Level sensor for hygiene consumable

Abstract

A sensor arrangement for detecting a filling state of a reservoir of a hygiene consumable comprising a sensor arranged to measure a figure indicating a filling state along a depletion direction of the reservoir, a processing section configured to compile information indicating the filling state of the reservoir on the basis of the measured figure, an access to a memory configured to store learning data, wherein the processing section is configured to store said learning data in relation to a plurality of measured figures indicating a filling state, to identify an event associated to one or more assumed filling states of the reservoir, and to determine an association of one or more figures being measured by said sensor to one or more assumed filling states of the reservoir.

Description

[0001] LEVEL SENSOR FOR HYGIENE CONSUMABLE

[0002] Technical field

[0003] The present invention relates to detecting a filling level of a reservoir of a hygiene consumable, such as soap, disinfectant , tissue , towel , and the like . The present invention, in particular, relates to a level sensor for a hygiene consumable for use in a piece of hygiene equipment such as a dispenser o f that consumable .

[0004] Background

[0005] The benefits of proper hygiene , in particular in the form of hand hygiene , are widely acknowledged . It is commonplace that public or commercial facilities such as washrooms in public buildings , of fices , restaurants , airports , hospitals , shopping malls and so on are normally provided with dispensers for various hygiene consumables , for example paper towels , liquid soap, disinfectant , tissues , toilet paper, or sanitary napkins .

[0006] Such consumables are normally stored in dispensers , which may be fixedly located at suitable positions in the washroom or other locations . A dispenser can for example be in the form of a holder for paper towels or tissues , a holder for toilet paper, a holder for diapers , or a container for liquid soap, disinfectant or other consumable . Further, also used items , such as towels or tissues , may still be considered as a hygiene consumable and respective equipment for receiving such used consumables may be waste bins or other receptacles for receiving and containing such used consumables . In the above context it is oftentimes desirable to know about the filling level of a piece of hygiene equipment such as a dispenser or waste bin . Usually, knowledge on the filling state is desired in order to initiate and plan the refilling of dispensers , emptying bins or other receptacles , or other service activities . For this purpose , it is already known to provide said hygiene equipment with level sensors that are configured to measure and report a filling state of the respective consumable . However, measuring a filling state of a consumable in a reliable manner oftentimes requires considerations on the reservoir, i . e . considerations on the si ze , capacity, and / or the depletion behavior of the consumable . This oftentimes necessitates the design and manufacturing of specific level sensor for speci fic hygiene equipment or at least configuring the sensor equipment such that it can detect a reliable filling state relative to a depletion span, i . e . from " full" to "empty" .

[0007] There is therefore a need for an improved sensor arrangement for detecting a filling state of a hygiene consumable that can be employed in hygiene equipment of a larger variety . In other words , there is a need for sensor arrangements that can be employed with many types of dispensers and receptacles without the need for speci fic or complex configuration or setup routines or other kinds of parametri zations . In addition, development and veri fication ef forts can be reduced as not all possible types for hygiene equipment needs to be considered

[0008] Summary

[0009] The mentioned problems are solved by the subj ect-matter of the independent claims . Further preferred embodiments are defined in the dependent claims .

[0010] According to an aspect of the present invention, there is provided a sensor arrangement for detecting a filling state of a reservoir of a hygiene consumable comprising a sensor arranged to measure a figure indicating a filling state along a depletion direction of the reservoir, a processing section configured to compile information indicating the filling state of the reservoir on the basis of the measured figure , an access to a memory configured to store learning data, wherein the processing section is configured to store said learning data in relation to a plurality of measured figures indicating a filling state , to identi fy an event associated to one or more assumed filling states of the reservoir, and to determine an association of one or more figures being measured by said sensor to one or more assumed filling states of the reservoir .

[0011] According to an aspect of the present invention, there is provided a piece of hygiene equipment for dispensing and / or receiving a hygiene consumable , comprising a sensor arrangement according to one of the disclosed embodiments .

[0012] According to a method aspect of the present invention, there is provided a method of operating a piece of hygiene equipment , such as a dispenser for a hygiene consumable , or a sensor arrangement according to one of the disclosed embodiments for detecting a filling state of a reservoir of a hygiene consumable . The sensor comprising a sensor, a processing section and an access to a memory configured to store learning data, and the method comprising the steps of measuring a figure indicating a filling state along a depletion direction of the reservoir ; compiling information indicating the filling state of the reservoir on the basis of the measured figure ; storing said learning data in relation to a plurality of measured figures indicating a filling state ; identi fying an event associated to one or more assumed filling states of the reservoir, and determining an association of one or more figures being measured by said sensor to one or more assumed filling states of the reservoir .

