Accelerometer selection for step detection, impact, free fall & activity/inactivity detection

[AB.4]

Hello STM Support,

We are currently using accelerometer LIS2DH12 for the detection of following events:

Strong impact - 2.5 g or above

Free fall - 352 mg or below

Activity/Inactivity - 160 mg or above

The register settings are as follows:

Scale - 4g

CTRL1_REG - 0x37

CTRL3_REG - 0x40

CTRL4_REG - 0x88

CTRL5_REG - 0x0A

CTRL6_REG - 0x28

FIFO_CTRL_REG - 0x00

INT1_THS - 0x0B

INT1_CFG - 0x95

INT1_DUR - 0x0A

INT2_THS - 0x4E

INT2_CFG - 0x2A

INT2_DUR - 0x01

ACT_THS - 0x05

ACT_DUR - 0x20

We have a new requirement to perform step detection also. So, I was looking for sensors to achieve the above functions & step detection but I was unable to find one that can satisfy all the four requirements:

LIS2DS12 - Cannot route inactivity event to an interrupt

ISM330DHCX, LSM6DSL, LSM6DS3H, LSM6DS3, LSM6DS3TR-C, LSM6DS3H, LSM6DS0, LSM6DSR, LSM6DSM, LSM6DS33, LSM6DS3US - Cannot set different thresholds for impact detection and activity/inactivity recognition since only one register WAKE_UP_THS is available

Can you please suggest a sensor that can be used for all the four requirements? Please let me know if you need more information regarding my use case.

Thanks,

Anusha

[Eleon BORLINI]

Hi @AB.4​ , if you have a lot (>3) of activities to be recognized from you sensor, I would suggest you to change your approach and use the finite state machine or the machine learning core features instead of the classical digital embedded features. I would suggest you to use the LSM6DSO or LSM6DSOX part numbers: up to embedded finite state machines can be programmed independently for motion detection. In the AN5273 you can find an explanation on how the FSM works, an you can find suggestions also on this Community dedicated topic flow. Regards

[AB.4]

Hi Eleon,

Thanks for your suggestion. I will check it out.

Regards,

Anusha