A SYSTEM OF SMART OBJECTS, IN PARTICULAR TILES Technical field

The present invention relates to a system of smart objects, in particular tiles.

Background art

Traditional tiles represent one of the most widely adopted element to build interior and exterior fagades in modern buildings. There are few existing works that aim at developing an innovative building material, namely an intelligent tile, which can add new features to the traditional building element. The new features are made possible by blending hardware and software solutions into the tile, and into the system made by the set of tiles composing a wall or a floor.

The advent of new technologies, capable to integrate into large area circuits semiconductor, and organic light emitters (LEDs and OLEDs) allow to fabricate large light emitting objects with sensory functionalities, that are perfectly suited to realize intelligent luminous tile. This opens the way to a revolutionary use of photonics and electronics to add novel and varied functionalities to the traditional ceramic tile, such as:

- the possibility to change the tile color;

- the possibility to use the tile as high-efficiency and energy-saving light source;

- the possibility to equip the tiles with electronic sensors in order to make the tile a sensing element;

- the possibility to use the tiles as individual pixels for the realization of very large indoors or outdoors video displays with unprecedented ruggedness and ease of installation.

There exist several commercial products on the market and also patent literature relative to modular wall screens, LED modules and luminous tiles.

However, the known solutions still require a manual configuration of the position of the tiles or, in case of automatic configuration, they are based on tiles of regular shape in order to map them as rows and columns of a matrix.

Disclosure of the invention

In this context, the technical task at the basis of the present invention is to propose a system of smart objects, in particular tiles, which obviates the drawbacks of the aforementioned prior art.

In particular, an object of the present invention is to provide a system of smart objects, in particular tiles, that has a higher flexibility, is self- configurable or at least reduces the manual intervention.

Another object of the present invention is to propose a system of smart objects, in particular tiles, that is scalable, i.e. able to manage very large sets of objects/tiles.

Another object of the present invention is to propose a system of smart objects, in particular tiles, that is fault-tolerant, that means it is able to detect possible faults and to properly react in order to maintain the best possible level of service.

The specific technical purpose and the specified aims are substantially attained by a system of smart objects, in particular tiles, comprising:

- a plurality of objects arranged and mutually connected to form a grid, each object comprising an electronic module that is electrically connected to the electronic module of each adjacent tile by means of a point-to-point connection;

- a control unit;

- a plurality of interface devices, each configured to act as a communication interface between the control unit and the electronic module of one of the object, the objects that are directly driven by the interface devices forming a subgroup of the objects.

In particular, the electronic module of each object is electrically connected to four or less electronic modules by means of a point-to-point connection. The control unit is configured to:

- obtain from the interface devices data that are used to identify the topology of the grid and the location of each object within the grid;

- store the data in a graph-based data structure where each object is mapped by a node.

According to one aspect of the invention, the electronic module of each tile comprises at least one sensor and/or at least one LED light source.

For example, the sensor is chosen among a temperature sensor, a strain gauge, a lighting sensor, a gesture sensor.

According to one aspect of the invention, all the objects are identical.

In one embodiment of the invention, the objects are tiles that are substantially square or rectangular.

Preferably, the grid comprises a plurality of cells of the same size, each cell housing a tile or being empty.

According to one aspect of the invention, the control unit is also configured to optimize the graph-based data structure, that means minimizing the maximum depth of each branch of the graph and reducing routing paths among the nodes.

According to one aspect of the invention, the control unit is also configured to detect a fault or error in the electronic modules of the objects and, in response to the detection of a fault in one of them, the control unit is configured to isolate the corresponding object.

The specific technical purpose and the specified aims are substantially attained by a computer program product directly loadable in a memory of the control unit of the system.

The computer program product comprises instructions which, when the program is executed by the control unit, cause:

• obtaining from the interface devices data that are used to identify the topology of the grid and the location of each object within the grid;

• storing the data in a graph-based data structure where each object is mapped by a node. Brief description of drawings

Further characteristics and advantages of the present invention will become more apparent from the following indicative and therefore non limiting description of a system of smart objects, in particular tiles, as illustrated in the appended drawings in which:

- figure 1 schematically illustrates a system of smart objects, in particular tiles, according to the present invention;

- figures 2(a), 2(b) and 2(c) illustrates three different configurations of the grid of the system of figure 1 ;

- figure 3 illustrates the flow diagram of a layout reconstruction algorithm executed by the control unit of the system of figure 1.

Detailed description of preferred embodiments of the invention With reference to the figures, number 1 indicates a system of smart objects, in particular tiles, comprising a plurality of tiles 2 arranged and mutually connected to form a grid 3.

The number of tiles 2 of the grid 3 can be very hight, i.e. millions of tiles 2 can be handled.

Each tile 2 comprises an electronic module (not illustrated) that is electrically connected to the electronic module of each adjacent tile 2 by means of a point-to-point connection.

In particular, the electronic module of each tile 2 is electrically connected to four or less electronic modules by means of a point-to-point connection. In particular, the tiles 2 are identical. In fact, they have the same size and the same shape.

