RFID Tag Wetness Detection for Care Articles
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Solution Overview
Problem
Conventional diapers with detection devices for wetness are complex in structure, uncomfortable for users, and require additional hardware that occupies space and is costly, with sensors often being affected by moisture and not reusable.
Innovation Solution
A system using an RFID tag attached to the outer surface of absorbent articles, with a RFID reader that sends detection signals and calculates water content based on signal strength indicators, allowing for wireless communication and notification of caregivers without direct skin contact or complex hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors and antennas are disposed on one side of the diaper in contact with users' skin, then wetness detection capability is achieved, but user comfort deteriorates due to direct skin contact
Solution Approach 1:
The patent introduces an RFID tag as an intermediary component that is attached to the outer surface of the diaper away from the user's skin. This tag serves as a mediator that allows wireless communication and wetness detection without requiring direct skin contact with sensors, thus resolving the contradiction between detection capability and user comfort.
2Ease of operation
If sensors are disposed inside the diapers to avoid contact with users' skin, then user comfort is improved, but sensing accuracy deteriorates due to interference from moisture source
Solution Approach 1:
The RFID tag attached to the outer surface acts as an intermediary that enables accurate sensing without being contaminated by moisture. By positioning the sensing component outside the moisture-prone interior while maintaining communication capability, the system achieves both user comfort and sensing accuracy.
3Measurement precision
If conventional detection systems with determination devices are implemented, then wetness detection function is achieved, but device complexity and hardware cost increase
Solution Approach 1:
The patent leverages the universality of RFID technology, which is already widely used for identification and tracking purposes. By utilizing the existing RFID tag and reader infrastructure, the system achieves wetness detection functionality without requiring specialized detection devices, thereby reducing overall system complexity and hardware costs.
Solution Approach 2:
The RFID tag continuously provides identification information and wetness status automatically without requiring additional active components or power sources in the diaper itself. The passive nature of the RFID tag allows the system to function with minimal hardware, as the tag serves multiple purposes including identification and environmental sensing.
4Device complexity
If RFID tag is attached onto outer surface of article, then device complexity is reduced and reusability is improved, but measurement precision may deteriorate due to distance from moisture source
Solution Approach 1:
The patent utilizes changes in RFID signal parameters (such as impedance, frequency, or signal strength) in response to moisture presence. By monitoring these parameter variations rather than requiring direct contact with moisture, the system achieves accurate detection from the outer surface position, resolving the contradiction between simplified structure and measurement precision.
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 detects wetness in absorbent articles without user discomfort, reduces hardware requirements, and enhances caregiver efficiency by providing accurate and reusable wetness detection.
Implementation Method 1
a radio frequency identity (RFID) tag to be attached onto an outer surface of an article used by the care-receiver... a RFID reader which comprises a first antenna module; a first wireless communication module, coupled to the first antenna module, configured to send a detection signal (excitation signal) through the first antenna module to the RFID tag
Implementation Method 2
a processor unit configured to exhibit a signal strength indicator (RSSI) corresponding to a response signal from the RFID tag in response to the sent detection signal (excitation signal), through the first antenna module, and denoting as RSSI(t) of the article after being used for a usage time (t)... and determining the water content (%) of the article at the usage time (t) by calculating from following formula (I) by using the RSSI(0) and RSSI(t)
Data Source
AI summary
A system for detecting wetness of article used by a care-receiver is provided, comprising: a radio frequency identity (RFID) tag to be attached onto an outer surface of an article used by the care-receiver, and a RFID reader. The RFID reader includes at least one first antenna module, a processor unit and a first wireless communication module. And the system further comprises a protective unit is configured for accommodating the RFID reader and buffering external pressure on the RFID reader to protect the RFID reader. The RFID reader is configured for being disposed on a back of a cushion. The first wireless communication module is configured to send a detection signal (excitation signal) through the first antenna module to the RFID tag and the processor unit determines the water content (%) of the article at the usage time (t) by using the RSSI(0) and RSSI(t).