FR3070214A1 - INTEGRATED INTEGRAL ACCOUNTING DEVICE FOR PASSAGES OF PERSONS ACCORDING TO AT LEAST ONE SENSE OF MOVEMENT - Google Patents

Abstract

An accounting device (DC) comprises: - a belt (T) equipped with a matrix of pressure sensors acquiring pressure measurements undergone, - an upper protective layer (CPS) placed above the belt (T), treatment means (MT) secured to the upper protective layer (CPS), deducing from the acquired measurements each passage of a person having walked on the upper protective layer (CPS) and the direction of movement of this person, and incrementing by one unit the current value of a counter associated with a direction of movement consecutive to each deduction of a passage in this direction of movement, - transmission means (ME) partially secured to the belt (T) and emitting a message containing the current value of the counter by means of waves, and - supply means (MA) supplying electrical energy to the pressure sensors, processing means (MT) and transmission means (ME).

Description

AN INTEGRATED ACCOUNTING DEVICE FOR PERSON CROSSINGS ACCORDING TO AT LEAST ONE DIRECTION OF MOVEMENT

The invention relates to counting devices which are responsible for counting the number of people crossing a passage area of a surface in at least one direction of movement.

Some accounting systems include:

- a mat intended to be installed on a surface on which people walk, and provided with a matrix of MxN pressure sensors responsible for acquiring each a representative measurement of the pressure undergone, with M> 2 and N> 2,

- an upper protective layer placed above the carpet,

- a first cable coupled to the mat and comprising conductive wires coupled to the MxN pressure sensors so that they transfer their measurements outside,

- a second cable coupled to the mat and responsible for supplying electrical power to the pressure sensors, and

- processing means distant from the mat and responsible for deducing measurements, transferred to the outside by the first cable, each passage of a person who has walked on the upper protective layer, and to increment by a unit a value during a counter following each deduction of a passage in this direction of movement.

Depending on the embodiment chosen, the processing means can be:

- either located in electronic equipment installed near the conveyor and possibly having a (or associated with a) communication module responsible for transmitting, by wire or by waves, to remote communication equipment, the value during the processing means passage counter,

- either located in a communicating electronic equipment, remote from the mat, and comprising a communication module (wired or non-wired) responsible for receiving the measurements acquired by the pressure sensors and transmitted, by wire or by waves, by another communication module installed near the carpet and coupled to the first cable.

In the first alternative, the accounting device is arranged in several parts which must be installed in different locations, not always available and / or possibly difficult to access and / or in visibility (which increases the probability of damage), and having to be coupled to each other, which does not facilitate their installation and / or maintenance.

In the second alternative, the accounting device is also arranged in several parts, which induces drawbacks similar to those described in the previous paragraph, and moreover imposes a permanent transmission of the measurements acquired by the pressure sensors, which requires in permanently a large bandwidth which is not always available and therefore can cause loss of measurements.

One of the object of the invention is to improve the situation.

To this end, it proposes an accounting device comprising, on the one hand, a mat intended to be installed on a surface on which people are walking and provided with a matrix of MxN pressure sensors each acquiring a measurement representative of the pressure undergone , with M> 2 and N> 2, and, on the other hand, an upper protective layer placed above the mat.

This accounting system is characterized by the fact that it also includes:

- processing means secured to the mat and / or to the upper protective layer, coupled to the pressure sensors, deducing from the measurements acquired each passage of a person who has walked on the upper protective layer and a direction of movement of this person , and incrementing by one unit a current value of at least one counter associated with a direction of movement consecutive to each deduction of a passage according to this direction of movement,

transmission means partially secured to the mat and transmitting by waves, on the order of the processing means and intended for at least one communicating equipment, a message containing the current value of the counter, and

- supply means supplying electrical energy to the pressure sensors, processing means and emission means.

Thus, we have a fully integrated accounting device and therefore can be very easily installed entirely in the area where we want to account for the number of people passing by, and moreover autonomous and therefore capable of directly providing the current value at least one counter associated with a direction of movement.

