Patent Publication Number: US-2023157490-A1

Title: Systems and methods for monitoring toilet paper rolls

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to sensors, and more specifically to systems and methods for monitoring toilet paper rolls. 
     BACKGROUND 
     Toilet paper dispensers are utilized by most businesses such as convenience stores. Toilet paper dispensers store and dispense one or more rolls of toilet paper. Due to the configuration of most toilet paper dispensers, it may be difficult or otherwise time consuming for workers to determine how much toilet paper is remaining on toilet paper rolls disposed inside a toilet paper dispenser. 
     SUMMARY 
     Toilet paper dispensers are utilized by most businesses such as convenience stores. Toilet paper dispensers store and dispense one or more rolls of toilet paper. Due to the configuration of most toilet paper dispensers, it may be difficult or otherwise time consuming for workers to determine how much toilet paper is remaining on toilet paper rolls disposed inside a toilet paper dispenser. 
     To address these and other problems associated with toilet paper rolls and dispensers, this disclosure contemplates measuring a toilet paper roll with a sensor, such as a time-of-flight (ToF) sensor, in order to determine how much toilet paper is remaining on the roll and then creating an alert for display on a user device based on the amount of toilet paper remaining. In one example, an alert may be displayed on a user device when a measured percentage of toilet paper remaining on a toilet paper roll is below a predetermined minimum threshold (e.g., less than 10% of the roll remaining). In another example, an alert may be displayed on a user device when it is determined that the difference between a current amount of toilet paper on a toilet paper roll and a previous amount of toilet paper on the toilet paper roll exceeds a threshold amount of change in toilet paper (e.g., the amount of toilet paper on the roll decreased by more than 60% from the previous measurement). As a result, workers in businesses such as convenience stores may be automatically notified when a toilet paper roll needs to be changed, thereby increasing worker productivity and increasing customer satisfaction. Furthermore, by monitoring toilet paper consumption over time, a business may be able to predictably order toilet paper at opportune times of the week, month, or year. By dynamically monitoring toilet paper demand, a business can have a consistent supply of toilet paper. 
     In some embodiments, a system includes a local device and a remote computing system. The local device is disposed in a toilet paper dispenser and includes a sensor and a first processor. The sensor is configured to measure a distance to a toilet paper roll. The first processor is configured to calculate, using the measured distance to the toilet paper roll, a percentage of toilet paper remaining on the toilet paper roll. The first processor is further configured to transmit, when it is determined that the percentage of toilet paper remaining is less than a minimum threshold, sensor data across a wireless communications network. The remote computing system includes a second processor configured to receive the sensor data and send an alert for display on a user device in response to receiving the sensor data. 
     The disclosed embodiments provide several practical applications and technical advantages, which include at least: 1) technology that utilizes a local device disposed inside a toilet paper dispenser to measure and report the amount of toilet paper remaining on a toilet paper roll; 2) technology that automatically provides alerts for display on a user device when a measured percentage of toilet paper remaining on a toilet paper roll is below a predetermined minimum threshold; and 3) technology that automatically provides alerts for display on a user device when the difference between a current amount of toilet paper on a toilet paper roll and a previous amount of toilet paper on the toilet paper roll exceeds a threshold amount of change in toilet paper. 
     Certain embodiments may include none, some, or all of the above technical advantages and practical applications. One or more other technical advantages and practical applications may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. 
         FIG.  1    is a schematic diagram of a toilet paper monitoring system, according to certain embodiments; 
         FIG.  2    is a flowchart of a method for monitoring a toilet paper roll, according to certain embodiments; and 
         FIG.  3    is a flowchart of another method for monitoring a toilet paper roll, according to certain embodiments 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure and its advantages are best understood by referring to  FIGS.  1  through  3    of the drawings, like numerals being used for like and corresponding parts of the various drawings. 
     Toilet paper dispensers are utilized by most businesses such as convenience stores. Toilet paper dispensers store and dispense one or more rolls of toilet paper. Due to the configuration and materials of most toilet paper dispensers, it may be difficult or otherwise time consuming for workers to determine how much toilet paper is remaining on toilet paper rolls disposed within a toilet paper dispenser. 
