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As I am (trying) to move away from the Moitessier, I am stumped by the behavior of my MPU.
It's a MPU 9250/6400 that I connected to the GPIO pins. When level I get proper readings.
I know tilt-compensation is a thing, but I naively assumed this was handled by PyPilot.
Sadly, this is very much not the case: At 30 degrees tilt (heel) the compass is off by more than 45 degrees.
Both the accelerometers and the compass have been calibrated using PyPilot.
Needless to say my Moitessier does not have this problem.
If this is a hardware thing, please advice me which MPU I should buy (including a link if at all possible) as specs are not always as clear as I'd like..
Thank you for your hints!
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Hi Baltika,
Thanks for the feedback, I will look at that MPU. Happy to hear you have got it working, but I'd love to hear the results of your tests!
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I found something quite confusing last night:
If I hold the sensor 'right side up' (as I see it) and calibrate, the broad side of the sensor board is pointing forward (x-axis), and tilt compensation seems to work reasonably OK.
If I flip the thing so its upside down, the narrow side becomes the forward pointing side, and tilt compensation gets wacky, really bad tilting to starboard, ok-ish tilting to port.
What gives with the 90 degree rotation of the x-axis? This seems to indicate that tilt compensation is less well performed when pitching (as opposed to heeling).Understandable, as heel is normally much stringer than trim but still- huh???
Anyone with a better understanding of PyPilot that can elaborate? Thanks again!
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2021-08-04, 08:11 AM
(This post was last modified: 2021-08-05, 04:51 AM by seandepagnier.)
You must level the sensors in pypilot calibration to get reasonable tilt compensation
as for different tilt compensations. Consider that it is not pitch vs roll but north/south vs east/west. The magnetic field is mostly vertical
It could be you have bad sensors. Often with these, one or more axes does not work. I just threw about 50 mpu9255 away because the z gyro did not work. Sometimes the x or y gyro does not, sometimes some accelerometer axes do not work.
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2021-08-08, 11:40 AM
(This post was last modified: 2021-08-08, 11:40 AM by seandepagnier.)
yes I perform quality control for the ones on pypilot.org
As I said, I can order 50 and all 50 are good (this is extreme luck) or sometimes maybe 48 are good. Maybe only 10 are good. Then I often get all 50 bad ones. I wish I knew how to only order good ones.