I'm using an ADXL345 for a shock detector and acceleration logger, but I have problems with the values returned by the sensor.
The system stores a value every 10 seconds by making a averaging of 32 readings. The ODR is 400 Hz.
As you can see from the chart that I enclose, I experience a periodic drift of the reading of which I can not understand the cause.
In the graph, Serie3 is the Z axis, Serie2 Y and Serie1 X. The top mean value of Z is around 1.07 g.
The sensor, of course, has been positioned at rest on the floor.
What do you think could be the cause of this behavior?