LIS2DS12 high output noise

[Avian.1]

Hello,

I have a LIS2DS12 accelerometer connected to an arduino MKR1000 through SPI.

For my application I need to use the highest ODR of 6400 Hz, and 2g FS.

In order to collect 1 s of acceleration data, I constantly pull data from the FIFO. I set the threshold to 5, and FIFO in continuous mode.

In the attached plot, you see X, Y and Z acceleration data with LIS2DS12 standing still on my table, with a very high noise!

In order to understand the origin of such a high noise, I first get a full FIFO and then I start to pull out data through SPI.

In such a way you can see that first 256 values have a certain noise, while as soon as I start SPI communication the noise increases.

Is this a knows issue?

Thanks a lot.

[Eleon BORLINI]

Hi @Avian.1​ , so you are basically filling the FIFO up to 5 samples (at ODR 6400Hz, threshold = 5), and then you read the FIFO content via SPI, right?

If you set a threshold, you should work in pure FIFO mode, i.e. stops collecting data when FIFO is full. As noted in the AN4748 p 43:

Follow these steps for FIFO Continuous configuration which sets a threshold to generate an interrupt to trigger a read by the application processor:

1. Set FTH[7:0] to 255.

2. Set INT2_FTH to ‘1’: Enable FIFO threshold interrupt

3. Activate Continuous mode by setting the FMODE[2:0] field to 110b in the FIFO_CTRL register (25h).

Regards

[YSong.3]

Hi @Avian.1 (Community Member)​ 

I have a same problem like you.

If you have solved this problem, please let me know how you solved it.

Thank you

-Yonghun

[Avian.1]

Hi Yonghun,

I'm sorry to tell you that I've tried a lot changing fifo mode, setting interrupts, and so but noise was always there.

At the end, I gave up and changed accelerometer (IIS3DWB).

I just think that LIS2DS12 is not made to work at high ODR.

[YSong.3]

Hi @Avian.1 (Community Member)​ 

thank you for helping me.

Do you know a site where I can get IIS3DWB??

I am currently struggling with the lack of stock for that sensor.

I mainly use Digi-Key and Mouser sites.

Thank you

-Yonghun

[Eleon BORLINI]

Hi @YSong.3​ ,

some products are still out of stock in this period, but things are recovering.

Especially in case you need more than 500 samples, I suggest you to directly check the ST eStore and to Contact Sales as indicated in the last row.

-Eleon