Abstract:
Incontinence management systems, methods, and sensors are provided that alert the caregiver when a patient&#39;s brief has been soiled. A resonant circuit includes a polyaniline/carbon black (PANI/CB) composite chemiresistor which undergoes a large impedance change upon exposure to the vapor or ‘smell’ of urine or feces. Due to the impedance change of the PANI/CB resistor, characteristics of the resonant circuit change when the sensor is exposed to urine or feces vapor. The sensor responds to an interrogating signal with a signal based least in part on the sensor&#39;s impedance and indicates the condition of the brief as soiled or clean.

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
       [0001]    Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. 
       BACKGROUND 
       [0002]    Incontinence rates are reported as high as 60% for residents in nursing homes and 66% for patients in acute care. Intensive care units generally have the highest incontinence rates. Skin injuries due to incontinent-associated dermatitis (IAD) occur in a third of hospitalized patients. As many as 41% of adults in long-term care facilities experience some form of skin condition in the perineal region. IAD increases the risk of microbial skin infections and pressure ulcers, which can lead to longer hospital stays, increased treatment cost, greater risk of nosocomial infection, and higher morbidity and mortality rates. The reason for the incontinence is often unknown. In some cases, incontinence may be caused by multiple factors including treatments which cannot be discontinued in hospitalized patients. 
         [0003]    Moreover, skin conditions are a metric of an acute care facility&#39;s quality. When applying to the American Nurses Association for Magnet Status, an acute care facility must report quarterly data on pressure ulcer prevalence. Similarly, long-term care facilities must report pressure ulcer rates and risk fines if proper actions were not taken to prevent the injuries 
         [0004]    Managing incontinence according to the Guidelines of the Wound, Ostomy, and Continence Nurses Society requires the skin be kept dry and clean and the application of skin protectant after each incontinent episode. Delays in changing a brief or diaper are cited as the leading cause of IAD, while more frequent changing of incontinence briefs was found to reduce the incidence of pressure ulcers. 
         [0005]    However, without a method to identify when an incontinent event has occurred, caregivers are often unaware of the patient&#39;s condition. As a result perineal hygiene occurs most often by schedule rather than by need. 
       SUMMARY 
       [0006]    Incontinence management systems and methods are provided that alert the caregiver when a patient&#39;s brief has been soiled. Incontinence or an incontinent event comprises an event resulting from a lack of voluntary control of an excretory function. This can occur in adults, children and infants. A bodily waste detector or sensor comprises a bodily waste sensing element or transducer and a passive resonant LC-circuit. In an embodiment, the bodily waste sensing element comprises a polyaniline/carbon black (PANI/CB) composite chemiresistor which undergoes a large impedance change upon exposure to the vapor or ‘smell’ of a bodily waste, such as urine or feces. Due to the impedance change of the PANI/CB resistor, characteristics of the resonant circuit change when the sensor is exposed to urine or feces vapor. 
         [0007]    In other embodiments, other properties of the bodily waste sensing element, such as, for example, capacitance, inductance, dielectric strength, conductivity, permeability, permittivity, magnet field strength, crystalline structure, reflectivity, refractivity, photosensitivity, thermal properties, and the like, undergo a change upon exposure to urine and/or feces. Due to the change one or more of the properties, characteristics of the circuit comprising the bodily waste sensing element change when the sensor is exposed to urine and/or feces. 
         [0008]    In other embodiments, a moisture detector comprises a moisture sensing element or transducer and a passive LC-circuit. In an embodiment, the moisture sensing element undergoes an impedance change upon exposure to moisture. Due to the impedance change, characteristics of the resonant circuit change when the sensor is exposed to moisture. 
         [0009]    In other embodiments, other properties of the moisture sensing element, such as, for example, capacitance, inductance, dielectric strength, conductivity, permeability, permittivity, magnet field strength, crystalline structure, reflectivity, refractivity, photosensitivity, thermal properties, and the like, undergo a change upon exposure to moisture. Due to the change in one or more of the properties, characteristics of the circuit comprising the moisture sensing element change when the sensor is exposed to moisture. 
         [0010]    With conventional RF technology, a reader or interrogator interrogates a sensor or a sensor insert placed in a patient&#39;s brief through clothing and blankets. In some embodiments, the reader reads the sensor response from a distance of up to approximately 5 meters. In other embodiments, the reader reads the sensor response from a distance that is greater than approximately 5 meters. The interrogating signal from the transponder powers the passive sensor and the sensor provides wireless communication using high frequency (HF) or ultra-high frequency (UHF) signals. In an embodiment, the sensor reflects back a signal modulated by the sensor&#39;s impedance and indicates the condition of the brief as soiled or clean. Once informed, the caregivers can provide the appropriate care in a timely fashion. 
