Acceleration Data Skewed

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ckowalc
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Acceleration Data Skewed

Post by ckowalc » Thu Nov 08, 2018 3:18 pm

Now, that V22 has come out my acceleration data is now working again but it is skewed about 40 degrees. I have tried the "Left Hand Traffic Preset" (since my mounting position is left of the driver) and "Automatic Preset" without success. I have been editing the CSV data and making a excel program to rotate the accel data points which is a bit tedious.

I believe I have tried "Individually Measured" setting too and for some reason I don't think it worked either but maybe I did not set it up correctly. I remember instruction to drive in a straight line, etc.

What setting should i use given my mounting position? Surely there has to be an easier way to calibrate the accelerometer?
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gplracerx
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Re: Acceleration Data Skewed

Post by gplracerx » Thu Nov 08, 2018 4:32 pm

See those little icons in the lower part of the g-g graph? The three on the bottom are used to change the angle. The one on the left rotates the data 2 degrees per touch counterclockwise and the one on the left rotates clockwise. The one in the center is supposed to orient the graph correctly. I'd try that first and then fine tune with the other two.

The driving position on the left calibration assumes the device is rotated about 30 degrees clockwise from perpendicular towards the driver. If you mount the device perpendicular to the vehicle axis, you should use the cam calibration.
ckowalc
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Re: Acceleration Data Skewed

Post by ckowalc » Fri Nov 09, 2018 11:58 pm

Not sure how I missed those buttons. Can you adjust the angle of the acceleration data for the entire day or session?

I'd say my setup is probably somewhere perpendicular and 30 degrees but I'll try the cam calibration. Maybe I can adjust my mount so it is perpendicular to the longitudinal axis of the car. Seems like there should be an easier way to calibrate the accelerometer though :/.
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Re: Acceleration Data Skewed

Post by gplracerx » Sat Nov 10, 2018 1:38 am

Can you adjust the angle of the acceleration data for the entire day or session?
Don't know. I suspect not, but have never tried it. I use HLT for autocross, so even for a day you're not talking many runs. Mine is never that far off.

Edit: I didn't look at the picture until just now. The orientation of the phone for accelerometer calibration assumes the phone is in the center of the windshield. So you are using the wrong calibration for the way your phone is pointed. Since your phone is turned to the right, you should be using the right calibration, not the left.
ckowalc
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Re: Acceleration Data Skewed

Post by ckowalc » Sat Nov 10, 2018 4:32 am

But it is "Left Hand Traffic" meaning Britain, Japan, etc where right hand drive cars are driven. That would mean the driver should be to the right side of the phone (when in the car looking out of the windshield)
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Harry
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Re: Acceleration Data Skewed

Post by Harry » Sat Nov 10, 2018 11:43 am

Yes, Left Hand Traffic means Right Hand Drive and vice versa. So with the device mounted like yours, Left Hand Traffic is correct. As long as you are not driving in Britain etc, you need to set this preset manually when mounting the phone in a non standard position.

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ckowalc
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Re: Acceleration Data Skewed

Post by ckowalc » Sun Nov 11, 2018 4:27 am

Any idea why the acceleration data is about 40 degrees off using the LHT preset? My phone is mounted about 10 degrees toward the driver so I'd expect the data to be ~20 degrees off at most?

Harry, what the best option for my phone mounting? Is there a way to adjust the accleration in all of the laps of a session? Thanks.
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Re: Acceleration Data Skewed

Post by Harry » Sun Nov 11, 2018 8:03 am

As a repair function, acceleration adjustment (rotation) needs to be done lap by lap. For the angle - please try with a the LHT setting next time, I’m not sure the math is simply adding up angles.

Harry
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