Dynamic Threshold Urination Detection in Absorbent Articles
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Solution Overview
Problem
Conventional disposable absorbent articles, such as training pants, often fail to accurately detect multiple insults and are prone to false positives due to their reliance on a single resistance threshold, which can be triggered by pressure or sweat, hindering effective potty training in children.
Innovation Solution
A method and system that monitor the electrical properties of absorbent articles by determining a threshold value based on the proportional difference and rate of change in resistance over time, using a microprocessor to activate an alarm only when specific criteria are met, thereby reducing false positives and improving the detection of multiple insults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single fixed resistance threshold is used to detect urination, then the device structure is simple, but false positives occur due to pressure or sweat triggering the sensor
Solution Approach 1:
The patent transitions from a static fixed threshold to a dynamic threshold system that adapts based on the article's wetness state. The threshold is no longer fixed but changes according to the measured resistance, allowing the system to distinguish between temporary resistance drops (sweat/pressure) and genuine urination events. This dynamic adaptation resolves the contradiction by maintaining detection accuracy without significantly increasing system complexity.
Solution Approach 2:
The patent changes the detection parameter from a fixed resistance value to a variable threshold that depends on the current wetness state of the absorbent article. By making the threshold parameter adaptive rather than static, the system can accommodate variations in resistance caused by sweat or pressure while still detecting actual urination events, thereby improving reliability without complex additional hardware.
2Device complexity
If a fixed resistance threshold is used, then the detection method is simple, but multiple insults cannot be accurately detected after the first urination event
Solution Approach 1:
The system dynamically adjusts the detection threshold based on the wetness state following each urination event. After the first insult, the threshold adapts to the new baseline resistance level, enabling accurate detection of subsequent insults. This dynamic behavior allows the simple detection algorithm to achieve high precision in detecting multiple urination events without requiring complex multi-sensor arrays.
Solution Approach 2:
The system uses feedback from the measured resistance to continuously update the threshold for detection. After each urination event changes the resistance baseline, the system feeds this information back into the threshold calculation, allowing it to adapt to the new state. This feedback mechanism enables accurate detection of multiple insults while keeping the algorithm relatively simple.
3Speed
If resistance monitoring is continuous, then urination events are detected promptly, but sweat and pressure may trigger false alarms
Solution Approach 1:
The patent changes the interpretation parameter from absolute resistance value to a relative threshold-based assessment. By comparing resistance changes against an adaptive threshold rather than a fixed value, the system can rapidly detect urination events while filtering out false triggers from sweat or pressure, thus maintaining both speed and reliability.
Solution Approach 2:
The dynamic threshold adapts to the current wetness state, allowing the system to respond quickly to genuine urination events while ignoring temporary resistance fluctuations. This dynamic behavior enables continuous monitoring with high speed detection while maintaining reliability by adjusting the detection criteria based on the article's state.
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
This approach enhances the accuracy of insult detection in absorbent articles, reducing false alarms and allowing for more reliable monitoring of urination events, thus aiding in the potty training process by providing caregivers with timely and accurate notifications.
Implementation Method 1
disposable absorbent undergarments which quickly draw and retain urine away from the wearer's skin after an insult occurs
Implementation Method 2
absorbent body disposed between an inner layer adapted for contacting the wearer's skin and an outer layer for inhibiting liquid waste absorbed by the absorbent body from leaking out
Implementation Method 3
When the undergarment is wet, more particularly when the absorbent material of the undergarment between the conductors becomes wet, the resistance of the undergarment at that area drops to a relatively lower value because urine acts as a conductor
Data Source
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AI summary
A method of detecting the presence of an insult in an absorbent article. An electrical property of the article is measured and digitized. To detect an insult, the digital values are used by a microprocessor to determine at least one of the following: (a) a slope in the electrical property compared to a threshold value; (b) a comparison of the electrical property over a period of time to a threshold value; and/or (c) a comparison of the electrical property to a determined threshold value.