Patent Description:
Existing solutions exist for determining a level of bodily exudate or excretion in an absorbent article are inadequate. For example, some existing solutions rely on use temperature or humidity sensors alone, which can lead to inaccurate measurements. For example, a humidity sensor may be located too far away from bodily exudate to detect a sudden increase in humidity. Or a temperature sensor may indicate an elevated temperature, but the location of sensing may not be representative of the temperature of the absorbent article overall.

Finally, other solutions for detecting a level of bodily exudate or excretion present are prone to erroneous measurements due to movement of the wearer. For example, a sensor measurement can include noise or error caused by either motion of the sensor relative to absorbent article or motion of the absorbent article itself (e.g., due to the wearer of the absorbent article moving).

Hence, new solutions are needed for at least the reasons described above.

<CIT> discloses a moisture monitoring system for monitoring wetness in one or more absorbent articles.

Features, embodiments, and advantages of the present disclosure are better understood when the following Detailed Description is read with reference to the accompanying drawings.

Aspects described herein provide solutions for accurately determining a volume of bodily exudate or excretion (e.g., urine or feces) in an absorbent article by using a color detection system in conjunction with an activity classification system. The absorbent article is preferably a wearable structure, e.g. an infant diaper, or the like. More specifically, an example color detection system may use a pulsed light source to accurately detect the color of an object such as a color changing indicator in an absorbent article (e.g., a diaper). The color detection system may compensate for or adapt its operation to minimize the effects of ambient light, so that the system can be used even in the presence of ambient light. An activity classification system can determine an activity state of an infant wearing the absorbent article by analyzing measurements obtained from an inertial sensor attached to the absorbent article.

More specifically, an example color detection system includes one or more light sources such as LEDs, one or more photodetectors configured to detect light, and an electronic circuit or device such as a photometric front end or a general purpose processor configurable to receive information about detected color, filter out a contribution of the ambient light, and output a signal indicative of the detected color, e.g. as diaper condition information, for use in determining or controlling further operations. A color detection system is attached to an infant's diaper and oriented to allow the color detection system to shine light on a portion of the diaper containing a color changing indicator. A color changing indicator can change color, for example, based on the presence or absence of a substance to be detected (e.g. bodily exudate or excretion in examples herein).

An example activity classification system receives measurements from a movement sensor such as an accelerometer or gyroscope. The sensor is placed on the wearer, e.g., secured to the absorbent article, for example by pinning to a diaper. By using a predictive model or state machine, the activity classification system determines whether the wearer is awake or asleep. Whether the wearer is awake or asleep, in conjunction with other data such as the diaper condition information discussed above, improves the accuracy and reliability of detecting a presence or volume of bodily exudate such as urine. As such, the systems disclosed herein provide advantages over systems that rely solely on detection of a color of a color changing indicator in a diaper or another sensor, thereby facilitating correction or avoidance of errors caused by movement of the sensor or the wearer of the sensor.

These illustrative examples are given to introduce the reader to the general subject matter discussed herein and the disclosure is not limited to this example. The following sections describe various additional non-limiting examples and examples of color sensing using pulsed light.

<FIG> depicts a block diagram of an example of an infant sensing system, according to certain aspects of the present disclosure. <FIG> depicts infant sensing system <NUM>, which includes color sensor <NUM>, movement sensor <NUM>, and microcontroller <NUM>. Microcontroller <NUM> includes diaper loading application <NUM>, color sensing application <NUM>, activity classification application <NUM>, and data <NUM>. Data <NUM> can include demographic data (sex, age, weight, etc.), data about the material qualities of an absorbent article, an activity state of an infant, and so on. Data <NUM> can be input via a user interface, e.g., from a caregiver, or downloaded from an external device.

In an example, diaper loading application <NUM> operates in conjunction with color sensing application <NUM> and activity classification application <NUM> to determine a volume of bodily exudate such as urine in absorbent article <NUM>. As explained further herein, absorbent article <NUM> can include a color strip <NUM> that responds to a presence or amount of urine. In one example, color sensing application <NUM> operates to determine a change in color in color strip <NUM>. In another example, color sensing application <NUM> can also be used to detect the color (e.g. output a signal indicative of detected color as opposed to a detected change in color) of any other object such as a color changing indicator that changes color based on the presence of another chemical. The color sensing application may be further configured to determine a presence of urine (or other chemical) in absorbent article <NUM> using the detected color or detected change in color. The color sensing application may output a signal indicative of the presence of urine. The signal may be binary, or may be a graded score based on the detected color of magnitude of color change.

Activity classification application <NUM> can determine a state of an infant wearing absorbent article <NUM>. Movement sensor <NUM>, which can be an accelerometer, gyroscope, or other sensor type, can be placed or adhered to absorbent article <NUM>. Activity classification application <NUM> can determine a state of an infant such as whether the infant is asleep, awake, resting, and so on.

In an example, the movement sensor <NUM> is attached to an infant's clothing or absorbent article <NUM>. The movement sensor <NUM>, which can include an accelerometer or a gyroscope, provides measurements. Activity classification application <NUM> receives the measurements from the movement sensor <NUM> and uses a predictive model such as a machine learning model, state-flow-model, or algorithm to determine activities performed by the infant wearing the movement sensor. The predictive model is trained to determine, based on the infant's movement, an activity that the infant is performing such as sleep or sitting up. The predictive model can be trained by data gathered for an individual or group of individuals.

For example, the predictive model can receive training data that represents a particular individual. The training data can include the individual's movements as determined by movement sensor <NUM> and an associated ground truth (correct activity, as designated by a training label). Thus, upon receiving new data from movement sensor <NUM>, the trained predictive model predicts an activity. In another example, the predictive model can be trained based on training data gathered from a group of individuals, which need not include the individual whose activity is later predicted. Therefore, the predictive model can learn from the recorded behavior of a particular individual or a group of individuals and use the learned behavior to predict an activity of the individual or another individual.

The activity classification system can then output a signal indicative of predicted activity information of the infant, for example that the baby is in a deep sleep, for use in determining or controlling further operations. Examples of suitable processes for activity classification are described with respect to <FIG> and <FIG>.

Using the diaper condition information, which may include an indication of a presence of urine from color sensing application <NUM>, and the predicted activity information, which may include a predicted activity state from the activity classification application <NUM>, the diaper loading application <NUM> can determine a volume of urine present in absorbent article <NUM>. A volume of urine can be referred to as a diaper load. In the invention, statistical approaches are used. Different factors can be used such as an elapsed time since a first urination event, a diaper size, or the state of an infant. An example of a process used to determine a volume of urine in an absorbent article is described with respect to <FIG>.

Infant sensing system <NUM> can be implemented as an accessory for attachment to a wearable article, e.g. on a slim material such as plastic or flexible substrate. For example, infant sensing system <NUM> can be <NUM>-<NUM> centimeters wide and <NUM>-<NUM> millimeters thick. Infant sensing system <NUM> can be made sufficiently small and thin to be placed in an absorbent article such as a diaper, as discussed with respect to <FIG>. In an example, infant sensing system <NUM> can be placed in a diaper that includes a color changing indicator such that a light source and a photodetector are aligned with the color changing indicator.

