Method and system for determining a relative position of two movable objects, in particular the status opened or closed of an open / close mechanism

Abstract

Method for determining a status opened or closed of an open / close mechanism (12-20) belonging to two objects movable relative to each other, comprising -providing one (1) of the objects with a contactless reader (RD) and providing the other object (2) with a contactless transponder (TG), -determining said status using a reader check whether reading the tag is possible or not.

Description

[0001] Method and system for determining a relative position of two movable objects, in particular the status opened or closed of an open / close mechanism.

[0002] Implementations and embodiments of the invention relate to contactless transponders, for example tags, and readers, in particular NFC (near-field communication) transponders and readers, and in particular to the use of such transponders and readers for detecting the relative positioning of two objects that are movable in relation to one another and one of which is fitted with a transponder while the other one is fitted with a reader, or for detecting the status opened or closed of a system including both objects .

[0003] Near-field communication, better known to those skilled in the art under the name NFC, is a wireless connectivity technology that allows communication over a short distance, for example 10 cm, between electronic devices, such as for example contactless chip cards or tags, and readers or any other NFC enabled device like smartphone or tablet.

[0004] NFC technology is particularly suitable for connecting any type of user device which is equipped with NFC technology and allows fast and easy communication.

[0005] A contactless transponder is a transponder that is capable of exchanging information via an antenna with a contactless reader, in accordance with a contactless communication protocol.

[0006] An NFC transponder, which is a contactless transponder, is a transponder that is compatible with NFC technology.

[0007] NFC technology is an open technological platform that has been standardized in the ISO / IEC 18092 and ISO / IEC 21481 standards, but incorporates numerous standards that already exist, such as for example the Type A and Type B protocols defined in the ISO- 14443 standard, which may be communication protocols able to be used in NFC technology.

[0008] Contactless technology may also be used in RFID (Radiofrequency Identification) transponders that are compatible with the ISO 15693 and ISO 18000-3 standards. During a transmission of information between a reader and a transponder, the reader generates a magnetic field by way of its antenna, which is generally a sinusoidal wave (the carrier) at 13.56 MHz in the standards that are conventionally used.

[0009] To transmit information from the reader to the transponder, the reader uses an amplitude modulation of said carrier.

[0010] The transponder, for its part, includes processing means configured to demodulate the received carrier in order to obtain the data transmitted from the reader.

[0011] For a transmission of information from the transponder to the reader, the reader generates the signal and modulation, and the reader’ s antenna generates the magnetic field (the carrier) without modulation. The antenna of the transponder then modulates the field generated by the reader, based on the information to be transmitted. The frequency of this modulation corresponds to a subcarrier of said carrier. The frequency of this subcarrier depends on the communication protocol that is used and may be for example equal to 848 kHz.

[0012] This modulation is performed by modifying the load connected to the terminals of the antenna of the transponder.

[0013] Two modes of operation are then possible, a passive mode or an active mode.

[0014] In passive mode, the transponder backscatter-modulates the wave coming from the reader in order to transmit information and, to transmit the information, does not incorporate transmission means as such, or a transmitter, that is capable for example of generating its own magnetic field during the transmission. Such a transponder without a transmitter is called a passive transponder, in contrast to an active transponder which includes a transmitter.

[0015] Generally, a passive transponder does not have a power supply, because it uses the wave coming from the reader to power its integrated circuit.

[0016] In some applications, the passive transponder may incorporate a power supply, for example a battery . In the active mode of operation, the reader and the transponder, called active transponder, both generate an electromagnetic field. In general, this mode of operation is used when the active transponder is provided with a dedicated power source, for example a battery.

[0017] Each of the NFC devices (reader and transponder) transmits the data using a modulation scheme.

[0018] In this case too, the modulation is reflected by a load modification, and reference is then made to communication through active load modulation.

