Vehicle Seat Magnetic Cardiogram Sensing Without Skin Contact
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Solution Overview
Problem
Existing methods for determining vital functions of vehicle occupants, such as cardiac activity, are inaccurate and require direct skin contact, making them unsuitable for comfortable integration in motor vehicles.
Innovation Solution
A method using a magnetic field sensor device, specifically a gradiometer with nitrogen vacancy sensors, integrated into a vehicle seat to measure magnetic cardiogram signals without contact, which eliminates environmental interference by calculating differences between signals from spaced-apart sensors, allowing for precise vital function determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If capacitive methods or camera/radar-based measurements are used to measure cardiac activity, then the measurement can be performed without direct skin contact, but the measurement precision is very inaccurate
Solution Approach 1:
The patent replaces capacitive sensing and optical/radar methods with magnetic field sensing. The magnetic field sensor device detects the magnetic field generated by the heart's electrical activity, providing contactless measurement with high precision. This substitution of the sensing mechanism resolves the contradiction by achieving both contactless operation and accurate measurement through a fundamentally different physical principle.
2Measurement precision
If direct skin contact electrodes are used to detect heart muscle signals, then the measurement precision is high, but the ease of operation deteriorates due to discomfort and unsuitability for vehicle integration
Solution Approach 1:
The patent substitutes direct skin contact electrodes with a contactless magnetic field sensor device integrated into the vehicle seat. The sensor detects the magnetic field generated by cardiac activity through the seat structure, eliminating the need for skin contact while maintaining measurement precision. This resolves the contradiction by providing accurate heart muscle signal detection without compromising occupant comfort or integration suitability.
3Measurement precision
If magnetic field sensors are used to detect cardiac magnetic fields, then contactless measurement with good precision is achieved, but environmental magnetic interference from the Earth and vehicle significantly affects measurement accuracy
Solution Approach 1:
The patent divides the magnetic field sensing function into multiple sensors arranged in a gradiometer configuration. By spacing sensors at different positions relative to the seat and heart, the system segments the measurement task to distinguish between environmental interference (affecting all sensors equally) and cardiac signals (creating differential patterns). This segmentation enables interference rejection while maintaining detection precision.
Solution Approach 2:
The patent introduces a gradiometer configuration as an intermediary processing mechanism. The gradiometer computes the difference or gradient of magnetic field measurements between spaced sensors, acting as a mathematical intermediary that eliminates common-mode environmental interference while preserving the spatially varying cardiac signal. This intermediary processing resolves the contradiction by filtering interference while maintaining signal integrity.
4Measurement precision
If a gradiometer with multiple spaced-apart magnetic field sensors is used, then environmental interference is eliminated through difference signal calculation, but the device complexity increases
Solution Approach 1:
The patent integrates the magnetic field sensor device into the existing vehicle seat structure, making the seat serve multiple functions: providing occupant support and housing the cardiac detection sensors. The seat back or cushion structure becomes a universal platform that both supports the occupant and positions the sensors optimally for detecting cardiac magnetic fields while maintaining a relatively simple overall device structure.
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 accurate detection of medically relevant cardiac emergencies, initiating safe vehicle stops, and providing health assessments without disturbing the occupant, enhancing passenger safety and comfort.
Implementation Method 1
it is further provided that the sensor device is a magnetic field sensor device and that the cardiogram signals are magnetic cardiogram signals
Implementation Method 2
the magnetic field sensor device is a gradiometer comprising at least two magnetic field sensors disposed at spaced-apart positions, wherein the at least two magnetic field sensors measure a magnetic field at the spaced-apart positions and generate the measurement signals, wherein the magnetic cardiogram signal is further preferably ascertained as a difference signal of the measurement signals of the at least two magnetic field sensors
Data Source
AI summary
A method for determining the vital functions of a vehicle occupant enables precise measurements and is easy to use without negatively affecting the vehicle occupant. The method includes determining the vital functions of the vehicle occupant using a sensor device integrated in a vehicle seat of a motor vehicle, and acquiring measurement signals of the vehicle occupant from which cardiogram signals are acquired. The method further includes using an evaluation unit to ascertain the vital functions of the vehicle occupant from the cardiogram signals. The sensor device is a magnetic field sensor device, and the cardiogram signals are magnetic cardiogram signals.