[0013] Brief Description of the Drawings

[0014] Embodiments of the present invention, which are presented for better understanding the inventive concepts and which are not to be seen as limiting the invention, will now be described with reference to the Figures in which : Figures 1A and IB show general device embodiments o f the present invention for a sensor arrangement detecting a filling state of a reservoir of a hygiene consumable ;

[0015] Figure 1C shows a schematic and exemplary behaviour of a measured figure that indicates a filling state along a depletion direction of the reservoir according to at least some embodiments of the present invention;

[0016] Figures 2A and 2B show general measuring concepts involved in detecting a filling state of a reservoir of a hygiene consumable according to embodiments of the present invention;

[0017] Figures 3A to 3D show di f ferent types of hygiene equipment in which a filling state of a reservoir of a hygiene consumable is detected according to embodiments of the present invention;

[0018] Figure 4 shows a schematic view of a modular implementation of a sensor arrangement according to an embodiment of the present invention; and

[0019] Figure 5 shows a flow chart of a general method embodiment of the present invention .

[0020] Detailed description

[0021] Figures 1A and IB show general device embodiments of the present invention for a sensor arrangement detecting a filling state of a reservoir of a hygiene consumable . More speci fically, Figure 1A shows a paper towel dispenser 1 as an example of the hygiene equipment . Following this example, the dispenser 1 comprises a reservoir 200 for holding a supply 20 of a consumable in the form of paper towels 2 . The current example considers a top-down arrangement in which one or more towels 2 can be dispensed from the bottom side 19 of the dispenser 1 . As a consequence , the supply 20 will deplete along the depletion direction D as the dispenser is used, and one or more individual ( s ) take and pull out towels 2 . The dispenser 1 comprises a sensor arrangement 10 which is provided for detecting a filling state of the reservoir 200 of the hygiene consumable 20 .

[0022] Figure IB shows a functional block diagram of the sensor arrangement 10 for detecting a filling state of the reservoir 200 of the hygiene consumable 20 . Speci fically, the sensor arrangement 10 comprises a sensor 110 arranged to measure a figure indicating a filling state along the depletion direction D of the reservoir 200 . For example , the sensor 110 may comprise a time of flight , TOF, sensor that is arranged to measure a figure that indicates a distance between a sensor location and a limit of hygiene consumable in the reservoir . In addition thereto or alternatively, the sensor 110 may comprise a set of sensors arranged along the depletion direction of the reservoir, each sensor being configured to detect presence of hygiene consumable in its respective proximity . Further details of the sensor technology is described elsewhere in the present disclosure and in particular in conj unction with Figures 2A & 2B .

[0023] At this point it is also referred to Figure 1C that shows a schematic and exemplary behaviour of a measured figure that indicates a filling state along a depletion direction of the reservoir according to at least some embodiments of the present invention . Speci fically, there is shown a plot of measured values F over time t . For example , the figure F is representative of a distance between a sensor and a top end of a supply of consumable in the reservoir and it is assumed that the larger the distance is the more depleted is the reservoir . As can be seen, measured values for F accumulate in two regions Rf and Re , wherein some measurement points are observed in the time between points in Rf and Re but j umps J between Re and Rf . This may reflect the situation in which a reservoir depletes gradually from full , f , to empty, e , whereas abruptly "j umps" back from empty, e , to full , f , when refilled .

[0024] The sensor arrangement 10 further comprises a processing section 120 which is generally adapted to drive and read out the sensor 110 for measuring the respective figure F that indicates a filling state along the depletion direction D . This may involve applying a well-defined voltage and / or current to the sensor 110 and to measure the detection response again by measuring a response voltage and / or current . This may involve analogue-to- digital conversion which is part of commonplace microprocessors today . Another option is digital inter-communication between the sensor 110 and the processing section 120 in which the sensor ( IC ) already converts any measured figure into a digital representation which can then be communicated to the processing section 120 over an applicable interface and protocol ( such as I2C, SPI , Iwire and the like ) . Such microprocessors may form a part of the processing section 120 and may provide other functions as well , including memory, storage , and / or communication functionalities .

