Accelerometer calibration

Discussion on the RaceCapture App - Windows, Android, OSX and Linux.

Moderators: JeffC, stieg

Post Reply
Copper280z
Posts: 30
Joined: Sun Mar 15, 2015 3:03 am
Location: United States

Accelerometer calibration

Post by Copper280z »

I'm mounting the RCP vertically, so that the label faces drivers left, green connector rear. Trying to calibrate the accelerometer for this I have switched the X and Z axes. If I click the Calibrate button, it sets AccelX to have a resting value of 1.0G, Z to have a resting value of 0G. If I tilt the RCP in the drivers left or right direction to simulate cornering I get the correct response.

As a workaround I set the RCP on a level surface, label up, and calibrated it, now in the installed position it reads zero for X and 1.0 for Z.

I believe AccelX should be set to zero and AccelZ set to 0 or 1.0(probably 1.0, although there's a good argument to having all zeros at rest) when you hit the button.

momostallion
Posts: 58
Joined: Wed Feb 12, 2014 1:48 pm
Location: dallas, tx

Post by momostallion »

when i press calibrate the numbers don't change for me. but my z axis reads 1 or -1. i would think it is supposed to be zero at rest but i dont really understand Z axis yet.

brentp
Site Admin
Posts: 5986
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Try the latest 2.7.9 firmware; we fixed the calibration for different orientations.

The Z axis is vertical, so when calibrated it will (should) read 1G.
Brent Picasso
CEO and Founder, Autosport Labs
Facebook | Twitter

unbalancedengineering
Posts: 20
Joined: Sat Jan 03, 2015 1:42 am

Post by unbalancedengineering »

Is the calibration button broken again in 2.8.5?

I have it mounted vertically, green connector down, label to the rear.

I noticed that all my vertical / longitudinal data cross talks. So I put the car back on the level scales to calibrate the unit again. Nothing changed. So I jacked the rear of the car up and hit calibrate again. Nothing changed. So what gives?



Jason
Attachments
Accel screen.png
Accel screen.png (61.15 KiB) Viewed 310 times

brentp
Site Admin
Posts: 5986
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Hi, Calibration should be working fine in 2.8.5; nothing was recently changed in this area.

However, if you change the default orientation (RCP upright, green terminal block facing forward) you need to re-map the channels.

Once you have the mapping in place, You'll need to calibrate, then read the configuration, then write the configuration back for it to stick.

On the feature list is an auto-learning procedure, so it can learn the orientation and calibration in one operation.
Brent Picasso
CEO and Founder, Autosport Labs
Facebook | Twitter

unbalancedengineering
Posts: 20
Joined: Sat Jan 03, 2015 1:42 am

Post by unbalancedengineering »

Does the orientation listed jive with the image I posted? I believe I got the correct settings from you, but wanted to confirm.

Also, when I hit the calibration button, it says calibration complete. Then I do get the option to read the calibration in the unit. The numbers do change. But there is no option to write the calibration back to the unit at that point.

Thanks,
Jason

unbalancedengineering
Posts: 20
Joined: Sat Jan 03, 2015 1:42 am

Post by unbalancedengineering »

Also, now after a few calibration / read cycles, I've noticed that the Z axis (mappped to y) is flopping from 32739 to -32739. Is this normal?

Thanks

unbalancedengineering
Posts: 20
Joined: Sat Jan 03, 2015 1:42 am

Post by unbalancedengineering »

Something clearly isn't right. Now I get -3 g in the z axis...

unbalancedengineering
Posts: 20
Joined: Sat Jan 03, 2015 1:42 am

Post by unbalancedengineering »

Brent?

unbalancedengineering
Posts: 20
Joined: Sat Jan 03, 2015 1:42 am

Post by unbalancedengineering »

Brent? I need to get this sorted before the next event.

Thanks,
Jason

brentp
Site Admin
Posts: 5986
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Hi- sorry for the delay.

This is what we'll try on our end, double-checking with the latest firmware. If you want to try along feel free to do so.

* Set your channel mappings as you need.
* Ensure firmware is written and synchronized with the app settings.
* Press calibrate, verify calibration is complete.
* Read back the configuration.
* Make a change to the sample rate, and then back again. Note the 'write config' button will be enabled (this is just to re-enable the write button).
* Write back the configuration.
* Read back the configuration to verify the data is present.
* Power cycle
* Re-connect and check dashboard read-out.

We'll test this process and let you know what we find on our end.
Brent Picasso
CEO and Founder, Autosport Labs
Facebook | Twitter

brentp
Site Admin
Posts: 5986
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Here's the orientation that should work for you (terminal block down, label pointing aft)

As before, make sure this orientation is written to the unit before performing the calibration, then do calibration, then read back, make change to sample rate, then write again so it's flashed.

Thanks for working through this, let us know how it goes!
Attachments
vertical_label_rear.png
vertical_label_rear.png (79.46 KiB) Viewed 265 times
Brent Picasso
CEO and Founder, Autosport Labs
Facebook | Twitter

Katmeho
Posts: 15
Joined: Mon Apr 27, 2015 3:54 am

Post by Katmeho »

Brent, whats the default orientation for the unit? I thought it was green block towards the rear of the car, logger button and other ports pointed forward, label up and mounting brackets down on the surface of the car? Also, is it recommended to calibrate each time you mount the unit? I take mine down after each trackday.

brentp
Site Admin
Posts: 5986
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Hi Katmeho,

The default orientation is label pointing up, green terminal block pointing forward.
Brent Picasso
CEO and Founder, Autosport Labs
Facebook | Twitter

Katmeho
Posts: 15
Joined: Mon Apr 27, 2015 3:54 am

Post by Katmeho »

Perfect thanks.

Post Reply