Adaptive PPG Sensor Configuration for Motion-Robust Wearables
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Solution Overview
Problem
Existing wearable devices face challenges in accurately collecting photoplethysmogram (PPG) data due to factors such as motion, ambient light, and varying skin properties, which affect signal quality.
Innovation Solution
A configurable PPG system that dynamically selects transmitter-receiver combinations and wavelengths based on signal quality metrics, such as strength, user movement, and ambient light, to optimize data acquisition across different scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed-ratio LED configuration is used, then the device structure is simple, but the system lacks adaptability to different measurement requirements and patient conditions
Solution Approach 1:
The patent implements dynamic configurability of LED parameters including wavelength, drive current, and pulse width. The system allows real-time adjustment of LED operating characteristics based on measurement requirements and patient conditions, transforming a static device into a dynamically adaptable system that can optimize performance for different scenarios without requiring multiple fixed devices
Solution Approach 2:
The patent creates a universal PPG system that can perform multiple measurement functions through a single device. By enabling configurable LED parameters and multiple measurement modes (including simultaneous multi-wavelength measurements), the system serves as a multi-functional platform that adapts to various clinical and research applications, eliminating the need for separate specialized devices
2Adaptability or versatility
If multiple LEDs with different wavelengths are used simultaneously, then measurement versatility is improved, but device complexity and control difficulty increase
Solution Approach 1:
The system dynamically controls multiple LEDs with different wavelengths by allowing independent configuration of each LED's drive current and pulse width. This dynamic control capability enables the system to activate only the necessary LEDs for each measurement type, simplifying the control process while maintaining measurement versatility across different wavelengths
Solution Approach 2:
The patent implements periodic or pulsed activation of different wavelength LEDs rather than continuous operation. By using configurable pulse widths and timing sequences, the system can systematically cycle through different wavelength combinations, making the control of multiple LEDs more manageable and reducing interference between simultaneous measurements
3Measurement precision
If LED drive current and pulse width are optimized for specific conditions, then measurement precision is improved, but the system loses flexibility for other conditions
Solution Approach 1:
The system resolves this contradiction by making LED drive current and pulse width dynamically configurable rather than fixed. Users can optimize these parameters for specific measurement conditions when needed, while retaining the ability to adjust them for other conditions. This dynamic optimization capability allows the system to achieve high measurement precision across multiple different scenarios without sacrificing flexibility
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
Enhances the accuracy and reliability of PPG signal measurement by adapting to changing conditions and user interactions, ensuring consistent data quality regardless of device orientation or environmental factors.
Implementation Method 1
a first light emitting diode (LED) to emit light at a first wavelength
Implementation Method 2
a photodetector to detect light emitted by the LED
Data Source
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AI summary
Methods, systems, and devices for optical signal measurement are described. A wearable electronic device may activate a first combination of optical sensors, the first combination of optical sensors including a set of transmitter sensors and a set of receiver sensors. In some cases, one or more optical sensor of the first combination of optical sensors may be positioned under a protrusion on an inner surface of the wearable electronic device. The device may measure, at the set of receiver sensors at a first time, one or more signals from the set of transmitter sensors, determine a signal quality metric associated with the one or more signals, and select a second combination of optical sensors for use at a second time based on the signal quality metric.