[0025] The processing section 120 is generally configured to compile information indicating the filling state of the reservoir on the basis of the measured figure . Speci fically, the measured figure may comprise at least one component that is dependent on and / or relates to the filling state . For example , a TOF sensor will produce at least at some point in time a figure that relates to the time it takes the signal to propagate , or " fly" , from the sensor to the target and back to the sensor . This may relate to the filling state as the distance between the sensor and an end of the consumable supply relates to how much supply is left in the reservoir . Similarly, the figure may relate to a number or a position of one of several sensors that detect presence of consumable in their respective proximity . For example , the smaller the number of sensors that detect presence of consumable , the more the reservoir is depleted . In one or other of such ways , the processing section 120 is therefore able to compile the information that indicates the filling state of the reservoir .

[0026] The sensor arrangement 10 further comprises an access 130 to a memory which is configured to store learning data . The access to a memory may comprise any one of a memory circuit , a memory integrated in said processing section, and an access to a remote memory via a network . The access 130 may comprise an interface to a local and / or remote data storage that in turn stores the learning data . The local data storage 1300 may be implemented as a separate memory device or may even be integrated into the processing section 120 or in a respective microprocessor . As already mentioned, such microprocessors may provide further functionalities , including non-volatile data storage e . g . in the form of so-called FLASH memory . A remote memory may be implemented by means of a data storage in a server, Internet or so-called Cloud 150 . In such situations , the access 130 may employ a communication network, such as GPRS , GSM, UWB, BLE , WLAN, WiFi , UMTS , 4G, LTE , 5G, 6G, and the like , to access that remote memory . The learning data generally includes data that reflects past measurements and allows for associating a measured figure to a speci fic filling state or at least a range thereof .

[0027] The processing section 120 is further configured to store the learning data in relation to a plurality of measured figures indicating a filling state . This may include that the processing section 120 identi fies any one of a maximum indicated by one or more measured figures , a minimum indicated by one or more measured figures , an inflection point indicated by one or more measured figures , an extremum value of one or more measured figures , and an invalid value of one or more measured figures as an event associated to one or more assumed filling states of the reservoir . Further, the processing section can perform a machine learning process for determining the association of the one or more figures to the one or more assumed filling states . In a way, the processing section may record over time behaviour patterns of the measured figure , store them in the form of learning data, and, as part of that , derive conclusions from that for the association of measured figures to respective filling states . This may also account for both unconventional as well as typical operation patterns may include situations in which a dispenser is refilled to a full state relatively promptly and from the beginning . In such a pattern it may take some time before the process gets the chance to learn the si ze of the ref ill / dispenser volume . It may be considered to deliberately run the dispenser empty during the installation process or in the early use time so that the processor can experience an empty level and accordingly learn what the dispenser refill and reservoir volume will look like .

[0028] For example , the processing section stores a plurality of measured figures from the sensor over time which then represents a history of figure values that relates to the history of filling states . Over time , the learning data may thus allow determining knowledge on situations that can be assumed to correlate with maximum and minimum filling states of the reservoir . For example , a measured distance ( from e . g . a TOF sensor ) may be observed to vary substantially between two values or set of values . Once one set of values is reached a sudden "j ump" to the other set of values may indicate a refill ( this may in principle be as already described in conj unction with Figure 10 ) . Further, there may be observed only one set of diverging values while the remainder of values varies for situations in which the refill cannot be assumed to be constant or intermediate filling states are more di f ficult to detect to states toward the end of the depletion direction . With again reference to Figure 10, the latter scenario would only show an accumulation of data points in region Re while outside this region may j ump but not to a reproducible , speci fic range or level .

[0029] The processing section 120 is further configured to identi fy an event associated to one or more assumed filling states of the reservoir . An event may be identi fied from the behaviour of the measured figure in that the respective values are indicative of such an event . For example , the measured figure may assume values in a convergent manner in that the respective values remain in some range for a longer time ( or pre-defined time , or time longer than a time span in which the value remains more or less constant otherwise ) . This may be the case for an empty scenario as the measured figure will no longer change due to absence of any supply . Likewise , an event may be identi fied in a behaviour that is quicker than usual . Speci fically, while it takes some time for the reservoir to deplete during regular use ( and the figure varying accordingly slow) , a refill results in a much more abrupt change of the value .

