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Baby Diaper Wetness Detector and Indicator Biomedical Engineering Senior Design I The City College of New York The City University of New York (CUNY) Prof. M. Bikson Prof. L. Cardoso T.A.: Limary Cancel Sponsor: Dr. Daniel Faber Seynabou Ndaw Sabera Islam LaToya Davis Lubna Choudhury Marwa Choudhury A.H. Rezwanuddin Ahmed May 19, 2008

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Page 1: Baby Diaper Wetness Detector and Indicator Biomedical ...bme.ccny.cuny.edu/faculty/mbikson/Courses/BMESeniorDesign... · Baby Diaper Wetness Detector and Indicator Biomedical Engineering

Baby Diaper Wetness Detector and Indicator Biomedical Engineering Senior Design I

The City College of New York The City University of New York (CUNY)

Prof. M. Bikson Prof. L. Cardoso

T.A.: Limary Cancel Sponsor: Dr. Daniel Faber

Seynabou Ndaw Sabera Islam

LaToya Davis Lubna Choudhury Marwa Choudhury

A.H. Rezwanuddin Ahmed

May 19, 2008

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Table of Contents 1.0 Abstract ------------------------------------------------------------------------------------------3 2.0 Introduction-------------------------------------------------------------------------------------3

3.0 Prior Art -----------------------------------------------------------------------------------------3

3.1 Color Change------------------------------------------------------------------------------------3 3.2 Gas Detector------------------------------------------------------------------------------------- 4 3.3 Capacitor Sensors------------------------------------------------------------------------------- 5 3.4 Thermal Sensors---------------------------------------------------------------------------------5 3.5 Electrodes Resistance Change-----------------------------------------------------------------6 3.6 RF Technology-----------------------------------------------------------------------------------6

4.0 Design Specifications for the Baby Diaper Wetness Detector and Indicator-------7

4.1 Required Specification------------------------------------------------------------------------- 8 4.2 Desired Specification--------------------------------------------------------------------------- 9

5.0 Failures------------------------------------------------------------------------------------------10

5.1 Radio Frequency (RF) Technology for urination------------------------------------------10 5.2 Ultra-sound for urination---------------------------------------------------------------------10 5.3 Light for urination------------------------------------------------------------------------------11

6.0 Our Design-------------------------------------------------------------------------------------12

6.1 Gas Detector------------------------------------------------------------------------------------13 6.2 Diaper with H2S Gas Detector Sensor------------------------------------------------------13

7.0 Methods of Evaluation-----------------------------------------------------------------------14

8.0 Future Approach------------------------------------------------------------------------------15

8.1 Defecation and Urination Detector with stand alone indicator-------------------------15 8.2 RF Technology using tags---------------------------------------------------------------------16

9.0 Conclusion--------------------------------------------------------------------------------------17

10.0 References-------------------------------------------------------------------------------------17

11.0Timeline----------------------------------------------------------------------------------------18

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1.0 Abstract

The objective of this project was to design a diaper wetness detector and indicator that would allow a caretaker to know when a wearer of the device had significantly defecated and/or urinated in a diaper and thus required changing. Over the years, a number of designs have been introduced to detect urine and defecation in the diaper, some of which were shown to be hazardous to the wearer. The safety and effectiveness of several designs were tested and evaluated. These included RF technology, light, and ultrasound sensors to detect urination, and gas sensors to detect feces. The gas detector design was shown to be safe and effective by meeting design specifications. The urination sensor shows great promise as a future endeavor. 2.0 Introduction:

Among caretakers of incontinent children and adults, there is a need and a desire to have a diaper or a device that would alert the caretaker when changing of the diaper is required. Such a diaper or device would improve the quality of life of the wearer and the caretaker. The baby diaper wetness detector and indicator will allow the caretaker to know when the wearer has significantly defecated and/or urinated in the diaper and thus requires changing. While the device will be applicable to adults, we will focus on its application to young children in this paper.

