Acoustic Liquid Immersion Sensor for Mobile Devices
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Solution Overview
Problem
Consumer electronic handheld devices, such as smartphones, often suffer from water damage when submerged, and existing water-resistant features do not reliably detect immersion or adapt operations effectively.
Innovation Solution
A liquid immersion sensor using at least two acoustic transducers to determine time lag values between emitted and received signals, indicating whether a mobile device is immersed in liquid, and potentially measuring liquid temperature and flow rates, triggering operational changes such as power down or mode shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a mobile device is made water-resistant with IPx8 rating, then the device can operate in water for extended periods, but the touchscreen becomes unreliable and water damage can still occur
Solution Approach 1:
The system performs preliminary detection of liquid immersion using acoustic transducers before water damage occurs. By continuously monitoring the acoustic environment and detecting changes in sound propagation characteristics, the system can identify immersion conditions early and trigger protective actions such as shutting down vulnerable components or adjusting operational modes before damage happens.
Solution Approach 2:
The patent introduces an intermediary detection system using acoustic transducers that mediate between the liquid environment and the device's operational state. These transducers act as sensors that detect changes in acoustic properties caused by liquid immersion, providing indirect but reliable information about the device's environmental state without requiring direct contact with water-susceptible components.
2Measurement precision
If acoustic transducers are used to detect liquid immersion, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The acoustic transducers serve multiple functions: they can detect liquid immersion, measure liquid temperature through acoustic velocity, and potentially detect liquid flow characteristics. By using a single type of sensor for multiple detection purposes, the system reduces overall complexity compared to using separate specialized sensors for each measurement function.
Solution Approach 2:
The existing acoustic transducers in the mobile device (such as speakers and microphones) are repurposed for liquid immersion detection. Instead of adding entirely new sensor systems, the invention leverages components already present in the device, making them serve dual purposes for their original function and for liquid environment detection.
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
Effectively detects liquid immersion and temperature, enabling mobile devices to adapt operations and prevent further damage by determining immersion status with high accuracy, allowing for reliable water resistance features.
Implementation Method 1
the controller is configured to determine a time lag value between the reference signal and the delayed signal... determining a time lag value between the reference signal and the delayed signal received via the second acoustic transducer
Data Source
AI summary
A liquid immersion sensor for a mobile device with at least two acoustic transducers is described. The liquid immersion sensor may include a signal generator having a signal generator output configured to generate a signal for transmission via a first acoustic transducer, and a signal receiver having a signal receiver input configured to receive a delayed version of the generated signal via a second acoustic transducer. The signal receiver includes a signal receiver output. The liquid immersion sensor includes a controller having a first controller input for receiving a reference signal and a second controller input coupled to the signal receiver output. The controller determines a time lag value between the reference signal and the delayed signal and generates a control output signal dependent on the phase difference. The control output signal indicates if the mobile device is immersed in liquid.