An unbalanced rigid body that rotates around its axis, causes forces and vibrations in supports. Vibrations can severely damage the structure of the device and affect its lifetime. The measurement of vibration signal allows us to characterize the imbalance of the unbalanced rotor. The work presents the theoretical and experimental analysis of the vibrations of an unbalanced rotor. For the measuring purposes, we presented the device for measuring the imbalance of the rotors. Program was written in the Arduino Software (IDE). The measurements were made using MEMS accelerometers, which were installed on the supports of the shaft. The balancing procedure was successfully performed on the test rotor.