Inactivity detection with BMA400

[baukespoelstra]

Hello,

I'm trying to implement a low-power solution for my project with inactivity detection.

The firmware is for a set of dice with NRF52805 as main processor. When the dice are thrown, BMA400 should wake up from low-power mode to normal mode, and when it is still on the table for set time and inactivity threshould it should wake up the NRF by a hardware interrupt pin.

First I am just trying to get the inactivity interrupt to work. I found this article: https://community.bosch-sensortec.com/t5/Knowledge-base/Introduction-about-BMA400-Auto-Wakeup-and-Au... but can't get this to work for my board. I confirmed other examples from the sensor API to work fine.

For now this is what I am testing with; but it keeps triggering the interrupt no matter what happens. I have attached main code. What best can I do to reach what I am aiming to do?

Also I am open for suggestions on how to implement this in a different way. (eg activity or some other way of triggering) As long as it consumes as little power as possible 😉

Thanks a lot!

[BSTRobin]

Hi baukespoelstra,

You could refer attached example code to enable Auto Wakeup and Auto Low Power for your application.
By default, the trigger of INT1 is a rising edge trigger. Ensure that your host can respond to the rising edge.

[baukespoelstra]

Hi BSTRobin,

Thanks for replying. Are you refering to  set_sensor_config function? I am a bit overwhelmed by your example code, but can see how auto low power and wake-up is set. I need the BMA to wake up from (in)acitivity after set time and trigger the host for it to ask for acceleration data. 

I just can't get the interrupt mapping to a pin to work. The host can trigger on a rising edge. However, for now I am using an oscilloscope on INT1 and can't see anything happening.

[BSTRobin]

Hi baukespoelstra,

Refer attached example code, you will get interrupt signal from INT1.