G meter not moving at all

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froggy47
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Re: G meter not moving at all

Post by froggy47 »

gplracerx wrote:froggy47,

As Harry points out, braking works a lot better than acceleration, unless you have an all wheel drive car with lots of horsepower and really good tires. Besides, you might actually be able to brake hard on the way to the starting line from the grid, but they really frown on hard acceleration. Calibration wouldn't be a problem except for two things, you have to rotate the phone 90 degrees to do video, which requires re-calibration. You may have to restart the app if you lose contact with your Bluetooth devices, recalibration again.

I actually had the app calibrate or change calibration in the middle of a run. I wasn't going in a straight line at the time either.

What would be nice for those of us who use ball mounts would be a way to specify the device orientation for calibration rather than have the app determine the orientation after the fact. I'm pretty sure that I can eyeball the orientation of the longitudinal axis as well as the calibration routine.
I have mine on a panavise suction cup/ball mount. I have rigged it so I can leave it landscape orientation & touch the screen & buttons without moving it at all.

How can you tell if your attempt at calibration is successful?
Autox & HPDE
2004 Corvette Z06
Moto X/android, Dual 160, generic OBD2
gplracerx
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Re: G meter not moving at all

Post by gplracerx »

Go to More. If there's a C next to Acceleration, you're not calibrated. If there isn't, you are. To check the calibration, go to Acceleration, drive in a straight line and hit the brakes hard. The arrow should point to 12 o'clock. That tells you the yaw is OK. Then stop on a level spot and look at the lateral and longitudinal numbers. They should be zero and total acceleration should be zero. That means roll (lateral) and pitch (longitudinal) are correct.

If you're not calibrated, touch the center of the Acceleration display. A menu comes up that tells you what to do. You need to be stationary and level to start. It's supposed to calibrate if you then drive in a straight line and brake hard. For me, sometimes it does and sometimes it doesn't. The app doesn't seem to be very good at detecting driving in a straight line. There's also a Force Calibration button on the menu. As I said, that doesn't always give you a good yaw calibration.

The other way to calibrate is go to GPS and touch the Last Max reading box. That initiates a calibration, too. That works if you turned on HLT after you started driving. No number in the Last Max box is another way to know that you aren't calibrated for acceleration.

If you're logging throttle data, you want to put the pedal to the floor for an instant to calibrate the throttle data. That may not work very well for throttle by wire where the pedal position is just an input to the engine management system. If that's a problem for you, one of the alternate throttle PID's in Expert Settings is actual pedal position. You still need a full throttle reading to calibrate that.

The throttle chart is one of my pet peeves. In autocross, the throttle changes rapidly, sometimes faster than the OBD updates. Extrapolation from the previous reading to fill in data for GPS fixes while waiting for a new OBD reading leads to nasty looking throttle charts, in my opinion. Autocross doesn't seem to be all that high on the priority list.
froggy47
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Re: G meter not moving at all

Post by froggy47 »

gplracerx wrote:Go to More. If there's a C next to Acceleration, you're not calibrated. If there isn't, you are. To check the calibration, go to Acceleration, drive in a straight line and hit the brakes hard. The arrow should point to 12 o'clock. That tells you the yaw is OK. Then stop on a level spot and look at the lateral and longitudinal numbers. They should be zero and total acceleration should be zero. That means roll (lateral) and pitch (longitudinal) are correct.

If you're not calibrated, touch the center of the Acceleration display. A menu comes up that tells you what to do. You need to be stationary and level to start. It's supposed to calibrate if you then drive in a straight line and brake hard. For me, sometimes it does and sometimes it doesn't. The app doesn't seem to be very good at detecting driving in a straight line. There's also a Force Calibration button on the menu. As I said, that doesn't always give you a good yaw calibration.

The other way to calibrate is go to GPS and touch the Last Max reading box. That initiates a calibration, too. That works if you turned on HLT after you started driving. No number in the Last Max box is another way to know that you aren't calibrated for acceleration.

If you're logging throttle data, you want to put the pedal to the floor for an instant to calibrate the throttle data. That may not work very well for throttle by wire where the pedal position is just an input to the engine management system. If that's a problem for you, one of the alternate throttle PID's in Expert Settings is actual pedal position. You still need a full throttle reading to calibrate that.

The throttle chart is one of my pet peeves. In autocross, the throttle changes rapidly, sometimes faster than the OBD updates. Extrapolation from the previous reading to fill in data for GPS fixes while waiting for a new OBD reading leads to nasty looking throttle charts, in my opinion. Autocross doesn't seem to be all that high on the priority list.

What is MORE under? I am still finding my way around HLT.

:)
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Harry
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Re: G meter not moving at all

Post by Harry »

LapTimer's top level navigation (iOS) is done using a tab bar shown in the lower end of the screen. Four items are visible, the rest is hidden behind the "More" tab. In case you do not see the tab bar in the bottom of your screen, tap on or above the small upward arrow in the bottom of the screen. This will reveal a hidden tab bar.

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froggy47
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Re: G meter not moving at all

Post by froggy47 »

Harry wrote:LapTimer's top level navigation (iOS) is done using a tab bar shown in the lower end of the screen. Four items are visible, the rest is hidden behind the "More" tab. In case you do not see the tab bar in the bottom of your screen, tap on or above the small upward arrow in the bottom of the screen. This will reveal a hidden tab bar.

- Harry

How about android?

Can't find it.
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Re: G meter not moving at all

Post by Harry »

In Android, there is no tab bar and no More button ;-) There is no Acceleration view either, the available views get selected using the Option Menu in the top right. This means you need to use the Max G field in Timer or the acceleration circle in Video View.

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froggy47
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Re: G meter not moving at all

Post by froggy47 »

Harry wrote:In Android, there is no tab bar and no More button ;-) There is no Acceleration view either, the available views get selected using the Option Menu in the top right. This means you need to use the Max G field in Timer or the acceleration circle in Video View.

- Harry
So in timer you press the wrench , press ok, and drive/brake straight line? I do not see any Max G field in timer.

:)
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G meter not moving at all

Post by Harry »

To start from the beginning, usually you do nothing and everything works fine. It us good practice however, to check the overall acceleration field in Timer View to show a value smaller than 0.1G while in the pits. In case it shows something strange, press the Max G field in the bottom right of Timer View to restart calibration. Once you press this field, you should see a confirmation calibration has been restarted.


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Re: G meter not moving at all

Post by gplracerx »

froggy47,

Sorry, I forgot you were using the Android version.
froggy47
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Re: G meter not moving at all

Post by froggy47 »

Harry wrote:To start from the beginning, usually you do nothing and everything works fine. It us good practice however, to check the overall acceleration field in Timer View to show a value smaller than 0.1G while in the pits. In case it shows something strange, press the Max G field in the bottom right of Timer View to restart calibration. Once you press this field, you should see a confirmation calibration has been restarted.


Harry

OK, so now I think I get it, thanks Harry.

:)
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