Optical PPG Monitoring With Adaptive Sampling for Motion and Power
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 varying optical coupling efficiency.
Innovation Solution
A monitoring device configured to be attached to a body, featuring a sensor that detects physiological information and a processor that adjusts signal analysis frequency and sensor interrogation power based on detected changes in activity, environmental conditions, or predetermined times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional PPG devices use a spring to clip the sensor onto the earlobe or fingertip, then the device can be easily attached to the body, but the device has large mass and cannot maintain consistent skin contact when subjected to large accelerations during exercise
Solution Approach 1:
The patent replaces the mechanical spring-based clipping system with an electrostatic adhesion system. The sensor housing includes an electrostatically charged surface that attracts and holds the sensor against the skin through electrostatic forces, eliminating the need for mechanical springs and clips. This substitution maintains ease of attachment while significantly improving reliability during high-acceleration activities, as electrostatic adhesion provides consistent contact force without the mass and mechanical complexity of spring systems.
2Weight of moving object
If the sensor mass is reduced to improve wearability during exercise, then the device can better withstand accelerations, but the electrostatic adhesion force may be insufficient to maintain skin contact
Solution Approach 1:
The patent employs parameter changes by controlling the electrostatic charge magnitude on the sensor housing surface. By adjusting the electrostatic adhesion force parameter, the system can maintain reliable skin contact even with reduced sensor mass. The electrostatically charged surface creates sufficient attractive force to counteract acceleration forces acting on the lightweight sensor, thereby maintaining consistent skin contact without requiring heavy mechanical components.
3Measurement precision
If signal analysis frequency and sensor interrogation power are increased to improve measurement accuracy during high activity, then physiological metrics can be accurately captured, but power consumption increases and battery life decreases
Solution Approach 1:
The patent implements dynamic adjustment of signal analysis frequency and sensor interrogation power based on detected activity levels. During high-activity periods when motion artifacts are present, the system increases sampling frequency and interrogation power to maintain measurement accuracy. During low-activity periods, the system reduces these parameters to minimize power consumption. This dynamic adaptation allows the device to maintain physiological metric accuracy when needed while optimizing battery life during extended wear.
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 enhances the accuracy of physiological metrics like heart rate and breathing rate by adapting to changing conditions, while also optimizing power consumption to extend battery life.
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
shining light into the human body
Data Source
AI summary
A monitoring device configured to be attached to a subject includes a photoplethysmography (PPG) sensor configured to measure physiological information from the subject, and at least one processor configured to process signals from the PPG sensor to determine heart rate and RR-interval (RRi) for the subject, and to determine a heart rate pattern for the subject over a period of time. The at least one processor is configured to change a sampling frequency of the PPG sensor for determining RRi in response to the determined heart rate pattern. The at least one processor is configured to reduce the sampling frequency of the PPG sensor in response to determining a pattern of heart rate below a threshold.