Patent Description:
As is known, traceability of products along the chain is becoming increasingly important in the agri-food sector. On the one hand, in fact, in many countries traceability is imposed by regulations governing hygiene and food safety and, on the other hand, it is especially interest of the companies that produce high-quality products to be able to ensure the public in the best way possible of the origin of raw materials and the nature of the processing carried out, as well as the integrity up to the commercialization. Therefore, essentially, there is the need to reduce the room for possible frauds carried out by replacing or adding raw materials having a different provenance from the one declared, everything also for the fundamental protection of the final consumer paying attention to quality.

Therefore, numerous solutions have been developed that have the aim to help the certification of the provenance and of the processing of the commercialized products. Generally, however, exactly the initial steps of the traceability chain of agricultural products, i.e. the collection and the transportation toward the processing site, have elements of weakness that make the certification difficult and still leave wide margins for fraud attempts. This is particularly true, for example, for the collection of fruits of any type and for many types of vegetables. The difficulties arise from the obvious lack of technological infrastructure at the collection sites, that currently prevents from carrying out operations necessary for the certification of the product.

In addition to the protection against frauds, it is also important to trace and document also the preservation conditions of the raw materials. Frequently, in fact, agri-food products are especially sensitive to temperature and to humidity and the organoleptic properties can deteriorate in an unrepairable manner if the preservation conditions are not suitable. Also the squashing due to the use of collection and/or storage containers that are too big can be a problem. Moreover, it is advisable to note that, even more than in storehouses, where the environmental conditions can be controlled, the risk of damage due to bad preservation is greater exactly at the collection sites and during transportation. Often, for example, the containers used for the collection remain exposed for a long time under the sun after being filled, because at the collection sites there is a lack of sufficiently spacious shaded areas.

The available sensors do not allow, though, combining in a satisfactory manner different needs, which not infrequently are in conflict. For example, especially with regard to the weight sensors, it is necessary to ensure not only precision and flexibility of use in extremely variable environmental conditions, but also compliance with sanitary or disciplinary regulations which are often very strict. Consider the use of said sensors during the collection of products in different seasons or in hill or mountain territories with differences of height sometimes of hundreds of meters and with the consequent variations of temperature and pressure. The need to seal the sensors in order to prevent contaminations of the products (but also damage to said sensors) may not allow keeping an acceptable level of reliability in very different environmental conditions.

<CIT> discloses a sensor assembly for an equipment for aiding traceability of agri-food products comprising a first plate, a second plate, facing the first plate, and a first chamber defined between the first plate and the second plate. A load cell is housed in the first chamber and coupled to the first plate and to the second plate so as to be responsive to a load applied on the second plate.

The object of the present invention is to provide a sensor assembly that allows overcoming or at least mitigating the described limitations.

According to the present invention, a sensor assembly for an equipment for aiding traceability of agri-food products is therefore provided substantially as defined in claim <NUM>.

Further characteristics and advantages of the present invention will be evident from the following description of non-limiting example embodiments, with reference to the figures of the accompanying drawings, wherein:.

With reference to <FIG>, an equipment for aiding traceability of agri-food products is indicated, as a whole, by reference numeral <NUM>. The equipment <NUM> is specially intended to support traceability in the collection step of fruits and vegetables of any type.

The equipment <NUM> comprises a container <NUM> for the collection of fruits and a frame <NUM>, provided with connecting members <NUM> for the connection to the container <NUM>.

The container <NUM> may be any container generally open at the top and usable for the collection of fruits or vegetables. In the example of <FIG>, the container <NUM> is a crate stackable with other crates of the same type (generally suitable to contain several kilos of product and thus easily transportable by hand). Alternatively, the container <NUM> may be a standard bin suitable to contain larger quantities of product and movable through mechanical forks. In an embodiment, the container <NUM> is provided with an identification tag 2a, that contains a unique identification code and may be of electromagnetic reading type (for example an RFID or NFC tag).

In an embodiment, the frame <NUM> comprises a vertical support 3a defined by one or more uprights fixed to the connecting members <NUM>, which are configured in particular to allow reversibly connecting the frame <NUM> to the container <NUM>. In the embodiment of <FIG>, in particular, the connecting members <NUM> comprise a base <NUM> designed to receive the container <NUM> and fixed to a ground resting portion 3b of the frame <NUM>. The base <NUM>, in particular, may be defined by a stackable crate identical to the container <NUM>. In this manner, the coupling between the frame <NUM> and the container <NUM> is simple and quick and, furthermore, the positioning of the container <NUM> is accurate and repeatable. In an embodiment not shown, the base may be planar, for example with a substantially horizontal plate for the resting of the container <NUM>. Alternatively, the connecting members may comprise vices, clamps or clutch or screw fixing systems and the like.