In an example, the infant sensing system <NUM> may be distributed between an accessory that is secured to the absorbent article, and an external device. For example, operations performed by microcontroller <NUM> can be performed by the external device. The accessory may thus include a communication module, e.g. transceiver or the like, for communication with the external device. Examples include a monitor connected by a local radio connection (e.g., WiFi or Bluetooth) and a remote server that connected to microcontroller <NUM> via the internet. For example, diaper loading application <NUM>, color sensing application <NUM>, and/or activity classification application <NUM> can delegate some or all of the operations described herein to an external device. Advantages include, but are not limited to, reducing battery life of infant sensing system <NUM>, or improved performance due to availability of additional data sets, e.g., training data, or processing power on the external device.

Any or all of the processes described herein, for example those discussed with respect to <FIG> can be performed by the external device. For example, microcontroller <NUM> transmits data such as measured color from color sensor <NUM> or movement data from movement sensor <NUM> to the external device. In turn, the external device processes the operations to determine a significance of the detected color or movements.

<FIG> depicts a block diagram of an example of a color sensing system, according to certain aspects of the present disclosure. <FIG> includes color sensing system <NUM>, which includes light source <NUM>, photodetector <NUM>, processor <NUM>, and microcontroller <NUM>. Microcontroller <NUM> can implement the functionality of color sensing system <NUM>, infant sensing system <NUM>, or both. Further, for example purposes, microcontroller <NUM> is depicted in color sensing system <NUM>, but a different microcontroller, microprocessor, or other processor can be used. In an aspect, only one of the processor <NUM> and the microcontroller <NUM> is present.

Color sensing system <NUM> can be configured to measure a color of an object <NUM> (e.g., an absorbent article or a color strip in an absorbent article) to determine a loading of an absorbent article. The system may obtain a measurement of color that is independent of the presence of ambient light, e.g. by measuring the ambient and compensating for it, or by adapting (e.g. tuning) the light source to reduce or minimize the effect of the ambient light on the detected signal.

Color sensing system <NUM> also includes a microcontroller <NUM>. Microcontroller <NUM> can be any controller, processor, application specific integrated circuit or other processing device. An example of a computing device is shown in <FIG>. Microcontroller <NUM> can execute color sensing application <NUM> as well as other processor-executable instructions to perform aspects of the present disclosure.

The functions of microcontroller <NUM> can be implemented by processor <NUM> or vice versa. Microcontroller <NUM> can store data <NUM>, which can include a state of an infant, demographic information about an infant, information about a particular absorbent article worn by an infant, and so forth.

Ambient light <NUM> can be any kind of light present in an environment that is not generated by light source <NUM>, which can include light from natural sources, e.g., sunlight, or artificial light such as light created via incandescent light sources, halogen light sources, light emitting diode ("LED") light sources, fluorescent light sources, laser sources, etc. Even though ambient light can have different color spectra depending on the ambient light source(s) present, infant sensing system <NUM> can electronically remove the contribution of such ambient light to light detected by the photodetector and accurately detect the color of object <NUM> based on reflected light from the light source <NUM>.

Light source <NUM> includes one or more light sources operable to shine light on object <NUM>. The light sources can be any suitable artificial light source according to this disclosure, including LEDs, incandescent light sources, or other light sources. Multiple discrete light sources can be implemented individually or via an integrated package that combines multiple individual light sources into a single light source.

Light from light source <NUM> can be generated at one or more specific wavelengths, or can encompass multiple wavelengths. In an example, light source <NUM> has three sources of light: red light at wavelength <NUM> nanometers ("nm"), green light at wavelength <NUM>, and blue light at <NUM> wavelength. Other wavelengths of light may be employed according to different examples, depending on the application, the expected color range of a target object or color changing indicator such as a strip of litmus paper, expected ambient light spectra, or any other suitable factor. In some examples, the light source may be tunable to allow selection of a wavelength or wavelengths of light having a small contribution to the ambient light. For example, if ambient light detected by the photodetector indicates a local or global minimum magnitude at a first wavelength, the infant sensing system <NUM> can tune the light source <NUM> to emit light substantially at the first wavelength.

In this example, the color detection system pulses the light emitted by light source <NUM> by activating for a short duration, e.g., <NUM>-<NUM> microseconds to <NUM> milliseconds, called a "pulse width," and then deactivating the light source. Any suitable pulse width may be employed for a particular application. Light source <NUM> can create a separate pulse for red, blue, and green, and output the corresponding values. For example, a pulse width of <NUM> microseconds may be advantageous to detect a color of a color changing indicator. Short pulse widths enable the infant sensing system <NUM> to pulse and detect different colors of light, e.g., red, green, and blue, in quick succession of each other.

The use of pulsed light enables color sensing system <NUM> to disambiguate the type of light reflected by the object. Specifically, color sensing system <NUM> can detect and filter the ambient light from detected light that includes light pulsed from the light source <NUM>. In some examples, the color sensing system <NUM> can pulse the light source <NUM> at regular intervals, e.g., every ten minutes, or in response to an event, such as a user pressing a button on the color detection system or a humidity sensor detecting a humidity level exceeding a threshold. Additionally, the use of pulsed light as compared to constant light can lower the power consumption of color sensing system <NUM>, thereby increasing the amount of time that the color sensing system <NUM> can operate from a battery.

When the light source <NUM> is pulsed, the detected light at photodetector <NUM> may be a combination of ambient light <NUM> and light from the pulsed light source <NUM> reflected from the object <NUM>. When the light source <NUM> is inactive, the light detected by the photodetector <NUM> is ambient light. By pulsing the light source <NUM>, color sensing system <NUM> is able to first obtain baseline information about the ambient light spectrum to enable the color detection system to filter light received when the light source <NUM> is active. Pulsing also allows the infant sensing system <NUM> to save power by deactivating the light source <NUM> when a color measurement is not being taken.

Photodetector <NUM> receives a light, including light reflected from the object <NUM>, whether ambient light or light emitted by the light source <NUM>, and generates sensor signals based on that received light. Photodetector <NUM> can be any device that can detect and measure light such as a photodiode, phototransistor, complementary metal-oxide-semiconductor (CMOS) image sensor, charge-coupled device (CCD) sensor, or a photo-resistor.

Photodetector <NUM> can detect a wide spectrum of light and output information that indicates the detected light. For example, photodetector <NUM> can create an electrical output that is proportional to the wavelength of the received light. Photodetector <NUM> can provide three outputs of an RGB triplet, e.g., a value that corresponds to red, another value for green, and another value for blue.

More specifically, the values of the triplet correspond to the amplitude of light at a range of wavelengths corresponding to a particular color. Therefore, a first value is proportional to an amplitude of red in the received light, a second value is proportional to an amplitude of green in the received light, and a third value is proportional to an amplitude of blue in the received light.