         [0011]    Systems and methods disclose a bodily waste sensor comprising a circuit comprising a polyaniline/carbon black (PANI/CB) chemiresistor. The circuit is energized by an interrogating radio frequency signal to produce a response signal based at least in part on an impedance of the PANI/CB chemiresistor. The impedance of the PANI/CB chemiresistor becomes greater upon exposure to bodily waste than in the absence of bodily waste. In one embodiment, the circuit is a resonant circuit. In other embodiments, the circuit is a telemetry circuit. 
         [0012]    In accordance with various embodiments, a method of detecting an incontinent event or a bodily waste event of a person is disclosed. The method comprises providing a sensor to detect bodily waste. The sensor comprising a polyaniline/carbon black (PANI/CB) chemiresistor configured to increase impedance in the presence of the bodily waste. The methods further comprises receiving an interrogating signal at the sensor, where the interrogating signal powers the sensor, and sending a response signal from the sensor in response to the interrogating signal, where the response signal is based at least in part on the impedance of the PANI/CB chemiresistor. 
         [0013]    In some embodiments, a bodily waste sensor is provided. The sensor comprises a resonant LC-circuit comprising a sensor and energized by an interrogating radio frequency (RF) signal to produce a response signal based at least in part on an impedance of the sensor, where the impedance of the sensor changes upon exposure to bodily waste. 
         [0014]    For purposes of summarizing the invention, certain aspects, advantages, and novel features of the invention have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    A general architecture that implements the various features of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements. 
           [0016]      FIG. 1  is a graph illustrating exemplary resistance change of a PANI/CB sensor to urine vapor, according to certain embodiments. 
           [0017]      FIG. 1A  illustrates an exemplary sensor and an exemplary reader, according to certain embodiments. 
           [0018]      FIG. 2  is a schematic diagram of an exemplary resonant LC-circuit incorporating a PANI/CB chemiresistor, according to certain embodiments. 
           [0019]      FIG. 3  is a graph illustrating a simulated sensor response upon activation of an exemplary PANI/CB sensor, according to certain embodiments. 
           [0020]      FIG. 4  is a schematic diagram illustrating an exemplary telemetry LC-circuit incorporating a PANI/CB chemiresistor, according to certain embodiments. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0021]    Several chemiresistor sensors are known to respond to chemical analytes. A polyaniline/carbon black (PANI/CB) sensor offers sensitivity to urine and feces through acid-base reactions between amines in the waste and the protonated polymer backbone of the polyaniline (PANI). The ammonia in urine, a byproduct of urea, deprotonates the PANI causing a resistance increase on the order of approximately 10 5  ohms. In some embodiments, the resistance can increase by between approximately 10% and approximately 100,000%, and varies with the area, such as the length and the width, of the PANI/CB sensor. 
         [0022]      FIG. 1  illustrates a graph  100  showing the resistance change of an exemplary PANI/CB sensor to urine vapor where the x-axis indicates time in seconds and the y-axis indicates resistance in kilohms. The initial resistance of the PANI/CB sensor is approximately 500 ohms. Urine vapor exposure is initiated at approximately 40 seconds. At approximately 60 seconds, the resistance of the PANI/CB sensor is approximately 470 kilohms. 
         [0023]    PANI/CB chemiresistors are also highly selective in their response to ammonia and organic amines such as skatole (3-methylindole), which is an aromatic component of feces. Water, alcohols, and other organics only increase the polymer composite&#39;s resistance by a factor of approximately 100. This is three orders of magnitude less than the resistance changed caused by the amines. 
         [0024]      FIG. 1A  is an illustration of a bodily waste sensor, incontinence sensor, or sensor insert  102  and a reader or interrogator  104 . A transponder is a device for receiving and transmitting a signal. In an embodiment, the incontinence sensor  102  comprises a PANI/CB chemiresistor and operates as a transponder. The reader or interrogating device  104  sends an interrogating signal, such as a radio frequency (RF) signal, to the incontinence sensor  102 . In one embodiment, the interrogating signal provides power to the incontinence sensor  102 . The incontinence sensor reflects back to the reader  104  a signal based at least in part on the resistance of the PANI/CB chemiresistor. Based on the signal from the incontinence sensor  102 , it is determined whether an incontinent event has occurred. 
