WO1992011529A1 - Material monitoring device - Google Patents

Material monitoring device Download PDF

Info

Publication number
WO1992011529A1
WO1992011529A1 PCT/US1991/009538 US9109538W WO9211529A1 WO 1992011529 A1 WO1992011529 A1 WO 1992011529A1 US 9109538 W US9109538 W US 9109538W WO 9211529 A1 WO9211529 A1 WO 9211529A1
Authority
WO
WIPO (PCT)
Prior art keywords
antenna
charge pump
moisture
diaper
output
Prior art date
Application number
PCT/US1991/009538
Other languages
French (fr)
Inventor
Noel Morgen Calvin
Original Assignee
Noel Morgen Calvin
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Noel Morgen Calvin filed Critical Noel Morgen Calvin
Publication of WO1992011529A1 publication Critical patent/WO1992011529A1/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
    • G01N27/223—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance for determining moisture content, e.g. humidity

Definitions

  • the present invention relates generally to moisture detection. More particularly, the invention relates to devices for sensing moisture of a material, such as a diaper.
  • U.S. Patent No. 3,818,468 discloses a portable detector which includes first and second probes. More particularly, this patent discloses a resistive type detector which is operated by attaching the probes to the article of clothing where moisture is to be detected. When sufficient moisture exists in the layers of the material being sensed, a reduced resistance path is formed between the ends of the probes attached thereto. A signal is transmitted to indicate when the ohmic resistance drops below a predetermined value.
  • U.S. Patent No. 2,579,316 relates to a pressure sensitive moisture testing instrument.
  • This patent discloses a circuit which establishes either a current flow or an electric field through a material for which moisture is to be tested.
  • the current flow or electric field is influenced by the moisture content present in the material, causing a corresponding change in current flow or voltage in the circuit.
  • column 1, lines 16-20 refer to several varieties of this general circuit, one of which includes "the dielectric type" dependent upon change in dielectric constant with variations in moisture, specific circuitry related to this type of device is not disclosed.
  • U.S. Patent No. 3,824,460 relates to a capacitive sensing system for detecting the presence of a liquid on a floor or the like using a sensing probe.
  • Two parallel wires are encased in a plastic material spaced by webbed portions made of the same material so as to form a flat cable assembly which may be installed on a floor where leakage is to be detected.
  • Leakage on the floor causes liquid to fill into the spaces between the two wires where the web is not present, thus changing the dielectric constant between the two wires and influencing the overall capacitance of the sensor. This change in dielectric constant results in a change of current through the capacitor and is used to provide an output alarm.
  • the present invention is directed to devices for detecting the moisture content of material such as a diaper using a change in dielectric constant. More particularly, the invention relates to a moisture sensing device which provides an accurate indication of the moisture content of a material when merely placed in the vicinity of the material.
  • the device is a hand-held device which can be readily transported and which can detect material moisture without piercing the material or attaching electrodes directly to the material.
  • Figure 1 shows a block diagram of an exemplary preferred embodiment of a device constructed in accordance with the present invention.
  • FIG 2 shows features of the Figure 1 block diagram in greater detail.
  • the present invention relates to devices for detecting moisture content of a material by detecting changes in the bulk dielectric constant of the material. Using changes in the bulk dielectric constant to determine moisture content permits the detector to be a portable sensing device which need not be directly connected with the material or brought into contact with the material in any way. Rather, the detector need merely be brought into the vicinity of the material to provide a determination that moisture is present therein.
  • FIG. 1 represents a block diagram of a moisture sensing device 10, such as a capacitance proximity sensing device, which uses changes in the bulk dielectric constant of a material in the vicinity of an antenna to detect moisture content.
  • the moisture sensing device 10 includes a square wave generator 1, a charge pump 2, an integrator and bias circuitry 3, peak-hold circuitry 4 and a liquid crystal display and driver 5.
  • An antenna 6 is the heart of the sensing device and represents a capacitance proximity sensor.
  • the sensor is composed of a metal plate, the square wave generator, the charge pump and the integrator, the output of which is a current that is proportional to the magnitude of the effective capacitance coupling between the metal plate and a ground plane.
  • the capacitance of the metal plate is affected by the size and relative location of surrounding objects placed in the proximity of the antenna. The sensor thus produces an output which is responsive to changes in the bulk dielectric constant of a material placed in the proximity of the antenna.
