Set sensitivity of the NoteCard accelerometer sensor

Notecard API
1

I am working on a location tracker and want to use the motion sensor of the NoteCard to wake up my MCU when the device is moving.
I have the ATTN activation working and get the signal every time I move my device.

But it is way to sensitive. Is there any NoteCard API request to set the sensitivity of the motion sensor?

Right now it gets triggered when it is just laying on my table and I knock with my fingers on the table.

Additional info:
I don’t need any note to be sent to NoteHub, I just need to wake-up on motion.

2

Hi @bernd,

You can dial down the sensitivity of the accelerometer, by using the card.motion.mode API.

Specifically, the sensitivity parameter:

sensitivity (Added in v3.3.1)
integer (Default -1)

Used to set the accelerometer sample rate. The default sample rate
of 1.6Hz could miss short-duration accelerations (e.g. bumps and jolts),
and free fall detection may not work reliably with short falls. The penalty
for increasing the sample rate to 25Hz is increased current consumption
by ~1.5uA relative to the default -1 setting.

-1 : 1.6Hz, +/-  2G range, 1 milli-G sensitivity
 1 :  25Hz, +/- 16G range, 7.8 milli-G sensitivity
 2 :  25Hz, +/-  8G range, 3.9 milli-G sensitivity
 3 :  25Hz, +/-  4G range, 1.95 milli-G sensitivity
 4 :  25Hz, +/-  2G range, 1 milli-G sensitivity
 5 :  25Hz, +/-  2G range, 0.25 milli-G sensitivity
3

Hi @zfields

Not exactly what I need. It sets the sample rate and the sensitivity, is sensitivity the trigger level?

I need low sample rate (1.6Hz is enough) and trigger on motion speed like a walking person.

maybe the card.motion.mode could have more setting options in the future?

4

Hey @bernd ,

Yes, sensitivity is the trigger level (milli-G). 1 will be the least sensitive. It will require a 7.8 milli-G disturbance to wake the accelerometer and fire the interrupt.

~Zak