Handheld Controller PPG Sensor Array for Motion-Tolerant Heart Rate Monitoring
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Solution Overview
Problem
Current heart rate monitoring technologies, such as smartwatches, face inaccuracies due to lower perfusion at the wrist, and VR/AR controllers face challenges with varying grip and motion, which affect the reliability of heart rate readings.
Innovation Solution
A PPG sensor array integrated into VR/AR controllers that dynamically adjusts sensing locations based on motion and pressure to optimize signal quality, recalibrating as needed to ensure accurate heart rate monitoring across different hand geometries and movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single PPG sensor is used in VR/AR controllers, then the device complexity is low, but the measurement precision deteriorates due to varying grip and motion
Solution Approach 1:
The patent divides the sensing function into multiple independent PPG sensors arranged in an array, where each sensor can independently measure heart rate at its specific location. This segmentation allows the system to handle varying grip and motion by selecting the most reliable sensor readings, thereby improving measurement precision without requiring a single complex sensor system.
Solution Approach 2:
The patent implements dynamic adaptation by continuously monitoring signal quality from multiple sensors and switching between them based on real-time conditions. The system dynamically adjusts which sensors are active and how data is fused based on detected motion and grip variations, enabling the system to maintain high measurement precision despite changing user interactions.
2Measurement precision
If a PPG sensor array is used to probe a larger area on the palm, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent implements a PPG sensor array with multiple discrete sensors positioned at different locations on the controller. Each sensor is a simple, standardized component, and the overall system complexity is managed by using modular sensor units that can be independently manufactured and assembled. This segmentation approach allows the system to probe a larger area for improved signal quality while keeping individual sensor components simple.
Solution Approach 2:
The patent designs the sensor array system to serve multiple functions: heart rate monitoring, signal quality assessment, and adaptive filtering. By making the sensor system multi-functional, the patent reduces the need for additional separate components, thereby managing device complexity while achieving improved measurement precision through the array's ability to handle various sensing tasks.
3Adaptability or versatility
If the sensor array dynamically adjusts sensing locations based on motion, then the adaptability improves, but the processing time increases
Solution Approach 1:
The patent performs preliminary characterization of motion patterns and signal quality metrics in advance, establishing thresholds and criteria before actual heart rate measurement begins. This preliminary preparation allows the system to quickly adapt to motion variations during operation without requiring time-consuming real-time recalibration, as the adaptation logic and decision thresholds are pre-established.
Solution Approach 2:
The patent implements periodic monitoring and adjustment cycles, where the system periodically assesses signal quality and motion conditions rather than continuously recalibrating. This periodic action allows the system to maintain adaptability to motion variations while reducing processing time by only performing recalibration and adjustment at discrete intervals rather than continuously.
4Ease of operation
If wrist-worn devices are used for heart rate monitoring, then the ease of operation is high, but the measurement precision deteriorates due to lower perfusion at the wrist
Solution Approach 1:
The patent inverts the traditional approach by placing the PPG sensor array on the user's hand/palm area rather than on the wrist. This inversion leverages the higher perfusion levels found in the hand to improve measurement precision, while the controller's handheld nature maintains ease of operation. The system effectively swaps the sensing location from the conventional wrist area to the hand area, achieving both precision and usability.
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
Provides more accurate and consistent heart rate monitoring compared to wrist-worn devices by probing a larger area on the palm, improving signal quality and user experience across various activities.
Implementation Method 1
A PPG sensor array integrated into VR/AR controllers that dynamically adjusts sensing locations based on motion and pressure to optimize signal quality
Data Source
AI summary
A method for motion-tolerant optical heart-rate monitoring may include calibrating an array of heart rate sensors of a handheld device by (i) evaluating, while the handheld device is being held by a user, an output of each sensor in the sensor array, (ii) selecting, based on the evaluation of the output of each sensor, a subset of sensors in the sensor array for use in detecting a heart rate of a user, and (iii) using the subset of sensors to monitor the heart rate of the user. Various other methods, systems, and computer-readable media are also disclosed.