     To address these and other problems associated with toilet paper rolls and dispensers, this disclosure contemplates measuring a toilet paper roll with a sensor, such as a time-of-flight (ToF) sensor, in order to determine how much toilet paper is remaining on the roll and then creating an alert for display on a user device based on the amount of toilet paper remaining. In one example, an alert may be displayed on a user device when a measured percentage of toilet paper remaining on a toilet paper roll is below a predetermined minimum threshold (e.g., less than 10% of the roll remaining). In another example, an alert may be displayed on a user device when it is determined that the difference between a current amount of toilet paper on a toilet paper roll and a previous amount of toilet paper on the toilet paper roll exceeds a threshold amount of change in toilet paper (e.g., the amount of toilet paper on the roll decreased by more than 60% from the previous measurement). As a result, workers in businesses such as convenience stores may be automatically notified when a toilet paper rolls needs to be changed, thereby increasing worker productivity and customer satisfaction. Furthermore, by monitoring toilet paper consumption over time, a business may be able to predictably order toilet paper at opportune times of the week, month, or year. By dynamically monitoring toilet paper demand to optimize toilet paper supply chain orders, a business can have a consistent supply of toilet paper. 
       FIG.  1    illustrates an example toilet paper monitoring system  100 , according to certain embodiments. As illustrated in  FIG.  1   , certain embodiments of toilet paper monitoring system  100  include a remote computing system  110 , a user device  120 , a network  130 , a gateway  140 , and a local device  150 . Remote computing system  110  is communicatively coupled to user device  120  and gateway  140  via a network  130  using any appropriate wired or wireless telecommunication technology. Local device  150  is disposed either partially or fully within a toilet paper dispenser  170 . In some embodiments, local device  150  sends sensor data  155  directly to remote computing system  110  or indirectly to remote computing system  110  via network  130  using any appropriate wired or wireless telecommunication technology (i.e., without using gateway  140 ). In other embodiments, local device  150  sends sensor data  155  to gateway  140  using an Internet-of-Things (IoT) communications protocol, and gateway  140  in turns sends sensor data  155  to remote computing system  110  via network  130 . Sensor data  155  may include one or more distances to a toilet paper roll  180  measured by a sensor of local device  150  (e.g., sensor  153 ) or data associated with the status of toilet paper roll  180  (e.g., how much toilet paper is remaining on toilet paper roll  180 , whether the amount of toilet paper remaining on toilet paper roll  180  is below a certain threshold, whether the amount of toilet paper on toilet paper roll  180  has changed more than a threshold amount, etc.). 
     In general, toilet paper monitoring system  100  provides alerts  160  about toilet paper roll  180  based on sensor data  155  from local device  150  that is disposed within toilet paper dispenser  170 . In some embodiments, remote computing system  110  sends alert  160  for display on user device  120  when a measured percentage of toilet paper remaining on toilet paper roll  180  is below a predetermined minimum threshold. As a specific example, alert  160  may be displayed on user device  120  when the percentage of toilet paper remaining on toilet paper roll  180  is below 10% of a full roll of toilet paper. In other embodiments, remote computing system  110  sends alert  160  for display on user device  120  when the difference between a current amount of toilet paper on toilet paper roll  180  and a previous amount of toilet paper on toilet paper roll  180  exceeds a threshold amount of change in toilet paper. As a specific example, alert  160  may be displayed on user device  120  when the amount of toilet paper on toilet paper roll  180  decreased by more than 50% from the previous measurement. 
     A technical advantage of some embodiments is that local device  150  can be used to continuously monitor a percentage of toilet paper used, as opposed to merely a binary determination of whether there is or is not any toilet paper available. The continuous measurement is tunable to a certain level of desired precision based on the selected sensor within local device  150  (i.e., sensor  153 ) and the radius of toilet paper roll  180 . For example, if it is desired to only measure to a 10% change in total radius of toilet paper roll  180 , then a particular sensor with that level of sensitivity can be used in local device  150 . However, if it is desired to measure a 1% change in total radius of toilet paper roll  180 , then a more sensitive sensor can be used in local device  150  to achieve that level of sensitivity. To conserve processing, memory, and networking resources, a particular sensor can be selected that will have a lower degree of precision but still a continuous measurement versus a binary measurement. This may reduce the number of reporting signals, which reduces the consumption of hardware resources such as processor, memory, and network resources. 
