Soil Moisture Probe Multiplexed Brass Ring Pairs
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Solution Overview
Problem
Conventional soil moisture probes are costly due to dedicated measurement circuits for each sensor ring pair, require individual calibration, and are difficult to repair, leading to inefficiencies in irrigation management for large corporate farms.
Innovation Solution
A soil moisture and electrical conductivity probe design featuring brass ring pairs with dual feedpoints, a single main control circuit for multiplexed operation, signal tuning assemblies to reduce noise, and integrated thermistors for temperature sensing, which reduces manufacturing costs, improves accuracy, and enhances durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated measurement circuits are used for each sensor ring pair, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple sensor ring pairs into a single measurement circuit that can multiplex between different ring pairs. Instead of having dedicated circuits for each sensor ring pair, one circuit serves multiple sensors by sequentially measuring them, thereby reducing overall circuit complexity while maintaining measurement precision through proper signal conditioning and timing.
Solution Approach 2:
The measurement circuit is designed to be universal and multi-functional, capable of measuring multiple sensor ring pairs using the same hardware resources. The circuit can adapt to different sensor configurations and depths, making it a versatile solution that replaces multiple specialized circuits with a single adaptable measurement system.
2Measurement precision
If individual calibration is performed for each sensor ring pair, then measurement precision is improved, but ease of manufacture and deployment are worsened
Solution Approach 1:
The calibration system is designed as a universal solution that can calibrate multiple sensor ring pairs using a single calibration process. The system establishes reference measurements that can be applied across different ring pairs, eliminating the need for individual calibration of each sensor while maintaining measurement accuracy through the multiplexed measurement approach.
3Reliability
If multiple dedicated circuits are used, then reliability is improved through redundancy, but ease of repair is worsened due to increased complexity
Solution Approach 1:
The patent merges multiple measurement functions into a single circuit, reducing the total number of components that could fail. With fewer dedicated circuits, there are fewer potential failure points in the system. The single multiplexed circuit design simplifies the overall system architecture, making it easier to diagnose and repair when issues arise.
4Measurement precision
If signal noise is not minimized, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent introduces signal tuning assemblies as intermediary components between the sensor ring pairs and the measurement circuit. These assemblies include capacitors and inductors that act as mediators to filter noise and condition signals before they reach the main measurement circuit, thereby improving measurement precision without requiring complex digital signal processing.
Solution Approach 2:
The system employs parameter changes in the signal conditioning approach by using RC time constants and resonant frequencies to optimize signal-to-noise ratio. By carefully selecting component values and operating frequencies, the system achieves precise measurements while keeping the signal conditioning circuitry relatively simple and analog-based.
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 proposed probe design reduces costs, increases reliability, and enhances accuracy by using a single control circuit for multiple sensor rings, minimizing noise, and calibrating for temperature variations, resulting in improved irrigation management.
Implementation Method 1
This creates an EMF field (actually doughnut-shaped) around that ring pair 24 that can be measured to determine the electrical conductivity of the soil 8 through which each EMF field passes.
Implementation Method 2
The temperature of each ring pair is detected by a thermistor associated with each ring pair.
Data Source
AI summary
A Soil Moisture and Electrical Conductivity Probe. The soil moisture probe employs brass ring pairs, wherein each pair incorporates dual feedpoints. There is a single main control circuit for operating the plurality of sensor ring pairs in a multiplexed approach. In order to allow for multiplexed operation, each sensor ring pair includes a signal tuning assembly. The signal tuning assembly includes apparatus for attenuating the signal noise at each sensor ring pair, as well as apparatus for matching the ring-pair to ring-pair lead impedence. The temperature of each ring pair is individually detected to improve the accuracy of all of the sensor ring pairs. This temperature sensing is accomplished by multiplexing a single reference voltage with all of the sensor rings, and by implementing a thermistor at each sensor ring pair.