In an aspect, a photodetector <NUM> can be an array of individual photodetectors. Each photodetector can be configured to measure a color of light. For example, one photodetector measures red, a second photodetector measures blue, and a third photodetector measures green.

Processor <NUM> is an electronic circuit or device such as a general-purpose processor. Processor <NUM> can operate in the analog domain, digital domain, or both. Processor <NUM> can discern the true color of the object <NUM> independent of any ambient light. Processor <NUM> receives a first output from photodetector <NUM> that represents the ambient light, for example, an output gathered when the light source <NUM> is off. Processor <NUM> receives a second output from photodetector <NUM> when the light source <NUM> is pulsed. Processor <NUM> discerns a difference between the first output and the second output and thereby isolates the color of the object, specifically the color of the reflected light on the object from the pulsed light.

In an aspect, processor <NUM> receives a level indicating an intensity of broad spectrum light that represents the ambient light, i.e., the point in time that the light source <NUM> is off, and a level indicating the intensity of for a second point in time at which one of the three colors red, blue, and green, is pulsed. Processor <NUM> can then disambiguate the contribution of the single pulsed color from the ambient light by comparing the intensity of the ambient light and the intensity with the single pulsed color.

Processor <NUM> receives a first set red, green, and blue levels from photodetector <NUM> for a point in time that the light source <NUM> is off and a second set of red, green, and blue levels from a second point in time that the light source <NUM> is pulsed. Processor <NUM> calculates a difference between the level of red between the first and second points in time, thereby calculating a contribution of red, green, and blue levels from the pulsed light.

Processor <NUM> may be a specialized photometric front end such as Analog Devices® ADPD105, ADPD106, or ADPD107. Processor <NUM> may be configured to activate light source <NUM> and measure a signal received by photodetector <NUM>. For example, processor <NUM> can receive an analog input from photodetector <NUM>, convert the analog input to a digital output by using a analog-to-digital converter (ADC), then store a numerical value indicating the detected color in an internal memory for later comparison with another value.

In this manner, processor <NUM> may be configured to disambiguate the contribution of the ambient light <NUM> in the analog domain and output an analog signal or digital value indicative of the color of object <NUM>. For example, the processor <NUM> can provide an output, such as an RGB triplet value representing the color of object <NUM>.

In an aspect, processor <NUM> can have multiple detection channels, each corresponding to a pair that of a light source <NUM> and a photodetector <NUM>. As described further with respect to <FIG>, each channel can be dedicated to a specific light source-photodetector pair, or a "cell. " Each cell can be physically separated so that the processor <NUM> may measure color in multiple places. Processor <NUM> can also pulse the light from a particular cell differently from a light from another cell.

Color sensing application <NUM> can provide additional functionality such as calibration or white balancing for the signal received from light source <NUM>. For example, microcontroller <NUM> receives a digital input indicating the color of the received light from processor <NUM>. The digital input can include red, green, and blue levels. Color sensing application <NUM> can convert the red, green, and blue levels to hue, saturation, and lightness/value and perform calculations on the hue, saturation, and lightness/value.

Color sensing application <NUM> may also calibrate the received color value. For example, color sensing application <NUM> can retrieve known values such as the detected values when a known color, e.g. represented by a white or gray card or object that is presented to photodetector <NUM>. Color sensing application <NUM> can adjust the received red, blue, and green levels according to the known calibration values.

In an aspect, microcontroller <NUM> may be connected to a transceiver <NUM>. Transceiver <NUM> may communicate according to any suitable wireless protocol, such as Bluetooth, WiFi, near-field communication, etc. Using transceiver <NUM>, microcontroller <NUM> may transmit the color of the object <NUM> or, if detecting bodily exudate in an absorbent article, notify an external device that an absorbent article has been soiled. Microcontroller <NUM> may transmit information to a remote device, such as a smartphone, smartwatch, or other wearable device, or a remote computer, such as a server, e.g., a cloud-based server, for further processing and analysis.

Microcontroller <NUM> can, via the transceiver <NUM>, transmit the detected color from processor <NUM> to a remote server, which can map values that represent an expected reflected color from an object to a predicted volume of bodily exudate present in an absorbent article. Such a mapping can be accomplished via a table. For example, a table can contain a mapping between a Red-Blue-Green (RGB) triplet or range of triplets to a predicted volume of bodily exudate.

Object <NUM> can be a color changing indicator or other material that changes color based on the presence of a chemical. In an aspect, a color changing indicator can dissolve in the presence of a liquid such as urine. Accordingly, infant sensing system <NUM> can detect a change in color, an appearance of color, or a disappearance of color.

For example and as discussed further with respect to <FIG>, in one application, infant sensing system <NUM> is used to measure the presence of bodily exudate by reading a color changing indicator that changes color based on a presence or volume of a liquid. Exemplary color changing indicators include a pH strip or litmus paper strip that changes color based on detected pH level. Color sensing system <NUM> pulses light onto the color changing indicator and determines the amount of the pulsed light that is reflected.

More specifically, microcontroller <NUM> is programmed with data points from one or more wavelength-absorbance curves that correspond to different levels of acidity or pH level. By matching an absorbance level of a particular wavelength of light to a particular level of acidity, microcontroller <NUM> can determine a volume of a particular liquid, e.g., bodily exudate, or a specific pH level. For example, for a wavelength of light of <NUM>, if the measured absorbance is <NUM>, then microcontroller <NUM> determines that a liquid present is basic, and is present in a low volume. In another example, if a measured absorbance of the <NUM> light is <NUM>, then microcontroller determines that the liquid is present in high volume due to a high level of acidity. In this manner, microcontroller <NUM> need not calculate an intermediate pH level, but rather, can map absorbance or reflectance directly to volume of bodily exudate. Microcontroller <NUM> can determine expected reflectance, i.e., the amount of light at a particular frequency that is expected to be measured by the photodetector <NUM>, based on an absorbance for that frequency.

The microcontroller <NUM> can retrieve stored calibration values from memory and determine, from the color and the calibration values, the amount of bodily exudate present in the absorbent article. For example, microcontroller <NUM> can store a table which maps a given value or range of color to a corresponding amount, or volume of bodily exudate present. Microcontroller <NUM> can have multiple tables, for example, one for each of a set of different color changing indicators. Additionally, the table can be updated, for example, in the event that a different color changing indicator is to be used.

The wavelength of light source <NUM> may be altered based on a particular application or color changing indicator. For example, a pH color changing indicator may have a greater response at specific wavelengths, and so the light source <NUM> may be selected or tuned to emit light at such wavelengths. In this manner, by using light sources with particular wavelengths that are better reflected by the color changing indicator, the system can receive stronger reflected pulsed light signals from the object. This can allow the system to more accurately determine the color of the object and therefore more accurately determine a pH value or a corresponding volume based on the determined color. Such accuracy can be particularly valuable when the color values of the color changing indicator do not change linearly with changes in pH.

