Ultrasonic Sensor User Presence Detection via Transducer Occlusion
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Solution Overview
Problem
Existing computing devices face challenges in designing components to fit within size constraints, operating within power limits, and improving user experience, particularly in detecting user presence without relying on time-of-flight techniques.
Innovation Solution
The use of an ultrasonic sensor that detects user presence by occluding transducers or changes in the audible noise floor, allowing for the control of device components to enhance user experience and power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time-of-flight techniques are used to detect user presence, then detection accuracy is improved, but the system fails when transducers are occluded by the user
Solution Approach 1:
The system divides the detection function into multiple independent transducers (first transducer and second transducer). By segmenting the detection task across multiple components, the system can detect user presence through different pathways - the first transducer detects when the user is close, while the second transducer detects when the user is even closer, ensuring continuous detection even when one transducer is occluded.
Solution Approach 2:
Instead of relying solely on the first transducer to detect user presence and using time-of-flight measurements, the system inverts the approach by using the second transducer to detect occlusion events. When the second transducer detects that the first transducer is occluded, it triggers a different detection mechanism, ensuring reliable detection continues without requiring time-of-flight techniques.
2Reliability
If multiple transducers are used to ensure continuous detection, then reliability is improved, but device complexity increases
Solution Approach 1:
The second transducer serves multiple functions: it acts as a backup detection component, an occlusion detector, and a trigger for alternative detection mechanisms. By making the transducer system multi-functional, the patent achieves reliable continuous detection without proportionally increasing complexity, as each additional transducer performs multiple roles in the detection ecosystem.
3Ease of operation
If ultrasonic sensors are used for proximity detection, then user experience is improved through automatic device control, but power consumption increases
Solution Approach 1:
The system uses periodic triggering of the ultrasonic sensor based on detected conditions. Instead of continuous operation, the sensor is activated periodically when the first transducer detects proximity, and the second transducer triggers additional detection only when needed (when occlusion is detected). This periodic action reduces overall power consumption while maintaining automatic device control functionality.
Solution Approach 2:
The detection system automatically triggers device control functions based on transducer readings without requiring continuous power-intensive processing. The transducers self-trigger the appropriate detection and control sequences, allowing the system to maintain ease of operation through automatic control while minimizing power consumption by only activating intensive functions when transducer data indicates user presence.
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 enables continuous detection of user presence even when transducers are occluded, improving user experience by controlling device components and conserving power.
Implementation Method 1
transmitting a first ultrasonic transmit signal using a first transducer of the ultrasonic sensor
Implementation Method 2
detecting that the second transducer is occluded
Implementation Method 3
operating at least one receiver of the computerized device to receive, during at least one reception window, one or more received signals that were reflected or scattered due to the transmitting
Implementation Method 4
detecting a change in an audible noise floor of at least one transducer
Data Source
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AI summary
Techniques and apparatuses are described that implement an ultrasonic sensor capable of detecting user presence. This ultrasonic sensor can detect user presence without relying on time-of-flight techniques. In particular, the ultrasonic sensor can determine that a user is present based on the occlusion of at least one receiving transducer (e.g., microphone occlusion), the occlusion of at least one transmitting transducer (e.g., speaker occlusion), or a detected change in an audible noise floor of at least one transducer. In this way, the ultrasonic sensor can continue to detect user presence in situations in which a user occludes one or more transducers of the ultrasonic sensor. The ultrasonic sensor can also control operation of another component within a computing device based on the presence of the user to improve the user experience and/or improve power management.