         [0025]    Embodiments of the incontinence sensor  102  reflect a signal that correlates with the impedance of the PANI/CB chemiresistor, operate passively, that is without the need for a battery or supplemental power supply, and keep the overall cost low so that the sensor insert can be treated as disposable. 
         [0026]    For a more detailed understanding of a first embodiment, reference is now made to  FIG. 2 .  FIG. 2  is a schematic diagram of an exemplary resonant or oscillating LC-circuit  200  which transmits the sensor responses when interrogated by a radio frequency (RF) signal. Resonant circuit  200  comprises a PANI/CB chemiresistor R chem , a first resistor R 1 , a second resistor R 2 , a first capacitor C 1 , a second capacitor C 2 , and an inductor L 1 . Resistors R 1  and R chem  electrically couple in series. The series combination of R 1  and R chem  electrically couples in parallel with each of R 2 , C 1 , L 1 , and C 2 . 
         [0027]    In the resonant circuit  200 , changes in the impedance of the PANI/CB chemiresistor R chem  are reflected in the quality (Q) factor of the circuit&#39;s response. The Q-factor, f 0 /Δf, is defined as the ratio of the circuit&#39;s center frequency or resonant frequency, f 0 , to its half-power bandwidth Δf (i.e. the bandwidth over which the power of vibration is greater than half the power at the resonant frequency). An LC-circuit with a high Q-factor has greater amplitude (signal) at the resonant frequency but also a smaller range of frequencies or smaller bandwidth at which the oscillator resonates. 
         [0028]    Initially, with no exposure to urine/feces vapor, the resistance of R chem  is very low, resulting in a low Q-factor. The first resistor R 1  is placed in series with R chem  to ensure that a short circuit does not occur. As the resistance of R chem  increases due to exposure to urine/feces vapor, the oscillation of the circuit  200  is dampened less, which leads to a higher Q-factor. 
         [0029]    The reader  104  interrogates the incontinence sensor  102  comprising the LC-circuit  200  and the sensor  102  reflects back to the reader  104  a signal based at least in part on the resistance value of the chemiresistor Rchem. In other embodiments, the circuit  200  reflects back to the reader  104  a signal when urine and/or feces are present and reflects no signal when urine and/or feces are absent. In other embodiments, the circuit  200  reflects back to the reader  104  a signal when urine and/or feces are absent and reflects no signal when urine and/or feces are present. 
         [0030]    In some embodiments, the reader  104  determines the Q-factor of this reflected signal and determines whether an incontinent event has occurred based on the Q-factor of the signal reflected from the sensor circuit  200 . In another embodiment, the reader  104  transmits the received signal to a determining device. The determining device determines the Q-factor of this reflected signal and determines whether an incontinent event has occurred based on the Q-factor of the signal reflected from the sensor circuit  200 . Thus, by monitoring the Q-value of the LC-circuit  200 , an incontinent event can be detected. 
         [0031]    In some embodiments, the determining device comprises a computer processor and memory including computer-executable instructions. In a further embodiment, the reader comprises the determining device. In some embodiments, the determining device comprises an alerting system including the sensing element. 
         [0032]    For example, in one embodiment, R 1 =15 kn; R 2 =30.616 kn; C 1 =2.8 pF; L 1 =5.343 uH; and C 2 =82 pF, and the LC-circuit  200  has a resonant frequency of approximately 6.6 MHz.  FIG. 3  is a graph  300  illustrating a simulated sensor response before activation  302  and a simulated sensor response upon activation  304  of an exemplary PANI/CB sensor R chem  in the circuit  200 . In the absence of urine and feces, R chem &lt;&lt;R 2  and the Q-factor is approximately 60. When an incontinent event occurs, the resistance of Rchem increases such that R chem , &gt;&gt;R 2 . The Q-factor of the reflected signal from the circuit  200  increases to approximately 120 indicating a positive sensor response. In one embodiment, the Q-value is proportionate to the resistance of R chem , which then yields a precise value or an approximately precise value of the chemiresistor&#39;s impedance rather than just identifying a positive result (incontinent event) or a negative result (absence of incontinent event). Advantageously, the precise or approximately precise value of the chemiresistor&#39;s impedance can be used to determine whether the sensor is exposed to urine or feces. Further, the precise or approximately precise value of the chemiresistor&#39;s value can be used to determine false positive or false negative events. 