<FIG> depicts an absorbent article with a pH-sensitive color changing indicator and a sensing device, according to certain aspects of the present disclosure. <FIG> depicts absorbent article system <NUM>, which includes an absorbent article <NUM>, sensor package <NUM>, and color strip <NUM>. In this example, the infant sensing system <NUM> of <FIG> is implemented on sensor package <NUM>. Further, in some examples, multiple color detection systems, or multiple light sources and photodetectors for a single multiple color detection system, may be employed at different locations within the absorbent article to better detect the presence of bodily exudate at multiple different locations within the absorbent article.

Color strip <NUM> is shown as extending down the middle of the absorbent article from one end, shown with straps, to the other. Because bodily exudate can be non-uniformly distributed within an absorbent article, placing the color strip <NUM> down the middle of the absorbent article increases the chance that the color strip <NUM> will detect bodily exudate in the absorbent article <NUM>. But color strip <NUM> can be located in different areas of the absorbent article <NUM>. For example, color strip <NUM> could be located at the front of the absorbent article, or at an edge of absorbent article <NUM>, or any combination of these or other locations.

As can be seen, sensor package <NUM> is aligned with color strip <NUM> such that the light source and photodetector elements are positioned over the color strip <NUM>. In some examples, sensor package <NUM> can be removable from the absorbent article <NUM>. For example, the sensor package <NUM> can be adhered to the absorbent article <NUM> to prevent the sensor package <NUM> slipping, while allowing its removal.

Absorbent article <NUM> can be any suitable absorbent article such as a common disposable diaper, a reusable cloth diaper, pantiliner, adult diaper, etc. Color strip <NUM> is a color changing indicator that is designed to change color in response to contact with a substance having a particular property, such as a pH level. For example, color strip <NUM> can be Bromocresol green, which changes color based on the pH of a liquid to which the color changing indicator has been exposed. The color of the Bromocresol green strip changes with the pH of bodily exudate detected. Other color changing indicators can be used. The detected pH level can be correlated with a volume of bodily exudate, because the pH level changes as the volume of bodily exudate in the absorbent article changes. Accordingly, a lookup table or function may be used to determine a volume for a given pH level, or color of the color changing indicator.

Sensor package <NUM> can include the infant sensing system <NUM> and/or the color sensing system <NUM>, can be included within a flexible, impermeable package. For example, sensor package <NUM> has a housing that can withstand bodily exudate and feces, and is sufficiently thin as to not cause discomfort to a wearer of the absorbent article. Sensor package <NUM> may be fabricated with flexible substrate such as a thin plastic, fluoroelastomer, or tpsiv.

Sensor package <NUM> can be placed in the absorbent article in various different ways. In an aspect, sensor package <NUM> may be removed and inserted in a new absorbent article. Sensor package <NUM> can be covered with a material or pouch that is washable or can be wiped. For example, sensor package <NUM> can be inserted into an absorbent article or adhered to the inside of the absorbent article. Sensor package <NUM> can also be inserted into a pocket or pouch inside the absorbent article. Such a pocket or pouch can be hermetically sealed, for example, in transparent plastic that allows light to pass through. Sensor package <NUM> can also be permanently attached into an absorbent article and discarded after a one-time use. Sensor package <NUM> can also be adhered to the outside of the absorbent article via velcro or similar material.

<FIG> depict an example layout of a sensor system that can be placed in or on the outer surface of an absorbent article, according to certain aspects of the present disclosure. <FIG> represents a top-down view of an example of a sensor layout for sensor package <NUM>. <FIG> represents a bottom-up view of an example of a sensor layout for sensor package <NUM>. Sensor package <NUM> can be used in conjunction with the absorbent article <NUM> depicted in <FIG>, e.g. to perform the functions associated with the color sensing application discussed above. A movement sensor (not shown) may be included in the sensor package <NUM> or provided separately to provide the functions associated with the activity classification application discussed above.

As depicted, the bottom is the side that is positioned to face and align with the color strip <NUM>. The sensor system shown in <FIG>, when placed in an absorbent article, by detecting a color of a color changing indicator in the absorbent article, can determine a presence and volume of bodily exudate present in the absorbent article in conjunction with an internal system such as microcontroller <NUM> that can map color to bodily exudate volume.

Sensor package <NUM> includes a battery <NUM> and one or more color detector cells 420a-n. Sensor package <NUM> may also include a switch <NUM>, two electrical connectors <NUM>-<NUM>, a volatile organic compound ("VOC") sensor <NUM>, a temperature sensor <NUM>, a humidity sensor <NUM>, an additional ambient light sensor <NUM>, processor <NUM>, microcontroller <NUM>, or transceiver <NUM>. Additional ambient light sensor <NUM> can be used in conjunction with the photodetectors to improve or augment the light detecting capability of sensor package <NUM>. Some aspects may not include all of the components described above, or include variants thereof.

In addition, the sensor package <NUM> can cause an alarm, such as an audible beep, based on a threshold level of bodily exudate being detected. Accordingly, sensor package <NUM> can include a speaker or other audio output device. Sensor package <NUM> can also cause a transmission of an alert to another device, for example, operated by a caretaker. In another aspect, sensor package <NUM> can transmit an alert to another device. Sensor package <NUM> can include a transmitter or transceiver capable of transmitting a radio signal to an external device. Color sensing application <NUM> operating on microcontroller <NUM> can also log events, such as when bodily exudate is detected, to memory for later transmission to a caregiver.

Sensor package <NUM> can include one or more color detector cells 420an. For example, multiple color detector cells 420a-n can increase the ability of the sensor package <NUM> to detect changes in bodily exudate across the absorbent article. Because bodily exudate may not be distributed uniformly in an absorbent article, the color of color strip <NUM> may not change uniformly along the length of the color changing indicator. Additionally, the presence of multiple color detector cells 420a-n enables a calculation of multiple data points to more accurately estimate the total load.

Each color detector cell 420a-n includes a light source such as an LED and a photodetector such as a photodiode. In some aspects, as discussed further with respect to <FIG>, a color detector cell may include multiple light sources or multiple photodetectors. Each color detector cell 420a-n detects light reflected by object <NUM> such as a color strip <NUM>, such as ambient light or pulsed light from the light source(s). The output of each color detector cell 420a-n is provided to a processor <NUM>. The output of processor <NUM> can be provided to microcontroller <NUM>. In some examples, each color detector cell 420a-n may have a dedicated processor <NUM>, while in some examples, multiple color detector cells 420a-n may be connected to a common processor.

Sensor package <NUM> can include a switch <NUM> to activate or deactivate the sensor package <NUM>. The switch <NUM> can be any suitable switch, such as a rocker-style on/off switch that connects the battery <NUM> to the electronics in sensor package <NUM> such as the color detector cells 420a-n and sensors <NUM>-<NUM>. Switch <NUM> can also be a pushbutton switch that activates power from battery <NUM> to sensor package <NUM> for a period of time. Sensor package <NUM> can be configured to automatically turn off to save battery power. In an aspect, in conjunction with microcontroller <NUM>, sensor package can be activated remotely. For example, a user can prompt an external device with a voice command, which causes the external device to transmit a request for a status of the absorbent article to the microcontroller <NUM> via a wireless connection, or a request to turn on or turn off the sensor package <NUM>.