Urine and defecation consists of H2S, CO2, H2, CH4, Methanethiol, sulfur gases, and water. [1] Direct skin contact with these compounds might lead to skin breakdown, skin rashes and irritation to the wearer. If the wearer’s diaper is not changed when it is required, the waste could also cause discomfort to the wearer. Since children do not cry every time the diaper is soiled, there

is a great need for this device because it is inconvenient to check a child’s diaper for waste in public places or while driving a car. Moreover, this device can be extended to meet the needs in hospitals, pre-schools, and nursing homes where it could benefit a wide population of children and adults. 3.0 Prior Art: Over the years, there have been a number of designs that have been introduced to detect urine and defecation in the diaper to alert the caretaker, some of which are hazardous to the wearer. The following sensors were used in prior art to detect urination and/or defecation. 3.1 Color Change: [I] Patent # 3675654 – Disposable article with moisture-actuated indicating agent [II] Patent # 20040087922 - Method of making early indicator color changing diaper or plastic color changing training pants [III] Patent # 4507121- Disposable diaper with isolated wetness indicator

Fig 3.1a: Cross-sectional view of the diaper

which uses color change as indication.

Fig 3.1b: Method in which color change occurs.

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A piece of litmus paper is placed between the absorbent layers inside and outside the diaper and gets wet when the subject urinates [Fig 3.1a]. Another piece of litmus paper is placed inside the back sheet of the diaper from where a caretaker can observe it from outside. The plastic outside that covers the visible litmus paper is transparent and facilitates visualizing the color change. When a subject urinates, the absorbent material inside makes contact with the litmus paper which facilitates a pH dependent reaction resulting in a color change that indicates that the diaper is soiled [Fig 3.1b]. The pH range of urine is 4.6-8.0. According to US patent 4231370, the average pH value of urine is 6.3. This patent also uses a coated surface of pH indicator and places the acid buffer pH color change material inside the diaper which is activated by the urine pH level. Instead of litmus paper thermochromic ink or color changing ink can be used also. When a subject urinates a temperature change occurs in the diaper and this temperature change causes the thermocromic ink to change color. There are two kinds of thermochromic ink used which are crystals and leucodyde.

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3.2 Gas Detector: Gas can be detected using different devices, such as an electrochemical device, semiconductor sensors, spectrum analysis devices, and catalyst-based devices. [I] Patent # 5709222 - Body waste detection and alarm system [II] Patent # 4141800 - Electrochemical gas detector and method of using same

Filter

Electrode

ElectrodeTerminals

Fig 3.2: Typical cross-section of a gas sensor.

The most frequently used gas detector is the Electrochemical Device [Fig 3.2]:

The gas components are collected in the gas chamber and then diffuse out of the chamber at a three phase border (it includes electrolyte) and it causes a change in electrochemical equilibrium. The electrodes are placed on the opposite sides of the three phase border. The change in electrochemical equilibrium induces an electrical current in the electrodes. The electrolyte has an organic gel which plays the role of a sorption filter. The filter is selectively permeable to the desired gas component. The filter consists of porous body; it has at least one reaction partner in solid form, one membrane layer of an inert material and several membrane layers and different reaction partners are incorporated in the individual membrane layer. For example: To detect hydrogen sulfide silver is used as electrodes, polymer polymethylmethacrylate (PMMA) and solvent propylene carbonate as gel electrolyte, sodium benzoate, benzoic acid and iron (III) sulfide as electrolyte additives and 3-hydroxydiphenylamine as reaction partner distributed throughout the porous membrane.