  • the bulk dielectric constant is the property of matter that describes how effective that form of matter is at increasing capacitance.
  • the dielectric constant of air is very low.
  • the dielectric constant of water is quite high.
  • the dielectric constant of dry cloth is typically only slightly higher than that of air.
  • the dielectric constant of wet cloth approaches that of water.
  • Figure 2 shows the exemplary moisture sensing device of Figure 1 in greater detail. More particularly, the square wave generator 1 is shown to include three standard invertors 12, 14, and 16. The input of the first invertor 12 and the output of the third invertor 16 are connected in series via two resistors 18, 20 of 47 kilo-ohms and 10 kilo-ohms, respectively. One plate of a capacitor 22 is connected to a junction between the resistors 18 and 20. The opposite plate of this capacitor 22 is connected to the junction between the output of invertor 14 and the input of invertor 16. The output of invertor 16 represents the output of the square wave generator which is fed to the charge pump 2.
  • the charge pump 2 includes an n-p-n transistor and a p-n-p transistor configured with their emitters coupled to each other and to the antenna 6.
  • the n-p-n transistor is labelled 24 while the p-n-p transistor is labelled 26.
  • the collector of transistor 26 is connected to ground while that of transistor 24 represents an output of the charge pump 2.
  • Both base inputs of transistors 24 and 26 are connected to the output of the square wave generator 1.
  • the output of the charge pump is connected to the integrator and bias circuitry 3. More particularly, when moisture is present such that current is conducted via the antenna 6, a capacitor 28 included in the integrator and bias circuitry is charged via a voltage source V re 30. When the capacitor 28 has been charged sufficiently, a p-n-p transistor 32 is activated such that the voltage V ec is connected to ground via a resistor 34. The voltage drop present across the resistor 34 appears at node 36 and is directed to the output of the integrator and bias circuitry.
  • a potentiometer 38, a transistor 40, resistors 42, 44 and 46, and a diode 48 are used to provide the bias setting of the moisture sensing device.
  • This bias setting enables the threshold of the sensing device to be adjusted so that the change in moisture of a given material can be detected merely by placing the detector in the vicinity of the material.
  • the voltage present at node 36 of the integrator and bias circuitry is input to a transistor 50 of peak-hold circuitry 4.
  • a capacitor 52 included in the peak-hold circuitry charges toward the value of V cc via a diode 54.
  • a second diode 56 connected to the non-grounded electrode of the capacitor 52 resets the peak-hold circuitry to zero by permitting the capacitor 52 to quickly discharge when the power is turned off.
  • the voltage at the capacitor 52 represents the output of the peak-hold circuitry 4, and is input to a liquid crystal display driver 58 of the liquid crystal display and driver 5.
  • a twelve segment LCD device 60 is provided.
  • the driver 58 is a ten segment driver. Accordingly, the eleventh and twelfth segments of the LCD device 60 are connected to the tenth segment of the driver 58 while the first segment of the device 60 is connected to ground via a capacitor 62.
  • Device 60 is a well-known LCD device which is connected to a drive source represented by three invertors 64, 66 and 68 in known fashion.
  • the known driver 58 responds to the voltage level at the capacitor 52 to provide outputs to one or more of the segment drive lines shown at the output of driver 58. Depending on the number of active segment drive lines provided by the driver 58, a corresponding number of segments in the LCD device 60 will be illuminated. Because the signal at the capacitor 52 is proportional to the bulk dielectric constant of a material placed in the proximity of antenna 6, the display will represent the moisture content of the material.
  • Figures 1 and 2 merely represent one exemplary embodiment by which the present invention can be implemented.
  • the capacitance sensed by the antenna 6 may be displayed in any number of ways. More particularly, the voltage at the capacitor 52 in the peak-hold circuitry can be connected to a voltage or current controlled oscillator. The voltage controlled oscillator can then be connected to a speaker or piezoelectric transducer such that a user of the moisture sensing device would hear a tone with a pitch proportional to the wetness of the diaper.
  • the Output voltage at the capacitor 52 can be displayed using a multi-colored LED such that the color of the display indicates the degree of moisture content in a material placed near the antenna 6. For example, green could be used to indicate a dry condition, yellow a damp condition and red a wet condition.
  • the voltage output at capacitor 52 can be fed to a pulse generator which drives a light or tone generator.
  • the repetition rate of flashes of light or beeps can be made proportional to the degree of wetness.