Sensor package <NUM> can include one or more electrical connectors such as electrical connectors <NUM>-<NUM>. Electrical connectors <NUM> and <NUM> can be used to debug the sensor package <NUM>, calibrate the sensor package <NUM>, reset the sensor package <NUM> to factory settings, upgrade software on the sensor package <NUM>, etc..

As discussed with respect to <FIG>, processor <NUM> can discern a color of an object such as a color changing indicator. Microcontroller <NUM> can execute an application such as color sensing application <NUM> that can perform calibration of the detected color value. Transceiver <NUM> can notify an external device if the sensor package <NUM> detects the presence of bodily exudate in an absorbent article.

In an aspect, sensor package <NUM> can also include a VOC sensor <NUM>. VOC sensor <NUM> can detect the presence of volatile organic compounds such as feces from a bowl movement or VOCs present in blood. In conjunction with data obtained from color detector cells 420a-n, the VOC sensor <NUM> can provide additional information to microcontroller <NUM> based on one or more detected volatile organic compounds.

In an aspect, sensor package <NUM> can also include a temperature sensor <NUM>. Temperature sensor <NUM> can detect heat from substances such as bodily exudate. In conjunction with data obtained from color detector cells 420a-n, the temperature sensor <NUM> can provide additional information such as a temporary increase in temperature to microcontroller <NUM>. Because a notification of a temporary increase in temperature can indicate a presence of bodily exudate, such information can improve the accuracy and reliability of the detection.

In another aspect, sensor package <NUM> can also include a humidity sensor <NUM>. Humidity sensor <NUM> can detect the presence of humidity, e.g., from bodily exudate. In conjunction with data obtained from color detector cells 420a-n, humidity sensor <NUM> can provide additional information such as a notification of a temporary increase in humidity to microcontroller <NUM>. Because a temporary increase in temperature can indicate a presence of bodily exudate, such information can improve the accuracy and reliability of the detection.

In a further aspect, sensor package <NUM> can also include additional ambient light sensor <NUM>. Additional ambient light sensor <NUM> can be placed, as shown, oriented away from the color detector cells 420a-n to more accurately detect the ambient light. In conjunction with data obtained from color detector cells 420a-n, additional ambient light sensor <NUM> can provide additional information to microcontroller <NUM> that allows microcontroller <NUM> to better disambiguate the contribution of ambient light to the color of the color changing indicator. Additional ambient light sensor <NUM> can also provide the microcontroller <NUM> with information as to whether an infant who is wearing an absorbent article in which the sensor package <NUM> is placed is in a dark room. For example, sensor package <NUM> can provide an indication or a notification to a caregiver that the light in a baby's room is either on or off.

As discussed, sensor package <NUM> can include multiple color detector cells 420a-n. The presence of more than one color detector cell 420a-n allows for increased accuracy and reliability. For example, one color detector cell 420a-n could become obstructed by an object, rendering detected values from that cell unusable, or because bodily exudate may not be evenly distributed in an absorbent article, and therefore not evenly distributed on a color changing indicator, the use of more than one of color detector cell 420a-n increases the probability that one of the color detector cells 420a-n detects bodily exudate. In this manner, additional color detector cells 420a-n help add robustness in the case that any one of color detector cell 420a-n fails or is misaligned. Further, the additional of more sells 420a-n can provide additional local information that may help estimate total load. In contrast, fewer color detector cells 420a-n can simplify the overall system architecture and may also lower power consumption.

In another example, in a system with three detector cells 420a-c, if one detector cell 420a returns a color measurement that is inconsistent with detector cells 420b and 420c, then microcontroller <NUM> can ignore the measurements from detector cell 420a.

<FIG> depicts an example color detector cell configuration, according to certain aspects of the current disclosure. As discussed, a sensor system such as sensor package <NUM> includes one or more color detection cells 420a-n. <FIG> shows an color detector cell <NUM> in more detail.

Color detector cell <NUM> includes two photodetectors, photodetector <NUM> and photodetector <NUM>, light source <NUM>, opaque barrier <NUM>, and opaque barrier <NUM>. Light source <NUM> can be any suitable light source according to this disclosure. As shown, light source <NUM> includes a red, a blue, and a green light source, though different numbers and types of light sources <NUM> may be used according to different examples, which can allow the light sources can be turned on and off, i.e., pulsed, separately. Pulsing the light sources <NUM> that emit different colors separately allows color detector cell <NUM> to tailor the light output to a specific wavelength of light. For example, a particular color changing indicator may be more responsive to a specific wavelength of light at a specific pH level.

Photodetectors <NUM> and <NUM> can be any suitable photodetector according to this disclosure. Photodetectors <NUM> and <NUM> are connected to the processor <NUM>. A separation distance <NUM> between the light source <NUM> and the photodetector <NUM> and separation distance <NUM> between light source <NUM> and photodetector <NUM> can be adjusted based on the application. In particular, the closer the light source <NUM> and a photodetector <NUM> or <NUM> are together, the greater the portion of light received at the photodetectors from the light source <NUM> (and less from ambient light <NUM>). As an example only, separation distance <NUM> and separation distance <NUM> can be adjusted from <NUM> to <NUM> in separation. Other distances and configurations are possible. As a distance increases, all else being equal, the intensity of the light from the light source received at the photodetector decreases. Additionally, as the distance increases, the focal area being measured increases. As the distance decreases, the sensor is more focused on a smaller area directly under the sensor.

As shown, two photodetectors <NUM> and <NUM> are used. Photodetectors <NUM> and <NUM> can be positioned to be parallel to each other. In this configuration, the combination of photodetectors <NUM> and <NUM> provides a stronger output signal to the processor <NUM> than otherwise. Using more than one photodetector also provides an advantage in that error can be reduced if the sensor system is misaligned with respect to the object, e.g., color strip <NUM>.

Color detector cell <NUM> can include one or more opaque barriers <NUM>-<NUM> positioned between the light source <NUM> and the photodetectors <NUM>, <NUM>. The opaque barriers <NUM>-<NUM> reduce the amount of light from light source <NUM> that travels directly to the photodetector <NUM> without reflecting off of the object. Opaque barriers <NUM>-<NUM> can be poron or similar material. In an aspect, the photodetectors <NUM> or <NUM> can include such an opaque barrier, or an opaque housing of the photodetector <NUM> or <NUM> can be extruded in such a manner that the opaque housing is located between the LED and photodiodes. In an aspect, the opaque barriers <NUM>-<NUM> are omitted to simplify the design.

