Capacitive Touch Sensors for Heart Rate Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional heart rate monitoring techniques using specialized sensors are inconvenient, costly, and uncomfortable, leading to infrequent monitoring and analysis of heart rates in everyday life.
Innovation Solution
Utilizing multi-use capacitive touch sensors integrated into computing devices to detect fluctuations in capacitance caused by heartbeats, allowing for heart rate detection during normal interactions, such as texting or browsing, by extracting raw capacitance data and processing it to isolate heartbeat waveforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized heart rate monitoring devices (ECG sensors, oximeters) are used, then measurement precision of heart rate is improved, but device complexity, cost, and user discomfort increase
Solution Approach 1:
The patent applies multi-functionality by enabling capacitive touch sensors to serve dual purposes: detecting user touch inputs for device control and simultaneously monitoring heart rate. The same sensor array that detects finger taps and swipe gestures also captures capacitance fluctuations caused by cardiac activity, eliminating the need for dedicated heart rate monitoring hardware.
Solution Approach 2:
The patent merges the function of general-purpose touch detection with specialized heart rate monitoring into a single integrated system. By combining these functions in the capacitive touch sensor array and unified processing pipeline, the system achieves both touch control and physiological monitoring without requiring separate device components.
2Productivity
If specialized heart rate monitoring devices are worn continuously, then heart rate monitoring frequency is improved, but ease of operation and user comfort deteriorate
Solution Approach 1:
The system applies self-service by automatically performing heart rate monitoring during normal device interaction without requiring user initiation or special actions. The capacitive touch sensors continuously capture capacitance data during everyday tasks like typing or scrolling, and the processing system automatically extracts heart rate information, making monitoring seamless and integrated into natural device usage.
Solution Approach 2:
The multi-functional capacitive touch sensor enables heart rate monitoring to occur during regular device interaction, transforming the device into both a computational tool and a continuous health monitor without requiring separate wearables or specialized user actions.
3Adaptability or versatility
If raw capacitance data is extracted from multi-use touch sensors, then heart rate detection capability is improved, but measurement precision deteriorates due to noise from AC chargers, LCD, and environmental interference
Solution Approach 1:
The patent applies extraction by isolating the heartbeat signal from the noisy raw capacitance data through spectral analysis. The system transforms the time-domain capacitance signal into the frequency domain using Fourier transform, then extracts the specific frequency components corresponding to heart rate while filtering out noise from AC chargers, LCD refresh rates, and environmental interference.
Solution Approach 2:
The patent uses frequency domain transformation as an intermediary process to separate the heartbeat signal from noise. By converting the capacitance signal to frequency spectrum and identifying peaks within the physiological heart rate band (typically 0.8-4 Hz), the system acts as a mediator that transforms noisy raw data into clean heart rate measurements through spectral filtering.
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
Enables continuous and convenient heart rate monitoring without the need for specialized devices, improving healthcare and personal well-being by providing regular heart rate data for stress analysis and other applications.
Implementation Method 1
capacitive touch sensors that are also used to detect touch inputs to control operations of a computing device... These capacitive touch sensors produce raw capacitance data that is indicative of contact made by a person's hand
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A heart rate detection device comprises multi-use capacitive touch sensors. Fluctuations in capacitance are detected (802) using capacitive touch sensors. These capacitive touch sensors are also used to detect touch inputs to control operations of a computing device. When contact of a person's hand with the computing device is detected, the capacitive touch sensors produce raw capacitance data that indicates detected capacitance fluctuations. The raw capacitance data is extracted (902) from the capacitive touch sensors using a modified device driver that bypasses default driver configurations that ignore fluctuations in capacitance due to heartbeats. Times during which the person's hand contacts the computing device and locations of the contact are determined (804) from the raw capacitance data indicative of the fluctuations. The extracted raw capacitance data is then processed to determine the person's heart rate (806, 808).