Trying to avoid hit or touch detection

abduuu · ‎2025-10-14

I am using the sensor LIs2DH, and I've read the datasheet and tried multiple values and manipulations of its registers.

Now I want to use the sensor should be on a car and detect when will the car move.

the problem I'm facing that it generates an interrupt at any vibratoin/touch on the board, and I want to avoid that.
Also what are the best configurations for a free fall detection (because I think that would be the best solution for my case)

Thanks in advance

Register values are

Register 0x0f has 0x33
Register 0x20 has 0x27
Register 0x21 has 0x00
Register 0x22 has 0x40
Register 0x24 has 0x08
Register 0x25 has 0x00
Register 0x30 has 0x2a
Register 0x32 has 0x27
Register 0x33 has 0x00
Register 0x34 has 0x00
Register 0x36 has 0x00
Register 0x37 has 0x00
Register 0x2e has 0x00

Federica Bossi · ‎2025-10-14

Ciao @abduuu ,

Here are some suggestions:

10 Hz ODR is quite low and may cause noisy measurements. Increase ODR to 50 Hz or 100 Hz for better responsiveness and filtering.
High-pass filtering removes static acceleration (gravity) and low-frequency vibrations. Enable high-pass filter on interrupt output to ignore slow changes.
Your current threshold is 0x27 (~39 decimal), duration 0x00 (no duration). To avoid false triggers increase threshold to a higher value to ignore small vibrations. Set a non-zero duration to require the acceleration to be above threshold for some consecutive samples.

Hope this helps.

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View solution in original post

Federica Bossi · ‎2025-10-14

Ciao @abduuu ,

Here are some suggestions:

10 Hz ODR is quite low and may cause noisy measurements. Increase ODR to 50 Hz or 100 Hz for better responsiveness and filtering.
High-pass filtering removes static acceleration (gravity) and low-frequency vibrations. Enable high-pass filter on interrupt output to ignore slow changes.
Your current threshold is 0x27 (~39 decimal), duration 0x00 (no duration). To avoid false triggers increase threshold to a higher value to ignore small vibrations. Set a non-zero duration to require the acceleration to be above threshold for some consecutive samples.

Hope this helps.

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.