<FIG> is a flowchart that describes a method of detecting color, according to certain aspects of the present disclosure. The example method of <FIG> will be described with respect to the color sensing application <NUM> of <FIG> or <FIG>; however, any suitable color detection system according to this disclosure may be employed according to different examples. Further, the operations described with respect to <FIG> can be performed by an external device such as a monitor device connected to infant sensing system <NUM> via a wireless or an external server.

At block <NUM> of method <NUM>, color sensing application <NUM> obtains a first measurement of ambient light received from the photodetector. Photodetector <NUM> detects the ambient light present and outputs a representation of the color of the light or a representation of an intensity of broad-spectrum light that is present. For example, photodetector <NUM> can create an electrical output that is proportional to the wavelength or the intensity of the received light. In an aspect, the photodetector <NUM> can provide three outputs that each correspond to red, green, or blue: a first that is proportional to an amplitude of red in the received light, a second that is proportional to an amplitude of green in the received light, a third that is proportional to an amplitude of blue in the received light.

Photodetector <NUM> provides the first measurement of light to the processor <NUM>. In this example, the first light measurement is taken while a light source <NUM> is off and represents ambient light reflected from the object <NUM>. The first light measurement can represent an intensity of broad-spectrum light.

The steps of method <NUM> can be performed by sensor package <NUM> of <FIG> placed in an absorbent article as described with respect to <FIG>. Because sensor package <NUM> can include one or more color detector cells 420a-n, in an aspect in which more than one color detector cell 420a-n are present, sensor package <NUM> can measure a level of ambient light at multiple photodetectors. The photodetector in each color detector cell 420a-n can independently perform the steps <NUM>-<NUM>.

At block <NUM> of method <NUM>, the color sensing application <NUM> causes the light source to transmit of light on an object. More specifically, processor <NUM> activates light source <NUM> for a predetermined pulse time interval. In this example, the infant sensing system <NUM> only includes one light source <NUM>. But in some examples, multiple light sources may be pulsed simultaneously or individually. For example, aspects using sensor package <NUM> may include more than one color detector cell 420an. The light source in each color detector cell 420a-n may be pulsed separately or together with the other light sources.

At block <NUM> of method <NUM>, the color sensing application <NUM> obtains a second measurement from the photodetector during the transmission, the second measurement including the ambient light and the transmitted light reflected from the object. Processor <NUM> obtains a second measurement of light during the time interval that the pulse from light source <NUM> is on. The second measurement includes the ambient light and the light from the pulsed light source <NUM>. In an aspect such as sensor package <NUM>, the photodetector in each color detector cell 420a-n each obtains a second measurement of light. Color sensing application <NUM> uses the first and second measurements to determine the color of an object.

In an aspect, color sensing application <NUM> can obtain more than one measurement with the ambient light and the pulsed light present. Processor <NUM> can average the multiple measurements together to form one single measurement that can be used as a second measurement.

At block <NUM> of method <NUM>, color sensing application <NUM> determines a normalized measurement of the reflected light by removing an ambient light signal from the second measurement based on the first measurement. Removal can be performed in the analog domain or the digital domain.

For example, processor <NUM> can remove the first measurement of light from the second measurement of light by filtering in the analog domain. For example, the processor <NUM> subtracts the first measurement, representing the ambient light, from the second measurement, representing the ambient light combined with the reflected light from light source <NUM>. The result of the subtraction is the light reflected from the object <NUM>, such as a color changing indicator.

Processor <NUM> can operate in the digital domain. For example, processor <NUM> converts the first measurement into a digital or numeric representation of the red, green, and blue levels. Processor <NUM> converts the second measurement into a digital or numeric representation of the red, green, and blue levels. Processor <NUM> computes a new red level by subtracting the first measurement from the red level of the second measurement, a new green level by subtracting the first measurement from the green level of the second measurement, and a new blue level by subtracting the first measurement from the blue level of the second measurement. The new red, green, and blue levels represent the color of the light reflected from the object.

At block <NUM> of method <NUM>, the color sensing application <NUM> determines, based on the normalized measurement, one of (i) a presence of bodily exudate or (ii) a volume of bodily exudate present. Processor <NUM> outputs the color of the object and provides the color to microcontroller <NUM>. The color sensing application <NUM>, executing on microcontroller <NUM>, receives the color value from processor <NUM> and uses a data structure such as a table to determine a presence of bodily or a value representing a volume of bodily exudate. Microcontroller <NUM> may store several tables, for example, one table which facilitates the mapping of a color on a color changing indicator such as Bromocresol green, to a pH level, and another table that facilitates the mapping of a color changing indicator to a measure or presence of a volume of bodily exudate.

Additionally, as discussed, color sensing application <NUM> can perform color calibration. Color sensing application <NUM> can convert the red, green, and blue levels to hue, saturation, and lightness/value and perform calculations on the hue, saturation, and lightness/value. Color calibration can be implemented via a table. For example, for a given triple of red, green, and blue, adjust the values by certain amount. Color calibration can also be performed in a different domain such as hue, saturation, and lightness, or hue, saturation, and value.

In an aspect, color sensing application <NUM> can determine the presence of bodily exudate in the presence of movement. For example, sensor package <NUM> caused to be moved by an infant at the same time as color sensing application <NUM> is performing measurements. In this case, color sensing application can use a known responsiveness of the absorbent article or color strip at two or more different wavelengths of light to determine a presence of exudate. In an example color sensing application <NUM> can detect that a response to red light is greater than a response to blue light even in the presence of motion.

In a further aspect, color sensing application <NUM> can detect when an absorbent article is not attached to an infant. In this case, the sensor responsiveness changes below a threshold, which is detected by color sensing application <NUM>.

<FIG> is a flowchart of an exemplary method used to determine activity from a movement sensor, according to certain aspects of the present disclosure. Method <NUM> can be implemented by activity classification application <NUM>. Further, the operations described with respect to <FIG> can be performed by an external device such as a monitor device connected to infant sensing system <NUM> via a wireless or an external server.

At block <NUM> of method <NUM>, activity classification application <NUM> receives, from movement sensor <NUM>, a time series of data including an inertial measurement for each of a set of time periods. Inertial measurements can include acceleration or angular velocity. For example, an accelerometer can provide a triplet of numerical values corresponding to the x, y, and z directions. Activity classification application <NUM> periodically samples the accelerometer to create a time series of data. Processor <NUM> annotates each triplet with a timestamp, creating a pair that includes sensor measurement and timestamp. Activity classification application <NUM> can also sample the gyroscope on a periodic basis. In conjunction with the measurement data from the accelerometer, activity classification application <NUM> can determine a set of data that includes a gyroscope measurement, e.g. angular velocity, an accelerometer measurement, e.g., a triplet of x-y-z values, and a timestamp.

In an aspect, activity classification application <NUM> analyzes measurement data in real-time and can update an activity measurement function or the predictive model in real-time. Alternatively, activity classification application <NUM> can analyze a block of samples at a time. For example, activity classification application <NUM> can buffer the pairs until a threshold number of pairs have been received and then analyze movement over a window of time.

