Recording Steering Wheel Angle and Brake Pressure?

[jvkelley]

Is anybody recording steering wheel angle and brake pressure? What hardware is needed? I have a Kiwi 3 OBD2 dongle, can any software/apps capture this information from this dongle?



Thanks

 

[Cliff]

That information is not exposed by OBD-II. It should be available via the CAN bus but you have to know the identifiers of the channels used to transmit it and the possible values in order to tap into that information via a software driver.

I use a CAN bus connection with my AiM SoloDL but the only AiM driver that works with my Mk7 car is the one for the SEAT Leon. It has a brake indicator that toggles between 0 and 1 to signal when the brakes are applied, but the brake pressure channels don't return values which would indicate the VW and the SEAT use different channels for that information. There is no steering angle channel for that driver.

AiM tech support indicated to me a couple of years ago that if I could provide the appropriate channel information they could create a CAN bus driver specific to the Mk7 car. I reached out to 034Motorsport and a local Audi dealer for help but they did not provide any assistance.

 

[replicate]

That information is not exposed by OBD-II. It should be available via the CAN bus but you have to know the identifiers of the channels used to transmit it and the possible values in order to tap into that information via a software driver.

I use a CAN bus connection with my AiM SoloDL but the only AiM driver that works with my Mk7 car is the one for the SEAT Leon. It has a brake indicator that toggles between 0 and 1 to signal when the brakes are applied, but the brake pressure channels don't return values which would indicate the VW and the SEAT use different channels for that information. There is no steering angle channel for that driver.

AiM tech support indicated to me a couple of years ago that if I could provide the appropriate channel information they could create a CAN bus driver specific to the Mk7 car. I reached out to 034Motorsport and a local Audi dealer for help but they did not provide any assistance.

What CAN connector did you use? Did you need to tap into the can manually? I'm looking into this now. really just interested in Brake and throttle.

 

[Cliff]

What CAN connector did you use? Did you need to tap into the can manually? I'm looking into this now. really just interested in Brake and throttle.

AiM sells a CAN bus cable for their Solo DL devices and they provide connection instructions on their web site. The wire bundle with the necessary cables is buried deeply behind the instrument cluster. I paid a local car stereo shop to connect in the AiM cable - they charged $65 to do the work. I had them route the cable to that little storage cubby on the lower left side of the dash.

edit: I presume that storage cubby gets moved to the driver side on RHD vehicles.

 

[replicate]

AiM sells a CAN bus cable for their Solo DL devices and they provide connection instructions on their web site. The wire bundle with the necessary cables is buried deeply behind the instrument cluster. I paid a local car stereo shop to connect in the AiM cable - they charged $65 to do the work. I had them route the cable to that little storage cubby on the lower left side of the dash.

edit: I presume that storage cubby gets moved to the driver side on RHD vehicles.

ahh yep I’ve seen the cable on the website. So I assume the main limitation you have now is just knowing the PIDs to get the data from the canbus to build the driver. Which is definitely possible as there are lots of devices out there now which do this. MFA and Veckor for example.

 

[JackRabbitSLIM]

I gave this a shot last night. All of these signals were on the powertrain CAN bus. This is the location I used, pins 1 and 2 on the seat side coupler.


All signals are little endian. All IDs are in hexidecimal, lengths are in bits.

Steering angle is on ID 0x86, startbit 16, length 13, multiply by 0.0818.
Steering angle sign (+- or left/right) is ID 0x86, startbit 29, length 1.
Steering angle direction (CW/CCW) is ID 0x86, startbit 30, length 1.

Unfortunately VW is not using a signed signal for steering angle, there are separate 1 bit signals for positive/negative angle and CW/CCW wheel direction. This makes it tough to set logging equipment up for a continuous +- steering angle value, I think I'd need to use an arduino or pi to make it work with my RaceCapture. But if you don't care about the sign, just use the angle and remember which way the wheel was turned.

Brake pressure: ID 0x106, startbit 16, length 10. Subtract 100 to get numbers between 0 and ~350.
RPM: ID 0x107, startbit 24, length 12. Mutliply by 3 to get RPM.
Throttle position: ID 0x391, startbit 40, length 8. Mutliply by 0.48309 for numbers between 18.8 and 100 (not great, I know).
Water temp: ID 0x365, startbit 32, length 8, subtract 40 for degrees C.
Oil temp: ID 0x640, startbit 16, length 8, subtract 60 for degrees C.