Abstract

The present invention is directed to devices for detecting the moisture content of material such as a diaper using a change in bulk dielectric constant. More particularly, the invention relates to a moisture sensing device (10) which provides an accurate indication of the moisture content of a material such as a diaper when merely placed in the vicinity of the diaper. In a preferred embodiment, the device (10) is a hand-held device which can be readily transported and which can detect diaper moisture without piercing the diaper or attaching electrodes directly to the diaper.

Description

MATERIAL MONITORING DEVICE
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates generally to moisture detection. More particularly, the invention relates to devices for sensing moisture of a material, such as a diaper.
State of the Art
In the past, liquid detectors have been devised for determining the presence of moisture in an article of clothing such as an infant's diaper or undergarment. For example, U.S. Patent No. 3,818,468 discloses a portable detector which includes first and second probes. More particularly, this patent discloses a resistive type detector which is operated by attaching the probes to the article of clothing where moisture is to be detected. When sufficient moisture exists in the layers of the material being sensed, a reduced resistance path is formed between the ends of the probes attached thereto. A signal is transmitted to indicate when the ohmic resistance drops below a predetermined value.
Further, U.S. Patent No. 2,579,316 relates to a pressure sensitive moisture testing instrument. This patent discloses a circuit which establishes either a current flow or an electric field through a material for which moisture is to be tested. The current flow or electric field, as the case may be, is influenced by the moisture content present in the material, causing a corresponding change in current flow or voltage in the circuit. Although column 1, lines 16-20 refer to several varieties of this general circuit, one of which includes "the dielectric type" dependent upon change in dielectric constant with variations in moisture, specific circuitry related to this type of device is not disclosed.
U.S. Patent No. 3,824,460 relates to a capacitive sensing system for detecting the presence of a liquid on a floor or the like using a sensing probe. Two parallel wires are encased in a plastic material spaced by webbed portions made of the same material so as to form a flat cable assembly which may be installed on a floor where leakage is to be detected. Leakage on the floor causes liquid to fill into the spaces between the two wires where the web is not present, thus changing the dielectric constant between the two wires and influencing the overall capacitance of the sensor. This change in dielectric constant results in a change of current through the capacitor and is used to provide an output alarm.
Although devices for detecting moisture are known, a relatively accurate, cost effective moisture detecting device for sensing the moisture content of a material such as a diaper would be desirable.
SUMMARY OF THE INVENTION
The present invention is directed to devices for detecting the moisture content of material such as a diaper using a change in dielectric constant. More particularly, the invention relates to a moisture sensing device which provides an accurate indication of the moisture content of a material when merely placed in the vicinity of the material. In a preferred embodiment, the device is a hand-held device which can be readily transported and which can detect material moisture without piercing the material or attaching electrodes directly to the material.
BRIEF DESCRIPTION OF THE DRAWING
Other objects and advantages of the present invention will become apparent from the following detailed description of preferred embodiments when read in conjunction with the accompanying drawing wherein like elements are assigned like reference numerals, and wherein:
Figure 1 shows a block diagram of an exemplary preferred embodiment of a device constructed in accordance with the present invention; and
Figure 2 shows features of the Figure 1 block diagram in greater detail.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following description of preferred embodiments, specific reference will be made to a moisture detector for sensing moisture present in a material such as a diaper. However, it will be readily apparent to those skilled in the art that such a detector can be applied to the detection of any material wherein the sensing of moisture is desired.
The present invention relates to devices for detecting moisture content of a material by detecting changes in the bulk dielectric constant of the material. Using changes in the bulk dielectric constant to determine moisture content permits the detector to be a portable sensing device which need not be directly connected with the material or brought into contact with the material in any way. Rather, the detector need merely be brought into the vicinity of the material to provide a determination that moisture is present therein.
Figure 1 represents a block diagram of a moisture sensing device 10, such as a capacitance proximity sensing device, which uses changes in the bulk dielectric constant of a material in the vicinity of an antenna to detect moisture content. Generally, the moisture sensing device 10 includes a square wave generator 1, a charge pump 2, an integrator and bias circuitry 3, peak-hold circuitry 4 and a liquid crystal display and driver 5. An antenna 6 is the heart of the sensing device and represents a capacitance proximity sensor. The sensor is composed of a metal plate, the square wave generator, the charge pump and the integrator, the output of which is a current that is proportional to the magnitude of the effective capacitance coupling between the metal plate and a ground plane. The capacitance of the metal plate is affected by the size and relative location of surrounding objects placed in the proximity of the antenna. The sensor thus produces an output which is responsive to changes in the bulk dielectric constant of a material placed in the proximity of the antenna.
The bulk dielectric constant is the property of matter that describes how effective that form of matter is at increasing capacitance. For example, the dielectric constant of air is very low. On the contrary, the dielectric constant of water is quite high. The dielectric constant of dry cloth is typically only slightly higher than that of air. However, the dielectric constant of wet cloth approaches that of water. Thus, when the metal plate of the capacitance proximity sensor is brought close to a wet diaper, the capacitance of the sensor plate will increase much more than it will when the sensor plate is brought close to a dry diaper. Thus, use of this property permits a device such as that shown in Figure 1 to detect moisture in a cloth when the sensor is brought close to the vicinity of the cloth.
Figure 2 shows the exemplary moisture sensing device of Figure 1 in greater detail. More particularly, the square wave generator 1 is shown to include three standard invertors 12, 14, and 16. The input of the first invertor 12 and the output of the third invertor 16 are connected in series via two resistors 18, 20 of 47 kilo-ohms and 10 kilo-ohms, respectively. One plate of a capacitor 22 is connected to a junction between the resistors 18 and 20. The opposite plate of this capacitor 22 is connected to the junction between the output of invertor 14 and the input of invertor 16. The output of invertor 16 represents the output of the square wave generator which is fed to the charge pump 2.
The charge pump 2 includes an n-p-n transistor and a p-n-p transistor configured with their emitters coupled to each other and to the antenna 6. The n-p-n transistor is labelled 24 while the p-n-p transistor is labelled 26. The collector of transistor 26 is connected to ground while that of transistor 24 represents an output of the charge pump 2. Both base inputs of transistors 24 and 26 are connected to the output of the square wave generator 1.