At block <NUM> of method <NUM>, activity classification application <NUM> calculates, from a subset of the time series of data, an activity function from statistical data derived from the inertial measurement. Statistical data can include data such as (i) a statistical variance of the inertial measurement or (ii) a root-mean-square of the inertial measurement. Activity classification application <NUM> uses an activity measurement function in order to determine activity level. Different measurements of activity can be derived. For example, activity classification application <NUM> can calculate the statistical variance, standard deviation, or the root mean square (RMS) of the signal. Activity classification application <NUM> can use another customized metrics based on the accelerometer or gyroscope data. For example, a customized metric that quantifies the level of activity A can be calculated for a given number n of samples with the following function, where Sx, Sy, and Sz are the sum of the square differences from the respective means in the x, y, and z dimensions respectively:
<MAT>.

At block <NUM> of method <NUM>, activity classification application <NUM> determines an activity indicated by the subset of time series data based on a measure from the activity function being greater than a first threshold and less than a second threshold. Activity classification application <NUM> can determine an activity such as sleeping or awake based on a level of activity being with a range of values. For example, if the activity function measures a level of activity below a first threshold but above zero, then activity classification application <NUM> determines that the infant is in light sleep. If the activity function measures a level of movement below a second, lower, threshold, then the monitor application determines that the infant is in a deep sleep. Activity classification application <NUM> can use a state machine to determine activity states.

As discussed, in an aspect, activity classification application <NUM> uses a predictive model to determine the infant's activity in addition to or instead of algorithms or state machines. Activity classification application <NUM> provides the accelerometer measurements, the gyroscope measurements, or the output of an activity measurement function to the predictive model. In embodiments of the invention, the predictive models are machine learning models such as decision tree classifiers or regression models. A predictive model is trained to determine whether a wearer of the sensor is feeding on the left hand side, feeding on the right hand side, sleeping, awake and playing on its back, being held, or sitting. Other detectable activities may include sitting, playing, crawling, walking, etc. Activity classification application <NUM> can provide data for one or more periods of time to the predictive model. In this manner, predictive model may determine an activity based on present or past activity level.

<FIG> is a flowchart of an exemplary method used to determine activity from a movement sensor by using a predictive model, according to certain aspects of the present disclosure. Further, the operations described with respect to <FIG> can be performed by an external device such as a monitor device connected to infant sensing system <NUM> via a wireless or an external server.

At block <NUM> of method <NUM>, activity classification application <NUM> receives, from a movement sensor, a time series of data including an inertial measurement for each of a set of time periods. At block <NUM>, activity classification application <NUM> receives the time series of data generally as described with respect to block <NUM>.

At block <NUM> of method <NUM>, activity classification application <NUM> calculates, from the time series data, an activity function such as (i) a statistical variance of the of the inertial measurement or (ii) a root-mean-square of the inertial measurement. At block <NUM>, monitor application uses an activity measurement function generally as described with respect to block <NUM>.

At block <NUM> of method <NUM>, activity classification application <NUM> provides the activity function the (i) statistical variance or (ii) the root mean square of the inertial measurement to a predictive model trained to identify an activity a list of activities. More specifically, activity classification application <NUM> provides sensor measurements or the output of the activity function to the predictive model.

The predictive model is trained to determine activity from measurements that indicate movement. The predictive model can be trained by providing training data to the predictive model and iteratively adjusting internal parameters of the model to reduce error. Training data can include pairs of movement data and a ground truth (an identified activity). For example, training data can include a set of movements and a training data tag "sleeping" or "feeding. " Then, the predictive model learns to associate particular movement patterns with an activity.

The trained predictive model determines, based on its training, from a predefined set of classes, to which class the activity belongs. An exemplary list of activity classes includes feeding on the left side, feeding on the right side, sleeping, awake but playing on back, being held, and sitting. Other training classes are possible. For example, the predictive model can be trained to distinguish deep sleep from light sleep, and activities such as crawling, rolling, sitting up, feeding, or nursing from each other. For example, activity classification application <NUM> may include a predictive model that is trained to distinguish between asleep, awake, stirring, or settled states, and another that is trained to distinguish between light sleep and deep sleep. Stirring represents a state in which an infant is moving more than a first threshold amount and settled represents a state in which the infant has calmed down and is moving less than a second threshold amount.

At block <NUM> of method <NUM>, activity classification application <NUM> receives, from the predictive model, a determination of an activity corresponding to the subset of time series data. For example, the predictive model provides a prediction to activity classification application <NUM> from one of the trained categories such as feeding on the left hand side, feeding on the right hand side, sleeping, awake and playing on its back, being held, or sitting.

<FIG> is a flowchart that describes a method <NUM> of detecting a volume of bodily exudate in an absorbent article, according to certain aspects of the present disclosure. Method <NUM> is explained from the perspective of diaper loading application <NUM>, activity classification application <NUM>, and color sensing application <NUM>, but as can be appreciated, different steps of method <NUM> can be performed by these or other applications. Additionally, one application can perform all of the steps. Further, the operations described with respect to <FIG> can be performed by an external device such as a monitor device connected to infant sensing system <NUM> via a wireless or an external server.

At block <NUM> of method <NUM>, color sensing application <NUM> obtains a first measurement of ambient light received from a photodetector while a light source is off. At block <NUM>, color sensing application <NUM> performs similar functions as described with respect to block <NUM> of method <NUM>.

At block <NUM> of method <NUM>, color sensing application <NUM> obtains a second measurement from the photodetector while the light source is transmitting light. The second measurement includes a measurement of the ambient light and the transmitted light reflected from an absorbent article. At block <NUM>, color sensing application <NUM> performs similar functions as described with respect to blocks <NUM>-<NUM> of method <NUM>.

At block <NUM> of method <NUM>, diaper loading application <NUM> determines a normalized measurement of the light reflected from an absorbent article by removing an ambient light signal from the second measurement based on the first measurement. At block <NUM>, diaper loading application <NUM> causes color sensing application <NUM> to perform similar functions as described with respect to block <NUM> of method <NUM>.

At block <NUM> of method <NUM>, diaper loading application <NUM> determines, from the normalized measurement, a presence of urine in the absorbent article. At block <NUM>, diaper loading application <NUM> causes color sensing application <NUM> to perform similar functions as described with respect to block <NUM> of method <NUM>.

At block <NUM> of method <NUM>, diaper loading application <NUM> determines a degree of fullness of the absorbent article. The degree of fullness reflects an amount of storage space in an absorbent article that is filled or has absorbed bodily exudate relative to a total amount of storage space that can be filled with bodily exudate. In some cases, the degree of fullness of the absorbent article is derived from a volume of urine present in the diaper. The volume can be determined using different inputs such as (i) an elapsed time since the presence of urine, (ii) when the diaper was changed, and (iii) a state of the infant (e.g., awake or sleeping).

A diaper replacement can be indicated by a caregiver, e.g., via a user interface or other input to the infant sensing system. Alternatively, diaper loading application <NUM> can detect a presence of a new diaper by detecting a removal of the sensor from the infant's diaper, or a decrease in or absence of wetness measured.