     Remote computing system  110  may be any appropriate computing system in any suitable physical form. As example and not by way of limitation, remote computing system  110  may be an embedded computer system, a system-on-chip (SOC), a single-board computer system (SBC) (such as, for example, a computer-on-module (COM) or system-on-module (SOM)), a desktop computer system, a laptop or notebook computer system, a mainframe, a mesh of computer systems, a mobile telephone, a personal digital assistant (PDA), a server, a tablet computer system, an augmented/virtual reality device, or a combination of two or more of these. Where appropriate, remote computing system  110  may include one or more remote computing systems  110 ; be unitary or distributed; span multiple locations; span multiple machines; span multiple data centers; or reside in a cloud, which may include one or more cloud components in one or more networks. Where appropriate, one or more remote computing systems  110  may perform without substantial spatial or temporal limitation one or more steps of one or more methods described or illustrated herein. As an example and not by way of limitation, one or more remote computing systems  110  may perform in real time or in batch mode one or more steps of one or more methods described or illustrated herein. One or more remote computing systems  110  may perform at different times or at different locations one or more steps of one or more methods described or illustrated herein, where appropriate. In some embodiments, remote computing system  110  includes an electronic display that may alternately or additionally display alert  160 . 
     Remote computing system  110  may be physically located within the same physical building in which local device  150  is located, or physically located at a location remote from the physical building in which local device  150  is located. For example, in certain embodiments, remote computing system  110  may located in one or more remote servers (e.g. in the cloud). 
     Processor  112  is any electronic circuitry, including, but not limited to a microprocessor, an application specific integrated circuits (ASIC), an application specific instruction set processor (ASIP), and/or a state machine, that communicatively couples to memory  114  and controls the operation of remote computing system  110 . Processor  112  may be 8-bit, 16-bit, 32-bit, 64-bit or of any other suitable architecture. Processor  112  may include an arithmetic logic unit (ALU) for performing arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that fetches instructions from memory and executes them by directing the coordinated operations of the ALU, registers and other components. Processor  112  may include other hardware that operates software to control and process information. Processor  112  executes software stored in memory to perform any of the functions described herein. Processor  112  controls the operation and administration of remote computing system  110  by processing information received from local device  150 , gateway  140 , network  130 , user device  120 , and memory  114 . Processor  112  may be a programmable logic device, a microcontroller, a microprocessor, any suitable processing device, or any suitable combination of the preceding. Processor  112  is not limited to a single processing device and may encompass multiple processing devices. 
     Memory  114  may store, either permanently or temporarily, data such as sensor data  155 , user preferences, operational software such as toilet paper monitoring module  116 , or other information for processor  112 . Memory  114  may include any one or a combination of volatile or non-volatile local or remote devices suitable for storing information. For example, memory  114  may include random access memory (RAM), read only memory (ROM), magnetic storage devices, optical storage devices, or any other suitable information storage device or a combination of these devices. 
     Toilet paper monitoring module  116  represents any suitable set of instructions, logic, or code embodied in a computer-readable storage medium. For example, toilet paper monitoring module  116  may be embodied in memory  114 , a disk, a CD, or a flash drive. In particular embodiments, toilet paper monitoring module  116  may include toilet paper monitoring instructions  117  (e.g., a software application) executable by processor  112  to perform one or more of the functions described herein. In general, toilet paper monitoring module  116  sends alert  160  for display on user device  120  either directly or via network  130 . As described in more detail herein, alerts  160  are generated by toilet paper monitoring module  116  based on sensor data  155  from local device  150 . 
     User device  120  is any appropriate device for communicating with components of remote computing system  110  over network  130 . For example, user device  120  may be a handheld computing device such as a smartphone, wearable computer glasses, a smartwatch, a tablet computer, a laptop computer, and the like. User device  120  may include an electronic display, a processor such as processor  112 , and memory such as memory  114 . The electronic display of user device  120  may display an alert  160  that is provided by remote computing system  110 . 
     Network  130  allows communication between and amongst the various components of system  100 . For example, remote computing system  110 , user device  120 , and gateway  140  may communicate via network  130 . This disclosure contemplates network  130  being any suitable network operable to facilitate communication between the components of system  100 . Network  130  may include all or a portion of a local area network (LAN), a wide area network (WAN), an overlay network, a software-defined network (SDN), a virtual private network (VPN), a packet data network (e.g., the Internet), a mobile telephone network (e.g., cellular networks, such as 4G or 5G), a Plain Old Telephone (POT) network, a wireless data network (e.g., WiFi, WiGig, WiMax, etc.), a Long Term Evolution (LTE) network, a Universal Mobile Telecommunications System (UMTS) network, a peer-to-peer (P2P) network, a Bluetooth network, a Near Field Communication (NFC) network, a Zigbee network, and/or any other suitable network. 
