Optical PPG Heart Monitoring With Adaptive RRi Sampling Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional photoplethysmography 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 when used in wearable forms like earbuds, which can be uncomfortable and ineffective in accurately measuring heart rate and other physiological parameters.
Innovation Solution
A monitoring device with a processor that adjusts signal analysis frequency and sensor interrogation power based on detected changes in activity, using optical sensors with adjustable algorithms and power management to optimize data collection during varying activity levels, and environmental conditions, while also considering circadian rhythms and stress levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional photoplethysmography devices use a spring to clip the sensor onto the earlobe or fingertip, then the device can be easily attached, but the device has large mass and cannot maintain consistent skin contact when subjected to large accelerations during exercise
Solution Approach 1:
The patent transitions from a static spring-based clipping mechanism to a dynamic system that actively responds to motion. The device uses motion sensors to detect acceleration and gyroscopic data to determine orientation, then dynamically adjusts the sensor's position and contact pressure in real-time to maintain optimal skin coupling during exercise activities.
Solution Approach 2:
The device employs self-adjusting mechanisms that automatically respond to detected motion without user intervention. The processor analyzes motion sensor data and autonomously controls actuators to reposition the optical sensor, maintaining consistent skin contact through self-service rather than requiring manual adjustment by the user.
2Measurement precision
If the sensor is continuously interrogated at high frequency to capture physiological data during exercise, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic sampling rate adjustment based on detected activity level. During periods of high motion or exercise, the processor increases the interrogation frequency to capture rapid physiological changes with high precision. During low-activity periods, the sampling rate is reduced to conserve battery power, creating an adaptive power management strategy.
Solution Approach 2:
The system changes operational parameters (sampling frequency, interrogation power) based on detected conditions. Motion sensors trigger parameter adjustments that match the physiological state - higher sampling rates during exercise when heart rate and blood flow changes are more variable, and lower rates during rest to extend battery life.
3Ease of operation
If optical sensors are used to measure blood flow changes through photoplethysmography, then non-invasive monitoring is achieved, but motion artifacts from physical activity swamp out the blood flow signal
Solution Approach 1:
The patent employs feedback from motion sensors (accelerometers and gyroscopes) to the processing system. The processor uses this feedback to distinguish between signal variations caused by motion artifacts and those caused by actual physiological changes. This feedback mechanism enables real-time compensation and filtering to maintain measurement precision during exercise.
Solution Approach 2:
Motion sensors serve as intermediary devices that detect physical movement and provide data to the processor. This intermediary information acts as a reference signal that helps the system separate motion-induced noise from true physiological signals, enabling accurate measurement despite physical activity.
4Reliability
If earbuds incorporate elastomeric surfaces and springs to dampen acceleration during vigorous activity, then retention in the ear is improved, but optical skin coupling requirements are not adequately addressed
Solution Approach 1:
The patent replaces static elastomeric retention mechanisms with dynamic active retention. Instead of relying solely on passive elastic forces, the system uses motion detection to trigger active adjustments in sensor positioning and contact pressure, dynamically adapting to maintain both retention and optimal optical coupling during vigorous activity.
Solution Approach 2:
The patent substitutes passive mechanical retention (elastomeric surfaces and springs) with an active system combining motion sensors, processors, and controlled actuators. This replacement enables precise control over sensor positioning and skin contact, improving optical coupling beyond what passive mechanical retention can achieve.
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 enhances the accuracy and reliability of physiological data collection by adapting to different activity levels and conditions, reducing power consumption and improving comfort, thereby providing more precise and efficient monitoring of vital signs.
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 and measuring how the scattered light intensity changes
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.