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3.3 Capacitor Sensors: [I] Patent # 4653491- Water content sensing and informing system for a disposable diaper

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This device is composed of a pair of uniformly spaced coplanar metal layers disposed on an outer sheet of the diaper and engaged with a water absorber and a metal layer having a surface covered with an electrical insulating layer and an absorber being disposed between the metal layers [Fig 3.3]. A capacitor has an electrostatic capacity which varies in response to the water absorbed by the absorber. The degree of wetness of the diaper is detected by the level of the electrostatic capacitor. [II] Patent # 2005/0195085A1- Wireless monitoring system of diaper wetness, motion, temperature and sound This device is composed of conductivity sensors, a capacitive sensor, a motion sensor, a microphone, and a temperature sensor. The output of each sensor is analyzed by a microcontroller. The output of the microcontroller enters a wireless transmitter which relays to a remotely

monitored pager. The pager display shows audibly and visually the stream of data coming from the pager wireless receiver. [III] Patent # 5903222 - Wet garment detector This device is composed of a capacitive sensor and of electronic circuitry. The capacitive sensor is located within a housing compartment and made of two coplanar solid conductor plates. When the diaper is wet the capacitance between the conductors rises above a predetermined value, the electronic circuitry responds to the electrical capacitance of the capacitive sensor, and it produces an output signal. 3.4 Thermal Sensors:

Fig 3.3: Cross-section of a capacitor sensor.

Fig 3.4: Thermal sensor emitting signal of temperature change in the diaper.

[I] Patent # 5790035 - Reusable temperature and wetness alarm device for the diaper The sensor detects the new urine temperature and the temperature deviation is used as input for the sensor. Then the sensor sends a signal to the alarm controller. By

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this, the caretakers are informed about the wetness of diaper. [II] Patent # 2002/0026164 A1 The combination of thermal sensor, humidity sensor, and chemical sensor constitute an emitter. When the diaper gets wet, the circuit of the wetness detection sensor is closed and the thermal micro-electrode circuit captures the temperature. The electrochemical sensor analyzes the urine and sends a signal to the receiver-emitter of a mobile and/or fixed telephone with the data of temperature in degrees and the chemical analysis in percentages [Fig 3.4]. 3.5 Electrodes Resistance Change:

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This device places removable electrodes in one of two pads placed according to boy/girl or comfort of the baby. Another form places the electrodes into the super absorbent gel. The sensor contains an oscillating voltage or pulse source, preferably having a low duty cycle, which capacitively couples to the electrodes in the pads using a sheath which acts as a dielectric medium and an alarm device which responds to the source. The

spaced electrodes form a switch that remains open (non-conductive) when the diaper is dry. The sensor is set so varying current from the source cannot pass through the open switch formed by the electrodes. When the diaper is wet the electrolytic action of the urine in the diaper contacts the electrodes and closes the switch (makes it conductive across the gap between the electrodes). The sensor sets the alarm threshold very high to prevent false alarms due to contact with a metal surface or sitting on a wet surface. 3.6 RF Technology: Patent # 6774800 - Patient incontinence monitoring apparatus and method of use thereof Patent # US 20020145525 - Patient incontinence monitoring apparatus and method of use thereof

Fig 3.5: Top view of a diaper with Electrodes resistance change sensor. Fig 3.6: ‘Smart Diaper’ using RF technology

for moister detection. RF technology is used on a regular basis in antitheft devices, or as an automatic toll paying ID tag for vehicles, or even just for simple identification (and data storage purposes). As has been suggested in various patents, an RFID (an RF tag) could somehow be used as a remote sensor to incontinent conditions.

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Traditionally an RF tag is simply a tag (with an antenna) that would accept a radio frequency signal from a transmitter, modify the signal, and then send it back to the receiver. The idea behind a “smart” diaper wetness detector is that it will contain an RF tag, with a specific signal response. It is considered that the circuit will behave differently if the tag were to become wet, thereby allowing for a differently recorded signal. This different signal, when received by the receiver, will be able to ‘tell’ that there is a conditional or environmental change in the RF tag. Various models have been proposed with this in mind, although the primary idea is: place a tag in the diaper, and set the detector as per the initial signal

that is detected from the RF tag. This will be the standard for that particular tag, or the “dry” condition. When the diaper has become wet (assuming that this is due to urinary discharge), the wetness will cause the tag to resume a different response to the original transmitted signal. The idea of placing the tag inside the diaper of the user, with a transmitter/receiver system embedded outside the diaper (thus relieving the user of having any devices to him/her) and then reading the condition of the tag in the diaper. The operating frequency range for the transmitter and receiver are 902-928 MHz. Typical voltage supplies may vary from 2.0V-16V. .

