Optical PPG Monitoring With Adaptive Sampling and Power Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional photoplethysmography (PPG) devices face challenges in maintaining consistent skin contact during physical activity, leading to reduced signal quality due to motion artifacts and high power consumption, especially in wearable forms like earbuds, which are uncomfortable and inefficient in powering accurate heart rate monitoring during exercise.
Innovation Solution
A monitoring device with a processor that adjusts signal analysis frequency and sensor interrogation power based on detected activity levels, using optical sensors with adjustable algorithms and power management to enhance signal quality and conserve battery life, including the use of frequency-domain and time-domain processing, and wavelength adjustments for improved data accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PPG devices use spring-loaded sensors to maintain skin contact, then skin coupling is improved, but device mass increases and comfort during exercise deteriorates
Solution Approach 1:
The patent removes the spring-loaded sensor mechanism from the earbud device entirely. Instead, it uses a lightweight earbud that makes direct contact with the ear canal skin, eliminating the need for springs while maintaining reliable optical coupling through proper positioning and contact geometry
Solution Approach 2:
The patent replaces the mechanical spring-loaded contact system with an optical detection system that uses the earbud's natural position and contact pressure to achieve sufficient skin coupling for accurate PPG measurements without requiring active mechanical forcing
2Measurement precision
If optical sensor interrogation power is increased to improve signal quality during exercise, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of the optical sensor interrogation power based on detected activity levels. During exercise when motion artifacts increase, the system automatically increases sensor power to maintain signal quality, and reduces power during rest periods to conserve battery life
Solution Approach 2:
The system uses feedback from motion sensors and initial PPG signal quality assessment to automatically adjust the optical sensor interrogation power, creating a closed-loop control system that optimizes power consumption while maintaining measurement accuracy across varying activity conditions
3Measurement precision
If signal analysis frequency is increased to capture high-frequency physiological signals during exercise, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent dynamically adjusts the signal analysis frequency based on detected activity levels. During exercise, the system increases sampling and analysis frequency to capture high-frequency physiological signals and motion artifacts, then reduces frequency during rest to minimize processing power consumption
4Stability of the object's composition
If earbuds incorporate elastomeric features for retention during exercise, then device stability is improved, but optical skin coupling quality deteriorates
Solution Approach 1:
The patent applies different material properties to different parts of the earbud: the outer housing uses elastomeric materials for retention and comfort, while the sensor contact surface uses smooth, optically optimized materials that ensure consistent light coupling with the skin without the interference of elastomeric textures
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 solution improves the accuracy of biometric data collection during physical activity while reducing power consumption, allowing for more reliable and prolonged monitoring of physiological parameters like heart rate and breathing rate.
Implementation Method 1
Photoplethysmography (PPG) is based upon shining light into the human body and measuring how the scattered light intensity changes with each pulse of blood flow
Implementation Method 2
The sensor may be an optical sensor that includes at least one optical emitter and at least one optical detector
Data Source
AI summary
A monitoring device configured to be attached to a subject includes a photoplethysmography (PPG) sensor configured to detect/measure physiological information from the subject, and a processor configured to process the physiological information to detect subject stress, and to determine an origin of the subject stress. The processor can determine the origin of the subject stress by increasing a sampling rate of the PPG sensor to collect higher acuity physiological information. The processor also can determine the origin of the subject stress by processing data from the PPG sensor to determine whether the subject is likely to have atrial fibrillation. In response to determining that the subject is likely to have atrial fibrillation, the processor can increase a frequency of pulsing of an optical emitter of the PPG sensor and/or increase a sampling rate of the PPG sensor to collect higher acuity data for diagnosing that atrial fibrillation is truly occurring.