Non-Invasive Liquid Level Sensor Using Capacitance Detection
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Solution Overview
Problem
Traditional liquid level sensors are expensive, complex, and invasive, making them unsuitable for user-friendly applications, especially in medical settings where sterility is a concern, and they often fail to provide accurate and easy-to-use liquid level monitoring.
Innovation Solution
A non-invasive liquid level sensing device using electrodes on the outer surface of a container, coupled with a sensing circuit, amplifier, and controller, which detects capacitance variations to determine liquid levels through a voltage-volume table, allowing for accurate and user-friendly monitoring without direct contact with the liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional liquid level sensors use image identification or ultrasound detecting technology, then liquid level can be detected, but the device becomes expensive and complicated
Solution Approach 1:
The patent replaces complex mechanical sensing systems (image identification, ultrasound) with a simple capacitive sensing system. The electrode detects liquid level through capacitance changes caused by dielectric constant differences between air and liquid, eliminating the need for complex optical or acoustic components while maintaining detection accuracy
Solution Approach 2:
The patent utilizes changes in electrical capacitance parameter to detect liquid level. As the liquid level changes, the capacitance between the electrode and ground changes due to the different dielectric constants of air and liquid, providing a simple yet effective measurement mechanism
2Measurement precision
If traditional liquid level sensors use invasive electrode contact with liquid, then detection can be performed, but sterility cannot be maintained
Solution Approach 1:
The patent introduces the container wall as an intermediary between the electrode and the liquid. The electrode is placed on the outer surface of the container wall, which acts as a dielectric barrier, allowing capacitance-based detection without direct contact between the electrode and liquid, thus maintaining sterility while enabling detection
Solution Approach 2:
The patent replaces the invasive mechanical contact method with a non-contact capacitive sensing method. By detecting changes in electrical field capacitance through the container wall, the system eliminates the need for physical penetration or direct contact, preserving the integrity and sterility of the liquid environment
3Measurement precision
If traditional liquid level sensors are designed for accuracy, then detection precision improves, but ease of use deteriorates
Solution Approach 1:
The patent implements a self-calibrating system where the controller automatically adjusts measurement parameters based on detected capacitance values. The system performs self-diagnosis and adaptation, eliminating the need for manual calibration or complex user setup procedures while maintaining high measurement accuracy
Solution Approach 2:
The patent replaces complex manual adjustment mechanisms with automated electronic control. The microcontroller automatically processes capacitance signals, performs calculations, and displays results, replacing what would otherwise require complex mechanical adjustments or manual intervention
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 solution provides a cost-effective, user-friendly, and sterile method for accurately monitoring liquid levels, suitable for various applications including medical settings, by using capacitance detection and a voltage-volume table to determine liquid levels without invasive mechanisms.
Implementation Method 1
determines the liquid level according to a capacitance value corresponding to the liquid level and a lookup table
Implementation Method 2
uses at least one electrode to detect the liquid level of a liquid to be tested, and acquires the liquid-level information according to a sensing capacitance corresponding to the liquid level
Data Source
AI summary
An embodiment of the invention provides a liquid-level sensor to detect liquid-level information of a liquid to be tested in a container. The sensor includes an electrode, a sensing circuit, an amplifier and a controller. The electrode is disposed on the outer surface of the container, comprising a first electrode and a second electrode. The sensing circuit is coupled to a first electrode and a second electrode, and receives a clock signal to generate a first voltage signal and a second voltage signal. The amplifier receives the first voltage signal and the second voltage signal to output an output voltage. The controller acquires liquid-level information of the liquid to be tested according to the output voltage and a voltage-volume table.