The shifter in the G27 is basically an analog joystick whith a chip somewhere in the G27 that translates it into button presses.
I haven't seen a switch based shifter hacked into it.

Has it been done?

Searching didn't result in much info other than the shifter contains 3 chips and one of them is only available in surface mount.

I'd think it would be possible work out some circuit that results in the appropriate resistances to make the G27 report the appropriate gear.
Basically, you only have 3 positions for the X axis and 3 positions for the Y axis.  So the G27 is probably comparing the two and generating outputs based on that.
If this is done by the chips in the shifter itself, I'd think you could tap in on the output side.  If it were that easy, it would probably have been done already.
So I'm assuming we need to start at the pots in the shifter and make a circuit that mimics them.

I'm on the verge of ordering a spare shifter so I can tinker.
(why oh why did I sell my old G27?!?)

Thoughts?
More info?

[Brian74]

I could swear the g25 has pots in the shifter.

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[Fursphere]

I haven't taken mine apart yet.  Do they sell spare shifters seperately?  I should buy one with the way my 3 year old hammers the thing. 

Check this out:

[BadMouth]

I haven't taken mine apart yet.  Do they sell spare shifters seperately?  I should buy one with the way my 3 year old hammers the thing. 

Check this out:

I saw that, but was figuring that he was still using the original G27 mechanism since he's using the same shifter knob and didn't even hack the buttons.

Thought maybe someone had come across his hack or a different one in a sim forum.
All I've come across is how to change the feel of the shifter.

Now I'm divided between paying $35 for a spare shifter or going ahead and putting it toward the $235 for another G27.

I'm still not 100% decided on using the G27 in my cab. 
The biggest thing going for it is the steering wheel and buttons on it.
The clutch pedal can only be used in a few games and causes problems in some PC games that I'd like to play.
I dislike everything about the shifter.

I put my Happ/ServoAmp/MOMO hack back together last night and plan to start tinkering with it again for comparison.
The new optical encoder I got mounts differently than the last one, so I have to make a new mount.

I have a feeling that I'll end up using the G27s with an extension like Brian74 did.
I really want a different shifter though and it would be nice to hack it in place of the original rather than use up other buttons or keyboard inputs.

[BadMouth]

Went ahead and ordered a spare.
Here is the cheapest I found ($25+shipping)
http://www.ebay.com/itm/231064029206?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Will post teardown pics and results of experiments when it arrives.

[Brian74]

I bet you could tap into the inputs and use a happ or other 4 speed. Im thinking about getting rid of my peddles and going back to the stock peddles.

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[BadMouth]

I bet you could tap into the inputs and use a happ or other 4 speed. Im thinking about getting rid of my peddles and going back to the stock peddles.

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Nah, it's not that easy since it uses pots instead of switches.

Still, I don't think it will be that hard.
I'm guessing it will use the same 10k pots that seem standard in all controllers nowadays.
Making a lot of assumptions here, horizontal would be 0k for left, 5k for center, & 10k for right.
Vertical would be 0k for down, 5k for center, & 10k for up.

1st Gear would be 0k on pot 1 and 10k on pot 2.
2nd Gearwould be 0k on pot 1 and 0k on pot 2.
and so on....

We just need to make a circuit that has those amounts of resistance when a switch is tripped.
I bet there is some way to utilize the NC and NO positions on the switches to pull this off using only a handfull of resistors and no logic chips.

Actually, thinking about how the 3 switch ketz shifters are made to register forward or back, left or right, this might actually be easier with them.

I'm getting a bit ahead of myself here.  Need to tear down the shifter and see how it actually works first.
But that's my theory.
 

[Fursphere]

if its simple resistence per position.

make a board with resistors and switches for the happ interface.

1st gear = closes switch with 0k resistor (or nothing...)
2nd gear = closes switch with 10k resistor
3rd gear = closes switch with 20k resistor and 10k resistor  (might need double switches, or relays or something if two isolated circuits are involved)

Once you figure out what its doing, just build switches to close circuits with the right Resistance.  Don't even need pots.

That would be EASY to build and to test.   bread board that sucker with radio shack parts

[Brian74]

To get my buttons to work when  did that happ Logitech hack, I used resisters.

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[BadMouth]

3rd gear = closes switch with 20k resistor and 10k resistor  (might need double switches, or relays or something if two isolated circuits are involved)

lost you there.  3rd gear would be center for the left/right pot (5k) and up for the up/down pot (10k)

Getting waaaaaay ahead of myself since we haven't even tested to see how it works, but I made a chart in paint to help me conceptualize.

[Fursphere]

So for the G27....

When you move the shifter into 1st gear - you're really adjusting the potentiometers to like 0k and 10k  (for example).  Now, is it averaging those together, or is it two unigue inputs.

