Moisture-Sensing RFID Tag Using Frequency Switching in Diapers
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Solution Overview
Problem
Existing moisture detection systems using RFID technology face challenges in accurately distinguishing moisture generation from IC tag breakage due to reduced receiving sensitivity and complex configurations, leading to communication failures.
Innovation Solution
A wireless communication device with a circuit unit and antenna that transmits different signals based on contact with moisture, utilizing materials like carbon nanotubes and organic semiconductors to change electrical resistance or frequency, enabling accurate moisture detection with a simple configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RFID technology is used for moisture detection, then moisture detection capability is achieved, but receiving sensitivity is markedly reduced and communication reliability deteriorates
Solution Approach 1:
The patent changes the detection parameter from direct moisture sensing (which causes impedance changes and signal loss) to frequency-based identification. The IC tag transmits different frequencies (e.g., 2.4 GHz when dry, 5.8 GHz when wet) to indicate moisture state, avoiding the sensitivity and reliability issues of conventional RFID moisture detection while maintaining accurate moisture detection capability.
2Measurement precision
If conventional RFID moisture detection is implemented, then moisture presence is detectable, but distinction between moisture generation and IC chip breakage becomes impossible
Solution Approach 1:
The patent uses frequency as the detection parameter instead of signal presence or impedance changes. When the IC tag detects moisture, it actively changes its transmission frequency to a predetermined value (e.g., from 2.4 GHz to 5.8 GHz). This frequency change provides unambiguous information that distinguishes moisture generation from IC chip failure, as a broken IC would cannot change frequency and would simply not transmit or transmit at a fixed frequency.
3Measurement precision
If complex IC tag configurations are used to change signal state based on wetness detection, then moisture detection is achieved, but device complexity increases
Solution Approach 1:
The patent simplifies the IC tag configuration by using frequency change as the detection mechanism. The IC tag includes a communication unit that can transmit at different frequencies and a control unit that switches between frequencies based on moisture detection. This approach avoids complex signal modulation or multiple antenna configurations, achieving accurate moisture detection with a relatively simple device structure.
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
Accurately detects moisture generation with a simple and cost-effective design, allowing for reliable communication and easy production, suitable for mass-produced products like diapers.
Implementation Method 1
utilizing materials like carbon nanotubes and organic semiconductors to change electrical resistance or frequency, enabling accurate moisture detection
Data Source
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AI summary
The present invention provides a wireless communication device including: a circuit unit; and an antenna which is connected to the circuit unit and which transmits and receives signals to and from a transceiver in a non-contact manner. The wireless communication device transmits different signals to the transceiver, depending on the presence or absence of contact between at least a part of the circuit unit and moisture.