Some of these signals wrap from one byte to the next which might make things hard to log on equipment that can't be programmed on the bit level.

 

[replicate]

Awesome work.
As an aside, I had a RaceCapture but it broke after about 12 months. GPS stopped working. cool device though.

 

[jmblur]

See https://golfmk7.com/forums/index.php?threads/datalogging.370107/post-7470961 for how to do it with OBDeleven. A little finicky, I still need to get an example vid out.

 

[LBmk7r]

See https://golfmk7.com/forums/index.php?threads/datalogging.370107/post-7470961 for how to do it with OBDeleven. A little finicky, I still need to get an example vid out.

Were you ever able to log those items? especially across 2 modules such as throttle & brake?

 

[jmblur]

I was able to get logs, just haven't had time to put things together due to a move. The fields exist as noted above though!

 

[Calubi]

I gave this a shot last night. All of these signals were on the powertrain CAN bus. This is the location I used, pins 1 and 2 on the seat side coupler.
View attachment 181050

All signals are little endian. All IDs are in hexidecimal, lengths are in bits.

Steering angle is on ID 0x86, startbit 16, length 13, multiply by 0.0818.
Steering angle sign (+- or left/right) is ID 0x86, startbit 29, length 1.
Steering angle direction (CW/CCW) is ID 0x86, startbit 30, length 1.
View attachment 181049
Unfortunately VW is not using a signed signal for steering angle, there are separate 1 bit signals for positive/negative angle and CW/CCW wheel direction. This makes it tough to set logging equipment up for a continuous +- steering angle value, I think I'd need to use an arduino or pi to make it work with my RaceCapture. But if you don't care about the sign, just use the angle and remember which way the wheel was turned.

Brake pressure: ID 0x106, startbit 16, length 10. Subtract 100 to get numbers between 0 and ~350.
RPM: ID 0x107, startbit 24, length 12. Mutliply by 3 to get RPM.
Throttle position: ID 0x391, startbit 40, length 8. Mutliply by 0.48309 for numbers between 18.8 and 100 (not great, I know).
Water temp: ID 0x365, startbit 32, length 8, subtract 40 for degrees C.
Oil temp: ID 0x640, startbit 16, length 8, subtract 60 for degrees C.

Some of these signals wrap from one byte to the next which might make things hard to log on equipment that can't be programmed on the bit level.

What did you use to tap the CAN high/low wires? Posi-taps? I'm interested in doing the same as you, but I'm trying to find a way that doesn't damage the OEM wiring. Perhaps something like pulling the pins for these wires from that connector and instead connecting them to a home made splitter wire using 2-port connectors, which itself would be connected to the original connector. Then reversing the tap would just be reinserting the original pins in the original connector.

 

[JackRabbitSLIM]

What did you use to tap the CAN high/low wires? Posi-taps? I'm interested in doing the same as you, but I'm trying to find a way that doesn't damage the OEM wiring. Perhaps something like pulling the pins for these wires from that connector and instead connecting them to a home made splitter wire using 2-port connectors, which itself would be connected to the original connector. Then reversing the tap would just be reinserting the original pins in the original connector.

I haven't made anything permanent. I just used T pins to back probe the coupler.

I've been thinking about coming back to this. I'm not as scared about cutting the wires, terminating and adding another coupler.

If you come across the OE terminals, will you link them here?

 

[jmblur]

I haven't made anything permanent. I just used T pins to back probe the coupler.

I've been thinking about coming back to this. I'm not as scared about cutting the wires, terminating and adding another coupler.

If you come across the OE terminals, will you link them here?

The other way to do a non-permanent install is to get both male and female sides and make a pass thru harness that just pulls the signals you need off. Super easy to add/remove and not bad to pin since everything is straight thru 1:1 except for the signals you care about. No permanent harness damage, but a lot of crimping work depending on the connector.

 

[Mini7]

Has anyone used OBDlink to pull data? And then use the RealDash App to display the info?

Trying to find a way to display live coolant temps while on track. Got oil temps on the dash. Would like to see IAT but not really worried about those.

 

[Mini7]

Im brain farting. I just need to get a ram mount for my android tablet and use my OBD11 to show the live gauge for coolant temp.