Capacitive Plant Tissue Sensor for Non-Invasive Water Measurement
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Solution Overview
Problem
Current methods for measuring water/solute content and thickness of plant tissue are invasive, destructive, or inaccurate, and often hinder plant growth or block light, making them unsuitable for non-invasive, automatic monitoring.
Innovation Solution
A system comprising a capacitive tissue sensor with coplanar conductive plates and a tissue thickness sensor using permanent magnets and a magnetic sensor, which can be clipped onto plant tissue to measure dielectric constant and dimensional aspects non-invasively, allowing for accurate water/solute content and thickness determination without damaging the plant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive methods (pressure bomb, detachment weighing) are used to measure water/solute content, then measurement accuracy is improved, but plant tissue is destroyed and growth is hindered
Solution Approach 1:
The patent replaces mechanical/invasive measurement methods (pressure bomb, physical detachment) with a capacitive sensing system that uses electrical fields to measure dielectric constant. The sensor clips onto the plant tissue surface and measures capacitance changes caused by water content variations, eliminating the need to detach or apply mechanical pressure to the tissue.
Solution Approach 2:
The patent introduces an intermediary measurement approach by measuring the dielectric constant of plant tissue through capacitance sensing rather than directly measuring water content. The dielectric constant serves as an indirect but accurate indicator of water/solute content, allowing non-invasive measurement while maintaining measurement precision.
2Measurement precision
If bulky measurement devices are used, then measurement capability is improved, but device portability and ease of operation deteriorate
Solution Approach 1:
The patent divides the measurement system into separate functional components: a capacitive sensor module for dielectric constant measurement and a separate thickness measurement module. This segmentation allows each module to be compact and easily attached to different plant locations, improving portability while maintaining measurement capabilities.
Solution Approach 2:
The sensor is designed as a thin, flexible clip that can conform to plant tissue surfaces. This thin-film design eliminates the bulkiness of traditional devices while maintaining sufficient measurement capability, allowing easy attachment and portability for field operations.
3Measurement precision
If devices that block light are used on plant tissue, then measurement accuracy is improved, but photosynthetic activity is reduced
Solution Approach 1:
The capacitive sensor uses periodic electrical field application at different frequencies to measure dielectric constant. This periodic electrical measurement does not continuously block light, allowing photosynthetic activity to proceed normally while obtaining accurate water content measurements at measurement intervals.
Solution Approach 2:
The patent replaces optical measurement methods that physically block light paths with electrical field-based capacitive sensing. The electrical fields used for measurement do not interfere with light transmission to the plant tissue, maintaining both measurement accuracy and photosynthetic activity.
4Object-affected harmful factors
If indirect measurement methods (leaf reflectance, thickness) are used, then non-invasive measurement is achieved, but measurement accuracy deteriorates due to interfering factors
Solution Approach 1:
The patent measures the dielectric constant of plant tissue, which is directly related to water content and solute concentration. By changing the measurement parameter from indirect proxies (reflectance, thickness) to a physically direct parameter (dielectric constant), the system achieves both non-invasive operation and high measurement accuracy.
Solution Approach 2:
The patent replaces optical measurement methods (reflectance, color) with electrical field-based capacitive sensing. This substitution eliminates interference from optical factors such as solar angle, shadowing, illumination variations, and canopy coverage, providing accurate water content measurements without being affected by these environmental variables.
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 non-invasive, accurate measurement of water/solute content and thickness, allowing for precise irrigation control and stress monitoring without harming the plant or blocking light, supporting automatic and efficient plant management.
Implementation Method 1
One potential solution to these problems is to measure the dielectric constant of the plant tissue to estimate the water/solute content thereof
Implementation Method 2
devices and methods for measuring a dimensional aspect of the plant tissue... using a single permanent magnet with high sensitivity magnetic field sensor
Data Source
AI summary
Systems and methods for non-invasively determining a water content, a solute content, and a thickness of plant tissue are disclosed. A system includes a sensing device having a first piece and a second piece, where the first piece and the second piece are coupled together to form a clip. The system further includes a capacitive tissue sensor including a capacitor. The capacitor includes a plurality of coplanar conductive plates. The first piece and the second piece are biased in a closed position to provide a gripping force around the plant tissue such that at least a portion of the plant tissue contacts the plurality of coplanar conductive plates.