[0030] Therefore , the processing section 120 can identi fy an event associated to one or more assumed filling states of the reservoir, by looking for example at converging and / or abruptly changing figure values . Generally, the processing section may identi fy an event associated to one or more assumed filling states of the reservoir on the basis of processing and / or observing the stored learning data that is indicative of a value history of the measured figure . Speci fically, events could indicate that a dispenser is refilled, relate to an activity level in dispenser (high demand vs . low demand) , long periods of an empty dispenser, and / or abnormal behaviour . Any event can then also be reported toward the network 150 , or could also be first stored locally and then sent periodically .

[0031] The processing section 120 is further configured to determine an association of one or more figures being measured by said sensor to one or more assumed filling states of the reservoir . Based on the stored learning data and one or more identi fied events , the processing section can " interpret" the values of a measured figure and associate the value to a likely corresponding filling state . For example , i f a measured figure has a value close to a range that indicates an empty state , the filling state can be determined as such . The mentioned range , such as Re as explained in conj unction with Figure 1C, may be a range to which figure values converge to and / or from which j umps or abrupt changes are observed to another range ( e . g . Rf ) .

[0032] I f , however, a measured figure has a value close to a range that indicates a full state , the filling state can be determined as such . This j ust mentioned, second range , such as Rf , may be a range to which figure values j ump or abruptly change to from another range ( e . g . Re ) . In addition, interpolation techniques may apply in order to associate measured figures to intermediate filling states . Further, the learning data may also be employed for identi fying any non-linearities in the depletion behaviour of the reservoir, as the latter may not feature a uni form crosssection along the depletion direction (which may be the case for reservoirs for a liquid consumable that may thin toward the end of the depletion direction . The values in the sensor can also be calculated or identi fied as "abnormal" i f , for example , a sensor reading is "much" outside a plausible range or range of values to be expected during normal operation . For example , the paper supply is exhausted and a probe beam from the sensor is reflecting on the floor and not the paper stack . Such values or measurement results can be identi fied and, for example , ignored or discarded .

[0033] The sensor arrangement may further comprise a communication section 140 , wherein the processing section 120 is further configured to compile a message on the basis of said information indicating the filling state and to transmit via the communication section the compiled message toward a network . In this way, the sensor arrangement can inform a monitoring platform about the filling state in periodic or regular intervals and / or in response to speci fic events , such as the filling state of the reservoir depleting beyond a pre-determined threshold . The communication section 140 can also be employed by the memory access 130 for providing access to remotely stored data .

[0034] Figures 2A and 2B show general measuring concepts involved in detecting a filling state of a reservoir of a hygiene consumable according to embodiments of the present invention . In Figure 2A there is shown a sensor arrangement 11 with a so-called time of flight , TOF, sensor 111 which is arranged to measure a figure that indicates a distance d between a sensor location L and a limit of hygiene consumable in the reservoir, in the shown case an upper end of a supply 20 at S . In principle , the distance d can lie substantially in the depletion direction D . In a TOF arrangement , the time of flight will relate to the time the probe signals travels from the sensor to the consumable and back therefrom which would at some point in time require considerations that the measured time indicates a distance which is longer than and roughly twice as much as the distance d of interest . The TOF sensor 111 may comprise any one of an ultrasonic sensor, a radar sensor, a light sensor, a laser sensor, a mirror, an a reflective surface . For example , a suitable TOF sensor may be sensor "VL53L1X" manufactured by ST Microelectronics . Such sensors may provide accurate ranging up to 4 m and a ranging frequency up to 50 Hz . Housed in a compact package , such sensors may integrate a so-called, single photon avalanche diode , SPAD, receiving array, a 940 nm invisible Class i laser emitter, physical infrared filters , and optics to achieve the desired performance in various ambient lighting conditions . Such sensors may allow for absolute distance measurement relatively independent from the target colour and reflectance .

[0035] In Figure 2B there is shown a sensor arrangement 12 with wherein the sensor comprises a set of sensors 122- 1 , 122-2 , ... which may be arranged along the depletion direction D of the reservoir 200 . In such a configuration, each sensor 122-i is configured to detect presence of hygiene consumable in its respective proximity . This may be implemented by means of capacitive or light sensors that produce a distinguishable output in relation to whether or not there is supply of consumable next to it ( i . e . in the respective vicinity) . Generally, the sensor can be any one of light barrier sensor, a reflection sensor, a proximity sensor, and a capacitive sensor . For example , a light signal may be reflected ( at least in part ) by the consumable while it may be absorbed A by a reservoir wall when there is no consumable . Likewise , a light signal may be reflected R by a reservoir wall when there is no consumable but absorbed by the consumable .