The output of the charge pump is connected to the integrator and bias circuitry 3. More particularly, when moisture is present such that current is conducted via the antenna 6, a capacitor 28 included in the integrator and bias circuitry is charged via a voltage source Vre 30. When the capacitor 28 has been charged sufficiently, a p-n-p transistor 32 is activated such that the voltage Vec is connected to ground via a resistor 34. The voltage drop present across the resistor 34 appears at node 36 and is directed to the output of the integrator and bias circuitry.
A potentiometer 38, a transistor 40, resistors 42, 44 and 46, and a diode 48 are used to provide the bias setting of the moisture sensing device. This bias setting enables the threshold of the sensing device to be adjusted so that the change in moisture of a given material can be detected merely by placing the detector in the vicinity of the material.
The voltage present at node 36 of the integrator and bias circuitry is input to a transistor 50 of peak-hold circuitry 4. During the time that the transistor 50 is activated, a capacitor 52 included in the peak-hold circuitry charges toward the value of Vcc via a diode 54. A second diode 56 connected to the non-grounded electrode of the capacitor 52 resets the peak-hold circuitry to zero by permitting the capacitor 52 to quickly discharge when the power is turned off.
The voltage at the capacitor 52 represents the output of the peak-hold circuitry 4, and is input to a liquid crystal display driver 58 of the liquid crystal display and driver 5. In the exemplary embodiment shown in Figure 2, a twelve segment LCD device 60 is provided. The driver 58 is a ten segment driver. Accordingly, the eleventh and twelfth segments of the LCD device 60 are connected to the tenth segment of the driver 58 while the first segment of the device 60 is connected to ground via a capacitor 62. Device 60 is a well-known LCD device which is connected to a drive source represented by three invertors 64, 66 and 68 in known fashion.
In operation, the known driver 58 responds to the voltage level at the capacitor 52 to provide outputs to one or more of the segment drive lines shown at the output of driver 58. Depending on the number of active segment drive lines provided by the driver 58, a corresponding number of segments in the LCD device 60 will be illuminated. Because the signal at the capacitor 52 is proportional to the bulk dielectric constant of a material placed in the proximity of antenna 6, the display will represent the moisture content of the material.
It will be appreciated by those skilled in the art that Figures 1 and 2 merely represent one exemplary embodiment by which the present invention can be implemented. For example, the capacitance sensed by the antenna 6 may be displayed in any number of ways. More particularly, the voltage at the capacitor 52 in the peak-hold circuitry can be connected to a voltage or current controlled oscillator. The voltage controlled oscillator can then be connected to a speaker or piezoelectric transducer such that a user of the moisture sensing device would hear a tone with a pitch proportional to the wetness of the diaper. Alternately, in place of an LCD device 60 as shown in Figure 2, the Output voltage at the capacitor 52 can be displayed using a multi-colored LED such that the color of the display indicates the degree of moisture content in a material placed near the antenna 6. For example, green could be used to indicate a dry condition, yellow a damp condition and red a wet condition.
Further, the voltage output at capacitor 52 can be fed to a pulse generator which drives a light or tone generator. In such a case, the repetition rate of flashes of light or beeps can be made proportional to the degree of wetness.
It will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalence thereof are intended to be embraced therein.