Preferably, all the tiles 2 are substantially square or rectangular, as in figure 1.

According to an alternative embodiment, all the tiles 2 are substantially hexagonal.

In general, the tiles 2 can have a polygonal shape.

The grid 3 has a planar extension. The number of tiles 2 and the layout of the grid 3 can vary. Possible configurations of a grid 3 are shown in figure 2(a)-(c).

The grid 3 comprises a plurality of cells. Each cell has the size of a tile 2, and all the cells have the same dimension. A cell may house a tile 2 or being empty.

For example, in the grid 3 illustrated in figure 3(a)-3(b) all the cells are occupied by tiles 2.

In the grid 3 illustrated in figure 3(c) some cells are occupied by tiles 2, other are empty.

A hole is essentially made by one or more empty cells where no tiles are present. Holes produce irregular shapes that allow the grid 3 to fit onto irregular surfaces.

In figure 3(c) there are some holes, indicated with number 20.

As already stated above, the electronic module of each tile 2 is electrically connected to the electronic modules of the adjacent tiles 2. For each tile 2, the adjacent tiles 2 may be four or less (in case there are holes o in case of tiles 2 located in the perimeter of the grid 3).

Each tile 2 is independent from the other from a logical point of view. According to an aspect of the invention, the electronic module of each tile 2 comprises a microprocessor.

The electronic module of each tile 2 comprises at least one sensor and/or at least one LED light source.

For example, the sensor may be a temperature sensor, a strain gauge to measure the presence of persons/objects on the tiles, a lighting sensor, a gesture sensor to allow the interaction of wall-mounted luminous tiles with the user.

According to one aspect of the invention, the electronic module of each tile comprises a plurality of sensors (i.e. chosen from the list above) and/or a plurality of LED light sources.

In case of a plurality of LED light sources per tile, it is envisaged that each tile may be separated into sectors, each with a LED of a different colour. According to one aspect of the invention, tiles 2 with different equipment can be combined in the same grid 3. For instance, it is possible to manage a grid 3 composed by tiles with sensors, tiles with LED light sources and tiles with both sensors and LED light sources.

According to one aspect of the invention, tiles 2 are made of ceramic and have a translucent top layer that allows to diffuse the light.

The system 1 also comprises a control unit 4 and a plurality of interface devices 5.

The control unit 4 may be a server, a standard computer or a dedicated embedded device. The control unit 4 represents the bridge between the users and the system 1 , through which the users can authenticate themselves to access the functionalities of the system 1 , initialize the tiles 2, specify the orientation of the interface devices 5, switch on/off the LED light sources of the tiles 2 or changing the colors associated to the tiles 2, monitor the values retrieved from the sensors.

For example, these values can be raw data directly sensed like the temperature or the weight of a person/animal/object stepping on a tile, or aggregate data obtained as a result of elaboration by the control unit 4, like the average temperature in a room.

Each interface device 5 is configured to act as communication interface between the control unit 4 and the electronic module of one of the tiles 2. The tiles 2 that are directly driven by one of the interface devices 5 form a subgroup of the tiles 2. Hereafter, these tiles 2 are referred to as “entry points”.

The interface devices 5 receive commands and/or data from the control unit 4 and forward them to the entry points 2 and/or receives data from the entry points 2 and forward them to the control unit 4.

For example, this bidirectional communication can be supported by Ethernet or Wi-fi.

The control unit 4 is configured to:

- obtain from the interface devices 5 data that are used to identify the topology of the grid 3 and the location of each tile 2 within the grid 3; - store the received data in a graph-based data structure where each tile 2 is mapped by a node.

In this context, the topology of the grid 3 is the layout of cells that form the grid 3, either housing the tiles or being empty holes.

The identification of the topology of the grid 3 and the location of each tile 2 within the grid 3 is carried out in an initialization phase that starts with the execution of a configuration algorithm.

The control unit 4 sends to the interface devices 5 a message that is referred to as init_all. The init_all message is forwarded from each interface device 5 to the corresponding entry point 2. The entry point 2 forwards the init_all message to the adjacent tiles 2. Finally, the init_all message is propagated using a flooding approach from tile to tile until all the tiles are reached.

Intuitively, during this process there is a high chance that a tile receives more than one the init_all message. To avoid the grid 3 to be stuck into an infinite loop of messages forwarding, a tile that has already received an init_all message message immediately reacts to the next the init_all message sending a retrieved message.

The information contained in the init_all message allows a tile to identify its X-Y co-ordinates and orientation.

A temporary parent interface device 5 and parent tile 2 are also associated to the tile 2. In fact, the tile 2 sets its parent interface device 5 as the parent interface device 5 of the sender of the init_all message, and its parent tile as the sender tile itself. After this configuration operations, the tile answers to the init_all message by transmitting another message, referred to as “tile message”, containing relevant information about itself. Whenever the tile detects that one of its neighbours is associated to a different interface device 5, it packs this information into a boundaryjnfo message, which is also transmitted to its parent tile. Both this kind of messages are forwarded from tile to tile until they reach the entry point. The entry point forwards them to the interface device, which in turn forwards them to the control unit 4.

