Hygroscopic Rain Sensor Control for Irrigation Schedule Interruption

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Solution Overview

Problem

Existing irrigation control systems lack efficient mechanisms to dynamically adjust watering schedules based on rainfall, often relying on fixed thresholds and requiring manual adjustments, which can lead to overwatering or underwatering.

Innovation Solution

A system that includes a rain sensor with hygroscopic material to detect rainfall, an interface unit to process signals from the sensor, and a control unit to interrupt or resume watering schedules based on set thresholds and user-defined parameters, with a user interface for adjusting settings and displaying operational status.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed rainfall threshold is used to interrupt irrigation, then the system is simple to operate, but it cannot dynamically adapt to varying rainfall conditions leading to overwatering or underwatering

Engineering Contradiction:

Improvedynamic adjustment capabilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic threshold adjustment by allowing the irrigation controller to automatically modify rainfall thresholds based on historical weather data, current conditions, and plant-specific requirements. The system transitions from static fixed thresholds to dynamic adaptive thresholds that automatically adjust to varying environmental conditions, resolving the contradiction between adaptability and complexity through automated control algorithms.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms by continuously monitoring rainfall data from sensors, comparing actual rainfall against required irrigation amounts, and automatically adjusting future irrigation schedules based on this feedback. This closed-loop control enables the system to adapt to varying conditions while maintaining manageable complexity through algorithmic decision-making.

Inventive Principle:

Principle #23Feedback

2Extent of automation

If manual adjustments are required for irrigation schedules, then the system is easy to understand, but it requires continuous user intervention and cannot respond to real-time conditions

Engineering Contradiction:

Improveautomatic control levelVSAvoiduser interaction requirement

Core Design Contradiction:

Extent of automationVSEase of operation

Solution Approach 1:

The patent implements self-service automation where the irrigation controller autonomously monitors rainfall through integrated sensors, compares data against stored irrigation requirements, and automatically adjusts watering schedules without user intervention. The system performs self-diagnosis and self-adjustment, achieving high automation while maintaining ease of operation through intuitive initial setup and automatic adaptation to changing conditions.

Inventive Principle:

Principle #25Self-service

3Loss of energy

If irrigation continues during rainfall, then the irrigation schedule is maintained, but water is wasted through overwatering

Engineering Contradiction:

Improvewater wasteVSAvoidirrigation schedule reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent replaces manual mechanical irrigation control with an automated electronic control system that uses rainfall sensors and microprocessor-based logic to dynamically adjust irrigation timing and duration. This substitution enables real-time detection of rainfall events and automatic interruption or reduction of irrigation, preventing water waste while maintaining reliable and accurate irrigation scheduling through electronic control mechanisms.

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 effectively interrupts and resumes watering schedules based on rainfall accumulation and user-defined thresholds, optimizing water use by preventing overwatering during rainfall and ensuring adequate irrigation after rainfall cessation.

Implementation Method 1

a rain sensor including hygroscopic material... the hygroscopic material being configured to expand in response to being contacted by the rainfall

Methodology Applied

Scientific EffectHygroscopic expansion: Absorption (physical)

Implementation Method 2

the hygroscopic material being configured to expand in response to being contacted by the rainfall and to contract in response to an absence of the rainfall

Methodology Applied

Scientific EffectHygroscopic contraction: Desorption

Data Source

PatentUS20240215502A1Sensor-based interruption of an irrigation controller

Publication Date: 2024.07.04 RAIN BIRD CORP

AI summary

Some embodiments provide a system and method for interfacing with an irrigation controller based on rainfall, the system comprising: an interface unit including a housing and a control unit within the housing and configured to: cause an interruption of one or more watering schedules executed by the irrigation controller, which is separate from the interface unit, based on signaling received from a rain sensor including hygroscopic material, when a sensed expansion of the hygroscopic material is above a set rainfall accumulation threshold parameter, the rain sensor being separate from the interface unit and the hygroscopic material being configured to expand in response to being contacted by the rainfall and to contract in response to an absence of the rainfall; and remove the interruption after a completion of a predetermined interval of time after a sensed contraction of the hygroscopic material indicative of a rainfall stop.