Methods and apparatus to detect proximity of objects to computing devices using near ultrasonic sound waves

A computing device comprising:

• a speaker;
• at least one storage device;
• instructions;
• and
• at least one processor to execute the instructions to:
• cause the speaker to produce a series of pulses;
• generate a full echo profile based on pulses and corresponding echoes sensed by a microphone;
• identify peaks in the full echo profile, different ones of the peaks corresponding to respective one of the pulses or the corresponding echoes;
• identify repeating reference signals based on the peaks identified in the full echo profile, the repeating reference signals corresponding to the pulses;
• identify an echo signal between separate occurrences of the repeating reference signals, the echo signal corresponding to one of the echoes;
• and
• determine whether an object is within an activation region associated with the computing device based on a time difference between the echo signal and a preceding one of the repeating reference signals.

A method comprising:

• producing, via a speaker of a computing device, a first series of pulses, successive ones of the pulses in the first series spaced at first intervals during a first time period;
• processing, by executing an instruction with at least one processor, noise information from an output of a microphone to determine whether an object is within an activation region associated with the computing device, the noise information representative of at least some of the pulses in the first series and first echoes of the pulses in the first series reflected off surfaces in a vicinity of the computing device;
• in response to detection of the object within the activation region during the first time period, producing second series of pulses spaced at second intervals during a second time period after the first time period, the second intervals being shorter than the first intervals;
• and
• verifying the object is within the activation region based on at least some of the pulses in the second series and corresponding second echoes sensed during the second time period.

A non-transitory computer readable medium comprising instructions to cause a computing device to at least:

• produce a series of pulses, successive ones of the pulses spaced at first intervals during a first time period;
• access noise information output by a microphone, the noise information representative of the pulses and echoes of the pulses reflected off surfaces in a vicinity of the computing device;
• process the noise information to determine whether an object is within an activation region associated with the computing device;
• in response to detection of the object within the activation region during the first time period, produce additional ones of the pulses spaced at second intervals during a second time period after the first time period, the second intervals being shorter than the first intervals;
• and
• verify the object is within the activation region based on the pulses and corresponding echoes sensed during the second time period.

A non-transitory computer readable medium comprising instructions to cause a computing device to at least:

• produce a series of pulses;
• access noise information output by a microphone, the noise information representative of the pulses and echoes of the pulses reflected off surfaces in a vicinity of the computing device;
• generate a full echo profile based on the pulses and corresponding echoes;
• identify peaks in the full echo profile, different ones of the peaks corresponding to either the pulses or the corresponding echoes;
• identify repeating reference signals based on the peaks identified in the full echo profile, the repeating reference signals corresponding to the pulses;
• identify an echo signal between separate occurrences of the repeating reference signals, the echo signal corresponding to one of the echoes;
• and
• determine whether an object is within an activation region associated with the computing device based on a time difference between the echo signal and a preceding one of the repeating reference signals.

A computing device comprising:

• means for producing a first series of first pulses, successive ones of the first pulses spaced at first intervals during a first time period;
• and
• means for processing noise information, the noise information corresponding to an output of a microphone, the noise information representative of the first pulses and first echoes of the first pulses reflected off surfaces in a vicinity of the computing device, the processing means to:
• determine a presence of an object within an activation region associated with the computing device based on the noise information;
• in response to detection of the object within the activation region during the first time period, cause the means for producing to produce a second series of second pulses spaced at second intervals during a second time period after the first time period, the second intervals being shorter than the first intervals;
• and
• verify the object is within the activation region based on the second pulses and corresponding second echoes sensed during the second time period.