Self-Heating Thermistor Switching for Multi-Parameter Respiration
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Solution Overview
Problem
Existing respiratory monitoring technologies lack the ability to non-invasively measure multiple parameters such as breath temperature, velocity, volume, carbon dioxide level, and heart rate efficiently using a single, lightweight sensor.
Innovation Solution
A single thermistor-based system that switches between self-heating and temperature sensing modes to measure breath temperature, velocity, volume, and carbon dioxide level, utilizing intelligent control and processing circuitry to determine these parameters and transmit data wirelessly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple separate thermistors are used to measure different respiratory parameters, then measurement capability is improved, but device complexity and weight increase
Solution Approach 1:
A single thermistor is designed to perform multiple measurement functions by switching between different operational modes. The thermistor can measure breath temperature, breath velocity, breath volume, and carbon dioxide level by alternating between temperature sensing mode and self-heating power dissipation sensing mode, eliminating the need for multiple separate sensors
Solution Approach 2:
The patent combines temperature sensing and flow rate measurement capabilities into a single thermistor device. By merging these functions into one component, the system reduces device complexity and weight while maintaining comprehensive respiratory monitoring capability
2Measurement precision
If a thermistor is heated to measure flow rate via thermal dissipation, then flow rate measurement is improved, but power consumption increases
Solution Approach 1:
The thermistor operates in periodic cycles, alternating between temperature sensing mode and self-heating power dissipation sensing mode. The electronic switching circuitry controls the thermistor to be heated only during specific time intervals for flow rate measurement, then switches to temperature sensing mode to reduce power consumption, achieving a balance between measurement precision and energy efficiency
Solution Approach 2:
The system changes the operational parameters of the thermistor dynamically. By adjusting the heating duration, voltage level, and switching frequency based on respiratory phase detection, the system optimizes the balance between measurement accuracy and power consumption, heating only when necessary for flow rate measurement
3Measurement precision
If separate thermistors are used for temperature sensing and flow rate measurement, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
A single thermistor is designed to perform both temperature sensing and flow rate measurement functions by switching between different operational modes. The thermistor measures temperature during temperature sensing mode and measures flow rate via thermal dissipation during self-heating mode, eliminating the need for multiple separate sensors while maintaining measurement accuracy
Solution Approach 2:
The thermistor dynamically switches between different operational states based on measurement requirements. The electronic switching circuitry controls the thermistor to alternate between temperature sensing and self-heating modes, allowing one component to adaptively perform multiple measurement functions with high accuracy
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 efficient, real-time monitoring of respiratory parameters with low power consumption, allowing for patient-specific health condition prediction and integration with wearable devices.
Implementation Method 1
a self-heating temperature sensor switched between a temperature sensing mode and a heated power dissipation sensing mode
Implementation Method 2
they can self-heat and thus measure flow rate via thermal dissipation
Implementation Method 3
the startup circuit configured to initiate self-heating of the self-heating temperature sensor by energizing the self-heating temperature sensor at an increased voltage level
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Various examples of methods and systems related to thermistor sensing for measurement of respiration are shown. In one example, a breath sensing system includes a self-heating temperature sensor that can be positioned in respiratory air of a subject and processing circuitry that can monitor operation of the self-heating temperature sensor. Respiratory information associated with physical or physiological properties of the subject can be communicated to a remotely located computing device. Electronic switching circuitry can be included to change operation of the self-heating temperature sensor between a temperature sensing mode and a heated power dissipation sensing mode. The processing circuitry can control switching between the modes. In another example, a method includes monitoring operational conditions of a self-heating temperature sensor positioned in respired air and determining, e.g., breath velocity, breath period, breath volume, breath carbon dioxide level, and heart rate based at least in part upon the operational conditions.