Inquiry Regarding Abnormal IMU Data from FFC4P Module

Daehyun

Hello, we have purchased and are currently using multiple units of your FFC4P module, and overall they have been working well.

However, we have encountered an issue with one specific board. On this board, the X-axis accelerometer consistently outputs unusually large values (greater than 1), even when the board is stationary and placed on a flat surface.

It seems that the IMU on this particular board may be faulty. Is there any recommended procedure to resolve this issue, or would you advise a replacement?

For your reference, we’ve attached a log file showing data collected while placing the FFC4P boards flat and then slightly moving them.

We would appreciate it if you could take a look and advise us on how to proceed.

Thank you for your support.

Best regards,
Daehyun Hwang

jakaskerl

Hi Daehyun
-9.81 is the gravity acceleration. Very much expected. Are other boards not behaving that way?

Thanks,
Jaka

Daehyun

@jakaskerl I believe that a Z-axis value of -9.81 is quite reasonable — as long as the X and Y axes are close to zero.
However, the fact that the X-axis is reading around 1.8 seems quite odd, doesn't it?

jakaskerl

Daehyun
The PCB isn't perfectly straight so there is some acceleration in x axis as well (also gravity). If you combine the XYZ components, you should get a vector of around 9.8 amplitude.

Thanks,
Jaka

Daehyun

@jakaskerl Even when placed on a level surface, one of the FFC4P boards shows an unusually high X-axis acceleration (about 1.8), unlike the others.
So we suspect the IMU might be tilted inside the board, and we are inquiring whether this could be due to a mounting/alignment issue or not.