     Local device  150  is a computing device that is housed either partially or wholly within toilet paper dispenser  170 . In some embodiments, local device  150  includes a processor  112 , memory  114 , a radio  152 , and one or more sensors  153 . In general, local device  150  provides sensor data  155  to remote computing system  110  regarding toilet paper roll  180 . Various embodiments of sensor data  155  are described in more detail below. 
     In some embodiments, local device  150  is an IoT sensor. In general, IoT describes a network of physical objects that are embedded with sensors, software, and other technologies for the purpose of connecting and exchanging data with other devices and systems over the Internet. For example, some embodiments of local device  150  include a microprocessor (e.g., processor  112 ), a transceiver (e.g., radio  152 ) for wirelessly communicating sensor data  155  (e.g., via an IoT communications protocol), an antenna, and a power supply such as a battery. In embodiments where local device  150  is an IoT device, toilet paper monitoring system  100  may include gateway  140  for communicating with local device  150 . Gateway  140  may be any appropriate IoT gateway, computer system, or electronic device that is capable of wirelessly communicating with local device  150  using any appropriate IoT communications protocol (e.g., Message Queuing Telemetry Transport (MQTT), Constrained Application Protocol (CoAP), Advanced Message Queuing Protocol (AMQP), Data Distribution Service (DDS), HyperText Transfer Protocol (HTTP), WiFi, Bluetooth, ZigBee, Z-Wave, a media access control (MAC) protocol such as LoRaWAN, and the like). For example, local device  150  may wirelessly transmit sensor data  155  to gateway  140 , and gateway  140  may in turn send sensor data  155  to remote computing system  110  via network  130 . In other embodiments, local device  150  is not an IoT device. In embodiments where local device  150  is not an IoT device, local device  150  does not utilize gateway  140  but instead transmits sensor data  155  directly to remote computing system  110  or indirectly via network  130  (e.g., via Bluetooth or WiFi). 
     Local device instructions  151  represents any suitable set of instructions, logic, or code embodied in a computer-readable storage medium. For example, local device instructions  151  may be embodied in memory  114  of local device  150 , a disk, a CD, or a flash drive. In particular embodiments, local device instructions  151  may include a software application executable by processor  112  of local device  150  to perform one or more of the functions described herein. In general, local device instructions  151  sends sensor data  155  to remote computing device  110  either directly, indirectly via network  130 , or indirectly via gateway  140 . 
     Radio  152  is any transmitter or transceiver that is capable of wirelessly transmitting sensor data  155 . In some embodiments, for example, radio  152  is a Bluetooth transceiver. In these embodiments, sensor data  155  is transmitted via Bluetooth to either gateway  140  or remote computing system  110 . In other embodiments, radio  152  is a Wi-Fi transceiver and sensor data  155  is transmitted via Wi-Fi to either gateway  140  or remote computing system  110 . 
     Sensor  153  is any device for sensing or measuring the physical distance to an object. In some embodiments, sensor  153  may be a ToF sensor that utilizes a laser to produce a beam of infrared light that is bounced off an object and returned to the sensor  153  in order to measure distance to the object. In these embodiments, sensor  153  may include a laser diode and a photodetector. For example, a laser diode of sensor  153  may produce a laser beam  154  at a predetermined frequency that travels towards toilet paper roll  180 , is reflected off of toilet paper roll  180 , and travels back to sensor  153  where it is detected by the photodetector of sensor  153 . The photodetector of sensor  153  may be any appropriate device that can detect each reflected laser beam  154 . In some embodiments, processor  112  may be communicatively coupled to the laser diode of sensor  153  and to the photodetector of sensor  153 . Processor  112  of local device  150  (or, in other embodiments, a processor within sensor  153 ) determines a distance  158  to toilet paper roll based on a difference in time between production of the laser beam  154  by the laser diode of sensor  153  and reception of the reflected laser beam  154  by the photodetector of sensor  153 . 
