Radio frequency wetness detection system
First Claim
1. A system for detecting the presence of an electrically conductive liquid, wherein the system comprises (a) a passive resonant tag having a substrate, an inductor, and a capacitor comprising a LC circuit that provides a substantially constant resonant frequency that is eliminated when the inductor is contacted by an electrically conductive liquid, and (b) a remote detection means having a transmitter that emits a substantially constant swept frequency, an alarm, an antenna for receiving the swept frequency and means for processing the received swept frequency, wherein the detection means activates the alarm when the resonant frequency is eliminated.
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Accused Products
Abstract
A moisture monitoring device is provided having a resonant tag and a remote detector. The resonant tag comprises a plastic substrate having holes punched through it, a capacitor plate on one side that is connected to a second capacitor plate and inductor coils on the other side. The resonant tag comprises a live LC circuit having a natural resonant frequency that does not activate the detector. The resonant tag is affixed to absorbing materials in a diaper or other sanitary undergarment. Upon the introduction of moisture into the circuit, the resonant frequency is eliminated as the circuit is deactivated and an alarm in the detector is triggered. At this point it would be apparent to a parent or caretaker that the diaper is wet and in need of replacement.
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Citations
33 Claims
- 1. A system for detecting the presence of an electrically conductive liquid, wherein the system comprises (a) a passive resonant tag having a substrate, an inductor, and a capacitor comprising a LC circuit that provides a substantially constant resonant frequency that is eliminated when the inductor is contacted by an electrically conductive liquid, and (b) a remote detection means having a transmitter that emits a substantially constant swept frequency, an alarm, an antenna for receiving the swept frequency and means for processing the received swept frequency, wherein the detection means activates the alarm when the resonant frequency is eliminated.
- 16. A sanitary undergarment comprising a system for detecting the presence of an electrically conductive liquid, wherein the system comprises (a) a passive resonant tag having a substrate, an inductor, and a capacitor comprising a LC circuit that provides a substantially constant resonant frequency that is eliminated when the inductor is contacted by an electrically conductive liquid, and (b) a remote detection means having a transmitter that emits a substantially constant swept frequency, an alarm, an antenna for receiving the swept frequency and means for processing the received swept frequency, wherein the detection means activates the alarm when the resonant frequency is eliminated.
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33. A system for detecting the presence of a liquid, wherein the system comprises (a) a passive resonant tag having a substrate, an inductor, and a capacitor comprising a LC circuit that provides a substantially constant resonant frequency that is eliminated when the inductor is contacted by an electrically conductive liquid, and (b) a remote detection means having a transmitter that emits a substantially constant swept frequency, an alarm, an antenna for receiving the swept frequency and means for processing the received swept frequency, wherein the detection means activates the alarm when the resonant frequency is eliminated and wherein the inductor comprises a water-soluble material.
Specification