The accounting device according to the invention may include other characteristics which can be taken separately or in combination, and in particular:

- it can also include, on the one hand, first multiplexing means interposed between the processing means and the pressure sensors and selectively transmitting to subsets of pressure sensors, designated respectively by different addresses, requests for 'obtaining measurement, and, secondly, second multiplexing means interposed between the pressure sensors and the processing means and transmitting to the latter groups of messages containing the measurements acquired in response to the requests received;

> each sub-assembly may include M pressure sensors belonging to the same column and aligned in a preferred direction of movement of people;

- The upper protective layer may include a housing in which are housed at least the processing means and part of the transmission means which is complementary to an antenna of the latter secured to the carpet;

- in the presence of a matrix of N rows and M columns aligned in a preferred direction of movement of people, its processing means can assign N different weights respectively to the pressures represented by the measurements acquired by the N pressure sensors of a same column, then determine for each column at P successive instants, with P> 2, an average of the weights associated with the pressure sensors having undergone pressure, then determine for each column an average slope of evolution of the means associated with the P successive instants , then deduct from the average slope of at least one column the passage of a person in a direction of movement;

> its processing means can deduce the passage of a person in a direction of movement from a comparison of the average slope of at least one column to at least one record characteristic of the average slope of at least one column during the passage of a test person in two opposite directions of movement;

its processing means can periodically store the measurements acquired respectively by the pressure sensors when they are not under pressure, as tare measurements, and can subtract from each measurement acquired by a pressure sensor the associated tare measurement and stored to obtain sustained pressure;

> its processing means can record several successive measurements for each pressure sensor and, when these measurements are identical, they can store this measurement as a tare measurement;

- It can also include a lower protective layer placed below the carpet;

- its processing means can use two counters associated respectively with two opposite directions of the same direction of movement of people and having respectively two current values;

- its carpet can be subdivided into K parts, with K> 2, coupled together by connectors and participating at least in the supply of electrical energy to the pressure sensors;

> the connectors can also participate in the coupling of the first and second multiplexing means to the pressure sensors of each part of the mat;

> the K parts of the mat can be coupled one after the other and can each comprise a sub-matrix, of M / K columns and N rows, of the matrix.

Other characteristics and advantages of the invention will appear on examining the detailed description below, and the attached drawings, in which:

FIG. 1 schematically and functionally illustrates, in a perspective view, an exemplary embodiment of an accounting device according to the invention, coupled to a communication network to which is also coupled communicating equipment,

FIG. 2 schematically and functionally illustrates an example of a mat intended to be part of an accounting device according to the invention and comprising a matrix of 16 × 8 pressure sensors, subdivided into two sub-matrices of 8 × 8 pressure sensors, and

- Figure 3 illustrates schematically and functionally an example of coupling between different constituents of an accounting device according to the invention.

The purpose of the invention is in particular to propose a DC accounting device intended to account for the number of people crossing a passage area of a surface in a preferred direction of movement and in at least one direction of movement.

In what follows, it is considered, by way of nonlimiting example, that the surface on which the DC accounting device according to the invention is installed is an outside area for receiving people in a stadium enclosure. But the invention is not limited to this application. It concerns in fact any surface comprising at least one passage zone that can be crossed by people. Consequently, it could be a corridor of a building, or an interior or exterior area of access to a public or private place, or even a station or port platform, for example.

There is schematically and functionally illustrated in FIG. 1 an embodiment of a DC accounting device according to the invention, coupled by waves to a communication network RC to which is also coupled a communicating equipment EC, such as for example a computer or a server.

In FIGS. 1 and 2, the direction X is a longitudinal direction parallel to the preferred direction of movement of the people in the area of passage of the surface on which the DC counting device is installed, and the direction Y is a perpendicular transverse direction in the longitudinal direction X.

As illustrated in FIG. 1, a DC accounting device, according to the invention, comprises at least one mat T, an upper protective layer CPS, processing means MT, emission means ME and supply means MY.

