Soil Moisture Detection Using Conductive and Capacitive Sensors

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Solution Overview

Problem

Traditional soil moisture detection devices are not accurate for multiple soil types and are susceptible to corrosion, leading to high maintenance costs, especially when used in corrosive soils.

Innovation Solution

A soil moisture detection system comprising conductive and capacitive sensors that measure soil moisture through DC resistance and AC impedance measurements, respectively, with a network server and user terminal for data processing and transmission, using a p-channel metal-oxide-semiconductor field-effect transistor to minimize oxide buildup and corrosion, and a microcontroller for data collection and processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional soil moisture detection devices are used, then soil moisture detection is provided, but measurement precision deteriorates for multiple soil types

Engineering Contradiction:

Improvesoil moisture detection accuracyVSAvoidapplicability to multiple soil types

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies universality by designing a single soil moisture detection device that can accurately measure moisture across multiple soil types (sandy soil, loamy soil, clay soil) through a unified measurement system using voltage divider circuits with adjustable reference resistors, eliminating the need for multiple specialized devices for different soil types

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If electrochemical reactions are used for soil moisture detection, then measurement is enabled, but reliability deteriorates due to corrosion

Engineering Contradiction:

Improvesoil moisture measurement capabilityVSAvoiddevice durability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces electrochemical measurement methods with an electrical resistance-based measurement system using voltage divider circuits. This substitution eliminates electrochemical reactions and associated corrosion issues while maintaining measurement capability through ohmic resistance measurements of the soil

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If electrochemical reactions are used for soil moisture detection, then measurement is enabled, but maintenance cost increases due to corrosion

Engineering Contradiction:

Improvesoil moisture measurement capabilityVSAvoidmaintenance cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent substitutes electrochemical sensing mechanisms with simple electrical resistance measurement circuits comprising voltage sources, reference resistors, and measurement amplifiers. This replacement eliminates corrosion-related maintenance requirements and reduces manufacturing complexity while preserving measurement accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 system provides accurate and real-time soil moisture data across various soil types, reducing maintenance costs and improving irrigation management, while minimizing corrosion and oxide buildup.

Implementation Method 1

a conductive sensor configured to detect a conductive soil moisture raw data by a DC resistance measurement on a conductive voltage divider for a soil, wherein the soil operates as a variable resistor wherein a soil resistance is inversely proportional to the soil moisture

Methodology Applied

Scientific EffectDC resistance measurement: Electrical Resistance

Implementation Method 2

a capacitive sensor configured to detect a capacitive soil moisture level raw data by an AC impedance measurement on a capacitive voltage divider for the soil, wherein the soil operates as a variable capacitor wherein a soil impedance is inversely proportional to a current

Methodology Applied

Scientific EffectAC impedance measurement: Electrical Resistance

Data Source

PatentUS20240402145A1Systems, methods, and devices for soil moisture detection

Publication Date: 2024.12.05 EARTHONE INC

AI summary

A system, method, and device for soil moisture detection and monitoring is provided. The system comprises a plurality of soil moisture detection devices. Each soil moisture detection device comprises a processing unit; a conductive sensor configured to detect a conductive soil moisture raw data by a DC resistance measurement on a conductive voltage divider for a soil, wherein the soil operates as a variable resistor wherein a soil resistance is inversely proportional to the soil moisture; and a capacitive sensor configured to detect a capacitive soil moisture level raw data by an AC impedance measurement on a capacitive voltage divider for the soil, wherein the soil operates as a variable capacitor wherein a soil impedance is inversely proportional to a current. By providing a combination of conductive sensor and capacitive sensor, accurate soil moisture detection is provided for a variety of soil profiles.