Moisture Sensor with Spaced Probes for False Alarm Reduction
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Solution Overview
Problem
Current moisture sensors face challenges in accurately detecting leaks due to surface condensation, innate conductivity of materials, and false alarms from non-leak sources, and they often require extended time to dry due to low surface-to-volume ratios and binary reporting methods.
Innovation Solution
A moisture sensor with multiple probes, both in contact with and spaced from the surface, using resistive and capacitive sensing to measure moisture levels and orientation, featuring a circuit board enclosure for reduced cost and enhanced functionality, including an accelerometer for tampering detection and temperature sensing to filter out false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If probes are placed in direct contact with the floor to detect moisture, then moisture detection sensitivity is improved, but false alarms increase due to surface condensation and innate conductivity of materials
Solution Approach 1:
The sensor divides the detection function into multiple independent probes (first probe in contact with surface, second probe spaced above surface) that work together to distinguish between condensation and actual moisture leaks, reducing false alarms while maintaining detection sensitivity
Solution Approach 2:
The second probe spaced above the surface acts as an intermediary element that detects moisture in the air or on the sensor housing, allowing the system to differentiate between environmental condensation and actual leak conditions through comparative analysis
2Reliability
If moisture is trapped beneath the sensor to enable detection, then leak detection capability is improved, but drying time increases due to low surface-to-volume ratio
Solution Approach 1:
The sensor incorporates probes at different spatial dimensions (contact probe at surface level, spaced probe above surface), enabling moisture detection from multiple perspectives and facilitating faster evaporation pathways while maintaining reliable leak detection capability
3Device complexity
If binary reporting method is used to simplify moisture detection, then device complexity is reduced, but measurement precision deteriorates due to inability to detect partial moisture conditions
Solution Approach 1:
The system uses partial action by selectively activating different probes based on detection needs - the contact probe for surface moisture and the spaced probe for air-borne moisture - enabling precise moisture level detection without requiring complex reporting mechanisms for all possible conditions
4Measurement precision
If multiple probes and sensing circuits are added to improve detection accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The sensor housing serves multiple functions: it protects internal electronics, provides structural support, and acts as a mounting surface for the spaced probe, thereby reducing overall device complexity while enabling multiple detection functions through shared components
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 precise moisture detection, reduced false alarms, and extended battery life, enabling accurate leak identification and reporting, with improved durability and reduced maintenance needs.
Implementation Method 1
the capacitive sensor measures the total volume of water contained beneath or in the proximity of the sensor
Implementation Method 2
water has a much larger dielectric constant than other substances found in a residence or business
Implementation Method 3
monitoring the electrical conductivity between one or more probes
Implementation Method 4
based on a predetermined resistance threshold between moisture probes
Data Source
AI summary
A moisture sensor includes a circuit board and a plurality of circuits monitoring a plurality of moisture probes, wherein at least two sets of a plurality of probes are on the bottom of the sensor, one set in direct contact with the floor, a second set separated from the floor; a set of conductive pins that enable the body of the circuit board to be spaced from the floor to help any moisture accumulation beneath the sensor to evaporate, preventing mold growth; two sets of a plurality of probes along the edge of the sensor, such that when the sensor is installed edge on, these edge sensors will be in direct contact with the floor. The sensor transmits data periodically when sensed resistance is below a predetermined value.