The mat T is intended to be installed on a surface on which people walk, preferably with the interposition of a lower protective layer CPI placed below it (T) to ensure the protection of its lower face in the presence of aggressive elements present on the surface, such as gravel or pebbles. In addition, and as illustrated without limitation in FIG. 2, this mat T is provided with a matrix of MxN pressure sensors CP which are responsible for acquiring each a measurement mp which is representative of the pressure undergone. The matrix contains M columns, with M> 2, and N rows, with N> 2.

For example, the pressure sensors CP can be of the resistive type (they then measure variations in electrical resistance linked to the variations in pressure undergone). But they could be of the piezoelectric type, for example.

It will be noted, as illustrated without limitation in FIGS. 1 and 2, that the mat T can be subdivided into K parts PTk, with K> 2 and k = 1 to K, coupled together by connectors CN. The upper protective layer CPS and the possible lower protective layer CPI can also be subdivided into K parts. But it is not compulsory. Indeed, they can be monobloc in order to protect all the PTk parts simultaneously. This promotes the protection of any different PTk parts of the carpet T.

In the example illustrated without limitation in FIGS. 1 and 2, the mat T is subdivided into two (K = 2) parts PT1 and PT2. But it could be subdivided into more than two PTk parts, it indeed depends on the width of the passage area that we want to equip and the dimensions (in the X and Y directions) that a PTk part can have.

Furthermore, in the example illustrated without limitation in FIGS. 1 and 2, the K parts PTk of the mat T are coupled one after the other in the transverse direction Y, and each comprise a sub-matrix (of M / K columns and N rows) of the matrix. However, these K parts PTk could be coupled together in the longitudinal X and transverse Y directions, forming a square or a rectangle or any other more or less geometric shape.

Note that it is possible to cut a sub-part of the mat T which is located beyond the zone where the antenna AN is defined, following the longitudinal direction X between two columns, in order to adapt the mat T the dimensions of the passage area concerned. Indeed, the removed columns will then be interpreted by the MT processing means as always delivering zero pressure measurements. In order to facilitate cutting, you can print cutting lines (possibly dotted lines) between neighboring columns, starting from the first column which can be removed.

Also in the example illustrated without limitation in FIGS. 1 and 2, the matrix of the mat T is of the 16 × 8 type. It therefore includes sixteen columns (M = 16) and eight rows (N = 8). Due to the subdivision of the mat T into two parts PT1 and PT2, the matrix is also subdivided into two sub-matrices of type 8x8 (ie (M / K) xN = (16/2) x8). But the matrix of the mat T can include any number M of columns, as long as M is greater than or equal to two, and any number N of rows, as long as N is greater than or equal to two.

The upper protective layer CPS is placed above the mat T, in order to ensure the protection of each element present on its upper face. It is preferably fixedly secured to this upper face, for example by gluing. For example, this upper protective layer CPS can be made of polycarbonate.

The possible lower CPI protective layer can, for example, be made of polycarbonate. It is preferably fixedly secured to the underside of the mat T, for example by gluing.

The processing means MT are secured to the mat T and / or to the upper protective layer CPS and coupled to the pressure sensors CP. In addition, they are responsible for deducing from the measurements acquired each passage of a person who has walked on the upper protective layer CPS and a direction of movement sd, of this person, and to increment by one unit a current value v _C i of at least one counter ci which is associated with a direction of movement sd ,, following each deduction of a passage in this direction of movement sd ,.

According to the needs, the MT processing means can use either a single counter having a current value and associated with a predefined direction of movement of a direction of movement of people, or two counters c1 and c2 (i = 1 or 2) having respectively two current values v _c i and v _c2 and associated respectively with two directions of movement sdi and sd ₂ opposite from the same direction of movement of people. It will be noted that the processing means MT can also use a single counter to count the passages in the two directions of movement sd,. Furthermore, the processing means MT can also and possibly count the people stationing on the carpet T and / or the average parking time of the people on the carpet T and / or the average travel speeds of the people on the carpet T. L analysis of the movements of people can also possibly be done in any direction, and in particular the transverse direction Y. It is also and possibly possible to "qualify" the typologies of movements: for example adult, child, wheelchair, cycle, animal.

For example, these MT processing means can be arranged in the form of a microcontroller or a specialized circuit (such as an ASIC) or even a microprocessor.