[0036] It is noted that the embodiment shown in Fig . 2B may be o f particular relevance i f the sensor arrangement / strip is not predefined to match a given piece of hygiene equipment ( e . g . dispenser ) . For example , the sensor arrangement 12 could have some default length with equally distanced sensors 122-i , and which is shortened to a non-pre-def ined but speci fic length to match the height of the target reservoir in the actual dispenser . For example , the sensor arrangement may have a housing which provides for a number of predetermined breaking points or lines so as to shorten the sensor arrangement by cutting and / or folding . There may be a printed circuit board ( PCB ) inside the housing that features breaking points that correspond to the points or lines of the housing so as to allow for easy shortening ( e . g . by means of a line of holes ) . The signal traces that feed the individual sensors 122-i on the PCB may be linear along the depletion direction so that they can be cut without causing any signal or supply distortion for the remaining sensors ( e . g . for the case of a linear arrangement of I2C sensors , one line each for VDD, VSS , SCL, and SDA) . In such an embodiment there may be no pre-defined knowledge of the si ze , design, volume of the piece of hygiene equipment so the machine learning process can be employed for this embodiment in a similar manner as that of the Fig . 2A embodiment .

[0037] Figures 3A to 3D show di f ferent types of hygiene equipment in which a filling state of a reservoir of a hygiene consumable is detected according to embodiments of the present invention . Figure 3A shows a schematic view of a dispenser 1-2 that is arranged to dispense a hygiene consumable in a liquid form . For example , this may be a soap dispenser or a dispenser for a disinfectant such as alcohol or alcogel . Predominantly for such a dispenser type the depletion direction D will be from the top to the bottom as the supply of the consumable will accumulate toward the bottom . The measured figure may be in relation to a top surface of the supply and a maximum height of the reservoir .

[0038] Figure 3B shows a schematic view of a dispenser 1-3 that is arranged to dispense a hygiene consumable such as a tissue or paper towel . The shown case may be similar to the dispenser type as explained in conj unction with Figure 1A but may be di f ferent insofar the depletion direction D may be from the bottom to the top . Namely, there exist tissue dispenser that push a supply upwards so that a user can pull out one or more towels / tissues from the top . Mechanical spring action may be involved to push up the tissue supply as consumables are dispensed . This configuration may provide the opportunity for measuring a distance between a sensor position and the position of a well- defined element such as the support that pushes the consumable supply upwards . In this way, the sensor ( e . g . TOF or light ref lection / absorption) may be more independent from the consumable as such as measurement do not depend on optical or other physical properties of the consumable .

[0039] Figure 3C shows a schematic view of a dispenser 1-4 that is arranged to dispense a hygiene consumable in the form of a roll , such as toilet paper . In such types , a diameter of the roll can act as an end or limit of the supply, whereas the position of the sensor may be again a fixed point for any distance measurements . It is noted that this concept may apply to both types of roll dispensers , namely rolls that supply from the outside ( depletion direction D, distance to be considered between outer roll diameter and sensor position) as well as rolls that supply from the inside ( depletion direction D' , distance to be considered between inner roll diameter and sensor position) .

[0040] Figure 3D shows a schematic view o f a piece of hygiene equipment in the form of a waste bin 1-5 that is arranged to receive a used hygiene consumable in the form of towels , tissues , and the like . In such types , the reservoir is for used consumables and the filling state will increase over time rather than decrease as is the case for the earlier discussed types of hygiene equipment . A full reservoir is then an indication for the need of emptying the bin or replacing a full bin liner with a new one . However, the general concepts of the present invention naturally apply accordingly . Especially, also any considerations relating to a filling state and a depletion direction, in that the reservoir is seen as free capacity to receive further used consumables . Thus , during use of a piece of hygiene equipment of that type the reservoir will al so deplete along a depletion direction, as , for example , the reservoir for holding additional material will deplete upwards , and as shown with D in Figure 3D, while the bin is in use . In a further embodiment , the processing section can vary an acquisition interval for measuring the figure indicating the filling state on the basis of compiled information indicating the filling state . Speci fically, the processing section can determine whether the filling state has decreased below a predetermined threshold, and, i f so , decrease the acquisition interval . In this way, the frequency of acquiring a measured figure is increased once the reservoir is approaching depletion . This can provide additional benef its in terms of responsivity and / or power consumption . Namely, while it may not be necessary to have precise information on the filling state when the reservoir is still suf ficiently full of supply, that may change when the piece of hygiene equipment approaches depletion as it may then be a suitable point in time to initiate a refill ( or replacement ) . It is also during this time when the increased power consumption by the increased measurement frequency may be j usti fied . As the reservoir is running low, one may accept increased power consumption for being warned in time to initiate a ref ill / replacement which in all provides a more reliable availability of the piece of hygiene equipment .

