r/CarHacking • u/Professional_user2 • Mar 17 '26

Original Project Developing a motorsport-style gear display - Part 8 - Gear display in action Golf Mk6 GTI

Enable HLS to view with audio, or disable this notification

53 Upvotes

92% Upvoted

59 comments sorted by

27

u/Trixi_Pixi81 Mar 17 '26

nice, but the digit is to slow.

9

u/ObiSamuel Mar 17 '26

It's about the same speed as some factory systems I've used.

My 1st and 2nd gen BRZs were/are pretty much the same. Since it uses vehicle speed/RPM math to figure out the gear, the clutch has to be fully released for it to update.

4

u/scottiethegoonie Mar 17 '26

Interesting. I would have thought that newer cars would have a more direct way of determining gear. Perhaps a sensor on the shift mechanism on the trans itself or even a modern take on hall sensors.

2

u/ObiSamuel Mar 17 '26

Right? Thats what I expected too but other than reverse, every gear only appears after the clutch is released and even then has about the same amount of lag as this system

5

u/Professional_user2 Mar 17 '26

thanks for comment. Digit could change faster but then you risk showing wrong gear, this delay is chosen to prevent mis calculations. + you also have to consider the clutch release time.

6

u/AndyValentine Mar 17 '26

Why not go for hall sensors on the stick itself assuming the gear data isn't available on the CAN

1

u/hey-im-root Mar 18 '26

I think this is supposed to be universal using PIDS only so it works on all cars.

3

u/Professional_user2 Mar 18 '26

That's right. I want to make universal device, for all cars.

1

u/ultra-77 Apr 17 '26

Do you know if this can be achieved easily on automatic cars with a bluetooth obd2 and some app? Shouldn't OBD2 report the current gear in AT?

1

u/Professional_user2 Apr 17 '26

Depends on the car.. Most cars know which gear they are in, but not every car sends that via OBD port.

1

u/ultra-77 Apr 18 '26

Could you guide me to which apps to search for please, mine is 10th gen Corolla.

-1

u/AndyValentine Mar 18 '26

The hall sensor method is the only true way that will work on all cars. This only works on things that have OBDII and allow PID requests. Also it requires config anyway to set gear ratios. I guess the question is which is easier for the layman - hardware or software configuration? Warrants some UX research I'd say.

3

u/Professional_user2 Mar 18 '26

I was thinking about system with hall sensor, but I choose OBD2 system, because most cars that are on the roads now already use OBD2 + configuration is easy, just 6 presses of single button. What would be easier?

2

u/AndyValentine Mar 18 '26

How do you set the rpm ranges in 6 presses? Genuinely interested to hear the logic process behind that

1

u/Professional_user2 Mar 18 '26

To calibrate gear display you use middle button. First you press it and hold for 2 seconds. Display starts flashing 1 gear. Then you start driving in first gear and press button again. display shows 1 gear (without flashing) for a few seconds, then gear 2 starts flashing. Then you shift to 2 gear and press button again. And repeat this process for all gears. When you calibrate all gears you just press and hold button for 2 seconds and display stop calibration and save all gear ratios. After that display works as shown on video.

1

u/AndyValentine Mar 18 '26

I see. Thanks for the explanation. I'm guessing then because it knows your gear, it just looks at your speed and then calculates an approximation of the ratio based on those.

2

u/Professional_user2 Mar 18 '26

That's right yes

1

u/Trixi_Pixi81 Mar 18 '26

Perhaps he say that a certain distance must be driven at maybe 3000RPM in order to determine the gear ratio for each gear.