At the end of this process, therefore, the control unit 4 has all the necessary information to identify the topology of the grid 3 and the location of each single tile 2.

Then, the control unit 4 is involved in organizing the data into a graph- based data structure where each tile 2 is mapped by a node.

The graph-based data structure provides a representation model of the grid. This structure is composed by various trees, one for each entry point, that are used to disseminate and retrieve the information.

For building the graph-based data structure, the control unit 4 is configured to execute a layout reconstruction algorithm, whose flow diagram is illustrated in figure 3.

At 100, a set of objects that represent each tile 2 is instantiated using the data contained in the tile messages.

After having created an empty matrix at 101 , the objects are consistently placed into the matrix at 102, according to the co-ordinate included in the tile messages and by following the information given by the boundaryjnfo. At the end of this process, the matrix representing the neighborhood of tiles is completed, while a graph-like data structure is generated on the basis of location information and the relationship information (parent and child) stored into the objects. When this algorithm completes its execution, the initialization is concluded.

After the initialization phase, an optimization phase is preferably started during which the trees are optimized. The optimization targets the balancing of the number of nodes (and so the number of tiles) among the interface devices 5, while the maximum depth of each three is minimized. The advantage of the optimization phase it that it allows to obtain the best performance (i.e., lowest latency) in operations that require data dissemination in the network.

The optimization process is done by sequentially executing some algorithms, for example: - partition balancing

- tree finding

- re-configuration

- image to tile mapping.

The partition balancing algorithm allows to efficiently divide the tiles 2 between all the existing interface devices 5. This algorithm is a heuristic algorithm. It starts by assign to each interface device 5 only the corresponding entry point. Afterwards, each set of tile is expanded by adding all the unassigned tiles that are adjacent to a tile in the set. This step is iterated until it produces at least one change in the current sets of tiles (i.e., at least one set of tiles can expand).

The tree finding algorithm is then applied to each set of tiles determined with the partition balancing. The goal is to extract the tree with the minimal depth connecting the tiles to the interface device. This algorithm applies the shortest-path tree procedure to the graph made by the tiles associated to the interface device.

Then, a re-configuration algorithm is used to dynamically update the configuration parameters of the tiles. This means that the control unit generates and sends a proper sequence of set_tile messages. This kind of message, intuitively, carry out the new configuration parameter for a particular tile. Whenever a tile receives a set_tile message, indeed, instantly change its configuration parameters.

After re-configuration, an image is converted into a sequence of pixels to be displayed on the tiles 2. So, the algorithm called “image to tile mapping” starts. This algorithm works by associating one or more pixels to each tile 2, depending on the number of independent colours that can be displayed by the tile 2 (that in turn depends on the different light sources embedded in the tile).

When the association is done, the control unit 4 generates a sequence of set_pixels messages for each interface device 5 by taking into account the trees that support the grid 3. The sequence is generated according to the post-order visiting order of the corresponding tree.

The sequence of set_pixels are then sent to the interface devices 5.

The optimization phase preferably comprises also a sensor configuration algorithm that depends on the type of the sensors involved.

The data coming from the sensors are also collected and sent to the control unit 4.

When a tile 2 is not used for a predefined time interval, i.e. it does not receive any message for the predefined time interval, it may switch to a sleep mode. There could be cases in which a tile 2 erroneously falls in the sleep mode, so there is envisaged a refresh operation that triggers the periodic transmission of a hearbeat message to the tile 2. This hearbeat message is used to awake the tile 2.

According to one aspect of the invention, the control unit 4 is also configured to detect a fault or error in the electronic modules of the objects 2 and, in response to the detection of a fault in one of them, the control unit 4 is configured to isolate the corresponding object 2.

Afterwards, the control unit 4 is able to define new paths to reach one or more tiles, not passing through the tile that has been excluded.

All the previous description refers to tiles, in particular ceramic tiles. The tiles can also be made by other material, i.e. glass or PMMA, and be used to create puzzle of a smart game.

However, other types of smart objects may be considered.

From the description given, the features of the system of smart tiles according to the present invention appear clear, as do the advantages thereof.

In particular, the system shows a high flexibility of installation and self configuration capabilities. No manual configuration is necessary.

There is no need to specify the shape of the grid, the locations of holes within the grid, the orientation of tiles and the types of sensors embedded in the tiles.

The number of tiles may vary, as well as the number of entry points. In practice, the shape and layout of the grid may be arbitrary.

In addition, the tiles may be rotated during installation, thus simplifying the procedure and avoiding possible errors.

In addition, each entry point handles the communication with a subset of installed tiles. In case of failure of an entry point, the multiple entry points add fault-tolerance through redundancy. In fact, the use of a point-to-point connection between pairs of adjacent tiles allows each tile to send messages in multi-hop mode, that means that each tile sends messages to the adjacent tiles until the target tile is reached. The tiles are physically/electrically insulated, so that a fault in one of the them do not affect the whole system.

In addition, in case of failure of a connection between two tiles, said link is excluded from the paths and a different path may be established to reach a target tile.