Claims

WHAT IS CLAIMED IS;
1. A moisture sensing device for detecting moisture content of a material comprising: a capacitance proximity sensor; and an indicator responsive to an output of said capacitance proximity sensor, said capacitance proximity sensor further including: a square wave generator; a charge pump for controlling periods of moisture detection in an output of the square wave generator; and an antenna formed as a metal plate for detecting changes in the bulk dielectric constant of a material placed between said metal plate and a variable ground plane.
2. Device according to claim 1, wherein said device is a portable, hand-held device.
3. Device according to claim 1, wherein said capacitance proximity sensor further includes: a square wave generator for providing an input to said charge pump; an integrator and bias circuit for receiving an output from said charge pump and antenna; and a peak-hold circuit for storing a maximum signal proportional to the bulk dielectric constant of a material.
4. Device according to claim 1, wherein said indicator is a liquid crystal display.
5. Device according to claim 1, wherein said indicator is a multi-colored LED display.
6. Device according to claim 1, wherein said indicator is a light generator which flashes at a rate proportional to the degree of moisture sensed.
7. Device according to claim 1, wherein said indicator is a tone generator having a tone which is adjusted in proportion to the degree of moisture detected by said sensing device.
8. A portable, hand-held moisture sensing device for detecting moisture content of a material comprising: a capacitance proximity sensor; and a liquid crystal display indicator responsive to an output of said capacitance proximity sensor, said capacitance proximity sensor further including: a charge pump; an antenna formed as a metal plate for detecting changes in the bulk dielectric constant between said metal plate and a variable ground plane; a square wave generator for providing an input to said charge pump; an integrator and bias circuit for receiving an output from said charge pump and antenna; and a peak-hold circuit for storing a maximum signal proportional to the bulk dielectric constant of a material.
9. Device according to claim 8, wherein said antenna is a first electrode of a capacitor for storing a voltage relative to an earth ground plane.
10. Device according to claim 1, wherein said antenna is a first electrode of a capacitor for storing a voltage relative to an earth ground plane.
11. Device according to claim 3, wherein said square wave generator produces a square wave to measure charge accumulated on said metal plate.
12. A detector for sensing moisture in a diaper, the detector comprising: a waveform generator for generating a drive waveform; a single plate antenna for sensing bulk dielectric changes during transition periods of the drive waveform, said bulk dielectric changes representing a moisture content of the diaper when the diaper is placed in a vicinity of the antenna; and a detector output for providing a signal proportional to the moisture content of the diaper.
13. Detector according to claim 12, further comprising: a sensing device for measuring charge accumulated on said single plate antenna.
14. Detector according to claim 13, further comprising: a charge pump for applying a charge to the single plate antenna during a first period of time and for connecting the antenna to the sensing device during a second period of time.
15. Detector according to claim 14, further comprising: a square wave generator for driving the charge pump, said first and second periods corresponding to amplitude transition periods of the square wave.
16. Detector according to claim 15, wherein said charge pump further includes: an n-p-n transistor and a p-n-p transistor coupled in series at their emitters, said single plate antenna being connected to said emitters.
17. Detector according to claim 16, further comprising: a peak-hold circuit for storing a maximum signal proportional to the bulk dielectric constant proportional to moisture content of the diaper.
18. A device for measuring the moisture content of material comprised of: a) a conductive antenna for capacitively coupling with a ground plane of the earth, the effective capacitive coupling being proportional to the conductivity and/or moisture content of material in close proximity to said conductive antenna; b) an electronic circuit for measuring a magnitude of said capacitive coupling; and c) a display device for displaying an output of said electronic measuring circuit.
19. A device as in claim 18 wherein said antenna is a metal plate placed in a hand-held device such that the antenna may be easily brought into proximity to external materials such as an infant's diaper.
20. A device as in claim 18 wherein said electronic measuring circuit comprises: a charge pump which electronically switches said antenna betweeen two reference voltages and produces an output current responsive to the amount of charge required to change the voltage of the conductive antenna.
21. A device as in claim 20 wherein said charge pump operates such that the transition from one voltage to the other occurs very rapidly with respect to the period of the frequency with which the voltage is changed.
22. A device as in claim 21 wherein said current output of said charge pump is responsive to noise electronically coupled to said conductive antenna only during said voltage transition, resulting in a degree of noise rejection related to the ratio of the period between transitions to the time occupied by the transitions themselves.
23. A device as in claim 20 wherein said charge pump is composed of an n-p-n and a p-n-p transistor connected such that said conductive antenna is charged and discharged through the emitter terminals and said output current is measured at either collector terminal.
24. A device as in claim 23 wherein base terminals of said transistors are driven by a square wave signal whose rise and fall times determine a rate at which voltage transitions on the conductive antenna are accomplished.
25. A device as in claim 18 wherein said display device incorporates a storage circuit such that a highest reading is displayed until the circuit is reset.
PCT/US1991/009538 1990-12-21 1991-12-19 Material monitoring device WO1992011529A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US07/633,031 US5121630A (en) 1990-12-21 1990-12-21 Material monitoring device
US633,031 1990-12-21

Publications (1)

Publication Number Publication Date
WO1992011529A1 true WO1992011529A1 (en) 1992-07-09

Family

ID=24538008

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1991/009538 WO1992011529A1 (en) 1990-12-21 1991-12-19 Material monitoring device

Country Status (2)

Country Link
US (1) US5121630A (en)
WO (1) WO1992011529A1 (en)