4.0 Design Specifications for the Baby Diaper Wetness Detector and Indicator All specifications are applicable to otherwise healthy individuals of all age groups and sexes who are potential wearers/users of the stated device. 4.1 Definitions:

i. Alert Cases are situations in which the device alerts the caretaker that it has detected urine or feces.

ii. Abnormal motion is defined as motion in which the device and/or any device related component(s) undergoes rapid acceleration or deceleration resulting in a force or forces that would cause a 1 (one) year old child minimal or serious physiological harm or death.

iii. Normal motion is defined as situations in which the device is operated and/or handled in ways that do not involve abnormal motion for any period of time.

iv. False indication is when the device falsely alerts the caretaker when there is less than 10ml of urine in the diaper.

v. False detection is when the device’s sensors react as if it detected urine or stool in the absence thereof AND as a consequence, the device falsely alerts the caretaker. Such situations may be caused by the wearer sitting on a wet and/or metal surface or as a result of normal motion.

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4.2 Required Specifications:

Parameter Justification

Applicable Diapers Compatible with Pampers sub-brands: Swaddlers (N, 1,2,2-3), Cruisers (3,4,5,6,7), Baby Dry (1,2,3,4,5,6), and Easy Ups (4,5,6)

The device will not compromise the integrity of any part of the diaper

If the device and/or any device related components will be attached to the diaper, such articles will do so without cutting through the

diaper.

Should not reduce holding integrity

(A) No component of the device will decrease the diaper manufacturer’s holding capacity of urination and defecation. (B)

No component of the device shall interfere with the absorbent polymer gel.

Reliability (A) The device will accurately detect the stated minimum amount of urine and stool in at least 90% of alert cases. (B) The device

will undergo false indication in no more than 20% of alert cases. (C) The device will undergo false detection in no more than 10%

of alert cases. (D) All standards will be demonstrated through trials and testing. (E) The device will not be held to any reliability

standards under abnormal motion. Comfortable The child will not show evidence of discomfort while in contact

and/or while wearing the device and/or any device components (i.e. crying, grimacing)

Will not be hazardous

(A) The device and/or any device related components will not compromise the child’s skin integrity as will be demonstrated

through the absence of device-related rash and skin breakdowns. (B) No materials used in the device or in any device components

that are directly in contact with the child will cause harmful physiological effects and no physiological harm will be caused to the child or caregiver as a result of the device and/or any device

related components. User-friendly

Caregivers will be able to use the device without requiring written instructions.

Price of disposable sensor(s)

Price of disposable sensor(s): under $20 per week Price of one-time purchase of device: under $50

Total initial cost: $50 + $20 = $70 Disposable Any components of or relating to the device that are placed or

attached inside of the diaper must be disposable Urination and defecation sensor(s) and sensor(s) sensitivity

(A) Sensor(s) must be able to detect a minimum of 100 ml of urine and 0.2 lb of stool. (B) Sensors will not detect less than 10 ml of

urine.