With reference also to <FIG>, the equipment <NUM> further comprises an image detecting device <NUM>, a movement sensor <NUM>, a satellite localization device <NUM>, an identification tag reader <NUM>, a processing unit <NUM> provided with a storage device <NUM>, and a wireless communication module <NUM>, which, in a non-limiting embodiment, are all mounted on the frame <NUM>. A local control interface <NUM> is provided with a screen 13a and may be supported by the frame <NUM> and connected via cable to the processing unit <NUM> or may be defined by a mobile device, such as a smartphone or a tablet and communicably coupled to the processing unit <NUM> through the wireless communication module <NUM>, for example by using the standard Bluetooth communication. Alternatively, a remote interface <NUM> may be communicably coupled to the processing unit <NUM> for the same purpose through the wireless communication module <NUM>. At least the satellite localization device <NUM>, the identification tag reader <NUM>, the processing unit <NUM>, the storage device <NUM>, the wireless communication module <NUM> and the control interface <NUM> may be housed inside a same case fixed to the frame <NUM>. In an alternative embodiment, the functions of the satellite localization device <NUM>, of the identification tag reader <NUM>, of the processing unit and of the storage device <NUM> may be integrated in a mobile device (smartphone or tablet).

In an embodiment, the image detecting device <NUM>, comprises image sensors <NUM>, <NUM>, provided with respective fixed or variable optics not shown, and an illuminator <NUM>.

The image sensors <NUM>, <NUM> may essentially be sensors in the visible band, such as CMOS or CCD sensors, or infrared or ultraviolet radiation sensors, laser scanners or, generally, of any type suitable to be mounted on the frame <NUM>.

The image sensor <NUM> is oriented toward the base <NUM> so as to frame an observed region R1 including the mouth of the container <NUM> when the latter is placed in the base <NUM>, as is shown in <FIG>. The image sensor <NUM> is configured to acquire single images and/or image sequences for a planned period of time on the basis of the type of activity to be observed and traced in response to movements detected by the movement sensor <NUM> and to remain in a standby condition in the absence of signals indicative of movements detected by the movement sensor <NUM>. The coupling to the movement sensor <NUM> may be direct or indirect through the processing unit <NUM> (<FIG>). In other words, the image sensor <NUM> may be directly responsive to signals coming from the movement sensor <NUM> or to commands generated by the processing unit <NUM> in turn in response to signals coming from the movement sensor <NUM>. In an embodiment, the image acquisition is carried out with a lag, for example of several seconds, with respect to the instants in which the movement sensor <NUM> detects a movement or the last of a sequence of movements in its sensible range.

The image sensor <NUM> is oriented so as to take panoramic images of a portion of the ground around the equipment <NUM> where the collection is carried out, in particular of trees from which fruits are collected, besides installations, fences, portions of premises and any present objects (<FIG>). The image sensor <NUM> may be manually activated through commands provided by an operator through the control interface <NUM> or in response to a change of spatial coordinates indicated by the satellite localization device <NUM> (for example, following shifts beyond a minimum planned distance).

In an alternative embodiment not shown, it is possible to use a single image sensor orientable both toward the base <NUM>, and toward the surrounding area and/or variable optics that allow manually or automatically commuting between the different frames on the basis of a preset mode.

The movement sensor <NUM> may be, for example, a passive infrared sensor, a DMT ("Digital Motion Technology") sensor, a microwave sensor, an ultrasound sensor or combinations thereof. The movement sensor <NUM> is oriented toward the base <NUM> for detecting movements in a surveillance region R2 including at least a portion of the observed region R1 framed by the image detecting device <NUM>. In particular, the movement sensor <NUM> is configured to be activated by the insertion of the container <NUM> in the base <NUM> and by transfer operations into the container <NUM> already in the base <NUM> of collected fruits. Essentially, therefore, the movement sensor <NUM> allows identifying the introduction of the container <NUM>, empty or full, in the base <NUM> and the actions that imply a variation of the content of the container <NUM> when the latter is in the base <NUM>.

