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

A computing device comprising:

• at least one memory storing instructions;
• and
• at least one processor to execute the instructions to:
• determine power levels of noise in different frequency bands associated with sound waves sensed by a microphone of the computing device:
• cause a speaker of the computing device to produce a series of acoustic pulses, a central frequency of the pulses defined based on the power levels of noise in the different frequency bands, the sound waves sensed by the microphone to include the pulses and echoes of the pulses reflected off objects in a vicinity of the computing device;
• and
• determine whether a first object is within an activation region associated with the computing device based on the pulses and the echoes sensed by the microphone.

A non-transitory computer readable medium comprising instructions that, when executed, cause at least one processor to at least:

• determine power levels of noise in different frequency bands associated with sound waves sensed by a microphone of a computing device:
• cause a speaker of the computing device to produce a series of acoustic pulses, a central frequency of the pulses defined based on the power levels of noise in the different frequency bands, the sound waves sensed by the microphone to include the pulses and echoes of the pulses reflected off objects in a vicinity of the computing device;
• and
• determine whether a first object is within an activation region associated with the computing device based on the pulses and the echoes sensed by the microphone.