BMA253 Activity Detection

[samd_jldtech]

Hello,

I am working on an application with the BMA253 and am running into issues with the sensitivity of the device.

After reviewing the datasheet and comparing the modes to what we need for our applications, we have configured the device in the slow motion interrupt setting with 2g sensitivity and tried varrying bandwidth, threshold, duration, the low power modes, and sleep durations. 

Our device has two similar applications: a wrist wearable and pocket token. They both need to detect whether the user is active and in motion and has a timeout to determine if the user has ceased motion or taken the device off their person. 

Currently our settings cannot detect the smooth motion of walking even though it is so sensitive that while sitting on a desk, it registers when someone is typing on a keyboard.

Can you provide any guidance on the proper configuration of the BMA253 for our application? Are there some pre-defined and tested settings approved for a wearable & pocket motion/activity tracking?

Thanks,

Sam

[FAE_CA1]

Hi,

[-48,-1,90,0,27,-1] doesn't look correct, because the lowest bit of the low byte of x/y/z axes should always be 1.

 -48 = -0x30 = 0xD0, this should be 0xD1, for example

-1 = 0xFF

90 = 0x50, this should be 0x51 for example

27 = 0x1B, this looks OK

-1 = 0xFF

Please check the BMA253 raw data again from register 0x02 to 0x07.

Thanks.