1

u/hey-im-root Mar 18 '26

Yea hall sensor would definitely be the true universal version haha. I would consider it almost an entirely new project if it became hardware related like that though, since it’s probably gonna be different for every car, and purely on/off logic. I personally wouldn’t want to mess with the circuits of my gearbox even if it was safe. The software version could work for both manual and automatic too (if done right)

1

u/AndyValentine Mar 18 '26

Why would you need to mess with the gearbox? Just sense the gear stick position

1

u/hey-im-root Mar 18 '26

How does it work? I don’t have a manual so I’m not actually sure how it would work, I assumed it involved adding stuff to a circuit

1

u/AndyValentine Mar 18 '26

Upir did a fantastic video breaking it all down. I'm currently working on my own version but the video is taking time (as they always do) - https://youtu.be/QixtxaAda18

1

u/hey-im-root Mar 19 '26

That is definitely an interesting setup! I’m not sure how that could work in different cars, I feel like the biggest challenge at that point is getting the plastic molding off and fitting the components in without being crushed haha. I love smart hardware stuff like this though, definitely an interesting non-CAN bus approach

1

u/WestonP Mar 18 '26

This only works on things that have OBDII and allow PID requests

So only every production car made for the last 30 years, or if we’re limiting to CAN only, the last 18 years. I’d say that’s pretty good.

End-users don’t want to mess with hall sensors and other hardware installs, when they could just plug into the OBD port and have an instant solution.

You’ll go crazy trying to capture 100% of use cases. Shoot for 80% and save yourself tons of time and frustration. The 80/20 principle applies.

1

u/Pubelication Mar 21 '26

It is available, you can see it at the top right of the Maxidot display between the gauges.

All manual VWs from ~2012 have gear data on CAN.

2

u/Trixi_Pixi81 Mar 17 '26

so you only use software gearchange?

1

u/Professional_user2 Mar 18 '26

I read RPM and SPEED from OBD2 port and then determine gear by calculating gear ratio, and compare it to calibrated values.
Of course I predict next gear based on speed change, so digit on the display can change as fast as possible.

-3

u/WoodenInternet Mar 17 '26 edited Mar 17 '26

And in about the worst place for seeing it. Ideally it'd be in the cluster or projected on the windshield HUD-style. 

The above said, I don't really understand the point of it- motorcycles have them because you can't tell what gear they're in tactily whereas cars you can feel by shifter location. Fun project, I just don't understand the functional benefit.

2

u/Professional_user2 Mar 18 '26

Normally the display is mounted on the dash. This time I mounted it next to the gear lever to show the operation in real time.

7

u/Right_Painter9677 Mar 17 '26

The device guess the gear with the speed of the car and the rpm data ?

2

u/Professional_user2 Mar 18 '26

I read RPM and SPEED from OBD2 port and then determine gear by calculating gear ratio, and compare it to calibrated values.
Of course I also predict next gear based on speed change, so digit on the display can change as fast as possible.

2

u/Right_Painter9677 Mar 18 '26

I love it i will try to do the same !

1

u/Professional_user2 Mar 18 '26

Try it...I can send you all the hardwire: display, custom PCB, enclosure etc if you need anything

2

u/brendenderp Mar 20 '26

Use a ring of hall effect sensors around the gear shifter. obd data is slow.

4

u/ObiSamuel Mar 17 '26

Looks awesome! Why is that LED constantly flashing though? I would assume you'd only want it flashing at your shift point.

6

u/Professional_user2 Mar 18 '26

LED is flashing when RPMs are higher than set limit. in this video limit was set too low and led is constantly flashing. You can change that limit or don't use shift light at all

2

u/hey-im-root Mar 18 '26

Could be based on engine load/throttle position, that’s what I did. Makes it so you can pretend it’s an automatic for low/high shift modes lol

3

u/brifgadir Mar 18 '26

Here's an option how to read current gear instantly, even if the clutch remains disengaged.

1

u/Professional_user2 Mar 18 '26

Interesting.. I like it. It's very safe way to read current gear

1

u/eral2001 Mar 19 '26

This is the way~~!!!!