     In some embodiments, laser beam  154  generated by sensor  153  is coincident with a radial line that extends from the laser of sensor  153  to a center  182  of toilet paper roll  180 . For example, laser beam  154 A is coincident with a radial line that extends from the laser of sensor  153  to center  182  of toilet paper roll  180 A. In some embodiments, toilet paper dispenser  170  includes two toilet paper rolls  180  (i.e., toilet paper rolls  180 A-B). In such embodiments, sensor  153  may include two laser diodes that generate two separate laser beams  154 A-B that are separated by an angle  156  (e.g., 90 degrees). In these embodiments, second laser beam  154 B generated by sensor  153  is coincident with a radial line that extends from the second laser of sensor  153  to center  182  of toilet paper roll  180 B. 
     In general, local device  150  provides sensor data  155  to remote computing system  110  that is used to generate alert  160 . In some embodiments, sensor data  155  is the raw distance to toilet paper roll  158  as measured by sensor  153 , which may be any appropriate distance value (e.g., inches or millimeters). In these embodiments, the calculations described herein regarding toilet paper roll  180  are performed by remote computing system  110 . In other embodiments, local device  150  performs the calculations described herein regarding toilet paper roll  180 , and sensor data  155  includes the calculations performed on distance to toilet paper roll  158  by local device  150 . For example, sensor data  155  may include a percentage of toilet paper remaining on toilet paper roll  180  that is calculated by local device  150  using distance to toilet paper roll  158 . In summary, the calculations described herein regarding toilet paper roll  180  using distance to toilet paper roll  158  may be performed by either remote computing system  110  or local device  150  (or, in some embodiments, a combination of local device  150  and remote computing system  110 ). 
     In some embodiments, sensor data  155  is provided automatically by local device  150  at periodic intervals (e.g., every five minutes). In other embodiments, sensor data  155  is provided by local device  150  when requested by remote computing system  110 . In yet other embodiments, in order to conserve power, sensor data  155  is provided by local device  150  only when certain conditions regarding toilet paper roll  180  are met (e.g., local device  150  may only send sensor data  155  once the percentage of toilet paper remaining on toilet paper roll  180  falls below minimum threshold  157 ). 
     Alert  160  is a message or other indication that is displayed on user device  120  regarding toilet paper roll  180 . In some embodiments, alert  160  includes one or more of an indication of toilet paper roll  180 , a timestamp associated with toilet paper roll  180 , a location, a percentage of toilet paper remaining on toilet paper roll  180 , and an amount of change in the amount of toilet paper remaining on toilet paper roll  180 . For example, alert  160  may be: “The toilet paper in Bathroom A has less than 10% remaining at 10:20 AM.” As another example, alert  160  may be: “The toilet paper in Bathroom C has decreased by more than 50%.” 
     Toilet paper dispenser  170  is any physical housing that holds one or more toilet paper rolls  180 . For example, as illustrated in  FIG.  1   , toilet paper dispenser  170  may hold two toilet paper rolls  180 . In other embodiments, however, toilet paper dispenser  170  may hold only a single toilet paper roll  180 . Toilet paper roll  180  may have any appropriate dimensions. A full toilet paper roll  180 B (i.e., a new toilet paper roll  180  that has not been used) has a full radius  184 , and an empty toilet paper roll  180  (i.e., a toilet paper roll  180  that has been completely used) has an empty radius  186 . A partially-used toilet paper roll  180 A has a current radius  188 , which may be calculated using distance to toilet paper roll  158 , as described in more detail below. 
     In operation, remote computing system  110  provides alerts  160  for display on user device  120  based on sensor data  155 . Generally, remote computing system  110  generates alerts  160  in response to two situations: 1) when a measured percentage of toilet paper remaining on toilet paper roll  180  is below a predetermined minimum threshold  157 , and 2) when the amount of toilet paper on toilet paper roll  180  has changed by more than a threshold amount of change in toilet paper. Each situation is described in more detail below. 
