Roll and pitch values

[Sten-Helge]

Hi there,
doing some testing on the orientation and angles of the IMU, I’m using the code in “gyro_accelerometer_tutorial01.c”.
The board have the skull facing downwards and the bmp180 chip in the front.
While reading the values, roll is given with negative values when tilting to the left and positive values when tilting to the right as it should.
Tilting forward gives positive values and likewise tilting backward gives negative values.
Shouldn’t be the other way around, ie negative values forward and positive values backwards.

Thanks and regards

Please right click on link bellow to see orientation.

[Mark Williams]

Have a look at this image

It shows the orientation of the LSM9DS0 used by BerryIMU. What you are seeing is correct.
Look at the chip on your PCB and find the pin indicator to match it up.

What makes you think it should be around the other way?

Mark --OzzMaker.com --

[Sten-Helge]

Thanks for the replay,
Given the orientation of the board, as shown in the picture I attached, is correct, tilting the nose of the platform on which the board is mounted forward and down should give negative values. Tilting the platform backwards should give positive values.
In one of my setups I’m using the IMU board onboard a vessel. The compass and roll is correct, but the pitch give negative values when the vessels bow are going up, and positive values when the bow goes down.
Please advice.

[Mark Williams]

No.. tilting it forward should give a positive value on Y
And tilting to the right should give a positive value on X

On the image below, you can see the pin marker. Match this up with the image above to work out the orientation.

Mark --OzzMaker.com --

[Sten-Helge]

Thanks,
I have to look more closely into this issue. The navigation equipment I’m passing information to, expect negative values when tilting the nose down.

Regards

[Sten-Helge]

Solved the issue temporarily by turning the the IMU upside down, ie the skull facing up. I will look into the math more closely.

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