Weight of the (A) The sum total weight of the device including sensor(s),

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device (related to child safety)

indicator(s), and all other device related components must be less than 250g if such components are attached to the child and/or any

article(s) of clothing or apparel such as diapers that the child would be wearing. (B) If the device or any device components are placed

on a stroller, crib, or playpen, the sum total of all components of the device placed in this way must be less than 5 1bs. (C) The

device and/or any related components that are not in contact with the child in the ways stated above must weigh less than 20 1bs total

sum. Maximum dimensions of sensor(s) (inside the diaper)

385 mm x 250mm x 5 mm

4.3 Desired Specification:

Parameter Justification Applicable to wide range of the diapers

The device is preferred to be compatible with all Huggies, Pampers, and Luvs brands and sub brands

Weight of the device

If the device and/or any components of the device are inside of the diaper, the sum total weight of all such objects is preferred to be

under 70g. Cost of the disposable sensor

Under $5 per week. Total initial cost: $55

Urination and defecation sensor(s) and sensor(s) sensitivity

It is preferred that the urination and defecation sensor(s) detect from outside of the diaper. It is preferred that the sensor(s) will be able to detect a minimum of 40 ml urination and 0.2 1b defecation

Maximum Dimensions (inside the diaper)

40mm x 40mm x 5mm.

Materials It is preferred that the sensor(s) be biodegradable. Electric wires It is preferred not to have electric wires inside of the diaper. Reliability The device will accurately detect the stated preferred amount of

urine and defecation 100% of the time with no false positives or failures in all motion (normal and abnormal) cases.

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5.0 Failures

There were several designs that were put into consideration; however due to cost, size, time and efficiency we have concluded the following designs to be failures: 5.1 Radio Frequency (RF) Technology

for urination

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Two 2.4 GHz Bluetooth were placed across the outer, bottom surface of a diaper to transmit a signal from the emitter Bluetooth to the receiver Bluetooth [Fig 5.1]. 2.4 GHz microwave signal was chosen because it is biologically safe and is of higher frequency than the radio wave spectrum. Bluetooth networking transmits data via low-power radio waves. It communicates on a frequency of 2.45 GHz. This frequency band has been set aside by international agreement for the use of industrial, scientific and medical devices (ISM). The ISM band is not known to be part of the ionization range, which means they are not known to break down the bonds that keep our biological make up together. This band does not have enough power to disrupt our DNA. The 2.4GHz frequency is close to the frequency of the natural resonance of water. One of the advantages of using Bluetooth is that Bluetooth devices don’t interfere with

one another. One of the ways Bluetooth devices avoid interfering with other systems is by sending out very weak signals of about 1 mill watt [1].

In our device design case, while the emitter Bluetooth sent a 2.4 GHz signal through the diaper to the receiver Bluetooth, the signal was not absorbed significantly by the diaper water. When any two frequencies in the electromagnetic spectrum match, they will act upon each other with a potential for energy transferal and will transfer the most amount of power possible to the emitter Bluetooth at each available opportunity. The more dissimilar the frequencies are the more wasted energy in the transfer.

Fig 5.1: Emitter Bluetooth is sending signal through diaper to receiver Bluetooth.

5.2 Ultra-sound for urination

Ultrasound is a non invasive method which can be used to measure depth of a

Fig 5.2a: Ultrasound is used to detect urination in the diaper.

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liquid level and detect the presence or absence of liquid in a medium. The basic principle of ultrasound is that when the transducer is placed under the wet diaper the sound wave transmits through a wet diaper and hits a boundary between the wet diaper and soft tissue. It emits a sound wave and detects the reflected sound wave. The reflected waves are picked up by the transducer probe and are transmitted to the function generator. If the diaper is not wet there will be no reflected or backward echo except the echo generated by the surface of the diaper that is in contact with the transducer. When the diaper is wet it becomes a gel and thickness of the diaper increases. As a result the velocity of sound wave impulse stays the same or decreases and thus the time to receive an echo increases. The plot of time vs. amplitude is shown in the following graphs [Fig 5.2a,b]. [5]

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In this ultrasound technique a 5MHz piezoelectric transducer was used with

electrolytic gel on dry diaper first then the reflected sound wave was recorded. The transducer with gel was placed outside the diaper and hand was placed inside the diaper. Following again a wet diaper was used in a same way to determine if the sound wave echoed and bounced back was different than that observed in the dry diaper. In this technique the sound wave generated by the dry diaper was the same as the sound wave generated by the wet diaper. There was no significant difference in frequency observed when both conditions were compared. The reason this result was observed could be due to the size of the transducer, thickness of the medium or the inaccurate coupling of transducer to the diaper. 5.3 Light for urination

Am

plitu

de

Time

Fig 5.2b: No echo present in between the blue lines which determine absence of liquid.

