Acoustic Sensor for Mobile Device Ambient Temperature and Humidity
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Solution Overview
Problem
Existing temperature sensors in mobile devices are affected by the device's casing temperature and self-heating, leading to inaccurate ambient temperature measurements, and they lack effective methods for measuring relative humidity and wind speed.
Innovation Solution
An environmental parameter sensor using acoustic transducers to determine time-of-flight and attenuation values of acoustic signals, allowing for the measurement of ambient temperature, relative humidity, and wind speed, which are unaffected by the device's internal temperature and utilizing shared components with audio functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing temperature sensors are used in mobile devices, then temperature measurement function is provided, but measurement accuracy deteriorates due to casing temperature and self-heating effects
Solution Approach 1:
The patent replaces traditional contact-based temperature sensors with acoustic wave-based sensing. Acoustic waves propagate through the air medium between the transducer and the target object, eliminating thermal conduction through the device casing. The time-of-flight and attenuation of acoustic signals are used to determine temperature, avoiding the harmful thermal effects that plague conventional sensors.
Solution Approach 2:
The patent introduces air as an intermediary medium for temperature sensing. Instead of direct thermal contact between the sensor and the measured environment, acoustic waves travel through the air medium to carry temperature information. This intermediary approach isolates the sensing system from thermal influences of the device casing and internal components.
2Measurement precision
If acoustic transducers are used for environmental parameter sensing, then measurement accuracy improves and independence from device internal temperature is achieved, but device complexity increases due to additional sensor components
Solution Approach 1:
The patent makes acoustic transducers serve multiple functions: they act as both audio output devices (speakers) and temperature/humidity/wind sensing elements. The same transducer that plays audio can emit acoustic waves for environmental sensing, and the received signals are processed to extract multiple environmental parameters simultaneously, reducing the need for separate dedicated sensors.
Solution Approach 2:
The patent combines audio functionality and environmental sensing functionality into a single integrated system. The acoustic transducers are used for both audio playback and environmental parameter measurement, merging two distinct functions into one component system, thereby reducing overall device complexity.
3Adaptability or versatility
If acoustic signals are used to measure multiple environmental parameters, then versatility of sensing improves, but signal processing complexity increases
Solution Approach 1:
The patent employs periodic acoustic wave emission at different frequencies to measure multiple environmental parameters. By transmitting acoustic signals at varying frequencies and analyzing the frequency-dependent attenuation and time-of-flight characteristics, the system can simultaneously determine temperature, humidity, and wind speed through a series of periodic measurements rather than requiring complex simultaneous multi-parameter analysis.
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
Provides accurate and independent measurements of ambient temperature, relative humidity, and wind speed, improving the accuracy of environmental parameter detection in mobile devices by using acoustic signals to determine these parameters without being influenced by the device's internal temperature.
Implementation Method 1
determine at least one of a time-of-flight value and an attenuation value of an acoustic signal between the first acoustic transducer and the second acoustic transducer and to determine at least one environmental parameter from the at least one of the time-of-flight value and the attenuation value
Implementation Method 2
determine at least one of a time-of-flight value and an attenuation value of an acoustic signal between the first acoustic transducer and the second acoustic transducer
Data Source
AI summary
An environmental parameter sensor for a mobile device is described comprising a first acoustic transducer; a second acoustic transducer arranged at a predetermined distance from the first acoustic transducer; a controller coupled to the first acoustic transducer and the second acoustic transducer; wherein the controller is configured to determine at least one of a time-of-flight value and an attenuation value of an acoustic signal between the first acoustic transducer and the second acoustic transducer and to determine at least one environmental parameter from the at least one of the time-of-flight value and the attenuation value The environmental parameter sensor may determine environmental parameters such as temperature, wind speed, and humidity from acoustic measurements.