     First, certain embodiments generate alert  160  for display on user device  120  when a measured percentage of toilet paper remaining on toilet paper roll  180  is below a predetermined minimum threshold  157  (e.g., a static value such as 10%). To calculate the percentage of toilet paper remaining on toilet paper roll  180 , local device  150  may first access a stored radius measurement that indicates a radius of toilet paper roll  180  when toilet paper roll  180  is full of toilet paper (i.e., full radius  184 ). Full radius  184  may be stored in memory  114  and may be configurable by a user. Local device  150  may also access a stored distance measurement that indicates a total distance from sensor  153  to center  182  of toilet paper roll  180  (i.e., distance to center  159 ). Distance to center  159  may be stored in memory  114  and may be configurable by a user. Local device  150  then calculates a current radius  188  of toilet paper roll  180  by subtracting distance to toilet paper roll  158  from distance to center  159 . Finally, local device  150  calculates a current percentage  171  of toilet paper remaining on toilet paper roll  180  as a ratio of the current radius  188  to full radius  184 . If the calculated current percentage  171  of toilet paper remaining on toilet paper roll  180  is less than minimum threshold  157 , toilet paper monitoring system  100  generates alert  160  to indicate to a worker that toilet paper roll  180  needs to be replaced. In some embodiments, the calculated current percentage  171  of toilet paper remaining on toilet paper roll  180  is stored in memory  114  of local device  150  or remote computing system  110 . 
     Second, certain embodiments generate alert  160  for display on user device  120  when the amount of toilet paper on toilet paper roll  180  has changed by more than a threshold amount of change  172  in toilet paper. In general, alert  160  is provided in these situations in order to alert a worker that the amount of toilet paper on toilet paper roll  180  has recently decreased by a large amount. For example, alert  160  may be generated if the amount of toilet paper on toilet paper roll  180  has recently decreased by over 50%. An alert  160  for such a decrease may allow a worker to take proactive action to restock toilet paper roll  180 . In these embodiments, local device  150  first calculates a current percentage  171  of toilet paper remaining on toilet paper roll  180  as described above. Next, local device  150  accesses a previously-calculated percentage  172  of toilet paper remaining on toilet paper roll  180  stored in memory  114 . Next, local device  150  calculates a difference between the current percentage of toilet paper remaining on toilet paper roll  180  and the previous percentage of toilet paper remaining on toilet paper roll  180 . Local device  150  then accesses a threshold amount of change  173  in toilet paper stored in memory  114  and compares the calculated difference between the current percentage  171  of remaining toilet paper and the previous percentage  172  of remaining toilet paper to the threshold amount of change  173  in toilet paper. When the difference between the current percentage  171  of toilet paper remaining on toilet paper roll  180  and the previous percentage  172  of toilet paper remaining on toilet paper roll  180  exceeds the threshold amount of change  173  in toilet paper, toilet paper monitoring system  100  generates alert  160  to indicate to a worker that the amount of toilet paper on toilet paper roll  180  has recently changed by a large amount. In some embodiments, when the difference between the current percentage  171  of toilet paper remaining on toilet paper roll  180  and the previous percentage  172  of toilet paper remaining on toilet paper roll  180  exceeds the threshold amount of change  173  in toilet paper, toilet paper monitoring system  100  may send one or more instructions to dispense air freshener in the room in which local device  150  is physically located. 
     While certain calculations regarding toilet paper roll  180  are described above with respect to local device  150 , it should be understood that, in other embodiments, remote computing system  110  may perform some or all of the calculations regarding toilet paper roll  180  instead of local device  150 . In embodiments where local device  150  performs calculations regarding toilet paper roll  180 , local device  150  disposed in toilet paper dispenser  170  measures a distance to toilet paper roll  158  using sensor  153 , uses the measured distance to toilet paper roll  158  for the various calculations regarding toilet paper roll  180  described herein, and then sends the calculations via sensor data  155  to remote computing system  110 . In embodiments where remote computing system  110  performs calculations regarding toilet paper roll  180 , remote computing system  110  receives or otherwise accesses distance to toilet paper roll  158  as measured by sensor  153  and then uses measured distance to toilet paper roll  158  for the various calculations regarding toilet paper roll  180  described herein. 
     Certain embodiments of local device  150  utilize various techniques to reduce power consumption of local device  150 . For example, certain embodiments of local device  150  only transmit sensor data  155  when certain conditions are met (e.g., when a measured percentage of toilet paper remaining on toilet paper roll  180  is below a predetermined minimum threshold  157  or when the amount of toilet paper on toilet paper roll  180  has changed by more than a threshold amount of change in toilet paper). In some embodiments, local device  150  remains in a low power consumption “sleep” mode for extended periods of time. While in sleep mode, local device  150  consumes less power by reducing or avoiding using components such as radio  152  and sensor  153 . In these embodiments, local device  150  may wake from the sleep mode after a predetermined amount of time (e.g., every five minutes), measure distance to toilet paper roll  158  and possibly perform calculations regarding toilet paper roll  180 , transmit sensor data  155  to remote computing system  110  or gateway  140 , and then return to sleep mode after transmitting sensor data  155 . As a result, embodiments of local device  150  that utilize batteries for power may be able to operate for a longer duration of time before requiring new batteries. 