A photodetector and an emitter (visible red light or infrared light) were used to detect urination in the diaper. A photodetector produces an electrical output (current or voltage) by detecting changes in light from an emitter and converting it into a voltage response that can be measured. The response gives a

Fig 5.3: A photodetector and an emitter were used to detect voltage change when the baby urinates.

Am

plitu

de

Time

Fig 5.2c: Echo presents in between blue lines which determine presence of liquid.

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measure of the intensity or irradiance of the incident light.

To test this concept light was passed through a dry diaper. The spectral response of the detector was visualized using LabVIEW [Fig 5.3]. The next step was to pour water on the diaper to simulate urine. The spectral response

was then visualized using the same procedure as with the dry diaper. There was no significant difference between the two spectral responses observed. We concluded that water did not induce change in the electrical response of the photodetector.

6.0 Our Design 6.1 Gas Detector

H2S gas is the most common gas in 0-3 month old babies’ defecation [Table 1]. As babies get older the amount of H2S gas increases.[1] Defecation was detected using a H2S gas sensor. H2S gas sensor circuit was attached outside of the diaper with a belt. H2S gas sensors were attached at the end of flexible strip

which was suspended from the gas detector circuit through the inner surface of the diaper. It detected the H2S gas particles from the feces and induced a voltage change in the output. This change in output was transmitted via Bluetooth to the receiver [Fig 6.1].

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Fig 6.1: The gas detector detects minimum of 5ppm of H2S gas [Part #VQ101, Manufacturer e-2v]. There is a significance voltage change when it detects H2S gas. This voltage difference is amplified and filtered then used as analog input for the Bluetooth. The Bluetooth transmits the data to Computer which indicates whether the diaper is soiled.

6.2 Diaper with H2S Gas Detector Sensor

Fig 6.2(b): 3- Dimensional schematic of diaper with gas detector. Fig 6.2 (a): The assembled Device

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7.0 Methods of Evaluation Parameter

Methods of Evaluation

Satisfied

Applicable Diapers

The device will be tried on different diaper brands such as Pampers sub-brands: Swaddlers (N, 1,2,2-3), Cruisers (3,4,5,6,7), Baby Dry (1,2,3,4,5,6), and Easy Ups (4,5,6) at least once

The device will not compromise the integrity of any part of the diaper

If the device and/or any device related components would be attached to the diaper, such articles will do so without cutting through the diaper.

Should not reduce holding integrity

Two diapers will be tested using weight and/or volume of water (saline) it can hold. One will be with the device on (Experimental) and another one is without the device on (Control) and then compared.

Reliability

The device will be tested 20 times keeping a controlled condition. Then under normal condition the number of times device detects stated minimum of urine and stool of alert cases, false indication and false detection cases will be determined and calculated the percentage.

Comfortable

The part of device that goes against the baby skin will be tested for any sharp angles; any extra pressure and the overall weight of the device will be calculated.

Will not be hazardous

(A) The device and/or any device related components will not compromise the child’s skin integrity as will be demonstrated through the absence of device-related rash and skin breakdowns. (B) No materials used in the device or in any device components that are directly in contact with the child will cause harmful physiological effects and no physiological harm will be caused to the child or caregiver as a result of the device and/or any device related components.

User-friendly

Caregivers will be able to use the device without requiring written instructions.

Price

The price of each component will be added together.