         [0033]    In the above example, the Q-factor of the resonant circuit  200  upon the occurrence of an incontinent event is approximately twice the Q-factor of the resonant circuit  200  in the absence of an incontinent event, as illustrated in  FIG. 3 . Other embodiments of the LC-circuit  200  may comprise different values of R 1 , R 2 , C 1 , C 2 , and L 1 , different resonant frequencies, and the change in the Q-factor of the reflected signal before activation of R chem , and upon activation of R chem , may be approximately a factor of 2, may be less than a factor of 2, and may be greater than a factor of 2. However, the Q-factor of the circuit  200  upon activation of the PANI/CB sensor R chem , is greater that the Q-factor of the circuit before the activation of the PANI/CB sensor R chem . 
         [0034]    Advantageously, the low power requirements of the resonant circuit  200  enable the reader  104  to read the sensor insert  102  from a distance. Further, the urine/feces sensor inserts  102  comprising the LC-circuit  200  remains within the electric and magnetic fields of the reader  104  for a prolonged time, which permits the reader  104  to interrogate the sensor insert often. For example, a 6.6 MHz reader  104  can interrogate the resonant circuit  200  thousands of times per second and process the data. Operating as part of an incontinence management system, the reader  104  could make an assessment every few seconds, in one embodiment. In an embodiment, the reader  104  can take multiple readings of the sensor inserts  102  and signal average many thousand responses for an improved signal-to-noise ratio. Further yet, the electrical components of the resonant circuit  200  are low cost devices. For example, the cost of R 1 , R 2 , C 1 , C 2 , and L 1  in the above example are priced at approximately $0.08 per device, making for a very cost efficient system. 
         [0035]    In further embodiments, a bodily waste sensor comprises a resonant LC circuit, such as circuit  200 , for example, and a sensor element having a property that varies or changes in the presence of bodily waste. The resonant LC-circuit is configured such that it comprises a characteristic that is based at least in part on the property of the sensor element that changes in the presence of bodily waste. In response to an interrogating signal from the reader, the circuit provides a signal based at least in part on the property of the sensor element that changes in the presence of bodily waste. Thus, the bodily waste sensor provides a first signal in the absence of bodily waste and a second signal in the presence of bodily waste, where the first and the second signals are different. Examples of the sensor element are moisture sensors, metal oxide moisture sensors, capacitance moisture sensors, electrolyte activation moisture sensors, and the like. 
         [0036]    In another embodiment, the sensor insert  102  comprises one or more digital LC circuits. A specific ID number is assigned to each circuit. Activation of the sensor component and the resulting change in its electronic properties cause a change in the specific ID numbers transmitted by the tags or the number of numbers transmitted. For example, a tag may have two digital circuits which reflect two specific and different ID numbers when interrogated. When the sensor is activated, only one of these numbers is reflected back. In another example, an insert has a single digital LC circuit which transmits a specific ID number to the interrogator. When the sensor&#39;s electronic properties change due to a positive response to urine/feces, the ID number reflected back is different by some amount. This amount can be related to the magnitude of the change in the sensor&#39;s electronic property or not. 
         [0037]    Another embodiment of the incontinence sensor  102  comprises a telemetry circuit which includes the versatility of adding an identification (ID) component. Telemetry circuits modulate the interrogating signal from the reader  104  by a frequency proportional to the impedance of the PANI/CB chemiresistor R chem .  FIG. 4  is a schematic diagram illustrating an exemplary telemetry LC-circuit  400  incorporating the PANI/CB chemiresistor R chem . Telemetry circuit  400  comprises an antenna E 1 , capacitors C 3 -C 6 , C 11 , C 12 , resistor R 1 , diode D 1 , transistor Q 1 , timer integrated circuit (IC) U 1 , and the PANI/CB chemiresistor R chem . 
         [0038]    As illustrated in  FIG. 4 , a first end of antenna E 1  electrically couples to a drain of transistor Q 1  via capacitor C 5 , and electrically couples to an anode of diode D 1 . A source of transistor Q 1  and a second end of antenna E 1  each electrically connect to ground. A cathode of diode D 1  electrically connects to the power supply voltage VCC. LED 1 , C 11  and C 12  each electrically connect between VCC and ground and C 11  and C 12  each electrically couple between the first end of antenna E 1  and ground. 