Furthermore, as mentioned, the movement sensor <NUM> determines, directly or indirectly through the processing unit <NUM>, the acquisition of images by the image sensor <NUM>.

The satellite localization device <NUM> is, for example, a GPS localizer or a GNSS navigator and is communicably coupled to the processing unit <NUM> for providing, in response to a command, a pair of spatial coordinates (longitude and latitude).

The identification tag reader <NUM> is of a type suitable to read the identification tags 2a indicated on the container <NUM>. Depending on the identification tags 2a used, the identification tag reader <NUM> may comprise, for example, an RFID reader.

With reference to <FIG>, the equipment <NUM> is further provided with a sensor assembly <NUM>, configured to be removably coupled to the container <NUM>. More precisely, the container <NUM> and the sensor assembly <NUM> placed inside the container <NUM> define a tool <NUM> for aiding traceability usable in the equipment <NUM>.

The sensor assembly <NUM> (<FIG>) comprises a weighing device <NUM> and a plurality of sensors, among which for example an accelerometer <NUM>, an inclinometer <NUM>, an internal temperature sensor <NUM>, external temperature sensors <NUM>, an internal humidity sensor <NUM>, external humidity sensors <NUM>, a pressure sensor <NUM> and pH-meters <NUM>. Furthermore, the sensor assembly comprises an on-board processing unit <NUM>, a storage module <NUM>, an identification tag reader <NUM>, a communication module <NUM>, a battery <NUM> and a recharging device <NUM>.

The weighing device <NUM> defines a case of the sensor assembly <NUM> and has a width and a length much greater than the thickness and plan for example quadrangular, with a main first face 101a and a main second face 101b opposite each other. The weighing device <NUM> is removably fixed to the bottom wall 2b of the container <NUM> by fixing elements <NUM>, such as tamper-resistant screws or, in embodiments not shown, biadhesive strips, release elements and the like. Alternatively, if the container <NUM> is provided with aeration holes, the fixing may be obtained by clips. In use, the first face 101a faces the bottom wall 2b of the container <NUM>.

The weighing device <NUM> comprises a base plate <NUM>, a load plate <NUM> and one or more load cells <NUM>, that may be manufactured with any available technology. The base plate <NUM> and the load plate <NUM> are made of a dielectric material and are sufficiently rigid to bear the maximum load allowed inside the container <NUM> without appreciably deforming. The base plate <NUM> has a face 110a fixed to the bottom wall 2b of the container <NUM>, whereas the load plate <NUM> has a face 111a opposite the face 110a of the base plate <NUM> and facing toward the inside of the container <NUM>. The faces 110a, 111a of the base plate <NUM> and of the load plate <NUM> are flat and parallel to each other. The base plate <NUM> has a perimetral frame 110b that projects toward the load plate <NUM>. Similarly, the load plate <NUM> has a perimetral frame 111b that projects toward the base plate <NUM>. Furthermore, the base plate <NUM> has such dimensions as to receive the load plate <NUM> slidably and with play inside a recess defined by the perimetral frame 110b.

Specifically, the load plate <NUM> is constrained to slide relative to the base plate <NUM> exclusively in a direction perpendicular to the face 111a of the load plate <NUM>, for example by a coupling to linear guide and cursor, as is shown in the example of <FIG>. In this case, linear guides <NUM> are fixed to the base plate <NUM> and extend perpendicular to the face 110a in direction of the load plate <NUM> and are received between pairs of pins <NUM> made on an internal lateral surface of the perimetral frame 111b of the load plate <NUM>. The linear guides <NUM>, for example T-shaped, also define stopping elements <NUM> that prevent the load plate <NUM> from separating from the base plate <NUM>. It is understood that the slidable coupling between the base plate <NUM> and the load plate <NUM> may be obtained by any other suitable device.

Thanks to the perimetral frames 110b, 111b and to the recesses defined thereby, a sensor chamber <NUM> is defined between the base plate <NUM> and the load plate <NUM> (see in particular <FIG>).

The load cells <NUM> are arranged in the sensor chamber <NUM> between the base plate <NUM> and the load plate <NUM> so as to be responsive to the loads on the face 111a of the load plate <NUM> and on the face <NUM> of the base plate <NUM>. Essentially, when the base plate <NUM> rests on the ground (in particular inside the container <NUM>) and a load is applied to the face 111b of the load plate <NUM>, the load plate <NUM> stresses the load cells <NUM>.

