I am measuring BLDC motor vibrations with ADXL345. I use 2 propellers, one perfectly balanced and other bad, which vibrates a lot. The problem is I get similar results from accelerometer with both props. I tried ODRs from 200 to 3200 and results look similar with both props (1000-5000 RPM). I get real time data from MCU which reads raw data from accelerometer, then my program draws a real time chart (amplitude vs time, no processing just raw accelerometer data), so I visually check the results while trying different things.
What can be the problem here? I want to be able to detect vibrations on the motor.