Loudspeaker Acoustic Sensor for Mobile Power Reduction
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Solution Overview
Problem
Current mobile devices with 'always-on' functions consume excessive power due to the continuous operation of microphones, which are necessary for voice activation and environmental sensing, despite multi-stage activation methods that aim to minimize power consumption.
Innovation Solution
Implementing a first mode of operation where a loudspeaker detects acoustic inputs without power consumption, generating an activation signal to enable further components like the microphone and system processor only when necessary, significantly reducing overall power usage during standby modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microphones are continuously operated for voice activation and environmental sensing, then voice activation functionality is maintained, but power consumption increases
Solution Approach 1:
The always-on sensing function is segmented into two distinct paths: a low-power acoustic path using the loudspeaker to detect non-stationary sounds, and a higher-power audio path using the microphone for detailed voice processing. This segmentation allows the system to maintain voice activation functionality while minimizing power consumption by using the appropriate path based on acoustic activity levels.
Solution Approach 2:
The loudspeaker serves as an intermediary component for acoustic detection in the low-power path. Instead of continuously powering the microphone, the system uses the loudspeaker's electrical response to acoustic stimuli as an intermediate detection mechanism. This intermediary approach enables the system to detect potential voice inputs without committing to full microphone operation, thereby reducing overall power consumption.
2Reliability
If microphones are operated in always-on mode, then environmental sensing capability is maintained, but power consumption increases
Solution Approach 1:
Environmental sensing is segmented into two operational modes: a passive acoustic detection mode using the loudspeaker's electrical response to detect non-stationary environmental sounds, and an active audio recording mode using the microphone. This segmentation enables the system to maintain environmental sensing capability while operating at minimal power consumption during standby, only activating the power-consuming microphone when acoustic activity thresholds are exceeded.
Solution Approach 2:
The system implements periodic acoustic detection using the loudspeaker in the low-power path, continuously monitoring for non-stationary sound components. This periodic detection approach maintains environmental awareness without requiring continuous microphone operation, thereby reducing power consumption while preserving sensing capability.
3Use of energy by moving object
If multi-stage activation methods are implemented, then power consumption is minimized, but device complexity increases
Solution Approach 1:
The loudspeaker is given a dual function: it serves both as an audio output device and as a passive acoustic sensor for detection. This multi-functionality eliminates the need for separate always-on sensing hardware, reducing device complexity while maintaining the multi-stage activation approach. The same component performs multiple roles, simplifying the overall system architecture.
Solution Approach 2:
The loudspeaker's electrical response to acoustic stimuli is used to serve the detection function without requiring external power for sensing operations. The system leverages the inherent electrical characteristics of the loudspeaker when exposed to acoustic waves, allowing it to self-serve as a sensor without additional power consumption or complex control circuitry.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces power consumption in always-on sensing modes by leveraging the loudspeaker's ability to detect acoustic stimuli without power, minimizing the power usage of microphones and enabling efficient transitions to active modes with reduced overall energy expenditure.
Implementation Method 1
The loudspeaker is adapted to generate an electrical signal in response to acoustic stimulation
Data Source
Figure 1
Figure 2~3
Figure 4A
AI summary
Mobile devices such as mobile phones have always-on modes using sensors which respond to changes in the environment. A mobile device (200, 300, 400) is described comprising a loudspeaker (38); a controller (46) having an input (42) coupled to the loudspeaker (38). The controller (46) is operable in a first mode of operation to detect an electrical signal generated by the loudspeaker (38) in response to an acoustic input signal. This signal can be used to activate further circuitry. Using a loudspeaker as an acoustic sensor may reduce the power consumption of the mobile device.