The sensor chamber <NUM> further houses the accelerometer <NUM>, the inclinometer <NUM>, the internal temperature sensor <NUM>, the internal humidity sensor <NUM>, the pressure sensor <NUM>, the on-board processing unit <NUM>, the storage module <NUM>, the identification tag reader <NUM>, the communication module <NUM>, the battery <NUM> and the recharging device <NUM>.

An impermeable membrane <NUM> made of yielding material, for example a silicone sheath, seals the space between the base plate <NUM> and the load plate <NUM>. More precisely, the membrane <NUM> is fluid-tight coupled to the perimetral frame 110b of the base plate <NUM> and to the perimetral frame 111b of the load plate <NUM> along the whole perimeter thereof and delimits a sealed closed space containing the sensor chamber <NUM>. For example, the membrane <NUM> may be comolded or glued to the perimetral frame 111b of the load plate <NUM> and sealingly fixed to the perimetral frame 110b of the base plate <NUM> by a fixing frame <NUM>. In an embodiment, the fixing frame <NUM> may be removably applied by screws or release fixings not shown for favoring the execution of maintenance interventions inside the sensor chamber <NUM> or for the replacement of the membrane <NUM>. The fixing frame <NUM> is provided with a protective structure <NUM> (in <FIG> shown only in part) for the membrane <NUM>. The protective structure <NUM> is defined by a plurality of arched teeth, that extend comb-like toward the load plate <NUM> so as to form a cage.

It is further understood that the sensor assembly <NUM> may also be overturned. In this case, the base plate carries out the function of load plate and vice versa. The number and the arrangement of the load cells <NUM> may be selected on the basis of the design preferences. In the embodiment of <FIG> there are four load cells <NUM>, for example of piezoelectric type, arranged in the center of respective dials of the weighing device and coupled to the base plate <NUM> and to the load plate <NUM>. The load cells <NUM> are communicably coupled to the on-board processing unit <NUM> for providing load signals SW, indicative of the respective load state of each load cell <NUM> (<FIG>). The overall surface of the load plate <NUM> may be substantially equal to the surface of the bottom wall 2b of the container <NUM> or smaller.

Alternatively, it is possible to use load plates coupled to a set of load cells <NUM> and arranged adjacent to one another so as to form a single load plane (for example two load plates <NUM>' each coupled to two load cells <NUM>, as in the embodiment of <FIG> or four load plates <NUM>" coupled to respective load cells <NUM>, <FIG>). Analogously, it is possible to use several base plates instead of the single base plate <NUM> shown in <FIG>.

The membrane <NUM> is shaped so as to define, around the load plate <NUM>, a compensation chamber <NUM> which is in fluid communication with the sensor chamber <NUM> through the play between the base plate <NUM> and the load plate <NUM>. The compensation chamber <NUM> is a loose pocket in the absence of a load on the load plate <NUM> and in calibration conditions, for example at <NUM> and <NUM> atmosphere (<FIG>). In an embodiment, the membrane <NUM> is bellows-shaped, with corrugated portions that expand and retract depending on the pressure difference between the inside and the outside of the compensation chamber <NUM>. When a load is applied to the load plate <NUM> (<FIG>), for example following the introduction of collected products in the container <NUM>, the lowering of the load plate <NUM> causes a reduction in the volume of the sensor chamber <NUM>, which is compensated by a corresponding expansion of the compensation chamber <NUM>, for the transfer of fluid through the play between the base plate <NUM> and the load plate <NUM>. The material forming the membrane <NUM> and the shape and the maximum volume of the compensation chamber <NUM> are selected so that the compensation chamber <NUM> substantially expands without exerting stress, i.e. without counterpressure, at least through a whole available motion range for the load plate <NUM> relative to the base plate <NUM> (essentially from a condition of absence of a load on the load plate <NUM> up to a stop imposed by the maximum compression of the load cells <NUM>). Furthermore, the protective structure <NUM> is shaped so as not to interfere with the expansion of the compensation chamber <NUM>. The pressure inside the sensor chamber <NUM> is thus not modified by the variation of volume caused by the load and the weight measurement is not altered. When the load is removed, the compensation chamber <NUM> returns loose. In this manner, it is possible to ensure the separation between the sensor chamber <NUM> and the outside, in particular the collection volume of the container <NUM>, without compromising the reliability and the precision of the measurements and preventing on the one hand possible contaminations of the collected products and on the other hand damage to the sensors that could be caused by aggressive substances released by said products. The sensor assembly <NUM> thus ensures the compatibility with the use in the agri-food sector and with the relative strict regulations.