The transmission means ME are partially secured to the mat T and arranged so as to transmit by waves, on the order of the processing means MT and intended for at least one communicating equipment EC (via the communication network RC) , a message containing the current value of / each counter used by the processing means MT to count the passages.

This transmission can be done periodically or alternatively following the reception of a request for obtaining value (s) in progress v _ci coming from the communicating equipment EC, when the DC accounting device also comprises reception means. coupled to the RC communication network.

It will be noted that the transmissions and possible receptions can be done according to numerous communication protocols according to the needs, and in particular according to the protocol called LoRa ("Long Range") which offers a maximum range of about 15 km for low consumption. electric.

The supply means MA are responsible for supplying electrical energy to at least the pressure sensors CP, the processing means MT and the emission means ME. For example, the MA supply means can supply a voltage of 5 V.

These MA power supply means may include an adapter to be connected to a power outlet (possibly from the mains) and / or a battery or at least one battery, possibly rechargeable via a possibly dedicated connection.

The aforementioned adapter can, for example, be an AC / DC transformer, possibly of the same type as that included in smart phone (or "smartphone") chargers. In this case, the adapter may include a USB connector coupled to a power cable, the end of which includes a magnetic connector which is intended to be coupled to another magnetic connector secured to the mat T and / or to the protective layer. superior CPS. This solution is currently preferred because the integration of a conventional USB type connector into the thickness of the mat T or of the upper protective layer CPS poses problems of brittleness due to the very thin thickness of the multilayer structure (layer CPI lower protective layer, T mat, CPS upper protective layer). The thickness of this multilayer structure can indeed be very small, typically between 2 mm and 8 mm.

It is also possible to supply the accounting system

DC by means of an external rechargeable battery, for example of the type called "powerbank" (used in smartphones).

Thanks to the invention, the DC accounting device is fully integrated (or "monoblock") and therefore can be very easily installed entirely in the passage area where one wants to account for the number of people passing. In addition, this DC accounting device determining locally internally (MT) the current value v _C i of at least one counter ci (associated with a direction of movement sd,), and being arranged so as to transmit by means of d 'waves each value in progress v _C i, it is therefore autonomous and can be installed anywhere as soon as there is nearby network equipment allowing it to be coupled to a communication network.

It will be noted, as illustrated without limitation in FIG. 1, that the upper protective layer CPS can comprise a housing L in which are housed at least the processing means MT and a part PE of the transmission means ME which is complementary to an antenna AN for transmitting (and possibly receiving) the latter (ME).

As illustrated without limitation in FIGS. 1 and 2, this antenna AN can be fixedly secured to the upper face of the mat T in an area which does not include a pressure sensor CP, such as for example on a longitudinal side (X) and / or a transverse side (Y). Furthermore, this antenna AN can, for example, be screen printed on the upper face of the carpet T.

The part PE of the transmission means ME, which is complementary to the antenna AN and housed in the housing L, comprises, for example, at least one interface, control means and frequency generators. This PE part can be coupled to an input / output of the MT processing means (for example a microcontroller) via a UART type link ("Universal Asynchronous Receiver Transmitter" - universal asynchronous transmitter / receiver). Furthermore, in the example illustrated without limitation in FIG. 3 and adapted to the mat T illustrated in FIG. 2, the part PE is supplied with electrical energy by the supply means MA (via the connection partially illustrated and referenced "power supply" ").

It will be noted that the housing L can, also and possibly, accommodate at least part of the supply means MA.

It will also be noted that in order to protect the elements (or constituents) of the DC accounting device which are housed in the housing L, they may be partially surrounded in the latter (L), and at least above them, d 'a resin, for example epoxy or polyurethane.

It will also be noted, as illustrated without limitation in FIG. 3, that the DC accounting device can also include first MM1 and second MM2 multiplexing means.

These first multiplexing means MM1 are interposed between the processing means MT and the pressure sensors CP. They are arranged so as to transmit selectively to sub-assemblies of pressure sensors CP, designated respectively by different addresses, requests for obtaining a measurement.