[0041] Preferably, the processing section can use an acquisition interval of more than 30 minutes i f the information indicating the filling state indicates a filling state of more than 50% , 30% or 20% of the reservoir, and to use an acquisition interval of less than 10 minutes i f the information indicating the filling state indicates a filling state of less than 50% , 30% or, respectively, 20% of the reservoir . Further, the acquisition interval can vary based on time-of-day or activity in dispenser . For example , whenever there is little use of a dispenser ( e . g . during night for a venue primarily used during daytime , in winter for a venue primarily used in summer, or whenever that little use is detected) measurements can be made less often and the acquisition interval can be increased . Further, the processing section 120 can determine the interval dynamically and adj ust it according to current use patterns . For example , i f the reservoir depletes relatively fast , the interval can be decreased, while i f the reservoir depletes relatively slowly, the interval can be increased . Figure 4 shows a schematic view of a modular implementation of a sensor arrangement according to an embodiment of the present invention . Speci fically, the sensor arrangement can be provided as an individual unit 10 ' in principle independent from any speci fic piece of hygiene equipment . For this purpose , the sensor arrangement 10 ' may further comprise a housing 100 that accommodates at least the sensor 110 and the processing section 120 . The housing 100 may provide for a mechanical link for attaching and detaching the housing, and, with this , the sensor arrangement from a piece of hygiene equipment , such as a dispenser . In such a case , the piece of hygiene equipment may comprise at least one adapter for mating with a sensor arrangement for being removably mounted to or being removably mounted to the adapter . The sensor arrangement may then comprise the housing 100 accommodating the sensor elements as described and at least one mounting foot 101 for mounting the sensor arrangement 10 ' to the adapter .

[0042] In such configurations , the mounting foot 101 may include a supporting contact part 102 with a supporting surface 103 for supporting the sensor arrangement 10 ' on a respectively averted attachment surface of the mating adapter, and a connecting part 104 connecting the supporting contact part 102 and the sensor arrangement housing . The adapter may comprise an insertion opening for insertion of the supporting surface 103 of the modular sensor arrangement 10 ' , a slot-shaped opening for sliding therein the connecting part of the sensor arrangement , the slot-shaped opening being connected to the insertion opening, and the attachment surface for being averted to the sensor arrangement 10 ' , the attachment surface extending from and / or connected to the slot-shaped opening so as to allow the attachment surface and the supporting surface to be mated with each other .

[0043] Figure 5 shows a flow chart of a general method embodiment of the present invention . Generally, the method is for operating a sensor arrangement for detecting a filling state of a reservoir of a hygiene consumable in a piece of hygiene equipment . The sensor arrangement comprises a sensor arranged to measure a figure indicating a filling state along a depletion direction of the reservoir, a processing section and an access to a memory configured to store learning data . The sensor arrangement is operated by the following steps to be performed by said processing section subsequently and / or in parallel . These steps include a step S 100 of compiling information indicating the filling state of the reservoir on the basis of the measured figure , a step S200 of storing said learning data in relation to a plurality of measured figures indicating a filling state , a step S300 of identi fying an event associated to one or more assumed filling states of the reservoir, and a step S400 of determining an association of one or more figures being measured by said sensor to one or more assumed filling states of the reservoir .

[0044] For example , the step S200 can be performed once or continuously whenever learning data is available for being stored . The step S300 can be performed whenever learning data is available for it to be processed for identi fying an event , such as a refilling event as mentioned elsewhere in the present disclosure . Likewise , the step S400 can be performed whenever suitable , for example periodically or upon reception ( and storage ) of new learning data in step S200 and / or upon identi fying an event in step S300 for determining or determining anew ( in the sense of updating) the association between measured figures and corresponding filling states . The step S 100 can be performed at any time so as to compile the desired information from a measured figure by relying on the available association for interpreting the measured value in the sense of associating a particular measured figure to a speci fic filling state ( or range thereof ) .

