Nested Capacitive Soil Moisture Sensor for Fast Low-Energy Sensing
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Solution Overview
Problem
Existing soil moisture sensors are energy-intensive, costly, and provide delayed or inaccurate measurements, making them inefficient for real-time irrigation management.
Innovation Solution
A capacitive soil moisture sensor with nested capacitors that separate primary and secondary electric fields, allowing for accurate and efficient moisture measurement using a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermal measuring tip with heating process is used, then moisture measurement is achieved, but energy consumption is high and measurement time is long
Solution Approach 1:
The patent replaces the thermal/heating-based measurement system with a capacitive electric field-based system. The measuring electrode and reference electrode create an electric field that interacts with the soil moisture, allowing measurement through capacitance changes without thermal energy input, thus resolving the high energy consumption issue while maintaining measurement capability
2Measurement precision
If a thermal measuring tip with heating process is used, then moisture measurement is achieved, but measurement time is delayed
Solution Approach 1:
The patent replaces the slow thermal conduction-based measurement with an instantaneous capacitive electric field measurement. The electric field between electrodes responds immediately to moisture content changes, eliminating the thermal time constant and enabling real-time measurements without delay
3Use of energy by moving object
If a capacitive measuring method is used, then energy consumption is reduced, but sensor area becomes large
Solution Approach 1:
The patent implements a nested electrode configuration where the measuring electrode is positioned within or alongside the reference electrode structure. This nesting allows the electric field to be concentrated in a small volume of soil, achieving accurate capacitive measurement with a compact sensor footprint rather than requiring a large sensor area
4Use of energy by moving object
If a capacitive measuring method is used, then energy consumption is reduced, but measurement accuracy is affected by soil dependency
Solution Approach 1:
The patent introduces a reference electrode that acts as an intermediary to establish a stable reference potential. By measuring the capacitance between the measuring electrode and this stable reference, the system compensates for variations in soil properties and electrical conductivity, enabling accurate moisture measurement across different soil types without requiring high energy input
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 sensor provides rapid, cost-effective, and reliable moisture readings, enabling efficient irrigation control with minimal energy consumption and improved accuracy.
Implementation Method 1
a first capacitor (C1) configured to generate a primary electric field (E1) comprising primary electric field lines (L1), a second capacitor (C2) configured to generate a secondary electric field (E2) comprising secondary electric field lines (L2)
Implementation Method 2
the first capacitor (C1) is nested within the second capacitor (C2) such that the primary electric field lines (L1) are separated from the secondary electric field lines (L2)
Data Source
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AI summary
A soil moisture sensor (100) comprises a first conductive surface (210), a second conductive surface (220), and a third conductive surface (230). The first conductive surface (210) and the second conductive surface (220) form a first capacitor (C1) configured to generate a primary electric field (E1), wherein the primary electric field (E1) comprises primary electric field lines (L1). The soil moisture sensor (100) is characterized in that the soil moisture sensor (100) further comprises a fourth conductive surface (240), wherein the third conductive surface (230) and the fourth conductive surface (240) form a second capacitor (C2) configured to generate a secondary electric field (E2), and wherein the secondary electric field (E2) comprises secondary electric field lines (L2). Further, the first capacitor (C1) and the second capacitor (C2) are arranged such that the first capacitor (C1) is nested within the second capacitor (C2). Further, the primary electric field lines (L1) are separated from the secondary electric field lines (L2) such that a capacitance measuring of the moisture within the surrounding soil is allowed.