Logging (high resolution) IMU data ONLY


For an experiment, I want to use my Pixhawk as datalogger ONLY.
I want know the vibration during flight.
I think the best would be to log the acceleration and giro data as good as possible (high resolution). The CPU should just concentrate on logging the data for about 3 minutes on the SD card.

I’m not so familiar with the firmware but able to do some changes to it.
Maybe somebody would like to give me some advice how I can change the Pixhawk to a high resolution IMU data logger?

I also think the SD card might not be as fast. So I don’t know if it would make sense to use the internal storage as buffer?

Thank you very much.


And you will have the IMU data logged at 500 Hz
More info here

Thank you very much for your answer.

This will log the raw unfiltered IMU data, right?
What about the user-selectable filters inside the IMU itself (DLPF_CFG register) ? Is it possible to influence/change/deactivate those programmable filters?

I think if you really want to know 100% what’s happening to the sensor data you will have to dig for it in the drivers.
The highest frequency at which you can get IMU data on the Pixhawk is 1000Hz I think (not sure if you could go higher). I think some of the data is down-sampled and possibly filtered in the drivers (using a digital low pass filter). Some of the data I also assume is integrated and represented as delta angles / delta velocities with corresponding delta time.
So if you want to do analysis then I would suggest to look at the data sheet of the corresponding IMU and the drivers in PX4.
The experts on this topic are probably @LorenzMeier and @JulianOes

I just checked out the datasheet of the MPU6000 and for the gyroscope, the output data rate is 8000 Hz and for the accelerometer 1000 Hz.

Would be awesome if I could somehow log the data within the full resolution of the gyro/accelerometer.

Any ideas and help is welcome. Thank you.

Actually, how is the log triggered?
As soon as the “SWITCH” is turned on? Won’t this log all available data? Because I just want IMU data logged on the SD…

@michael_wintergarden I think logging starts when the vehicle is armed. The IMU data is logged but depending on what you want to do with the data you might want to know what kind of downsampling and filtering was done to it.

But how can I arm the pixhawk continuously? I can’t really use an extra remote control for that…

You will have to remove the -a from the startup script

Are you able to do it ? I would also like to log the sonar sensor data only. How can i do it?
Thank you.