Wearable Sensor Positioning for Heart Rate Signal Quality
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Solution Overview
Problem
Existing wearable devices with photoacoustic sensor systems face challenges in obtaining clear heart rate waveforms due to low signal-to-noise ratios and varying arterial orientations, which affect the positioning of ultrasonic receivers and lead to poor signal quality.
Innovation Solution
A wearable device with an adjustable sensor system that includes a photoacoustic sensor system with a light source and an ultrasonic receiver system. The control system determines the optimal wearable device configuration by comparing signal-to-noise ratios at different sensor positions and prompts the user to adjust the device accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor system uses a fixed configuration, then the device structure is simple, but the signal quality deteriorates when arterial orientation varies
Solution Approach 1:
The sensor system transitions from a fixed configuration to an adjustable configuration where the ultrasonic receiver can be repositioned along the wearable device. This dynamic adjustment capability allows the system to adapt to varying arterial orientations and maintain optimal signal quality by moving the receiver to positions that maximize photoacoustic signal detection.
Solution Approach 2:
The system changes the positional parameter of the ultrasonic receiver along the wearable device to optimize signal acquisition. By adjusting the receiver position as a variable parameter, the system can compensate for different arterial orientations and improve signal-to-noise ratio without requiring a complete redesign of the sensor geometry.
2Reliability
If multiple sensor positions are tested to find optimal configuration, then signal quality improves, but the time required for measurement increases
Solution Approach 1:
The system performs preliminary testing of multiple sensor positions during device setup or initialization to identify and store the optimal configuration. This preliminary action allows the system to memorize the best-performing position, so that during actual measurement operations, the system can quickly jump to the pre-identified optimal position without systematically testing all possibilities, thereby reducing measurement time while maintaining high signal quality.
3Reliability
If the ultrasonic receiver is repositioned to match arterial orientation, then signal-to-noise ratio improves, but the ease of operation decreases
Solution Approach 1:
The system implements self-service functionality where the control system automatically evaluates signal quality at different positions and determines the optimal configuration without requiring user intervention. The system autonomously tests multiple positions, compares signal-to-noise ratios, and selects the best position, thereby maintaining high signal quality while eliminating the need for users to manually adjust the sensor configuration.
Solution Approach 2:
The control system continuously monitors signal quality metrics and uses this feedback to automatically adjust the ultrasonic receiver position. By implementing a feedback loop where the system evaluates the current signal-to-noise ratio and automatically repositions the receiver to optimize detection, the system maintains high signal quality while removing the burden of manual user adjustment.
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
The wearable device can select an optimal configuration for obtaining high-quality heart rate waveforms, enhancing signal clarity and depth discrimination, which can lead to more accurate blood pressure estimations.
Implementation Method 1
The light source system is configured to emit light to a target object and generate photoacoustic signals from the target object
Implementation Method 2
The receiver system is configured to receive the photoacoustic signals
Data Source
AI summary
Some disclosed examples involve obtaining, via a sensor system of a wearable device, first heart rate waveforms at a first wearable device configuration corresponding with a first position at least a portion of the sensor system. Some examples involve prompting, via a user interface of the wearable device, a user to change the wearable device configuration to a second wearable device configuration, the second wearable device configuration corresponding with a second position of one or more sensors of the sensor system. Some examples involve obtaining second heart rate waveforms at the second wearable device configuration and determining, based at least in part on the first heart rate waveforms and the second heart rate waveforms, whether to change a wearable device configuration or maintain a current wearable device configuration. Some examples involve prompting the user either to change the wearable device configuration or maintain the current wearable device configuration.