The compensation chamber <NUM> expands or shrinks so as not to affect the weight measurements also following external temperature or pressure variations, for example on account of altitude variations. The use of the sensor assembly <NUM> is thus possible in different environmental conditions without the need for recalibration procedures, which in many circumstances would not even be possible. For example, during the use for the collection in the hills or in the mountains activities are commonly carried out throughout a same day at significantly different altitudes, without having at disposal the means and the conditions for recalibrating the sensor assembly <NUM>.

In the case of <FIG>, the membrane <NUM> with the compensation chamber <NUM> extends along the whole perimeter of the load plane of the weighing device <NUM> and along perimeter portions of each base plate and/or load plate.

The internal temperature sensor <NUM>, the internal humidity sensor <NUM> and the pressure sensor <NUM> provide data and information that may be sent to the processing unit <NUM> and used for example for monitoring and safety purposes.

In particular, the internal pressure of the sensor chamber <NUM> measured by the pressure sensor <NUM> may be used for diagnostic purposes for monitoring the integrity and the correct functioning of the membrane <NUM>. The processing unit <NUM> compares the pressure inside the sensor chamber <NUM> with a pressure reference of its own and signals a malfunction if the difference exceeds a planned threshold. In fact, the expansion of the compensation chamber <NUM> defined by the membrane <NUM> should ensure the balance between the internal pressure and the external pressure in the normal operating conditions.

The data detected by the internal humidity sensor may be equally used for indicating integrity defects of the membrane. The humidity rate is in fact kept at low levels by hygroscopic salts. A humidity increase, which may be detected by the processing unit <NUM> when the reading of the internal humidity sensor <NUM> exceeds a threshold, indicates an imperfect seal condition of the membrane <NUM> and exposes the electronic components to malfunctions due to oxidation and galvanic effects, reducing the useful life of the sensor assembly <NUM>.

Besides allowing the check of the use within the allowed temperature limits, the internal temperature sensor <NUM> may be useful in combination with the internal humidity sensor <NUM> and with the pressure sensor <NUM> for detecting critical operating conditions. In fact, a temperature increase in the sensor chamber <NUM> not associated with a corresponding external temperature increase detected by the processing unit <NUM> is indication of a pressure increase, which should not occur if the compensation chamber extends correctly.

The accelerometer <NUM> and the inclinometer <NUM> are also housed inside the sensor chamber <NUM> and may be for example of microelectromechanical type. The accelerometer <NUM>, in particular, is configured to provide an acceleration signal SA indicative of accelerations at least along an axis perpendicular to the faces 110a, 111a of the base plate <NUM> and of the load plate <NUM> and, consequently, perpendicular to the bottom wall 2b of the container <NUM> when the sensor assembly <NUM> is fixed thereto (essentially, a vertical axis when the container <NUM> is arranged flat). In an embodiment, the accelerometer <NUM> may be multiaxial. In an embodiment, the accelerometer <NUM> is used by the processing unit <NUM> as vibration sensor for activating and deactivating a low-consumption standby mode, as is explained below.

The inclinometer <NUM> is rigidly fixed to the case <NUM> and provides an inclination signal SI indicative of the inclination of a reference plane and, consequently, of the sensor assembly <NUM> and of the container <NUM> with respect to a horizontal plane. The reference plane is parallel to the faces 110a, 111a of the base plate <NUM> and of the load plate <NUM>. In an embodiment, the function of inclinometer may be implemented starting from the continuous component of the acceleration signal SA provided by the accelerometer <NUM>. The function may be completely integrated in the accelerometer <NUM>, if provided with processing capacity, or implemented by the on-board processing unit <NUM>, which may be configured to extract the continuous component of the acceleration signal SA.