For example, each sub-assembly may include M pressure sensors CP belonging to the same column and aligned in a preferred direction of movement of the people (here the longitudinal direction X).

In the example illustrated without limitation in FIG. 3 and adapted to the mat T illustrated in FIG. 2, the first multiplexing means MM1 comprise a first multiplexer (here of the 1x8 type) whose eight outputs are respectively coupled to the eight columns (or sub-assemblies) of eight pressure sensors CP of the first part PT1 of the mat T, via circuits (or a sheet) integrated (s) in the latter (T), and a second multiplexer (here of the 1x8 type ) whose eight outputs are respectively coupled to the eight columns (or sub-assemblies) of eight pressure sensors CP of the second part PT2 of the mat T, via circuits (or a sheet) integrated (s) therein (T). The respective inputs of these two multiplexers (1x8) MM1 can be coupled to an input / output of the processing means MT (for example a microcontroller) via a bus, for example of the I2C (“Inter-integrated Circuit”) type. Furthermore, these two multiplexers (1x8) MM1 are supplied with electrical energy by the supply means MA (via the links partially illustrated and referenced "power supply"). In addition, these two multiplexers (1x8) can, for example, be analog. Note that it is possible to perform a mounting variant by reversing the columns and rows and the inputs and outputs.

The second multiplexing means MM2 are interposed between the pressure sensors CP and the processing means MT. They are arranged so as to transmit to the latter (MT) groups of messages containing the measurements acquired by the pressure sensors CP of the same column in response to the requests received. In the example illustrated, each group of messages comprises eight messages containing respectively the last eight measurements acquired by the eight pressure sensors CP from one of the 16 columns.

In the example illustrated without limitation in FIG. 3 and adapted to the mat T illustrated in FIG. 2, the second multiplexing means MM2 comprise a multiplexer (here of the 16 × 1 type) whose sixteen inputs are respectively coupled to the sixteen columns of eight sensors pressure CP of the first PT1 and second PT2 parts of the mat T, via circuits (or a sheet) integrated (s) therein (T). The output of this multiplexer (16x1) MM2 can be coupled to the input / output of the MT processing means (for example a microcontroller) via the aforementioned bus (for example of the I2C type). Furthermore, this multiplexer (16x1) MM2 is supplied with electrical energy by the supply means MA (via the link partially illustrated and referenced "power supply"). In addition, this multiplexer (16x1) can, for example, be analog. Alternatively, instead of using a multiplexer (16x1), an analog / digital converter (or ADC) of the 16x1 type could be used, the output of which is coupled to a dedicated input of the MV processing means (for example a microcontroller) via an ADC In link.

It will be noted that when the mat T is subdivided into K parts PTk coupled together by connectors CN (possibly magnetized), the latter (CN) participate at least in the supply of electrical energy to the pressure sensors CP. They (CN) can, also and possibly, participate in the coupling of the first MM1 and second MM2 multiplexing means to the pressure sensors CP of each part PTk of the mat T via the circuits (or the web) integrated in this last. However, different connectors can be provided for the power supply and for coupling to the pressure sensors CP of each part PTk of the mat T.

It will also be noted, as illustrated without limitation in FIG. 3, that the DC accounting device can also include a connector CM connected to the processing means MT (for example a microcontroller), and allowing, when it is coupled to electronic equipment external, to update a software part (or "software") of its MV processing means.

It will also be noted, as illustrated without limitation in FIG. 3, that the DC accounting device can also include at least one DE light-emitting diode coupled to a CD controller, itself coupled via a bus (for example of the I2C type) to the means MV processing (for example a microcontroller). This makes it possible to visually indicate when the DC accounting device is in operation (for example in green) or is not in operation (for example in red or off) or possibly when it is the subject of a malfunction (by example in orange). The color codes are not fixed, it is only a purely illustrative example. They can also make it possible to display interpretations carried out by the processing means MT, such as for example a passage in one direction of displacement can be displayed in a certain way and a passage in the other direction of displacement can be displayed in another way.

