possible to install a tachometer to a g27?

[Michighani]

I know this sound silly but its worth a try... If any one know any thing about how to maybe install a nice aftermarket tachometer to a logitech G27 please help a fellow driver out I'd greatly appreciate it. I want to use it for gt6. Since the G27 already has an led tachometer I figured there has to be a way to use that for a better gauge. Thanks KS in advance

 

[polysmut]

A G27 is an electronic input device for a computer game & a tachometer measures rotation of moving vehicle parts?

So I would think definitely not.

Though this should probably have been asked in the Sim Racing Hardware Forum as it's not a question specific to GT6.

 

[eran0004]

In theory you could always code a tachometer recognizing software and link it to a camera that films the tachometer on the screen (provided that you play the game in Normal View). Your code would then analyse the footage, work out the engine speed and then send it to your aftermarket tachometer.

But it would be a long, complicated and probably expensive journey to get there, so for practical purposes let's just say that it can't be done.

Edit: But of course, then there is this...



So... anyone feels like accepting the challenge?

 

[IfAndOr]

Well the G27 does have functioning shift lights...

So it's certainly getting some information sent to it from the game (GT6). Whether there is enough to run a fully functioning tachometer - I don't know. It's worth investigating since I expect someone's had a go.

As @S_Bridge says it's probably best asked on the hardware section,

 

[Michighani]

A G27 is an electronic input device for a computer game & a tachometer measures rotation of moving vehicle parts?

So I would think definitely not.

Though this should probably have been asked in the Sim Racing Hardware Forum as it's not a question specific to GT6.

Sounds good I just didn't want it to get lost with all the truck Sims and PC games. I want it for turismo

 

[daan]

Moved to the correct forum.

 

[eran0004]

Well the G27 does have functioning shift lights...
View attachment 509607
So it's certainly getting some information sent to it from the game (GT6). Whether there is enough to run a fully functioning tachometer - I don't know. It's worth investigating since I expect someone's had a go.

As @S_Bridge says it's probably best asked on the hardware section,

Nice. I guess it depends on wether the signal is a continuos stream or if it only changes at certain rpm intervals (e.g. every 10%).

 

[IfAndOr]

Nice. I guess it depends on wether the signal is a continuos stream or if it only changes at certain rpm intervals (e.g. every 10%).

It is quite nice in a "oh look at that" way, but in practice I don't notice them because I'm looking at the screen and they are below my eye level.
They match up fairly accurately to the shift lights on the in game HUD. I would imagine that the game(s) sends a "light these LED's now" signal at certain points but maybe nothing before then - which would not allow a tachometer to work. But maybe someone who might know different has worked some magic and got one working.

I suppose any projects, such as the tachometer, are dependent on what data the game software outputs.

 

[Jet Badger]

The chip that appears to be controlling the LED strip on the small PCB behind the wheel rim is a HC595 - it's just a shift register. So it's job is just to reduce the amount of wires that go through the steering collumn - it just does whatever the microcontroller in the wheel tells it to, which in this case is turning on or off a set of LEDs, so all you can do with that information is just that. This means while the wheel does receive RPM data from the game, there's no way to extract it raw from there as it's processed inside the microcontroller, which you can't really get into.

 

[Outspacer]

I would think the LEDs are directly controlled, i.e. nothing like an RPM value is sent to the wheel. The alternative would be to set the LEDs up with redline and rev-limiter values, then send revs, but that sounds much less likely. The Logitech wheel SDK is included as part of Logitech Gaming Software on the PC (or was: http://forums.logitech.com/t5/Logitech-G-Controllers/G27-LED-SDK/td-p/400704) - maybe you could load that up and dig into it for a definitive answer.

 

[polysmut]

I would imagine that the game(s) sends a "light these LED's now" signal at certain points but maybe nothing before then - which would not allow a tachometer to work.

Just as a gut estimation, I wouldn't expect a game to send specifics like that to pieces of hardware. In the way of "light up a certain amount of the display on 'x' make/model of wheel now". My guess is that there's some processing going on within the hardware that's specifically designed to interpret RPM data that it's receiving?

The information in this thread so far is a revelation to me, I had initially pretty much dismissed the possibility of applying a tacho'. It's still guesswork at my end & I've become very interested to learn more.

 

[IfAndOr]

My guess is that there's some processing going on within the hardware that's specifically designed to interpret RPM data that it's receiving?

It's all guessing.
But to have the wheel hardware interpret the RPM data would mean it would have to know where the red line was for each car and light up the LED's at that point.


I found this which shows that you can have a tachometer in GT6 with a (highly modified) G27. But if you watch while he revs the gauge isn't running quite in sync with the game. More of a smoothed out interpretation. Impressive through.

 

[Michighani]

I never expected to see this much feedback. Rather it's possible or not I appreciate you guys for the time.

 

[Outspacer]

Well, heh, my guess could've been wrong... found some info on the SDK call that sets LEDs: https://www.lfs.net/forum/post/1336159. At that level at least, it's set as RPMs:

HRESULT Play(CONST LPDIRECTINPUTDEVICE8 device, CONST FLOAT currentRPM, CONST FLOAT rpmFirstLedTurnsOn, CONST FLOAT rpmRedLine);

Assuming that's what's sent to the wheel, the problem is to extract it from either the USB comms or the microcontroller inside the wheel - neither is easy!

 

[sesselpupser]

I've thought about this before too, while the 595 is technically capable of 256 output states it seems very likely to me, given that the microcontroller in the G27 already has so much to do, that the host console or PC sends the LED state data to the wheel rather than the rpm data which the microcontroller would then have to calculate before shifting out to the 595.

If it only has to deal with the LED data it could be as small as a 4-bit binary word which makes room for other data in the USB frame. I suppose the rpm data could be sent as a 4-bit integer too but that would still nix the idea of making a tach since the needle would only have as many positions as there are different LED patterns that the wheel can display.

In summary, no, I don't think it can be done well enough to be worthwhile.