I use ADXL345 for shock/acceleration measurement. I use Adafruit's breakboard connected to Raspberry Pi B+. For acquiring data I use program written on Python. This program request data from accelerometer about 10 times a second and write it into text logfile. However, it shows me strange result. Here is on graph (X axis is time of day, Y axis is acceleration in G) I see strange fluctuations. I can't explain such behavior. Could anyone help me to explain it please? Thank you!
Here is graph with similar fluctuations, one spike is proof that sensor works, I just shook it.