Eddy Current Damping Sensor for Non-Contact Respiratory Volume
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Solution Overview
Problem
Current pulmonary function testing methods pose risks of airborne disease transmission and require close contact for accurate results, failing to reliably measure respiratory metrics like FEV1 and FVC.
Innovation Solution
A wearable, non-contact sensor apparatus using an inductive device with a sensor coil and RLC circuit measures parallel resistance changes in the chest cavity to track respiratory cycles, enabling accurate pulmonary function assessment without direct skin contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional spirometry and lung plethysmography are used for pulmonary function testing, then accurate measurement of respiratory metrics is achieved, but risk of airborne disease transmission increases and direct skin contact is required
Solution Approach 1:
The patent replaces mechanical contact-based sensing systems with an electromagnetic field-based inductive sensor system. The sensor coil generates an electromagnetic field that interacts with the conductive tissues of the chest cavity, eliminating the need for direct skin contact and reducing airborne transmission risk while maintaining measurement accuracy through non-contact detection of respiratory movements
Solution Approach 2:
The patent introduces an electromagnetic field as an intermediary between the sensor and the respiratory system. The sensor coil detects respiratory movements indirectly by measuring changes in the electromagnetic field interactions with conductive tissues, rather than requiring direct mechanical contact or close proximity, thus reducing transmission risk while preserving measurement reliability
2Ease of operation
If accelerometers or acoustic-based sensors are used to monitor respiration, then non-contact measurement is achieved, but accurate measurement of respiratory volume and pulmonary metrics is not reliably obtained
Solution Approach 1:
The patent changes the detection parameter from mechanical acceleration or acoustic wave detection to electromagnetic field interaction. By measuring changes in electromagnetic field characteristics (inductance, resistance, capacitance) caused by the movement of conductive tissues during respiration, the system achieves both non-contact operation and accurate measurement of respiratory volume and pulmonary metrics
3Measurement precision
If mechanical strain sensors are placed on the chest to measure respiratory waveform, then respiratory waveform measurement is achieved, but calibration and tight skin contact are required for accurate results
Solution Approach 1:
The patent replaces mechanical strain sensors with an electromagnetic sensing system that detects respiratory movements through non-contact interaction with conductive tissues. This eliminates the need for calibration and tight skin contact while maintaining accurate measurement of respiratory waveform and volume metrics
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 apparatus provides accurate measurements of FEV1, FVC, and respiratory rate by correlating parallel resistance changes with these metrics, reducing exposure risks and simplifying pulmonary function testing.
Implementation Method 1
an inductive device including a sensor coil... a periodic current (such as a sinusoidal alternating current) may be applied through the sensor coil... detects changes to its relatively weak magnetic fields generated by the coil
Implementation Method 2
resultant eddy current damping (ECD) in nearby tissue to track changes in conductivity within the chest cavity
Data Source
AI summary
Medical diagnostic devices and related methods of use are described in which a sensor coil may be connected with a resistive, inductive, and capacitive (RCL) circuit including a power meter and a frequency counter, and the sensor may be positioned on a chest of a subject. The sensor apparatus may apply an alternating current through the sensor coil. The sensor apparatus may measure parallel resistance values in the sensor coil using the power meter for a time interval while the subject inhales and exhales. The sensor apparatus may record the parallel resistance values. The sensor apparatus may determine a first change in the parallel resistance values by measuring a difference between a crest and a trough of the parallel resistance values, wherein the crest of the parallel resistance value corresponds to the inhale and the trough of the parallel resistance value corresponds to the exhale of the subject's breath.