It will be noted that when supports are detected at close times on columns spaced by a transverse distance (Y) included in a predefined interval (corresponding to typical transverse distances between the two feet of the same person), and that they relate to the same direction of movement sdj, the processing means MT can, for example, consider that it is the same person and therefore only increment by one unit the current value v _C i of counter ci which is associated with this direction of movement sd ,. But many other techniques for recognizing the passage of a person, known to those skilled in the art, can be used here, and in particular those which are called “machine learning” in English and which are trained to recognize movements. a person and possibly a wheelchair and / or a cycle and / or an animal.

As a purely illustrative example, when the matrix comprises N rows and M columns aligned in a preferred direction of movement of people (here the longitudinal direction X), the processing means MT can carry out the treatments described below.

First of all, they (MT) can assign N different p _n weights (n = 1 to N) respectively to the N pressure sensors CP of the same column (or row). In this case, these N weights p _n can, for example, decrease by a first line (n = 1), located near an entry face of the mat T for people moving in the preferred direction of movement in a direction of movement sdi originating from this entry face, to a last line (here n = 8), located near an exit face of the mat T for people moving in this preferred direction of movement according to this direction of movement sdi originating from this entry face.

Then, the processing means MT can be determined for each column (or row) for P successive instants, where P> 2, an average p _n weights mp associated to the pressure sensors CP having undergone a pressure (due to the support of part of a person's foot).

Then, the processing means MT can determine for each column (or row) an average slope pm of evolution of the means mp associated with the successive P instants.

Then, the processing means MT can deduce from the average slope pm of at least one column (or row), over the successive P instants, the passage of a person in a direction of movement sd ,.

For example, the processing means MT can deduce from a negative average slope pm of a column (or row) considered that a person has passed according to the direction of movement sdi which (here) goes from the entry face ( near the first line (n = 1)) to the exit face (near the last line (n = 8)). If this average slope pm had been positive, it would have indicated that the person had passed in the direction of movement sd2 which goes from the exit face to the entry face.

The N weights can be different values or powers.

Note that to facilitate the detection of the direction of movement sd, of a person, we can classically consider that when a person walks he starts by placing the heel of one of his feet on the ground, then this whole foot, then a front part of this foot.

It will also be noted that the processing means MT can, for example, deduce the passage of a person in a direction of movement sd, from a comparison of the average slope pm of at least one column to at least one characteristic record of the average slope of at least one column during the passage of a test person in two opposite directions of movement sdi and sd ₂ .

It will also be noted that in order not to be disturbed by variations in the behavior of the pressure sensors CP, due to environmental variations (in particular thermal) and / or to wear (and resulting for example by variations in the electrical resistance inducing variations in the measured pressure), autocalibrations can be carried out, possibly periodically. The period can, for example, be between a few minutes and a few tens of minutes.

To do this, the processing means MT can, for example, periodically store the measurements acquired respectively by the pressure sensors CP when they are not under pressure, as tare measurements. The MT processing means then have a reference or tare matrix whose dimension is equal to the number MxN of pressure sensors CP of the mat T. In this case, the MT processing means subtract from each measurement acquired by a sensor CP pressure the associated tare measurement stored to obtain a pressure undergone. If this pressure undergone is greater than a predefined threshold, then the processing means MT consider that there is a support of one foot on the pressure sensor CP having acquired the measurement.

In order to be certain for each pressure sensor CP that its tare measurement is indeed a measurement obtained in the absence of applied pressure, the processing means MT can record for each pressure sensor CP several successive measurements and, when these measurements are identical, they store this measurement as a tare measurement. For example, we can consider that we have a tare measurement when three successive measurements are identical.

It will also be noted that the processing means MT, at least part of the supply means MA, the possible first MM1 and second MM2 multiplexing means, the possible connector CM, each possible light-emitting diode DE and the possible associated CD controller , can optionally be installed on an electronic card, for example of PCB (“Printed Circuit Board”) type. It is also possible to use a “giant” electronic card 10 having the dimensions of the mat T and on which the pressure sensors CP are fixedly installed.

The invention is not limited to the embodiments of accounting device described above, only by way of example, but it encompasses all the variants that a person skilled in the art may envisage within the sole scope of the claims. below.

