Lowest Data Rate of Accelerometer
Hi,
To log the data for a long term measurement (>2 days), I tried to lower the data rate with the line in log_acc.py example:
libmetawear.mbl_mw_acc_set_odr(d.board, 0.01)
so this should update a data per 100s. However, when I retrieved the data from the board it was logged per 1s. In specs, it says the accelerometer has the lowest rate of 0.001Hz. Is there anything I've done wrong?
Thanks!
Comments
@sd104400, the lowest native sampling rate of the accelerometer is 0.78125 Hz, which is slightly less than 1 per second. It is possible to use the data processing system to average or further down sample the sensor output.
Matt
Thanks Matt!
Do you mean the data processing can be done on the board? and do you have a demo for how it is done? I want the board to store the data at the rate much less than 0.78125 Hz.
Yes it can be done on the board. You could use an averager to downsample for example:
https://github.com/mbientlab/MetaWear-SDK-Python/blob/master/examples/acc_threshold_detector.py
Another great example of this is how we use the timer module built into the board to log temperature data as slow as once per 5 minutes, here is an example: https://github.com/mbientlab/MetaWear-SDK-Python/blob/master/examples/log_temp.py
What you need to do is read our tutorials and developer APIs/documentation to learn more about what our boards can do on board: www.mbientlab.com/tutorials.
Okay. Thanks a lot for the help!