Weight of the The weight of the device will be measured √

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device Disposable

Any components of or relating to the device that are placed or attached inside of the diaper must be disposable

Urination and defecation sensor(s) and sensor(s) sensitivity

The Hydrogen Sulfide gas sensor can detect concentration of 5ppm of H2S and above. Defecation: Normal baby’s (age ~ 3 months) 0.2 lb of stool has more than 100 ppm of H2S [1]

Maximum dimensions of sensor(s) (inside the diaper)

The dimensions of the device inside the diaper will be measured.

8.0 Future Approach 8.1 Defecation and Urination Detector with stand alone indicator

Fig 8.1: Urination and Defecation detector with stand alone wireless receiver

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Urination Detector (Fig 8.1a): Two 2.4 GHz Transceivers will be placed across the outer side of the bottom layer of a diaper. A microcontroller will be placed on the outer surface of the diaper between the transceivers to compare the signals transmitted and received. There is a significant change in signal amplitude when the diaper is wet. This change in amplitude is identified by the micro-controller and the signal transmitted via Bluetooth to receiver. Defecation Detector (Fig 8.1b): Gas sensors will detect the H2S gas particles

from the feces and induce a voltage change in the output. This change in output will transmit data via Bluetooth to the receiver. Receiver (Fig 8.1c): Bluetooth will collect data from Urination and Defecation Detectors which is processed by microcontroller and indicated by LED. The receiver can be placed within the range of 500 meters (line of sight). This approach was not completed due to time constraint and microcontroller complexity.

8.2 RF Technology using tags

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Fig 8.2a: RF tags Fig 8.2b: Transceivers Fig 8.2c: RF tags in diaper

Using passive RF was not completely a failed design, rather, it was not feasible. Current UHF (ultra-high frequency) transceivers are used in the processing/retail industry like normal barcodes and RF tags to “read” items. It has been established that the presence of any water-containing products (meat products, liquids, and such materials) interfere with the reading of these tags, making it almost impossible to read from these tags. The limitation, with this technology is the price and the size of the components. Current UHF passive card readers are on average as large as the average CPU housing of a home PC. The tags themselves cost on the order of about 29c per tag. Technological

advances predicted these tags to fall in price to 5c by 2009-2010, thus making it easy to use and discard. Intel recently came out with a UHF chip (the Intel UHF R1000 RFID transceiver) that incorporates the basic functions of an RFID reader, with a size of only 8mm x 8mm. It is easy to see that such small chips and reduction in tag prices will allow tags (and readers) to be used as a detector in the future: the tag would simply be slipped into the diaper (because of its passive nature, that is, because it has no power source, it will not cause any electrical hazard to the baby), and the small chip can read this from outside the diaper. The small size of the chip would prevent the need to

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attach a cumbersome and large device to the baby’s diaper. 9.0 Conclusion

Through our many months of research, testing, and evaluating, we have shown you why previous patented ideas were not safe and/or applicable, why light and ultrasound for urination don’t work, and why RF technology is not feasible at this time. Further we have shown you our successes with the manufacture of the gas detector, our continued plans for our urination detector, and how RF technology can become a very feasible idea in the future. With this knowledge earned through these months, we have paved the way for future endeavors and delivered insight of great value to readers. Through this project we have gained great understanding of the design and manufacture process. This understanding entails recognizing that failures are necessary to achieve success and thus failures are not really failures at all. Just as previous patents served this team in evaluating the safety and efficacy of previous ideas, it is the hope and confidence of the authors that this paper will serve as a guide to all future endeavors in this field.

10.0 References: [1] Jiang, T.; Gas Production by Feces of Infants, Journal of Pediatric Gastroenterology and Nutrition, 32:534–541, May 2001. [2] Images of transmitter and receiver: http://www.lemosint.com/scripts/tx3.asp [3] Images of RFID tag: http://www.gadgetell.com/images/032006/rfidlabel2.jpg[4] Image of H2S gas sensor: http://www.e2v.com/files/sensors/ec430.pdf[5] Ultrasound: http://www.olympusndt.com/en/ndt-application/183-id.209715246.html