Diaper Urine Volume Detection with Pulsed Light and Activity Sensing
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Solution Overview
Problem
Existing methods for determining the volume of bodily exudate in absorbent articles, such as diapers, are inaccurate due to reliance on temperature or humidity sensors that may not be representative of the actual conditions, and are prone to errors from wearer movement.
Innovation Solution
A system combining color detection using a pulsed light source and photodetector with an activity classification system based on inertial sensors to accurately determine the presence and volume of bodily exudate, compensating for ambient light and movement artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature or humidity sensors are used to detect bodily exudate, then the system can monitor absorbent article conditions, but the measurements become inaccurate due to sensor location and movement artifacts
Solution Approach 1:
The patent replaces mechanical/physical sensors (temperature and humidity sensors) with an optical detection system. The optical system uses a light source to illuminate a color-changing indicator and a photodetector to measure the reflected light, thereby determining exudate volume based on color changes rather than temperature or humidity measurements.
Solution Approach 2:
The patent employs a color-changing indicator that changes color in response to exudate contact. The optical detection system measures the color of this indicator to determine the volume of exudate, utilizing the color change as the primary detection mechanism instead of relying on temperature or humidity sensor readings.
2Adaptability or versatility
If ambient light is present during color detection, then the detection system can operate in various environments, but the accuracy of color measurement decreases due to light interference
Solution Approach 1:
The patent uses a pulsed light source that emits light in periodic pulses rather than continuous illumination. The photodetector is synchronized to detect light only during these pulses, allowing the system to distinguish between pulsed light from the indicator and continuous ambient light, thereby maintaining measurement accuracy in various lighting conditions.
Solution Approach 2:
The system incorporates feedback mechanisms where the detected light intensity is processed to determine exudate volume. The feedback loop allows the system to compensate for ambient light conditions by comparing expected versus actual light readings, maintaining color measurement accuracy despite environmental light variations.
3Ease of operation
If the absorbent article is worn by an active wearer, then the system can be used in real-world conditions, but sensor measurements contain noise and errors from movement
Solution Approach 1:
The patent replaces movement-sensitive physical sensors with an optical system that detects color changes. Since the optical detection measures light reflection from the color-changing indicator rather than relying on fixed sensor positions, it is less susceptible to measurement errors caused by wearer movement and changes in article positioning.
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 precise and reliable detection of bodily exudate by filtering out ambient light interference and correcting for movement-related errors, enhancing the accuracy of volume estimation.
Implementation Method 1
A color detection system may use a pulsed light source to accurately detect the color of an object such as a color changing indicator in an absorbent article
Implementation Method 2
A system combining color detection using a pulsed light source and photodetector
Implementation Method 3
detect the color of an object such as a color changing indicator in an absorbent article (e.g., a diaper)
Data Source
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AI summary
Systems and methods for detecting determining a volume of urine in an absorbent article such as a diaper. A diaper loading application obtains a first measurement of ambient light received from a photodetector while a light source is off and a second measurement from the photodetector while the light source is transmitting light on an absorbent article. The application determines a normalized measurement of light reflected from an absorbent article by removing an ambient light signal from the second measurement based on the first measurement. The application determines, from the normalized measurement, a presence of urine in the absorbent article. The application further determines an estimated volume of urine in the absorbent article, wherein the determining is based on an elapsed time since the presence of urine and an activity state of an infant wearing the absorbent article.