     In certain embodiments, user device  120  may receive sensor data  155  directly from local device  150  and then use sensor data  155  to perform the operations described above with respect to remote computing system  110 . That is, user device  120  may be used to analyze sensor data  155  from local device  150  and then display alerts  160  without instructions or interaction from remote computing system  110 . In such embodiments, toilet paper monitoring module  116  is stored in memory of user device  120  instead of remote computing system  110 . 
     In certain embodiments, user device  120  may receive sensor data  155  generated by local device  150  and use sensor data  155  to provide alerts  160  for display on user device  120 . In these embodiments, local device  150  may directly communicate with user device  120  instead of with remote computing system  110 . For example, in such embodiments, memory  114  of user device  120  may include instructions (e.g., toilet paper monitoring module  116 ) that, when executed by a processor  112  of user device  120 , enable user device  120  to monitor sensor data  155  in order to provide alerts  160  for display on user device  120  based on sensor data  155 , as described herein. For example, instructions stored in memory  114  of user device  120  may generate alert  160  for display on user device  120  when a measured percentage of toilet paper remaining on toilet paper roll  180  is below a predetermined minimum threshold  157 . 
       FIG.  2    illustrates a method  200  for monitoring a toilet paper roll, according to certain embodiments. In general, method  200  may be utilized by local device  150  and remote computing system  110  to automatically provide alert  160  for display on user device  120 . Method  200  may begin at operation  210  where method  200  measures a distance to a toilet paper roll. In some embodiments, operation  210  includes using a ToF sensor such as sensor  153  disposed in a toilet paper dispenser to measure the distance to the toilet paper roll. In some embodiments, the sensor includes a laser that is configured to generate a laser beam coincident with a radial line that extends from the laser to a center of the toilet paper roll. 
     At operation  220 , method  200  accesses a stored radius measurement and a stored distance measurement. The stored radius measurement indicates a radius of the toilet paper roll when the toilet paper roll is full of toilet paper. In some embodiments, the stored radius measurement is full radius  184 . The stored distance measurement indicates a total distance from the sensor to a center of the toilet paper roll. In some embodiments, the stored distance measurement is distance to center  159 . 
     At operation  230 , method  200  calculates a current radius of the toilet paper roll by subtracting the measured distance to the toilet paper of roll of operation  210  from the stored distance measurement of operation  220 . At operation  240 , method  200  calculates a percentage of toilet paper remaining on the toilet paper roll. In some embodiments, operation  240  includes calculating the percentage of toilet paper remaining on the toilet paper roll as a ratio of the current radius of operation  230  to the stored radius measurement of operation  220 . 
     At operation  250 , method  200  determines whether the percentage of toilet paper remaining on the toilet paper roll of operation  240  is less than a minimum threshold. In some embodiments, the minimum threshold is minimum threshold  157 . If method  200  determines in operation  250  that the percentage of toilet paper remaining on the toilet paper roll of operation  240  is less than the minimum threshold, method  200  proceeds to operation  260 . If method  200  determines in operation  250  that the percentage of toilet paper remaining on the toilet paper roll of operation  240  is greater than or equal to the minimum threshold, method  200  may end. 
     At operation  260 , method  200  sends an alert for display on a user device when it is determined in operation  250  that the percentage of toilet paper remaining is less than the minimum threshold. In some embodiments, the alert is alert  160 . In some embodiments, the alert indicates that the amount of toilet paper remaining on a toilet paper roll is below a predetermined minimum threshold. After operation  260 , method  200  may end. 
       FIG.  3    illustrates a method  300  for monitoring a toilet paper roll, according to certain embodiments. While method  200  of  FIG.  2    above generates an alert when the percentage of toilet paper remaining on a toilet paper roll is less than a minimum threshold, method  300  of  FIG.  3    generates an alert when the amount of toilet paper on a toilet paper roll has changed by more than a threshold amount of change in toilet paper. Method  300  may begin at operation  310  where method  300  measures a distance to a toilet paper roll. In some embodiments, operation  310  includes using a ToF sensor, such as sensor  153 , disposed in a toilet paper dispenser to measure the distance to the toilet paper roll. 