[0019] In comparison with a passive communication mode, greater operating distances are obtained, which may range as far as 20 cm depending on the protocol that is used. By increasing the size of the antenna of the reader and / or the sensitivity of the reader, it is then possible to increase the distance up to distances possibly ranging up to several tens of cm, for example 60 cm.

[0020] Moreover, the use of active load modulation makes it possible to use very small antennas .

[0021] The present invention applies to passive transponders or to active transponders, but using passive transponders is preferred, in particular for applications with an open / close mechanism.

[0022] NFC technology is used for example in US 1 1356830 for transmitting a positioning information on the relative position of two objects .

[0023] More precisely, this prior art document discloses a system comprising:

[0024] - a module having a contactless reader function;

[0025] - a first object including a transponder comprising an integrated circuit that has two terminals which may or may not be shorted,

[0026] - the module and the transponder being configured to communicate with one another using a contactless communication protocol;

[0027] - a second object, the two objects being movable in relation to one another; and - shorting means that are located at least partly on said second object and configured to short or not to short the two terminals depending on the relative positioning of the two objects, the transponder being configured to transmit, to said module, positioning information corresponding to said relative positioning.

[0028] Thus, according to this document, monitoring the relative position of the two objects uses these two terminals and the detection of their potential shorting caused at least partly by the second object in combination with the transmission of the positioning information by means of contactless communication.

[0029] There is thus a need to propose an easier solution for determining a relative position between two movable objects .

[0030] Such a solution may also be used for example in certain applications using an open / close mechanism but is not limiting it to this specific use case.

[0031] In such certain applications with an open / close mechanism, users do not have confirmation by default whether the mechanism has been opened or closed for sure, even if it has been locked. For example, a door can be locked without being properly closed in the frame. The lock bolt is moved but does not go into the opening in the door frame, as the door is still at least partially standing open.

[0032] This problem is also occurring in other applications and products, e.g. , windows, transport boxes, ...

[0033] At present some solutions exist for trying to solve this problem.

[0034] For example, simple visual confirmation is used, where a person needs to visually confirm the door is fully closed before locking. But visual confirmation is easy to forget or someone would need to go back to the door to double check)

[0035] Potentially, magnetic reed contacts may be used for high security doors and alarm systems .

[0036] However, magnetic reed contacts are not tamper-proof and can be tampered with by bypassing or overwriting it with external magnets or similar means of manipulation) . Therefore, there is a need to propose another solution for determining the status opened or closed of an open / close mechanism, which does not need any visual confirmation, which is more reliable and easier to implement, and which is more secure.

[0037] According to an embodiment, a NFC tag is placed on one part of the open / close mechanism, for example a part of a door or window frame, a transport box lid, ...

[0038] Next, the NFC reader as counterpart is placed on the other part of the open / close mechanism, e.g., the door, the window, the box.

[0039] The location of both reader and tag could be exchanged, depending on application requirements .

[0040] The NFC tag and reader are positioned and matched in a way, that a successful read is only possible in close range. This short read range ensures, that the mechanical mechanism is closed, when a read is successful and opened when the read is not successful.

[0041] In other words, according to such an embodiment, the determination of the status closed or opened of the mechanism is made by using only a reader check whether reading the tag is possible or not possible.

[0042] According to an aspect, a method is proposed for determining a status opened or closed of an open / close mechanism belonging to two objects movable relative to each other.

[0043] Said method comprises :

[0044] -providing one of the objects with a contactless reader, for example a NFC reader, and providing the other object with a contactless transponder, for example a NFC tag, -determining said status using a reader check whether reading the tag is possible or not.

[0045] This method is easy to implement, as the status is determined using only a reader check whether reading the tag is possible or not.

[0046] Thus , no visual confirmation is needed. The status closed can be confirmed for example in a smart lock and the information can be accessed directly at the smart lock or, if the smart lock is connected to the web, accessed via a connected object such as smartphones, smart watches or other means.