Families Citing this family (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5361627A (en) * 1992-12-31 1994-11-08 Johnson & Johnson Inc. Method and apparatus for the measuring the capillary attraction developed at a surface of an absorbent body
US5316035A (en) * 1993-02-19 1994-05-31 Fluoroware, Inc. Capacitive proximity monitoring device for corrosive atmosphere environment
US5570082A (en) * 1995-10-13 1996-10-29 Mahgerefteh; Nasser Remote wetness sensor for diapers
US5760694A (en) * 1996-05-07 1998-06-02 Knox Security Engineering Corporation Moisture detecting devices such as for diapers and diapers having such devices
EP0837329A1 (en) * 1996-10-15 1998-04-22 W.L. GORE & ASSOCIATES GmbH Test body for items of clothing
US20040089058A1 (en) * 1999-09-09 2004-05-13 De Haan Peter Hillebrand Sensor for detecting the presence of moisture
US6384728B1 (en) 2000-03-17 2002-05-07 Toys For Special Children, Inc. Personal care monitoring system
US6603403B2 (en) 2000-12-12 2003-08-05 Kimberly-Clark Worldwide, Inc. Remote, wetness signaling system
US6583722B2 (en) 2000-12-12 2003-06-24 Kimberly-Clark Worldwide, Inc. Wetness signaling device
US7147615B2 (en) 2001-06-22 2006-12-12 Baxter International Inc. Needle dislodgement detection
US7138088B2 (en) * 2002-04-10 2006-11-21 Baxter International Inc. Access disconnection system and methods
US10155082B2 (en) 2002-04-10 2018-12-18 Baxter International Inc. Enhanced signal detection for access disconnection systems
US20040254513A1 (en) * 2002-04-10 2004-12-16 Sherwin Shang Conductive polymer materials and applications thereof including monitoring and providing effective therapy
US7022098B2 (en) 2002-04-10 2006-04-04 Baxter International Inc. Access disconnection systems and methods
US7052480B2 (en) 2002-04-10 2006-05-30 Baxter International Inc. Access disconnection systems and methods
US7322472B2 (en) * 2002-09-20 2008-01-29 Kimberly-Clark Worldwide, Inc. Void volume indicator and method of consumer product selection
US8029454B2 (en) 2003-11-05 2011-10-04 Baxter International Inc. High convection home hemodialysis/hemofiltration and sorbent system
US7355090B2 (en) * 2005-08-31 2008-04-08 Kimberly-Clark Worldwide, Inc. Method of detecting the presence of insults in an absorbent article
US7498478B2 (en) * 2005-08-31 2009-03-03 Kimberly-Clark Worldwide, Inc. Method of detecting the presence of an insult in an absorbent article
US7649125B2 (en) * 2005-08-31 2010-01-19 Kimberly-Clark Worldwide, Inc. Method of detecting the presence of an insult in an absorbent article and device for detecting the same
US8114043B2 (en) 2008-07-25 2012-02-14 Baxter International Inc. Electromagnetic induction access disconnect sensor
US8866624B2 (en) * 2008-12-31 2014-10-21 Kimberly-Clark Worldwide, Inc. Conductor-less detection system for an absorbent article
CA2976512A1 (en) 2015-02-27 2016-09-01 Kimberly-Clark Worldwide, Inc. Absorbent article leakage assessment system
US11013641B2 (en) 2017-04-05 2021-05-25 Kimberly-Clark Worldwide, Inc. Garment for detecting absorbent article leakage and methods of detecting absorbent article leakage utilizing the same

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4163449A (en) * 1977-09-30 1979-08-07 Regal Robert A Enuresis treatment device
US4199984A (en) * 1977-03-14 1980-04-29 John Huddart Capacitive measuring apparatus
GB2113438A (en) * 1981-10-02 1983-08-03 Eastwood And Son Limited N H Improvements in and relating to devices for use in treating nocturnal enuresis