Its all "scan" lines right.    Or probes.   or whatever.   Meaning the circuit is "probing" those for value changes. 

So for a SWITCH type shifter - when you move to 1st gear - does ti close one switch?   or does it close two switches?   I'd have to look at the thing to really know.

Lets say it closes two switches.   Wire the switches to a resistor that when closed, feeds that probe a 10k reading, otherwise feeds an open reading (or whatever the pot reads).

We just need to make sure the probed values are there when they're supposed to be when they're in teh right gears.

[BadMouth]

So for the G27....

When you move the shifter into 1st gear - you're really adjusting the potentiometers to like 0k and 10k  (for example).  Now, is it averaging those together, or is it two unigue inputs.

Its all "scan" lines right.    Or probes.   or whatever.   Meaning the circuit is "probing" those for value changes. 

So for a SWITCH type shifter - when you move to 1st gear - does ti close one switch?   or does it close two switches?   I'd have to look at the thing to really know.

Lets say it closes two switches.   Wire the switches to a resistor that when closed, feeds that probe a 10k reading, otherwise feeds an open reading (or whatever the pot reads).

We just need to make sure the probed values are there when they're supposed to be when they're in teh right gears.

I'm guessing it's two unique inputs since each pot has its 3 wires going to the board with the chips (same board the buttons and D-Pad press)
This should be easy to do if each gear as two switches.  I did a quick search for double position lever microswitches, but didn't come up with anything.

All I'm basing this on so far is seeing pictures of the shifter torn down and it having pots.
I tore apart the one I had before, but didn't do any testing on it.
There are some decent pics here:
http://www.chilicoke.com/mods/shifterresistance.htm

Of course, just like using a wheel in Ridge Racer Unbounded, the solution might be much simpler, but nobody has tried it.
If the chips are doing the conversion to a single button press, then we just tap in on the other side of the chips.
We have 19 buttons total and a 9 pins connector though, so it can't be as simple as touching a couple wires together.

The buttons in the Logitech MOMO steering wheel had two different ground wires and the button which registered was different based on which ground wire was used.  Could be something like that or a matrix.  The other buttons on the shifter might even be set up for varying levels of resistance depending on which button was pressed.  Maybe that's why the old PS2 wheel hack required resistors?

All speculation at this point, but if we start at the beginning and mimic the pots, it will work regardless of what happens farther down the circuit.
I might have to tear my current shifter apart instead of waiting for the new one to come in!

[Fursphere]

I think you said this before - but its rare that a game has joystick support and DISABLES the keyboard support at the same time.

It may be as simple as getting an iPAC installed and wiring the 4-Speed HAPP shifter to that (or whatever you are using). 

[BadMouth]

I think you said this before - but its rare that a game has joystick support and DISABLES the keyboard support at the same time.

It may be as simple as getting an iPAC installed and wiring the 4-Speed HAPP shifter to that (or whatever you are using).

I like figuring out stuff that hasn't been done already (but should have been).
Some things are way above my skill level and would take too much time and resources.
This one has just the right amount of challenge for me, so I will enjoy working it out.

[Fursphere]

So whats the drive to take the 6 Speed + Reverse shifter out and replace it with a 4 speed shifter?  (I guess there is that 6 speed HAPP as an option too)

Since you'd have to keep the bulk of the G27 shifter, it doesn't really get you a whole lot. 

Are you trying to get it into the dash in its "native" location? 

[BadMouth]

So whats the drive to take the 6 Speed + Reverse shifter out and replace it with a 4 speed shifter?  (I guess there is that 6 speed HAPP as an option too)

Since you'd have to keep the bulk of the G27 shifter, it doesn't really get you a whole lot. 

Are you trying to get it into the dash in its "native" location?

   I want to ditch the ENTIRE THING and keep the interface.
If it goes the way I want, there will be nothing left but the PCB wired up to some barrier terminals.

I'm not just doing it for my own use.  I'm doing it to add to the knowledge base.  Sim guys should find it useful too.
I might not even use it when I'm done....but I'll know it can be done and that gives me satisfaction. 

I do things for the sake of learning how stuff works.  Just a continuation of tearing my toys apart as a kid.
You could present twenty other solutions and I'm still going to figure out how the G27 shifter works because it is a goal in and of itself.

[Brian74]

So here is what is left of the shifter of my g25. It has two pots with seven wires.

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[Brian74]

I used the mount from a old happ 4 speed shifter and jb weld.