     At operation  320 , method  300  accesses a stored radius measurement and a stored distance measurement. The stored radius measurement indicates a radius of the toilet paper roll when the toilet paper roll is full of toilet paper. In some embodiments, the stored radius measurement is full radius  184 . The stored distance measurement indicates a total distance from the sensor to a center of the toilet paper roll. In some embodiments, the stored distance measurement is distance to center  159 . 
     At operation  330 , method  300  calculates a current radius of the toilet paper roll by subtracting the measured distance to the toilet paper of roll of operation  310  from the stored distance measurement of operation  320 . At operation  340 , method  300  calculates a current percentage of toilet paper remaining on the toilet paper roll. In some embodiments, operation  340  includes calculating the current percentage of toilet paper remaining on the toilet paper roll as a ratio of the current radius of operation  330  to the stored radius measurement of operation  320 . 
     At operation  350 , method  300  accesses a previous percentage of toilet paper remaining on the toilet paper roll. In some embodiments, the previous percentage of toilet paper remaining on the toilet paper roll is previously-calculated percentage  172  of toilet paper remaining. 
     At operation  360 , method  300  calculates the difference between the current percentage of toilet paper remaining of operation  340  and the previous percentage of toilet paper remaining of operation  350 . At operation  370 , method  300  determines whether the difference between the current percentage of toilet paper remaining and the previous percentage of toilet paper remaining calculated in operation  360  is greater than a threshold amount of change. In some embodiments, the threshold amount of change is threshold amount of change  173 . If method  300  determines in operation  370  that the difference between the current percentage of toilet paper remaining and the previous percentage of toilet paper remaining is greater than the threshold amount of change, method  300  proceeds to operation  380 . Otherwise, method  300  may end. 
     At operation  380 , method  300  sends an alert for display on a user device when it is determined in operation  370  that the difference between the current percentage of toilet paper remaining and the previous percentage of toilet paper remaining is greater than the threshold amount of change. In some embodiments, the alert is alert  160 . In some embodiments, the alert indicates the amount of toilet paper on a toilet paper roll has changed more than a threshold amount (e.g., the amount of toilet paper has decreased by more than 50% from the previous measurement). In some embodiments, operation  380  may additionally include sending one or more instructions to dispense air freshener. After operation  380 , method  300  may end. 
     Modifications, additions, or omissions may be made to the methods described herein without departing from the scope of the disclosure. The methods may include more, fewer, or other operations. Additionally, operations may be performed in any suitable order. That is, the operations of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. 
     As used in this document, “each” refers to each member of a set or each member of a subset of a set. Furthermore, as used in the document “or” is not necessarily exclusive and, unless expressly indicated otherwise, can be inclusive in certain embodiments and can be understood to mean “and/or.” Similarly, as used in this document “and” is not necessarily inclusive and, unless expressly indicated otherwise, can be inclusive in certain embodiments and can be understood to mean “and/or.” All references to “a/an/the element, apparatus, component, means, step, etc.” are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. 
     Furthermore, reference to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. 
     The embodiments disclosed herein are only examples, and the scope of this disclosure is not limited to them. Particular embodiments may include all, some, or none of the components, elements, features, functions, operations, or steps of the embodiments disclosed herein. Certain embodiments are in particular disclosed in the attached claims directed to a method, a storage medium, a system and a computer program product, wherein any feature mentioned in one claim category, e.g. method, can be claimed in another claim category, e.g. system, as well. The dependencies or references back in the attached claims are chosen for formal reasons only. However, any subject matter resulting from a deliberate reference back to any previous claims (in particular multiple dependencies) can be claimed as well, so that any combination of claims and the features thereof are disclosed and can be claimed regardless of the dependencies chosen in the attached claims. The subject-matter which can be claimed comprises not only the combinations of features as set out in the attached claims but also any other combination of features in the claims, wherein each feature mentioned in the claims can be combined with any other feature or combination of other features in the claims. Furthermore, any of the embodiments and features described or depicted herein can be claimed in a separate claim and/or in any combination with any embodiment or feature described or depicted herein or with any of the features of the attached claims. 
     To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants note that they do not intend any of the appended claims to invoke 35 U.S.C. § 112(f) as it exists on the date of filing hereof unless the words “means for” or “step for” are explicitly used in the particular claim.