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wollewald / MPU9250_WE

An Arduino library for the 9-axis accelerometer, gyroscope and magnetometer MPU9250 and MPU6500. It contains many example sketches make it easy to use.
https://wolles-elektronikkiste.de/en/mpu9250-9-axis-sensor-module-part-1
MIT License
56 stars 26 forks source link

Sequence of execution of functions in setup arduino sketch #8

Closed RamkumarGorre closed 2 years ago

RamkumarGorre commented 2 years ago

Hi Wolfgang Ewald,

In the setup function call of [MPU9250_acceleration_data.ino] sketch, there is a comment before the setSampleRateDivider function to call this function only if the DLPF filter is enabled. But, the DLPF enable function call is made later. What is the sequence to follow? I altered the function calls, but do not see any difference in output values.

wollewald commented 2 years ago

Hi, the sequence doesn't matter. And at least I see differences if I change the DLPF. You need to look at the raw values. Here I have taken the unchanged settings, i.e. DLPF = 6. The module was just lying unmoved on the table. To see more values to compare I only printed the corrected raw values. DLPF_6

And here I have changed the DLPF to 0 and you will get similar results if you deactivate the DLPF with enableAccDLPF(false). Just commenting out is not enough as documented in the tutorial and the function list. DLPF_0

I would say this is quite a difference in noise.

To check if the sample rate divider works I have set the sample rate divider to 255. That means the output rate is 4 Hz. In order to see the effect you need to have an output rate on the serial monitor which is higher. I have applied reduced the delay of 100 ms in the example sketch and as expected I saw that only every second to third value is a new one:

sample_rate_divider_255

I also applied a sample rate divider of 1 and as expected after 100 ms I always got a new value.

sample_rate_divider_1

So, DLPF and a sample rate divider are working.

The interesting thing I found is that the the sample rate divider seems to work even if I deactivate the DLPF or set it level 0 or 7, which is in contrast to to what's being written in the data sheet:

Screenshot 2022-07-13 184850

But since I don't know if there are maybe different generations of the MPU9250 which behave diffenrently, I keep the comment.

wollewald commented 2 years ago

@RamkumarGorre , can I close this issue now? Or are you still checking?

RamkumarGorre commented 2 years ago

Hi Wolfgang Ewald,

You can close this case. Thanks for your support.

regards, Ram Kumar Gorre

On Thu, Jul 28, 2022 at 12:07 PM Wolfgang (Wolle) Ewald < @.***> wrote:

@RamkumarGorre https://github.com/RamkumarGorre , can I close this issue now? Or are you still checking?

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wollewald commented 2 years ago

You are welcome!