[0045] Although detailed embodiments have been described, these only serve to provide a better understanding of the invention defined by the independent claims and are not to be seen as limiting .

Claims

Claims :1 . A sensor arrangement for detecting a filling state of a reservoir of a hygiene consumable comprising : a sensor arranged to measure a figure indicating a filling state along a depletion direction of the reservoir, a processing section configured to compile information indicating the filling state of the reservoir on the basis of the measured figure , an access to a memory configured to store learning data, wherein the processing section is configured to store said learning data in relation to a plurality of measured figures indicating a filling state , to identi fy an event associated to one or more assumed filling states of the reservoir, and to determine an association of one or more figures being measured by said sensor to one or more assumed filling states of the reservoir .2 . The sensor arrangement according to claim 1 , wherein the processing section is configured to identi fy any one of a maximum indicated by one or more measured figures , a minimum indicated by one or more measured figures , an inflection point indicated by one or more measured figures , an extremum value of one or more measured figures , and an invalid value of one or more measured figures as an event associated to one or more assumed filling states of the reservoir .3 . The sensor arrangement according to claim 1 or 2 , wherein the processing section is configured to perform a machine learning process for determining the association of the one or more figures to the one or more assumed filling states .4 . The sensor arrangement according to any one of claims 1 to 3 , wherein the sensor comprises a time of flight , TOF, sensor arranged to measure a figure indicating a distance between a sensor location and a limit of hygiene consumable in the reservoir .5 . The sensor arrangement according to claim 4 , wherein said distance lies substantially in the depletion direction .6 . The sensor arrangement according to claim 4 or 5 , wherein the TOF sensor comprises any one of an ultrasonic sensor, a radar sensor, a light sensor, a laser sensor, a mirror, an a reflective surface .7 . The sensor arrangement according to any one of claims 1 to 3 , wherein the sensor comprises a set of sensors arranged along the depletion direction of the reservoir, each sensor being configured to detect presence of hygiene consumable in its respective proximity .8 . The sensor arrangement according to claim 7 , wherein the sensor is any one of light barrier sensor, a reflection sensor, a proximity sensor, and a capacitive sensor .9 . The sensor arrangement according to any one of claims 1 to 8 , wherein the processing section is configured to vary an acquisition interval for measuring the figure indicating the filling state on the basis of compiled information indicating the filling state .10 . The sensor arrangement according to claim 9 , wherein the processing section is configured to determine whether the filling state has decreased below a predetermined threshold, and, i f so , decrease the acquisition interval .11 . The sensor arrangement according to claim 9 or 10 , wherein the processing section is configured to use an acquisition interval of more than 30 minutes i f the information indicating the filling state indicates a filling state ofmore than 50% of the reservoir, and to use an acquisition interval of less than 10 minutes i f the information indicating the filling state indicates a filling state of less than 50% of the reservoir .12 . The sensor arrangement according to any one of claims 1 to 11 , wherein said access to a memory comprises any one of a memory circuit , a memory integrated in said processing section, and an access to a remote memory via a network .13 . The sensor arrangement according to any one of claims 1 to12 , further comprising a communication section, wherein the processing section is further configured to compile a message on the basis of said information indicating the filling state and to transmit via the communication section the compiled message toward a network .14 . The sensor arrangement according to any one of claims 1 to13 , further comprising a housing accommodating at least the sensor and the processing section, the housing providing for a mechanical link for attaching and detaching the housing from a dispenser .15 . A piece of hygiene equipment for dispensing and / or receiving a hygiene consumable , comprising a sensor arrangement according to any one of claims 1 to 14 .16 . A method of operating a sensor arrangement for detecting a filling state of a reservoir of a hygiene consumable , the sensor comprising a sensor, a processing section and an access to a memory configured to store learning data, the method comprising the steps of : measuring a figure indicating a f illing state along a depletion direction of the reservoir ; compiling information indicating the filling state of the reservoir on the basis of the measured figure ; storing said learning data in relation to a plurality of measured figures indicating a filling state ;identi fying an event associated to one or more assumed filling states of the reservoir, and determining an association of one or more figures being measured by said sensor to one or more assumed filling states of the reservoir .

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