How to distinguish two different kind of movement to wake up a microcontroller

[GFavr]

Hi everybody,

I would like to have your opinion about waking up a microcontroller using LIS3DSH sensor. I have two different motion and only one of them should wake up the controller.

The micro is a STM32L486.

The sensor is assembled on a board and the board is fixed on a metal box, only one axis has to be monitored, the box will move along Z axis with the two possible motions:

1) Vertical position is a sort of sine wave with an amplitude of only 10cm and a period of 1sec

2) straight movement for 10 second lifting the box up to 1.5m

The two motions are quite different and only the straight movement should wake up di microcontroller, do you thing this is something doable using the LIS3DSH SM embedded into the device?

Any advice will be appreciated

Thanks

Jule

[niccolò]

Hi @GFavr​,

The LIS3DSH has 2 Finite State Machines (FSM) that can be programmed to trigger an interrupt. This interrupt can then be used to wake up the STM32L486, so you can surely achieve your goal.

The FSM can be programmed to recognize a specific movement pattern, so that only the straight movement can wake up the microcontroller.

You can find all the necessary info about programming the FSM in this application note: https://www.st.com/resource/en/application_note/dm00026768-lis3dsh-3axis-digital-output-accelerometer-stmicroelectronics.pdf

It seems an interesting application, do you mind if I ask you what is your goal?