Fringe Capacitance Sensor Design for Low-False-Positive Pest Detection

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Solution Overview

Problem

Existing pest detection systems using parallel plate capacitance sensors are prone to false positives due to dielectric interference and environmental factors, limiting their versatility and accuracy in various environments.

Innovation Solution

The use of fringe capacitance sensors with un-grounded conductors on either side of a sensor conductor, supported on an electrically isolated conductive substrate, allows for directional detection of pests by measuring changes in fringe capacitance, reducing false positives and enabling detection through dielectric materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If parallel plate capacitance sensors are used for pest detection, then detection capability is provided, but false positive results occur due to dielectric interference from leaves, wet weather, and dirt

Engineering Contradiction:
Improvedetection accuracyVSAvoidfalse positives from dielectric interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the problematic parallel plate sensor configuration that is susceptible to dielectric interference. Instead, it employs fringe capacitance sensors with un-grounded conductors that are inherently less sensitive to such interference, effectively removing the source of false positives while retaining pest detection capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental sensing parameter from parallel plate capacitance to fringe capacitance measurement. This parameter change transforms the sensor's response characteristics, making it less sensitive to dielectric materials like leaves and moisture while maintaining sensitivity to pest-related capacitance changes

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If conventional capacitance sensing is used, then simple detection is achieved, but the sensors are limited in versatility across different environments and pest types

Engineering Contradiction:
Improveenvironmental flexibilityVSAvoidsensor configuration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal sensor design using fringe capacitance principles that can detect multiple types of pests (rodents, insects, burrowing animals) across diverse environments (above ground, underground, through dielectric materials). The un-grounded conductor configuration provides a platform that adapts to various detection scenarios without requiring fundamentally different sensor types

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The un-grounded conductors act as intermediaries that mediate between the sensing system and the target pest. This intermediary structure enables detection through dielectric materials and provides directional sensitivity, allowing the sensor to function effectively in various environmental conditions without direct contact with the target

Inventive Principle:
Principle #24Intermediary (Mediator)

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 versatile pest detection, reducing false positives, conserving power, and allowing deployment in diverse environments, with the ability to track pest movement and direction, and integrate into a self-healing wireless network for centralized data management.

Implementation Method 1

fringe capacitance is measured as a sensor conductor is approached (or moved away from) by an object e.g. a pest

Methodology Applied
Scientific EffectFringe capacitance: Capacitance

Implementation Method 2

when a non-capacitive object having a higher dielectric constant than air, such as a pest, approaches two spaced sensor electrodes, the capacitance between the two sensor electrodes increases

Methodology Applied
Scientific EffectDielectric effect: Dielectric

Data Source

PatentEP4184124B1Sensing of objects
Publication Date: 2025.08.20 CAUCUS LTD
  • EP4184124B1 patent drawingFigure 1A~1B
  • EP4184124B1 patent drawingFigure 2A~2B
  • EP4184124B1 patent drawingFigure 3A~3B

AI summary

The invention relates to a fringe capacitance sensor (10) for sensing objects, particularly, but not exclusively, pests, a sensor unit (100) comprising one or more fringe capacitance sensors, a system comprising a plurality of sensor units in a mesh topology or other wireless network and a method for intelligently detecting object activity, such as the presence of a pest, for example, a rodent or crawling, burrowing or flying insect. It can also be applied to the management of animals, whether in the wild or on farms. A preferred sensor (10) for detecting changes (Δ) in fringe capacitance (A) comprises an electrically conductive sensor conductor (12) and two electrically conductive un-grounded conductors (14a; 14b) disposed one on either side (16a; 16b) of the sensor conductor (12) to form a triplet (14a-12-14b). The conductors (12, 14a, 14b) are supported on an un-grounded conductive substrate (18) which is electrically isolated (20) from said conductors (12, 14a, 14b) and each conductor (14a,12;14b) is of a width (w), and thickness (t), and is spaced by a distance (d) from another such that the sensor is tuned to detect or identify a given animal.