[0047] Further this method is more secure than e.g. , reed contacts . The tamper-proof character is due to tag security features .

[0048] According to an embodiment the mechanism has the status closed if reading the tag is possible and the status opened if reading the tag is not possible.

[0049] Optionally, security can be implemented through additional checks, for example by checking whether the NFC tag provides the correct ID to the reader, cryptographical keys or similar means .

[0050] Through that, it can be ensured that even if someone tries to manipulate the mechanism with an external tag, the reader detects a wrongdoing and can prohibit access or issue an alert.

[0051] According to an embodiment, said contactless reader has a predetermined read range, and

[0052] -the open / close mechanism has the status closed when the two objects are in a first relative position corresponding to a distance between the respective antennas of the reader and the transponder smaller than or equal to said read range, and

[0053] -the mechanism has the status opened when the two objects are in a second relative position corresponding to a distance between the respective antennas of two objects greater than said read range.

[0054] The read range depends notably on the antennas geometries, the output power of the signal emitted by the reader, but is further impacted by the environment (e.g . metal in door frame, ... ), reader sensitivity.

[0055] The man skilled in the art will be able to define the read range depending on the application, for example by measures in laboratory using prototypes of the open / close mechanism. Also, calibration of the end product could be feasible.

[0056] Here below a few examples regarding read range vs antenna dimensions, in “free air”:

[0057] NFC reader with 20x20 mm reader antenna and 1W output power and NFC tag antenna with 23mm diameter lead to a read range of ~ 40mm. NFC reader with 47x34 mm reader antenna and 1W output power and NFC tag with 64 x 34 mm dimensions lead to a read range of ~ 120mm.

[0058] NFC reader with 12x 12 mm reader antenna and 1W output power and NFC tag with 9 x 9 mm dimensions lead to a read range of ~20mm.

[0059] A method according to another aspect is also proposed for determining a relative position of two objects movable relative to each other, said method comprising : -providing one of the objects with a contactless reader and providing the other object with a contactless transponder, -determining said relative position using a reader check whether reading the tag is possible or not.

[0060] This method clearly distinguishes from the prior art disclosed in US 1 1356830 mentioned above and is easier to implement.

[0061] As a matter fact, in the present embodiment, the relative position is obtained by using only a check whether reading the tag is possible or not, while in this prior art document, the relative position is determined by the two terminals shorted or not by the shorting means, and the reader actually reads the tag for transmitting the positioning information because the communication between the tag and the reader is actually possible.

[0062] According to an embodiment of the method according to this another aspect, said contactless reader has a predetermined read range, -the two objects are in a first relative position corresponding to a distance between the respective antennas of the reader and the transponder smaller than or equal to said read range if reading the tag is possible, and -the two objects are in a second relative position corresponding to a distance between the respective antennas of the reader and the transponder greater than said read range if reading the tag is not possible.

[0063] Whatever the aspect, according to an embodiment: -said reader check whether reading the tag is possible comprises sending by the reader a request command and receiving by the reader an answer to said request command, and

[0064] - said reader check whether reading the tag is not possible comprises sending by the reader a request command and not receiving by the reader any answer to said request command.

[0065] It is also possible to use the value of the Received Signal Strength Indicator-RSSI- of the communication between the tag and the reader for estimating a distance value between the two objects .

[0066] More precisely, according to an embodiment, the reader determines the value of the RSSI, and said method comprises estimating a distance value between the two objects by using the RSSI value.

[0067] In particular for an open / close application, one of the objects may comprise a part of a door frame or window frame and the other object may comprise a part of the door or the window.

[0068] Of course, other types of objects are possible such as transport boxes, this example being not limitative.

[0069] Other applications outside smart homes usage are possible, such as logistics, industrial ... .

[0070] According to another aspect, a system is proposed, comprising -two objects movable relative to each other, one of the objects including a contactless reader and the other object including a contactless transponder, said reader being configured to check whether reading the tag is possible or not, and -indication means for indicating a relative position of the two objects based only on said check.

