Method, device, and system of an earphone having increased comfort through external-facing charging connections, enhanced controls through direction and/or motion evaluation, and/or accurate physiological feature extraction through audio-motion sensor correlation

A method for identifying a control input of a user, the method comprising:

• receiving a control signal from a touch sensor of a first earphone generated by activation of the touch sensor,
• wherein the first earphone comprising a housing having an outside face of that faces outward when the first earphone is seated in an ear such that at least an exposed region is unobstructed to a finger of the user;
• receiving from an accelerometer of the earphone physically fixed relative to the outside face a first acceleration data comprising a positive acceleration indicating a direction of gravity;
• determining a direction of the touch sensor relative to the direction of gravity;
• and
• determining whether to generate the control input from the control signal based on criteria comprising the direction of the touch sensor relative to the direction of gravity, to reduce a probability of a false positive of the control signal while the user is engaged in a resting position.

A device for detecting physiological features of a user, the device comprising:

• a processor,
• a memory,
• an acceleration agent comprising computer readable instructions that when executed:
• receive from at least one of an accelerometer of an earphone and an inertial measurement unit of an earphone an accelerometer signal over a time period comprising one or more acceleration events, and
• store the accelerometer signal as an acceleration data for the time period in a computer readable memory;
• an audio agent comprising computer readable instructions that when executed:
• receive an audio signal over the time period from a microphone comprising two or more audio events, and
• store the audio signal as an audio data in the computer readable memory;
• an audio-motion overlay routine comprising computer readable instructions that when executed overlay the acceleration data and the audio data for the time period;
• an overlay correlation routine comprising computer readable instructions that when executed determine a correlation between two or more acceleration events and the two or more audio events over the time period;
• and
• a physiological indicator extraction routine comprising computer readable instructions that when executed extract two or more physiological indicators matching the correlation of the two or more acceleration events and the two or more audio events over the time period, to reliably determine a physiological indicator for determining a physiological feature.