[Shimmer-users] sampling rates >512Hz using the EXG shimmer module

[Puian Tadayon]

Hello everyone,



I have a question regarding the sampling rate and hope that somebody can
help me:
I'm using the shimmer3 EXG module with firmware BTstream V0.4.0. For data
acquisition and processing I use MATLAB. I want to capture EMG data as well
as IMU sensor data (e.g. from gyro and acceleration sensors).

The desired sampling rate for the EMG data is 1024Hz. Data acquisition with
1024Hz works fine as long as I only capture EMG data. But as soon as e.g.
the gyro sensor is enabled (in addition to EMG), the sampling rate is
automatically reduced to 512Hz (the value of the variable
thisShimmer.SamplingRate is still 1024Hz, but the time differences between
the time stamps of the collected data indicate an "effective" rate of about
512Hz).

Is that a limitation of the device? Or is something going wrong?



And in general: is there any way to use different sampling rates for
different sensors in the same shimmer module without manipulating the
firmware? While it makes sense to use 1kHz for EMG data acquisition, 50Hz
would generally be enough for gyro data acquisition.



I'd be happy for any advice. Thanks in advance,



Kind regards,



Puian