Problems of LSM6DS33 usage

Hello!

I tried to use LSM6DS33 board for a creation of a vibration sensor.
In order to reach with target I have connected it with a Teensy 3.6 board.
Software for these boards connection was created by the software developer
with the experience more than 8 years. So, I have no hesitation that they are
connected properly.

I have tested a made accelerometer on the calibrated shaker of Bruel & Kjaer
at the acceleration range 1 G. I expected that amplitude-frequency
charatcteristic (AFC) of LSM6DS33 board is close to a line. However,
the carried out experiments show that it differs with a line significantly.

Results of the measurements performed for 1G acceleration are given below

          Hz  5   16  32   64   125  250  500  600  700  800  900 1000  2000  3000

RMS_A (m/s2) 7.2  7.1 7.2  7.2  7.1  7.1  7.2  7.1  7.2  7.6  7.8  8.4   8.8  12.3

Results of measurements in other acceleration range are similar.

Can you give me some recommendations how to achieve linear AFC?

Thanks in advance

Hello.

We do not have any particular recommendations on how to achieve that with the LSM6. However, if you post a sample of the raw output of your LSM6, along with the code you used to generate that output, I can help check to see if it is behaving as we expect.

-Jon

I would like to ask you what is the resonant frequency of this sensor and do you have any information about its amplitude-frequency characteristic (maybe some graphs)? this information is absent in the sensor datasheet.

Unfortunately, we do not know the resonant frequency or amplitude-frequency characteristic of that, or any of our other accelerometers. All of the information we have available for them can be found inside their datasheets. You might try directly contacting the manufacturer, ST. If you decide to find out through testing, or if you are able to get in contact with ST, we would definitely be interested in hearing about it.

-Jon

According to your answer on my letter please find file in attachment.

LSM6DS33.ino (9.82 KB)

Try some other accelerometers. They are not expensive, and if you run into problems, perhaps a different manufacturer would be more responsive to questions.

@Mykhailo, it is not entirely clear to me what you expect from posting your code here, but it sounds like you are probably referring to what I said in this post, where I invited you to respond with a sample of your raw data and code if you suspected you were getting behavior that you did not expect or otherwise ran into other issues using the sensor. If you are having trouble, please describe in detail what the issue is and post a sample of your output.

Also, what Jim mentioned could be reasonable for you: if those specifications are important to you, it might be more straightforward and beneficial to find a sensor that has published explicit information about those before acquiring it and writing code for it (unless you want to test the sensors and characterize it yourself).

Like I mentioned earlier, we do not have any extra information beyond what is in the datasheet and other documentation provided by the IC manufacturer.

-Jon

Hello!

Please find in attachment file with data of correct and incorrect condition of sensor operation.

Maybe this information will be useful for better understanding og sensor operation.

Sampling frequency in both cases was - 6664 Hz.

Best regards

Sensor Test.xlsx (73.9 KB)

We do not see anything obvious in your code that could be causing the amplitude difference in your results, and we do not have any particular knowledge about the expected frequency response of these accelerometer ICs (and we do not have the equipment to perform this kind of characterization ourselves), so we do not have any advice for you. You could try posting your questions to ST’s forum.

-Jon