The external temperature sensors <NUM>, the external humidity sensors <NUM> and the pH-meters <NUM> are arranged on flexible rods <NUM>, fixed to the weighing device <NUM> and extending perpendicular to the faces 110a, 111a of the base plate <NUM> and of the load plate <NUM> and thus to the bottom wall 2b when the sensor assembly <NUM> is fixed to the container <NUM>. The number and the placing of the rods <NUM> and the number and the placing of the external temperature sensors <NUM>, of the humidity sensors <NUM> and of the pH-meters <NUM> may be chosen on the basis of the design preferences. In the non-limiting example of <FIG>, there are five rods <NUM>, one arranged centrally with respect to the weighing device <NUM> and the others in positions corresponding to the load cells <NUM>. Each rod <NUM> carries two external temperature sensors <NUM>, two external humidity sensors <NUM> and two pH-meters <NUM>. The positions of the sensors <NUM>, <NUM>, <NUM> on the rods <NUM> may be selected depending on the type of product to be collected, in addition to the shape and the volume of the container <NUM>, so as to obtain the desired accuracy in the monitoring of the environmental variables. The external temperature sensors <NUM>, the external humidity sensors <NUM> and the pH-meters <NUM> respectively provide temperature signals ST, humidity signals SH and pH SpH measurements to the processing unit <NUM>.

The on-board processing unit <NUM> receives and processes the signals provided by the load cells <NUM>, by the accelerometer <NUM>, by the inclinometer <NUM>, by the external temperature sensors <NUM>, by the external humidity sensors <NUM> and by the pH-meters <NUM> and communicates with the outside, in particular with the ground processing unit <NUM> through the communication module <NUM>, as is more specifically disclosed in the following. The communication module <NUM> is configured for the connection with an access point to a data network (for example, the wireless communication module <NUM>) and in an embodiment it is a BLE (Bluetooth Low Energy) modem or based on other LPRF (Low Power Radio-Frequency) technologies, advantageously allowing restraining the energy consumption. In other embodiments not shown, the communication module may be chosen also on the basis of other parameters, such as the sending distance, the data flow, the latency, the sturdiness to disturbances, according to design preferences.

The identification tag reader <NUM> has a winding <NUM> placed in a position corresponding to the identification tag 2a of the container <NUM>, so as to be communicably coupled wirelessly. The identification tag reader <NUM> may be an RFID or NFC reader, in accordance with the type of identification tag 2a used.

In the described embodiment, the battery <NUM> is of rechargeable type and provides power supply to all the users on board the sensor assembly <NUM>.

The recharging device <NUM> recharges the battery <NUM>. In the embodiment of <FIG>, the recharging device <NUM> is of inductive type and uses the same winding <NUM> of the identification tag reader <NUM>. Alternatively, the recharging device <NUM> may comprise an energy harvesting device <NUM> from the environment (<FIG>) and may use as energy source the movement (being the container <NUM> subjected to continuous loading and unloading operations, it is advantageous to exploit part of this work for harvesting energy through piezoelectric effect) or temperature differences. The recharging device may also be provided with a connector (not shown, for example a USB connector) for the connection to an external supply source, such as an electric network.

As mentioned, the on-board processing unit <NUM> receives and processes the signals provided by the load cells <NUM>, by the accelerometer <NUM>, by the inclinometer <NUM>, by the external temperature sensors <NUM>, by the external humidity sensors <NUM> and by the pH-meters <NUM>. In particular, the processing unit <NUM> stores temporal series of the load signals SW, of the acceleration signal SA, of the inclination signal SI, of the temperature signals ST and of the humidity signals SH in the storage module <NUM> and performs the following operations:.

Furthermore, in an initialization step after the sensor assembly <NUM> has been coupled to the container <NUM>, the processing unit <NUM>, through the identification tag reader <NUM>, reads the identification tag 2a of the container <NUM> and associates it with an identification code of its own stored in the storage module <NUM> (in use, the identification tag 2a is in the field of action of the identification tag reader <NUM>). The association allows, in an equipment for traceability of agri-food products, matching the container <NUM> and the signals collected by the sensor assembly <NUM>. The processing unit <NUM> may recover from the identification tag 2a data relative to the constructive characteristics of the container <NUM>, such as internal dimensions (bottom wall 2b and depth), maximum load, shape factor, material and other information required by the general management system, such as for example, type of use, name of the owning company, etc.. The initialization may thus be carried out in a completely automatic manner. Alternatively, the processing unit <NUM> may be initialized by an operator through a communication interface (not shown) that exploits the communication module <NUM>. The operator may make the association of the identification code of the sensor assembly <NUM> and of the identification tag 2a of the container <NUM> and, possibly, load the data relative to the characteristics of the container manually or from a database for example resident on the remote server.

The processing unit <NUM> uses the acceleration signal SA provided by the accelerometer <NUM> for activating and deactivating the standby mode. Essentially, the accelerometer <NUM> is used as a vibration sensor for determining the presence or the absence of activity in relation to the container <NUM>. More precisely, if the acceleration signal SA remains substantially null, or anyway below a threshold, for a period of time exceeding a control interval, and in the absence of other signals, the processing unit <NUM> activates the standby mode because the absence of vibrations indicates that there are no significant activities underway. When the activity resumes, for example for a load, the produced vibrations are immediately detected by the accelerometer <NUM> and the processing unit <NUM> deactivates the standby mode, so that the loss of information may be prevented during the recording of the weight signals SW.

With regard to the calculation of the weight measured value W, the processing unit <NUM> uses a first calculation mode or a second calculation mode on the basis of the acceleration signal SA provided by the accelerometer <NUM>. The first calculation mode is used ordinarily, whereas the second calculation mode is used following movements, shakes or knocks of the container <NUM> detected by the accelerometer <NUM>.

When the acceleration signal SA remains within a control amplitude band B, as shown in <FIG>, the processing unit <NUM> sets an enable signal EN at a first logic value, for example a high logic value, that allows determining and updating the weight measured value W of the product inside the container <NUM> according to the first calculation mode on the basis of current values of the load signals SW and of the inclination signal SI.

The processing unit <NUM> combines the data received through the load signals SW, corrected keeping into account the inclination signal SI from the inclinometer <NUM> so as to compensate the effect of the inclination of the ground on which the container <NUM> is situated. The combination of the load signals SW is carried out with procedures that may depend on the arrangement of the load cells <NUM> and on the coupling to the load plates <NUM>. In the example of <FIG>, the data extracted from the load signals SW for each load cell <NUM> may be independently compensated for the inclination and thus simply added up for obtaining the overall weight. If the surface of the load plate <NUM> is smaller than the surface of the bottom wall 2b of the container <NUM>, the processing unit <NUM> determines the estimate of the weight by using a correction factor, for keeping into account the fact that the weight measured directly is a fraction of the overall weight of the product in the container <NUM>. The correction factor may be obtained from the initialization data taken from the identification tag 2a (in particular from the data relative to the geometrical characteristics) or manually inserted by the authorized operator. In an embodiment, the weight measured value W may be determined also keeping into account the humidity rate indicated by the humidity signals SH provided by the external humidity sensors <NUM>. Generally, the processing unit <NUM> may execute statistic processing of all the signals received from the sensors (among which, not limitedly, mean value, standard deviation, medians, minimum-maximum, variable time windows, gradients, filters, spectral analyses, of Fourier) with the aim to determine the weight measured value W and possibly further useful values, such as the filling, transportation and unloading time of the containers <NUM>. In an embodiment, the processing unit <NUM> associates the stored signals, the measured weight and the information obtained with respective degrees of confidence, precision and tolerances.

When the acceleration signal SA remains outside of the control amplitude band B for a time exceeding a planned latency interval, the processing unit <NUM> sets the enable signal EN at a second logic value, for example a low logic value, and determines the weight measured value W on the basis of the second calculation mode. The interval of time in which the acceleration signal SA exceeds the control amplitude band B will be indicated in the following as interdiction interval IINT.

In the second calculation mode, the processing unit <NUM> determines the measured value W starting from the values of the acceleration signal SA and of the inclination signal SI at least in part temporally not corresponding to the interdiction interval IINT and on the basis of a planned criterion. In an embodiment, for example, the measured value W in the interdiction interval IINT is set equal to a mean of the measured value W on control interval IC immediately following the interdiction interval IINT. Alternatively, the measured value W in the interdiction interval IINT may be set equal to the measured value W immediately prior to the interdiction value IINT (essentially, the measured value W is "frozen" during the interdiction interval IINT) or it may be obtained from a low-pass filtering of the load signals SW. In this manner, spurious contributions in the load signals SW that may be linked to the shifting and to the transportation of the container <NUM>, for example between different collection sites or between a collection site and a storage or transformation plant, are eliminated. Nonetheless, possible actual weight variations occurred when the weight detection is disabled may be subsequently corrected, when the acceleration signal SA returns within the control amplitude band B.

As mentioned in the foregoing, the processing unit <NUM> stores temporal series of the load signals SW, of the acceleration signals SA, of the inclination signal SI, of the temperature signals ST and of the humidity signals SH in the storage module <NUM>. Optionally, also a temporal series of the values of the measured weight W may be stored in the storage module <NUM>. All the signals and the information stored by the processing unit <NUM> are associated with temporal markers. In this manner, besides keeping a history of the detections accessible upon request, it is possible to optimize the sending of data, for the total benefit of the autonomy of the sensor assembly <NUM>. With respect to the monitoring and collection activities of the measurement signals, in fact, the sending of data is extremely costly in terms of energy. Storing the temporal series of the signals in the storage module <NUM> allows preventing the waste of energy for establishing a connection in the absence of data to be sent or for long-distance sending. For example, the data stored in the storage module <NUM> may be forwarded to the processing unit <NUM> on the frame <NUM> through a short-range and low-power connection.

The stored data may be downloaded in a second moment, when the network connection becomes again available. Furthermore, also thanks to the temporal markers, the collected data may be processed for example at a remote server and correlated with further information, such as the images detected by the image sensor <NUM> or the coordinates detected by the satellite localization device <NUM>. The correlation of information allows, in turn, improving the tracing of the products, reducing the margin for fraud attempts.

The sensor assembly according to the invention advantageously allows monitoring the variations of fundamental parameters for traceability of agri-food products, reducing the margins for fraud attempts and making available accurate and continuously updated information on the state of preservation. Firstly, the continuous monitoring of the weight, associated with the detection of the accelerations, allows correctly identifying the events that correspond to actual variations of the weight of the product collected in the container. The possibility of communicating in low-consumption wireless mode, besides making available sufficient autonomy for the continuative use over long periods, allows immediately integrating the data detected by the sensor assembly with the images acquired by the image sensors and geolocation data.

The measurement of the temperature and humidity data allows monitoring the preservation conditions both during the period of the collection and the transportation, and during the storage prior to the processing. The exposure to excessive temperatures, with potentially damaging changes and to inadequate humidity levels may be thus documented for each container. The use of flexible rods allows positioning the temperature and humidity sensors in the manner deemed the most suitable, according to the type of container used and of the collected product.

The reversible fixing of the sensor assembly to the container offers further advantages in terms of cost, of flexibility of use and of maintenance. In this manner, in fact, it is not necessary for the sensor assembly to be integrated in the containers, which, outside of the period of collection, could be used for other purposes that do not require a constant monitoring of significant parameters. Furthermore, an event relatively such as the breaking of a container does not oblige to replace the whole sensor assembly. Also the transportation for the maintenance or the recharging of the batteries is simpler.

The sensor assembly has been described up to here in connection with the use in containers defined by stackable crates. It is however understood that the use of the sensor assembly according to the invention may be extended to any container for the collection of agri-food products. In particular, the sensor assembly may be used, possibly suited in the dimensions, with containers that are standard bins of the type indicated by <NUM> in <FIG>. Each container <NUM> is provided with a respective sensor assembly <NUM> substantially as already described, reversibly fixed to a bottom wall 50a inside the container <NUM>. Compared to the sensor assembly <NUM>, the sensor assembly <NUM> may be distinguished for example for:.

In this case, the image detecting device and the movement sensor, respectively indicated by <NUM> and <NUM> in <FIG>, may be mounted on a fixed structure <NUM>, adjacent the place where the containers <NUM> are arranged (for example on the load plane of a means of transportation or of a trailer or on the ground in a storehouse of a processing plant). The image detecting device <NUM> and the movement sensors <NUM> may each be associated also with several containers <NUM>.

Claim 1:
A sensor assembly for an equipment for aiding traceability of agri-food products comprising:
a first plate (<NUM>);
a second plate (<NUM>; <NUM>'; <NUM>"), facing the first plate (<NUM>) ;
a first chamber (<NUM>) defined between the first plate (<NUM>) and the second plate (<NUM>; <NUM>'; <NUM>");
at least a load cell (<NUM>), housed in the first chamber (<NUM>) and coupled to the first plate (<NUM>) and to the second plate (<NUM>; <NUM>'; <NUM>") so as to be responsive to a load applied on the second plate (<NUM>; <NUM>'; <NUM>");
characterized by a membrane (<NUM>) fluid-tight coupled to the first plate (<NUM>) and to the second plate (<NUM>; <NUM>'; <NUM>") along a perimeter thereof and delimiting a sealed closed space containing the first chamber (<NUM>);
wherein the membrane (<NUM>) forms a second chamber (<NUM>) fluidly communicating with the first chamber (<NUM>) and defined by a pocket which is expandable without counterpressure and retractable in response to a pressure difference between an inside and an outside of the second chamber (<NUM>).