A mobile device includes a vibrator, an accelerometer that senses a parameter of rotation, and a processor. The vibrator includes a drive motor and a drive circuit. The accelerometer senses a speed of rotation of the vibrator. The processor analyzes the sensed speed of rotation and generates a drive voltage that is received by the drive circuit to adjust the drive motor to produce a pre-determined, desired rotational speed. In another embodiment, the accelerometer senses an amplitude of a vibration produced by the vibrator. The processor analyzes the sensed amplitude of a vibration and generates a drive voltage that is received by the drive circuit to adjust the drive motor to produce a pre-determined, desired vibration amplitude. The processor may also compare the sensed parameter with a pre-determined desired parameter of rotation and generate a signal responsive to a result of the comparison and based on stored vibrator calibration curves.