         [0039]    A gate of transistor Q 1  electrically connects to the output of timer IC U 1 , and the series combination of R 1  and Rchem electrically connects between the output and the threshold and trigger inputs of timer IC U 1 . The threshold and trigger inputs of timer IC U 1  further couple to ground via capacitor C 7 . A reset input of timer IC U 1  is pulled high by VCC and timer IC is powered between VCC and ground. Capacitor C 6  acts as a filter capacitor between VCC and ground for the power input of timer IC U 1 . 
         [0040]    In an embodiment, C 11 =0.1 μF; C 12 =1 μF; C 3 =0.1 μF C 4 =0.1 μF; C 6 =0.1 μF; C 7 =1000 pF; and R 1 =24 kΩ. In some embodiments, D 1  is a Schottky diode, such as, for example, part numbers BAS56, BAS115, or the like. In some embodiments, transistor Q 1  is an N-channel depletion mode MOSFET with a body diode, such as, for example, part number FDV301N from Fairchild Semiconductor, or the like. In some embodiments, timer IC U 1  is a programmable timer and oscillator, such as, for example part number TLC555CDR from Texas Instruments, and the like. 
         [0041]    In some embodiments, LED 1  functions as a shunt voltage regulator for the circuit  400 . When the sensor or sensor insert is too close to the reader antenna, the rectified voltage rises exponentially and may exceed the tolerance of the timers. LED 1  may provide voltage regulation in this situation. For example, LED 1  may comprise a red LED which typically has a 1.8 VDC drop. Excess power is converted into photons, not heat, which reduces the burn risk to the person in close proximity to the sensor or sensor insert. In another embodiment, a zener diode functions as a shunt voltage regulator. Also, LED 1  can function as a visual indicator to indicate that the circuit  400  is receiving a signal of sufficient strength from the interrogator. Examples of LED 1  are part number HSMH-C190 by Avago Technologies and the like. 
         [0042]    Telemetry LC-circuit  400  modulates the effective magnetic field generated when the circuit  400  is interrogated by the reader  104 . The sensor comprising the telemetry LC-circuit  400  reflects sidebands that are shifted from the frequency of the reader&#39;s interrogating signal. The sidebands are generated when a signal with an oscillating frequency from the timer U 1  is applied to the gate of the transistor Q 1 . When the gate voltage reaches approximately 1 V, the impedance across the source-drain drops to approximately 4 ohms, which is significantly less than the antenna impedance. The impedance drop causes a decrease in the magnetic field experienced by the circuit  400 . The oscillating frequency of the timer U 1  is based at least in part on the resistance or impedance of the PANI/CB chemiresistor R chem . 
         [0043]    In the above example, the reader  104  transmits a 13.56 MHz signal. In an embodiment, the reader  104  transmits a precise 13.56 MHz signal. In the absence of urine or feces, R chem ≈30 kΩ, and the oscillating frequency from the timer U 1  is approximately 25 kHz. The shifted frequencies are approximately 5.87 kHz from the interrogator&#39;s 13.56 MHz signal. 
         [0044]    In the presence of urine or feces, R chem ≈1 MΩ and the oscillating frequency from the timer U 1  is approximately 600 Hz. The shifted frequencies are approximately 700 Hz from the interrogator&#39;s 13.56 MHz signal. 
         [0045]    Thus, instead of reflecting the incident RF signal, a new signal which is shifted in frequency based at least in part on the resistance or impedance of R chem , is reflected by the telemetry circuit  400 . In some embodiments, these reflected shifted signals are recorded and digitized using short band radio technology. The reflected signal can then be correlated to the PANI/CB R chem  resistance to determine if an incontinent event occurred. 
         [0046]    In some embodiments, the reader  104  determines based on the received signal whether and incontinent event has occurred. In some embodiments, the reader  104  transmits the received signal to a determining device. The determining device determines whether an incontinent event has occurred based on the signal reflected from the telemetry sensor circuit  400 . In an embodiment, the determining device comprises a computer processor and memory including computer-executable instructions. In further embodiments, the reader comprises the determining device. 
         [0047]    As in the resonant sensor inserts  102  comprising circuit  200 , the telemetry sensor inserts  102  comprising circuit  400  are powered by the interrogating RF field. The components of the telemetry circuit  400  are low cost devices. For example, the costs of C 1 -C 7 , R 1 , D 1 , Q 1 , LED 1 , and U 1  in the above example are priced at approximately $0.47 per device, making for an economical sensor insert. 
         [0048]    Other embodiments of the telemetry circuit  400  may comprise different component values, different components, and different resonant frequencies, which provide different oscillating frequencies from the timer IC and different shifted frequencies without departing from the operation described above. 
