Electronic Sphygmomanometer Dual Sensor Switching Circuit
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Solution Overview
Problem
Existing electronic sphygmomanometers for home use lack precision and reliability due to the absence of periodic calibration, with multiple pressure sensors increasing complexity and power consumption, and existing solutions require complex and costly circuits to manage multiple sensors effectively.
Innovation Solution
An electronic sphygmomanometer design utilizing a cuff with multiple pressure sensors, oscillation circuits, and a control circuit that switches between them to detect cuff pressures and determine sensor abnormalities, allowing for improved reliability with a simple system and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pressure sensors are used to improve measurement precision, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple pressure sensors (first pressure sensor and second pressure sensor) into a single integrated system where both sensors detect cuff pressure simultaneously. The oscillation circuits for both sensors are merged with a common oscillation circuit adjustment circuit, allowing the system to manage multiple sensors without proportionally increasing overall complexity.
Solution Approach 2:
The oscillation circuit adjustment circuit serves multiple functions: it adjusts the oscillation frequencies of both the first and second oscillation circuits, and also functions as a switching circuit to select which sensor's signal is sent to the CPU. This multi-functionality reduces the need for separate adjustment and switching circuits for each sensor.
2Reliability
If multiple pressure sensors are used to improve measurement precision, then reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic switching between the first and second pressure sensors based on measurement requirements. The CPU selectively activates one sensor or the other for blood pressure measurement, rather than continuously monitoring both sensors simultaneously. This periodic action reduces overall power consumption while maintaining measurement reliability through sensor redundancy.
3Device complexity
If a single pressure sensor is used to reduce complexity, then device complexity is reduced, but reliability deteriorates
Solution Approach 1:
The patent introduces a feedback mechanism where the CPU continuously compares the output signals from the first and second pressure sensors. When a discrepancy between the two sensors is detected, the system can identify sensor malfunction or drift and adjust measurements accordingly. This feedback loop enables the system to maintain high reliability while using a relatively simple circuit architecture.
Solution Approach 2:
The patent incorporates a second pressure sensor as a backup and validation mechanism from the outset. The presence of the second sensor provides beforehand cushioning against the potential failure or drift of the first sensor, ensuring that measurement reliability is maintained even if one sensor performs poorly. This redundant sensor is activated only when needed, balancing complexity and reliability.
4Manufacturing precision
If pressure sensor characteristics are corrected during production, then measurement precision is improved, but the system cannot detect drift over time
Solution Approach 1:
The patent performs preliminary characterization of each pressure sensor's output signal during the production stage and stores this information in the CPU. This preliminary action establishes a baseline for each sensor's behavior, enabling the system to detect and compensate for drift or changes in sensor characteristics over time during actual use.
Solution Approach 2:
The system uses feedback from continuous comparison of both pressure sensors to detect changes in sensor characteristics over time. When drift or degradation is detected, the CPU can adjust measurements or alert the user, maintaining long-term reliability despite the lack of periodic manual calibration.
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
This design enhances the reliability of blood pressure measurements by detecting sensor abnormalities and reducing power consumption, while maintaining a compact and cost-effective circuit scale, thus addressing the limitations of previous technologies.
Implementation Method 1
a plurality of oscillation circuits, provided in correspondence to the respective plurality of pressure sensors, that output a square wave signal of a frequency based on pressures
Data Source
AI summary
A first oscillation circuit and a second oscillation circuit are connected to a first pressure sensor and a second pressure sensor, respectively, and oscillate based on the capacity values of the corresponding pressure sensors. The first oscillation circuit and the second oscillation circuit operate in response to instruction from a CPU. The one of the first oscillation circuit and the second oscillation circuit that has received an activation signal from the CPU outputs a signal having a frequency that corresponds to the capacity value of the corresponding pressure sensor. An adjustment circuit is connected to the first oscillation circuit and the second oscillation circuit, and allows one of the frequency signals to pass therethrough, outputting the signal to the CPU.