Use of an accelerometer to control vibrator performance

A method for controlling a vibrator in a mobile device comprising:

• obtaining, from a vibrator calibration profile, a drive voltage corresponding to a desired rotational speed, wherein the vibrator calibration profile is a profile of voltages versus rotational speeds for the vibrator;
• delivering the drive voltage to a drive circuit associated with the vibrator to produce the desired rotational speed of the vibrator;
• receiving, from an accelerometer, a sensed speed of rotation of the vibrator;
• comparing the sensed speed of rotation with the desired rotational speed;
• in response to determining the sensed speed of rotation is different from the desired rotational speed, obtaining a correction drive voltage from the vibrator calibration profile;
• and
• delivering the correction drive voltage to control the vibrator to adjust a current rotational speed of the vibrator to produce the desired rotational speed, wherein the correction drive voltage increases or reduces the drive voltage.

A mobile device comprising:

• a vibrator, the vibrator including a drive motor and a drive circuit;
• a sensor, the sensor sensing an amplitude of vibration of the vibrator;
• and
• a processor configured for:
• obtaining, from a vibrator calibration profile, a drive voltage corresponding to a desired vibration amplitude, wherein the vibrator calibration profile is a profile of voltages versus vibration amplitudes;
• delivering the drive voltage to the drive circuit to produce the desired vibration amplitude;
• receiving, from the sensor, the sensed vibration amplitude of the vibrator;
• comparing the sensed vibration amplitude with the desired vibration amplitude;
• in response to determining the sensed vibration amplitude is different from the desired vibration amplitude, obtaining a correction drive voltage from the vibrator calibration profile;
• and
• delivering the correction drive voltage to the drive circuit to adjust a current vibration amplitude to produce the desired vibration amplitude, wherein the correction drive voltage increases or reduces the drive voltage.