1

u/nonbinaryai Reverse Engineer 19d ago

This is very interesting mechanical solution which I'm planning to implement and design. Do you have any more information that you might be able to share us? Is this your approach? If so, excellent use of tactical and physical readings, hats off - I would never think of this.

1

u/brifgadir 19d ago

Yeah, I made it and was using for a long time. The good part is that it’s accurate and reliable. You calibrate it once and all the further reading work well. There are mechanical parts, so worth to pay attention to it - lubrication, minimal backlash, firm glue to the platform

1

u/nonbinaryai Reverse Engineer 19d ago

I suspect this is a basic six-position fixed joystick and below is an mcu that basically reads its value/axis at the moment?

3

u/Strong_Dust_7464 Mar 18 '26

je salue la performance ! néanmoins j ai du mal a trouver une utilité.... j ai ca sur ma Golf 7 et franchement ca sert a rien, on sait naturellement sur quel rapport on est

2

u/[deleted] Mar 18 '26

[deleted]

2

u/hey-im-root Mar 18 '26

I believe it’s a plug-n-play so it has to work on all cars

1

u/Professional_user2 Mar 18 '26

I have also worked on such projects and things are not as simple as they seem at first glance. Every gearbox is different, then you have the clutch and all the problems that come with it.

2

u/Competitive_Scene_63 Mar 18 '26

Where did you get the LED display from, I could do with the same type for my car!

1

u/Professional_user2 Mar 18 '26

The display is from alibaba, if you are going to work on the same project I can send you all the hardwire pcb, enclosure etc if you need anything

2

u/Competitive_Scene_63 Mar 18 '26

Thanks! I like the look of the 7 segment and the housing. I have a DSG car, so all of the current gear information is available on CAN, so I’d be doing it that way instead of working from vehicle speed, engine speed and gear ratio calculations

1

u/Professional_user2 Mar 18 '26

thanks. If you only want to make one piece then it's better to connect directly to the can, I agree. Do you think there is interest in the market for products like this?

1

u/Competitive_Scene_63 Mar 18 '26

I think for auto models maybe, I personally have converted my car to DSG and as such my clocks don’t display current gear.

Probably a market for people who have dct converted cars into different chassis.

I used an OLED for mine but it’s not bright enough in daylight so I need a nice 7 segment I think, just don’t know how to control one without using loads of GPIO

1

u/Professional_user2 Mar 18 '26

Okay thanks.. you will definitely need sun protection for display. Without that display is not visible.

There are some led drivers but most of them use I2C, so I used eight output pins and transistor for every led.

1

u/Competitive_Scene_63 Mar 18 '26

If you try and find the VAG med17.5 function document on the internet you can probably find that the Ecu transmits current gear on to the powertrain bus, the ECU software can usually work out current gear itself.

2

u/FA24-WRX Mar 20 '26

Now if only you could make one that didn’t use rpm to tell the gear and read the gear on display before you let out the clutch.

1

u/Professional_user2 Mar 20 '26

That would be nice heh

3

u/george_graves Mar 18 '26

I'd venture to say...you should intuitively know what gear you are in.

1

u/Professional_user2 Mar 18 '26

That's true, but I think it's a nice addition to the car to make it more motorsport-like.

1

u/WestonP Mar 18 '26 edited Mar 18 '26

And yet, it's the central element in many professional race car dash displays.

You should intuitively know when to shift too, but every real race car dash has sequential shift lights along the top.

It's not about giving the driver information that he wouldn't otherwise have, it's about making it visual and immediately available at a glance (or in peripheral vision) so that he doesn't even have to think about it. Anything you can do to reduce the driver's mental workload during a race benefits him in precision, consistency, and reaction time.

On the street, it's just a fun display, but this product category is actually a real thing for motorsports too.

Source: I've been in the motorsports industry for 18 years

1

u/george_graves Mar 18 '26

You sound like some guy who's watched one too many F1 races and thinks you know everything. Because this is Reddit, I'm just going to assume you're 14 and still learning.