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2579316A (en) * 1947-08-18 1951-12-18 Moisture Register Company Pressure sensitive moisture test instrument
US2668202A (en) * 1952-08-02 1954-02-02 Benjamin D Kaplan Moisture responsive signaling device
US3171934A (en) * 1963-03-14 1965-03-02 Gen Motors Corp Liquid presence and temperature switch
US3508235A (en) * 1967-04-18 1970-04-21 Joyce B Baisden Combined diaper fastener and signalling device
US3530855A (en) * 1968-06-07 1970-09-29 George H Balding Enuretic control device
US3927370A (en) * 1972-07-11 1975-12-16 Bough Bjorn N De Audio signalling system having probes for monitoring the characteristics of a material
US3818468A (en) * 1972-09-15 1974-06-18 D Toth Self-contained liquid detector
US3824460A (en) * 1973-04-02 1974-07-16 R Gustafson Leakage sensor
US4013065A (en) * 1976-02-23 1977-03-22 American Cyanamid Company Moisture dermatometer
US4069817A (en) * 1976-08-25 1978-01-24 Fenole Joseph E Body waste detecting device
US4197530A (en) * 1977-02-09 1980-04-08 Laue Eric G Passive intrusion detection system
US4106001A (en) * 1977-05-12 1978-08-08 Kurt Mahoney Moisture detector
US4205672A (en) * 1977-11-28 1980-06-03 Karel Dvorak Conductivity sensing device for diapers
US4271406A (en) * 1979-07-31 1981-06-02 Wilson Reginald D Bed wetting tattler
JPS59203949A (en) * 1983-05-06 1984-11-19 Shiro Wada Method for announcing wet diaper
US4653491A (en) * 1984-06-20 1987-03-31 Nippon Kodoshi Corporation Water content sensing and informing system for a disposable diaper
US4800370A (en) * 1985-10-07 1989-01-24 I E Sensors, Inc. Wetness detection system
JPS63167263A (en) * 1986-12-27 1988-07-11 Toho Denshi Kk Sound wave type moisture content sensor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4199984A (en) * 1977-03-14 1980-04-29 John Huddart Capacitive measuring apparatus
US4163449A (en) * 1977-09-30 1979-08-07 Regal Robert A Enuresis treatment device
GB2113438A (en) * 1981-10-02 1983-08-03 Eastwood And Son Limited N H Improvements in and relating to devices for use in treating nocturnal enuresis

Also Published As

Publication number Publication date
US5121630A (en) 1992-06-16

Similar Documents

Publication Publication Date Title
US5121630A (en) Material monitoring device
US5091715A (en) Leak detection and alarm system
US6904789B2 (en) Moisture detection apparatus and method
US4002996A (en) Level detector using oscillator circuit with two capacitive probes
US4295475A (en) Probe and system for detecting probe dislodgement
US3774110A (en) Static electric field detector
CA2531886A1 (en) Multiple sensor vehicle occupant detection for air bag deployment control
EP0723166A1 (en) Capacitive sensor
US4449122A (en) Proximity detector employing a crystal oscillator
US4145619A (en) Two wire capacitance transmitter
US5264833A (en) Automatic leak detector
US4776203A (en) Gas monitor circuits
US3341774A (en) Capacitance detector having a transmitter connected to one plate and a receiver connected to another plate
US5717327A (en) Current sensor
US6184695B1 (en) Diagnostic circuit for potentiometric sensors
US3593119A (en) Electronic titrimeter
US4617512A (en) Capacitance measuring device including an overrange circuit
SE9603379D0 (en) Device for detecting when a measuring probe comes into contact with a liquid surface
EP0933641B1 (en) Automatic power turn-on circuit for a battery-powered voltage measurement apparatus
US4746816A (en) Spike detector circuitry
US4639618A (en) Spike detector circuitry
US6023976A (en) Prodder with force feedback
US4006415A (en) Fast reset integrator
EP0216288B1 (en) Interface circuit between a sensor, particularly a thick film pressure sensor, and an electrodynamic instrument, and a sensor incorporating such a circuit
KR970706488A (en) DEVICE AND METHOD FOR MEASURING CHARGE CARRYING ACTIVITY IN GENERALLY NONCONDUCTIVE MATERIALS

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA JP

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LU MC NL SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA