Adaptive vibration noise reduction
A portable electronic device provides adaptive vibration noise reduction by generating a user alert vibration that is one of a first magnitude and a second magnitude, with the first magnitude being greater than the second magnitude. The portable device is configured to alert the user by providing a first magnitude alert vibration except when the device is lying flat and ambient noise at the device is low, and to provide a second magnitude alert vibration when the device is lying flat and ambient noise at the device is low.
1. A portable electronic device configured to provide adaptive vibration noise reduction generating a user alert vibration of one of a first magnitude and a second magnitude, wherein the first magnitude is greater than the second magnitude and wherein the portable electronic device includes a vibrational actuator and is configured to alert a user by providing a first magnitude alert vibration via the vibrational actuator except when the portable electronic device is lying flat and an ambient noise level at the portable electronic device prior to the user alert vibration is low, and to provide a second magnitude alert vibration via the vibrational actuator when the portable electronic device is lying flat and the ambient noise level at the portable electronic device prior to the user alert vibration is low, wherein the portable electronic device is further configured to determine a vibrator noise level caused by the driven vibrational actuator during the user alert vibration, generate a modified drive level based on the ambient noise level at the portable electronic device and the vibrator noise level during the user alert vibration, the modified drive level corresponding to one of the first magnitude alert vibration and the second magnitude alert vibration, and drive the vibrational actuator with the modified drive level.
2. The portable electronic device in accordance with claim 1 , further comprising a device housing, wherein the device housing defines a primary plane of the portable electronic device.
3. The portable electronic device in accordance with claim 2 , wherein the portable electronic device is determined to be lying flat if its primary plane lies within 15 degrees of a horizontal plane perpendicular to gravity.
4. The portable electronic device in accordance with claim 1 , wherein a processor is configured to generate the modified drive level by setting the modified drive level to the first magnitude alert vibration if the vibrator noise level is low or if the vibrator noise level is high but the ambient noise level at the portable electronic device during the user alert vibration is also high.
5. The portable electronic device in accordance with claim 4 , wherein the processor is further configured to generate the modified drive level by setting the modified drive level to the second magnitude alert vibration if the vibrator noise level is high and the ambient noise level at the portable electronic device during the user alert vibration is low.
6. The portable electronic device in accordance with claim 1 , further comprising an audio sensor and a processor, the processor being linked to the audio sensor and the vibrational actuator and being configured to sense the ambient noise level at the portable electronic device prior to the user alert vibration and drive the vibrational actuator at a predetermined drive level, wherein the predetermined drive level includes a predetermined drive frequency and wherein the processor is further configured to generate the modified drive level by determining a modified drive frequency.
7. The portable electronic device in accordance with claim 6 , wherein the processor is further configured to retrieve the predetermined drive level from a timed buffer and write the modified drive level to the timed buffer.
8. The portable electronic device in accordance with claim 1 , wherein a processor is further configured to determine whether the user alert vibration will last for less than a predetermined time period, and to apply a predetermined drive level without generating the modified drive level if it is determined that the user alert vibration will last for less than the predetermined time period.
9. The portable electronic device in accordance with claim 1 , wherein the vibrational actuator is a single-axis vibrator.
10. The portable electronic device in accordance with claim 9 , wherein the single-axis vibrator is a linear resonant actuator (LRA).
11. The portable electronic device in accordance with claim 10 , wherein the single-axis vibrator includes multiple LRAs.