Patent ID: 8084968

Claim:
A mobile device comprising: a vibrator, the vibrator including a drive motor and a drive circuit; an accelerometer, the accelerometer sensing a speed of rotation of the vibrator; and a processor configured for: 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 the drive circuit to produce the desired rotational speed of the vibrator; receiving, from the accelerometer, the 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 the drive circuit 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.