         [0049]    Some embodiments of the telemetry sensor circuit  400  comprises a second timing element that can serve as an ID signature. The signature can be specific time delay in the sensor insert&#39;s response. For example, the second timer IC gates the output clock signal from the first timer IC U 1 , which is based on the PANI/CB&#39;s resistance as described above, to a frequency converter, a delay element, or the like. The reflected signal containing the sensor&#39;s data is then delayed by a preset or predetermined time. In some embodiments, the preset time delay can range from milliseconds to seconds. The time delay allows the reader  104  to interrogate multiple sensor inserts simultaneously or approximately simultaneously. Each sensor insert  102  is identified by the time delay of its signal. 
         [0050]    For example, the LC-circuit of a first sensor insert  102  will have a time delay of 100 msec and the LC-circuit of a second sensor insert  102  will have a time delay of 200 msec. Since the two circuits operate asynchronously, there will be periods of time when the signals do not overlap. To further reduce data collisions, a short duty cycle transmission can be employed. Thus, delayed timing sequences can be used as a mechanism for assigning an ID component to an LC-circuit of the incontinence sensor device. 
         [0051]    In some embodiments, the sensor insert  102  comprises a digital LC-circuit. A ten digit identification number, for example, is assigned to the circuit. The digital LC-circuit can comprise an off-the-shelf digital IC configured to transmit the chemiresistor&#39;s impedance and ID number in a digital data stream. Advantages of the digital incontinence sensor are ease of chemiresistor integration, accurate measurement of the PANI/CB chemiresistor impedance, and an ID element. 
         [0052]    According to some embodiments, the digital incontinence sensor comprises digital RFID tag or IC, such as, for example, part number MLX90129 from Melexis, and the like. The digital RFID IC is configured to monitor a resistive sensing element electrically coupled to the IC. The digital RFID IC comprises an A/D converter which is configured to digitize the response of a resistive sensor, such as the PANI/CB chemiresistor R chem . Upon interrogation by the reader, the digital circuit performs a resistive measurement on the sensor and transmits the measurement in a data stream. The digital circuit contains a numerical ID element and in addition to transmitting the measurement, the digital circuit also transmits the ID in the data stream. In an embodiment with the ID element, the reader or interrogator  104  can read multiple digital incontinence sensor inserts simultaneously or approximately simultaneous. 
         [0053]    Advantageously, the Melexis MLX90129 RFID tag employs a cyclic redundancy check to ensure accuracy in the data stream. A disadvantage of the digital RFID ICs is their high power requirements which limit their range and their cost, which is many times that of the resonant LC circuit  200  and the telemetry LC circuit  400 . 
         [0054]    In other embodiments, the sensor element is not limited to the PANI/CB chemiresistor, but can be any sensor or sensor element, such as, for example, a moisture sensor, metal oxide moisture sensors, capacitance moisture sensors, electrolyte activation moisture sensors, and the like. 
         [0055]    In some embodiments, the incontinence sensor insert  102  is placed in the posterior region of the patient&#39;s brief to selectively detect feces as fecal incontinence creates a greater risk for IAD, pressure ulcers, and urinary tract infections. In addition, the magnitude of the impedance change in R chem  can be used to differentiate between urine and feces. Alternatively, the placement of the sensor insert  102  is in the anterior region of the patient&#39;s brief to selectively detect urine. 
         [0056]    In some embodiments, the incontinence sensors  102  comprise a flexible substrate patterned with the passive circuit designs disclosed herein. The PANI/CB chemiresistors can be added to the flexible substrate via ink-jet printing of the polymer composite suspension. 
         [0057]    In some embodiments, the sensors or sensor inserts  102  are approximately the size of a large postage stamp and are battery free. In other embodiments, the sensors or sensor inserts  102  comprises a battery which extends its readable range. Embodiments of the sensor inserts  102  provide a reliable means for detecting an incontinent event, thereby providing caregiver the awareness for preventing IAD. Further, the sensor inserts provide a convenient and low-cost option for managing incontinence. 
         [0058]    Bodily waste sensors may include sensor that are capable of sensing urine, feces, bodily fluid, bodily secretions, signs of infection, such as tissue rot, and yeast, for example, and the like. 
         [0059]    In the specification the terms “comprise, comprises, comprised and comprising” or any variation thereof and the terms “include, includes, included and including” or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa. 
         [0060]    While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions, and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.