Understanding the amount of time in asleep and/or awake states facilitates improved predictions. For example, infants may urinate at a slower frequency and quantity during the night relative to the day. Additionally, with more accurate predictions in this respect, the infant sensing system has an added benefit of allowing a caregiver to sleep longer if a diaper change is not imminently necessary. As explained with respect to <FIG>, a movement sensor in conjunction with a predictive model is used by activity classification application <NUM> to determine whether an infant is asleep, awake, resting, etc. hence, at block <NUM>, example operations include operations performed in methods <NUM> and/or <NUM>.

Additionally, in some cases, the diaper loading application <NUM> receives an input about the particular type, brand, or size (e.g., standard sizes such as <NUM>, <NUM>, <NUM>. etc.) of diaper being used or whether the diaper is a regular (daytime) diaper or an overnight diaper. Overnight diapers may have a greater absorption capacity. Further, diaper loading application <NUM> can receive demographic information about the infant such as age, gender, weight, etc., which can be used for the basis of predictions. For example, larger infants may urinate more, resulting in a diaper needing to be replaced sooner than with a smaller infant.

Diaper loading application <NUM> can also determine a time until the absorbent article is full. For example, diaper loading application <NUM> access a capacity of the diaper (e.g., a volume of liquid that can theoretically be stored in the diaper), calculate a rate of volume increase (e.g., based on frequency and amount if urine events since the diaper was replaced) and calculate a time at which the diaper will be full. Diaper loading application <NUM> can cause infant sensing system <NUM> to send an alert on or before the time to remind a caregiver to tend to the infant.

Diaper loading application <NUM> can model how much liquid a diaper is expected to hold based on a particular size of the diaper, type of diaper, or other parameters. Then, based on the model, the diaper loading application can evaluate a loading of a particular diaper over time and based on one or more events. For example, the application can consider (<NUM>) when the diaper was replaced with a new one (e.g., how long the current diaper has been on an infant), (<NUM>) whether the diaper is wet (or when it first turned wet), (<NUM>) the amount of time spent in asleep or awake states since the diaper became wet, or (<NUM>) other data such as diaper type.

In aspects of the invention, statistical methods are used. For example, the diaper loading application <NUM> solves the function with one or more regression models (e.g., linear, quadratic, etc.) or machine learning models (e.g., a decision tree classifier or other classification model). By solving the model, diaper loading application <NUM> determines a volume of urine present in the diaper.

<FIG> is a diagram depicting an example computing system for performing functions related to color detection and detection of bodily exudate, according to some aspects of the present disclosure. Some or all of the components of the computing system <NUM> can belong to microcontroller <NUM> or the processor <NUM> of <FIG>. For example, the color sensing application <NUM> may operate on the computing system <NUM>. The computing system <NUM> includes one or more processors <NUM> communicatively coupled to one or more memory devices <NUM>. The processor <NUM> executes computer-executable program code, which can be in the form of non-transitory computer-executable instructions, stored in the memory device <NUM>, accesses information stored in the memory device <NUM>, or both. Examples of the processor <NUM> include a microprocessor, an application-specific integrated circuit ("ASIC"), a field-programmable gate array ("FPGA"), or any other suitable processing device. The processor <NUM> can include any number of processing devices, including one.

The memory device <NUM> includes any suitable computer-readable medium such as electronic, optical, magnetic, or other storage device capable of providing a processor with computer-readable instructions or other program code. Non-limiting examples of a computer-readable medium include a magnetic disk, a memory chip, a ROM, a RAM, an ASIC, optical storage, magnetic tape or other magnetic storage, or any other medium from which a processing device can read instructions. The instructions may include processor-specific instructions generated by a compiler or an interpreter from code written in any suitable computer-programming language, including, for example, C, C++, C#, Visual Basic, Java, Python, Perl, JavaScript, and ActionScript.

The computing system <NUM> may also include a number of external or internal devices such as input or output devices. For example, the computing system <NUM> is shown with an input/output ("I/O") interface <NUM> that can receive input from input devices or provide output to output devices. A bus <NUM> can also be included in the computing system <NUM>. The bus <NUM> can communicatively couple one or more components of the computing system <NUM> and allow for communication between such components.

The computing system <NUM> executes program code that configures the processor <NUM> to perform one or more of the operations described above with respect to <FIG>. The program code of the color sensing application <NUM>, diaper loading application <NUM>, or activity classification application <NUM>, which can be in the form of non-transitory computer-executable instructions, can be resident in the memory device <NUM> or any suitable computer-readable medium and can be executed by the processor <NUM> or any other one or more suitable processor. Execution of such program code configures or causes the processor(s) to perform the operations described herein with respect to the microcontroller <NUM>. In additional or alternative aspects, the program code described above can be stored in one or more memory devices accessible by the computing system <NUM> from a remote storage device via a data network. The microcontroller <NUM> and any processes can use the memory device <NUM>. The memory device <NUM> can store, for example, additional programs, or data used by the applications executing on the processor <NUM> such as the color sensing application <NUM>.

The computing system <NUM> can also include at least one network interface <NUM>. The network interface <NUM> includes any device or group of devices suitable for establishing a wired or wireless data connection to one or more data networks. Non-limiting examples of the network interface <NUM> include an Ethernet network adapter, WiFi network, Bluetooth, or Bluetooth Low Energy (BLE), a modem, or the like. The computing system <NUM> is able to communicate with one or more other computing devices or computer-readable data sources via a data network using the network interface <NUM>.

Unless specifically stated otherwise, it is appreciated that throughout this specification discussions utilizing terms such as "processing," "computing," "calculating," "determining," and "identifying" or the like refer to actions or processes of a computing device, such as one or more computers or a similar electronic computing device or devices, that manipulate or transform data represented as physical electronic or magnetic quantities within memories, registers, or other information storage devices, transmission devices, or display devices of the computing platform.

Claim 1:
A computer-implemented method for determining a degree of fullness of a wearable absorbent article, the method comprising:
obtaining a first measurement of ambient light received from a photodetector while a light source is off;
obtaining a second measurement from the photodetector while the light source is transmitting light, the second measurement comprising a measurement of the ambient light and the transmitted light reflected from an absorbent article;
determining a normalized measurement of light reflected from an absorbent article by removing an ambient light signal from the second measurement based on the first measurement of ambient light;
determining, from the normalized measurement of light, a presence of bodily exudate in the absorbent article;
determining, from a time series of data including an inertial measurement for each of a set of time periods, an activity state, wherein determining the activity state comprises calculating statistical data derived from the inertial measurements, providing the inertial measurements and statistical data to a predictive model, and receiving from the predictive model a determined activity state; and
determining a degree of fullness of the absorbent article, wherein determining the degree of fullness comprises using one or more of a regression model or a machine learning model to solve a function that has inputs indicative of (i) an elapsed time since the determination of the presence of bodily exudate determined from the normalized measurement of light and (ii) the activity state.