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[BadMouth]

FINALLY received the spare G27 shifter that I ordered.  Be careful if you ever take the shifter section apart.
There is a little spring loaded ball bearing that gives you the feel of going in and out of gears forward to back.
That sucker will take off when the two sides separate.  The sides are held together with a spring at the bottom and will fly apart when you lift the shifter section out.

Did some testing.  It has 10k pots and works about as expected, but it works off voltage instead of resistance.
Take everything I say with a  grain of salt, as I'm still a noob when it comes to electronics components.

Basically the G27 measures the voltage from the wiper(center) of the pot.
As far as I can tell the traces from the wiper go directly to the main connector, so this measurement isn't taking place in the shifter itself, but on the main pcb of the G27.

I tried using resistors, but it didn't work unless I used a pair to mimic the pot and divide the voltage.
Then I hooked up a bench power supply to the wires that would normally go to the ground and wiper of the pot.
Thankfully, it worked and didn't fry my G27.


Here is what I got:

Red is the lead from the left/right pot.
4v is left, 3v is center, 2v is right.

Brown is the lead from the up/down pot.
1v is up, 3v is center, 5v is down


Gear    Red   Brown
1st       4v       1v
2nd      4v       5v
3rd      3v        1v
4th      3v        5v
5th      2v        1v
6th      2v        5v
N         3v       3v

Reverse is just a simple switch.  The pots play no role in it.

What's all this mean?  I'm too tired to wrap my brain around it tonight.
The testing part is done.  I'll work on the thinking part while I'm tied to a desk at work.

Also for reference, gear shifter mech connector:

5v - yellow
Reverse - Orange
Left/Right - Red
Up/Down -  Brown
GND - Black

EDIT: This might not be too bad to work out.  Just have a line of resistors in series and each gear switch would tap into them where the appropriate voltage would be.  The only real PITA part is that you need both axis independent of each other.  Switches for up and down might have to be worked into the shifter design, but I was hoping for a simple single input for each gear.

[Brian74]

I had the same prob with the bearings when I took mine apart.

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[Fursphere]

FINALLY received the spare G27 shifter that I ordered.  Be careful if you ever take the shifter section apart.
There is a little spring loaded ball bearing that gives you the feel of going in and out of gears forward to back.
That sucker will take off when the two sides separate.  The sides are held together with a spring at the bottom and will fly apart when you lift the shifter section out.

Did some testing.  It has 10k pots and works about as expected, but it works off voltage instead of resistance.
Take everything I say with a  grain of salt, as I'm still a noob when it comes to electronics components.

Basically the G27 measures the voltage from the wiper(center) of the pot.
As far as I can tell the traces from the wiper go directly to the main connector, so this measurement isn't taking place in the shifter itself, but on the main pcb of the G27.

I tried using resistors, but it didn't work unless I used a pair to mimic the pot and divide the voltage.
Then I hooked up a bench power supply to the wires that would normally go to the ground and wiper of the pot.
Thankfully, it worked and didn't fry my G27.


Here is what I got:

Red is the lead from the left/right pot.
4v is left, 3v is center, 2v is right.

Brown is the lead from the up/down pot.
1v is up, 3v is center, 5v is down


Gear    Red   Brown
1st       4v       1v
2nd      4v       5v
3rd      3v        1v
4th      3v        5v
5th      2v        1v
6th      2v        5v
N         3v       3v

Reverse is just a simple switch.  The pots play no role in it.

What's all this mean?  I'm too tired to wrap my brain around it tonight.
The testing part is done.  I'll work on the thinking part while I'm tied to a desk at work.

Also for reference, gear shifter mech connector:

5v - yellow
Reverse - Orange
Left/Right - Red
Up/Down -  Brown
GND - Black

EDIT: This might not be too bad to work out.  Just have a line of resistors in series and each gear switch would tap into them where the appropriate voltage would be.  The only real PITA part is that you need both axis independent of each other.  Switches for up and down might have to be worked into the shifter design, but I was hoping for a simple single input for each gear.

Awesome findings man!  I was wondering about the external power supply vs. onboard power supply.   Curious if it was using the line voltage for reference or not - doesn't appear to be.

Check this sucker out:  http://www.wellgainelectronics.com/cherrye23110p800.aspx

At $25 ea its pricey though. 

Here is another two pole microswitch... http://www.alps.com/e/news_release/2013/0828_01.html

[BadMouth]

Check this sucker out:  http://www.wellgainelectronics.com/cherrye23110p800.aspx

At $25 ea its pricey though. 

LOL at two switches stacked together for $25.

I feel like there should be some crazy solution to this using clever routing and both contacts (NO&NC).
I just need to be in the mood for a puzzle.

Another possibility is a powered solution where each switch trips a pair of opto-isolators, but I'm hoping to avoid getting that complicated.
Not sure if the 5v going to the pots could handle enough current to power the LEDs in the optoisolators.  I'm afraid to find out.

[Fursphere]

Check this sucker out:  http://www.wellgainelectronics.com/cherrye23110p800.aspx

At $25 ea its pricey though. 

LOL at two switches stacked together for $25.

I feel like there should be some crazy solution to this using clever routing and both contacts (NO&NC).
I just need to be in the mood for a puzzle.

Another possibility is a powered solution where each switch trips a pair of opto-isolators, but I'm hoping to avoid getting that complicated.
Not sure if the 5v going to the pots could handle enough current to power the LEDs in the optoisolators.  I'm afraid to find out.

One multi-contact relay per shifter switch?     You could do it with transistors too I think. 

[BadMouth]

Was brushing my teeth and it dawned on me.
It's so simple, it's stupid. 

Run 5v to all the switches and step it down to the needed voltages after the switch.
So, the switch for gear 1 has 5v in (from the Logitech).  When it's triggered, it will pass the 5v to a circuit containing a couple resistors to divide the voltage into 4v and 1v.  The ones that require more than 5v total will need parallel circuits, but they'll both be fed by the same switch.
For good measure, the NC side of all the switches could be connected to a circuit that sends 3v to both.

I hope this still makes sense in the morning. 

[Fursphere]

Duh!  That makes perfect sense.   

Make sure its the same 5V supply line for both pots.  If its separate lines - might not work - although you said it worked with an external power supply, so I don't see why it wouldn't. 

[BadMouth]

Duh!  That makes perfect sense.   

Make sure its the same 5V supply line for both pots.  If its separate lines - might not work - although you said it worked with an external power supply, so I don't see why it wouldn't.

Power and ground are just jumpered between pots, so no worry there.

I'm sure this concept will work.  It shouldn't require anything but a few bucks worth of resistors and diodes.
The diodes will be needed to prevent voltage from going backward through the other gear circuits since all of them will be wired to the same two Logitech wires.

Now I'm trying to decide whether it makes more sense to:
have a set of resistors for all six gears + neutral followed by diodes
or
only have sets of resistors for the three values for left/right and the two values for up/down, but that would also require diodes before the resistors because each switch is going to be connected to two sets.  This might end up using just as many parts, just not duplicated parts.

The first one is probably the way to go, but need to diagram it to see if there are ways to simplify.

Not sure when I'll get to it.  In the mood to work on more mechanical things today.
If someone else wants to draw up a diagram, have at it!

EDIT: Here's the concept with just two gears.  The final design would have six, but another circuit for neutral.  The power for neutral would be daisychained through all the NC terminals of the switches, so that if no switches were pressed, the correct voltages for neutral would be sent.  A couple gears will require three resistors to get the correct voltages.
(I'm a noob at schematics if it doesn't show)

[RamjetR]

My Custom HID Arduino based shifter interface.

I made my own HID pluggable joystick libs and arduino compatible shifter lib based on a teensy C program from here http://www.isrtv.com/forums/topic/13189-diy-g25-shifter-interface-with-h-pattern-sequential-and-handbrake-modes/

I modified it to have setters and getters for new methods to make it object orientated programming compatible as a standalone library.

[Boomslang]

did you ever get further with this Badmouth?

I am converting some twin cab and just put in 2 x Logitech G29 wheels and pedals but Im using fanatec clubsport shifters cos logitech one is like a little toy to me

Only issue is I cannot use my fanatec shifter on logitech wheel directly for any console gaming, I have a couple spare g25 shifters here so would love to mod it into the mix somehow

[BadMouth]

did you ever get further with this Badmouth?

I am converting some twin cab and just put in 2 x Logitech G29 wheels and pedals but Im using fanatec clubsport shifters cos logitech one is like a little toy to me

Only issue is I cannot use my fanatec shifter on logitech wheel directly for any console gaming, I have a couple spare g25 shifters here so would love to mod it into the mix somehow

No.  The circuit in my last reply should work, but I never got around to testing.
I usually have more ideas than time, especially since buying a house that needed a complete remodel.
The G27 shifter interface isn't even on my radar at the moment.

I'm currently tinkering with a half dozen things, half of which I won't complete.    
(but I do enjoy figuring them out)

[Boomslang]

I've got my fanatec voltages etc. A little different to logitech they only have 1 hall effect sensor and then hits 2 micro switches for up and down.

Just need to work out best way so when 2.7v happens from 1st and 2nd gear it outputs 4v to logitech on red. WHEN 1.5v happens from 3rd and 4th it outputs 3v to logitech on red etc

Not sure if any board can be programmed for this or something 

Micro switches just need to change brown between 1v and 5v so shouldn't be too bad on that