Claims (13)

1. Accounting device (DC) comprising i) a mat (T) intended to be installed on a surface on which people are walking and provided with a matrix of MxN pressure sensors (CP) each acquiring a representative measurement of the pressure undergone, with M> 2 and N> 2, and ii) an upper protective layer (CPS) placed above said mat (T), characterized in that it further comprises a) treatment means (MT) secured to said mat (T) and / or to said upper protective layer (CPS), coupled to said pressure sensors (CP), deducing from said measurements acquired each passage of a person having walked on said upper protective layer (CPS) and a direction of movement of this person, and incrementing by one unit a current value of at least one counter associated with a direction of movement consecutive to each deduction of a passage according to this direction of movement, b) means of emission (ME) solidar partially linked to said mat (T) and transmitting by waves, on the order of said processing means (MT) and intended for at least one communicating equipment (EC), a message containing said current value of the counter, and c ) supply means (MA) supplying electric power to said pressure sensors (CP), processing means (MT) and emission means (ME). 2. Device according to claim 1, characterized in that it further comprises i) first multiplexing means (MM1) interposed between said processing means (MT) and said pressure sensors (CP) and transmitting selectively to sub sets of pressure sensors (CP), designated respectively by different addresses, requests for obtaining measurement, and ii) second multiplexing means (MM2) interposed between said pressure sensors (CP) and said processing means (MT) and transmitting to the latter (MT) groups of messages containing said measurements acquired in response to said received requests. 3. Device according to claim 2, characterized in that each sub-assembly comprises M pressure sensors (CP) belonging to the same column and aligned in a preferred direction of movement of said people. 4. Device according to one of claims 1 to 3, characterized in that said upper protective layer (CPS) comprises a housing (L) in which are housed at least said processing means (MT) and a part (PE) said transmission means (ME), complementary to an antenna (AN) of the latter (ME) secured to said mat (T). 5. Device according to one of claims 1 to 4, characterized in that in the presence of a matrix of N rows and M columns aligned in a preferred direction of movement of said people, said processing means (MT) i) assign N different weights respectively of said N pressure sensors (CP) of the same column, then ii) determine for each column at P successive instants, with P> 2, an average of the weights associated with the pressure sensors (CP) having undergone pressure, then iii) determine for each column an average slope of evolution of said averages associated with said P successive instants, then iv) deduce from the average slope of at least one column the passage of a person according to a direction of movement. 6. Device according to claim 5, characterized in that said processing means (MT) deduce the passage of a person in a direction of movement from a comparison of the average slope of at least one column to at least one record characteristic of the average slope of at least one column when a test person passes in two opposite directions of movement. 7. Device according to one of claims 1 to 6, characterized in that said processing means (MT) periodically store the measurements acquired respectively by said pressure sensors (CP) when they are not under pressure, as tare measurements, and subtract from each measurement acquired by a pressure sensor (CP) said associated tare measurement and stored to obtain a pressure undergone. 8. Device according to claim 7, characterized in that said processing means (MT) record for each pressure sensor (CP) several successive measurements and, when these measurements are identical, they store this measurement as a tare measurement. 9. Device according to one of claims 1 to 8, characterized in that it further comprises a lower protective layer (CPI) placed below said mat (T). 10. Device according to one of claims 1 to 9, characterized in that said processing means (MT) use two counters associated respectively with two opposite directions in the same direction of movement of said people and having respectively two current values. 11. Device according to one of claims 1 to 10, characterized in that said mat (T) is subdivided into K parts (PTk), with K> 2, coupled together by connectors (CN) participating at least in said supply of electrical energy to said pressure sensors (CP). 12. Device according to claim 11, characterized in that said connectors (CN) also participate in the coupling of said first (MM1) and second (MM2) multiplexing means to said pressure sensors (CP) of each part (PTk) of said mat ( T). 13. Device according to one of claims 11 and 12, characterized in that said K parts (PTk) of the belt (T) are coupled one after the other and each comprise a sub-matrix, of M / K columns and N lines, of said matrix.