[0071] According to an embodiment, said contactless reader has a predetermined read range, and said indication means are configured to -indicate that the two objects are in a first relative position corresponding to a distance between the respective antennas of the two objects smaller than or equal to said read range if reading the tag is possible, and -indicate that the two objects are in a second relative position corresponding to a distance between the respective antennas of the two objects greater than said read range if reading the tag is not possible. According to another aspect a system is proposed, comprising -an open / close mechanism belonging to two objects movable relative to each other, one of the objects including a contactless reader and the other object including a contactless transponder, said reader being configured to check whether reading the tag is possible or not, and -indication means for indicating a status opened or closed of said open / close mechanism based only on said check.

[0072] According to an embodiment, said indication means are configured to indicate that the mechanism has the status closed if reading the tag is possible and the status opened if reading the tag is not possible.

[0073] According to an embodiment, said contactless reader has a predetermined read range, and said indication means are configured to indicate that -the mechanism has the status closed when the two objects are in a first relative position corresponding to a distance between the respective antennas of two objects smaller than or equal to said read range, and -the mechanism has the status opened when the two objects are in a second relative position corresponding to a distance between the respective antennas of two objects greater than said read range.

[0074] According to an embodiment,

[0075] - for checking whether reading the tag is possible, said reader is configured to send a request command and to check it receives an answer to said request command, and

[0076] - for checking whether reading the tag is not possible, said reader is configured to send a request command and to check it does not receive any answer to said request command.

[0077] According to an embodiment, the reader is configured to determine the value of the Received Signal Strength Indicator-RSSI- of the communication between the tag and the reader, and, said reader is configured to estimate a distance value between the two objects by using the RSSI value. According to an embodiment, one of the objects comprise a part of a door frame or window frame and the other object comprises a part of the door or window.

[0078] The other object may comprise a smart lock or a similar product on the door or window .

[0079] Other advantages and features of the invention will appear in the detailed description below and in the appended drawings which are not limitative, in which:

[0080] Figures 1 - 12 illustrate particular embodiments of the invention.

[0081] In figure 1 , reference 1 designates a first object, for example a door or a smart lock on a door, provided with an NFC reader RD including an antenna ANT I and an integrated circuit IC.

[0082] The word “reader” includes in particular a reader itself but also other products capable of NFC communication such as a reader emulated smartphone, a NFC controller, a microcontroller unit implementing NFC functionality, ...

[0083] In this example, the integrated circuit IC of the reader RD may be connected to a microcontroller by a bus, for example a I2C bus or a SPI bus.

[0084] The NFC reader, having a conventional structure, may be for example the one of STMicroelectronics Company having the reference ST25R.

[0085] Reference 2 designates a second object, for example a door frame, provided with a conventional NFC tag TG having an antenna ANT2.

[0086] The NFC tag may be for example the one of STMicroelectronics Company having the reference ST25T or ST25DV.

[0087] As it is well-known by the man skilled in the art, the reader RD has a reader range RDRG.

[0088] As it will be explained more in details thereafter, the reader RD is configured to check whether reading the tag TG is possible or not possible. And, as illustrated in figure 2, if in step S20, reading the tag TG is possible, it means that the distance D between both antennas ANT2 and ANT I is smaller than or equal to the read range RDRG.

[0089] If in step S20, reading the tag TG is not possible, it means that the distance D between both antennas ANT2 and ANT I is greater than the read range RDRG.

[0090] The read range depends on the antenna geometries, the output power of the signal emitted by the reader and is further impacted by the environment (metal ... ), reader sensitivity, ....

[0091] The man skilled on the art will be able to define the read range depending on the application, for example by measures in laboratory using prototypes .

[0092] For example, an NFC reader with a 20x20 millimeters reader antenna ANT I and 1W output power and an NFC tag antenna ANT2 having a diameter of 23 millimeters lead to a read range of about 40 millimeters .

[0093] An NFC reader with a 12x12 millimeters reader antenna and 1W output power and an NFC tag with a 9x9 mm antenna lead to a read range of about 20 millimeters.

[0094] Those examples of read ranges are in free air.

[0095] The integrated circuit IC of the reader RD includes indication means INDM configured to give the information on whether reading the tag TG is possible or not possible.

[0096] The indication means INDM may be for example a logic circuit or a software module.

[0097] Many possibilities exist for checking whether reading the tag TG is possible or not possible.

[0098] For example, as illustrated in figure 3 , the reader may send a request command REQ (step S200) to the tag. If the reader RD receives in step ST201 an answer ANS from the tag, thus, it means that reading the tag TG is possible.

[0099] On contrary, if no answer is received in step S201 , reading the tag TG is not possible. For example, the request command REQ may be the request command REQA of the protocol type A of standard ISO / IEC 14443 and the answer ANS may be the answer to request ATQA of the same protocol.

[0100] Another embodiment is possible as illustrated on figure 4.

[0101] More precisely, when reading the tag is possible, the reader RD measures the RSSI value RSSIV in step S400.

[0102] Then the value RSSIV may be used to estimate more precisely the distance D between antennas ANT I and ANT2 (step S401 ) .

[0103] We refer now more particularly to figures 5-8 for describing an application of the invention related to the determination of a status opened or closed of an open / close mechanism.

[0104] More precisely, as illustrated in figures 5-8, the first object 1 , provided with the reader RD, comprises here a door having a smart lock 10 and a door latch 1 1.

[0105] The second object 2, which is provided with a tag TG, is a part of a door frame 2.

[0106] As illustrated in figure 6, the frame 2 includes an opening 20 intended to receive the lock bolt 12 located on the door 1.

[0107] Thus, both opening 20 and lock bolt 12 form an open / close mechanism.

[0108] When the lock bolt 12 is correctly locked into the opening 20, the status of the open / close mechanism is “closed” .

[0109] If the lock bolt 12 is not correctly locked into the opening, the status of the open / close mechanism is “opened”.

[0110] The tag TG with its antenna ANT2 is located near the opening 20.

[0111] The antenna ANT I of the reader is located near the lock bolt 12.

[0112] Both antennas are placed on both objects so that reading the tag is only possible when the lock bolt is correctly locked into the opening of the door frame.

[0113] In other words, both antennas are placed on both objects so that antenna ANT2 is within the read range only when the lock bolt is correctly locked into the opening of the door frame. As illustrated in figure 6, which a top view, when the lock bolt 12 is not inserted in the opening 20, the antenna ANT2 is outside of the read range RDRG of the reader RD and reading the tag TG is not possible.

[0114] Thus, the open / close mechanism 12-20 is open.

[0115] This information is transmitted by the indication means INDM of the reader to the microcontroller MC which is for example inserted in the smart lock 10 and the information of the status opened, or the open / close mechanism may be represented by a green light of the smart lock 10.

[0116] It is also possible to obtain this information by a smartphone through another NFC communication between the smartphone and an NFC interface coupled to the microcontroller MC.

[0117] The information of the status “opened” or “closed” can be also accessed if the smart lock is connected to the web . As a matter of fact, the status can be checked from any location from any device connected to the web.

[0118] In figure 7, which is also a top view, the lock bolt 12 is correctly locked into the opening 20. Thus, the antenna ANT2 is within the read range RDRG of the reader RD . Reading TG by the reader is thus possible and the open / close mechanism 12-20 is closed.

[0119] In such a case, a red light may appear on the smart lock 10.

[0120] Figure 8 is a side view corresponding to the top view of figure 7.

[0121] Figures 9 and 10 illustrate diagrammatically another possible application of the invention.

[0122] More precisely, as illustrated in figure 9, the first object 1 , provided with the reader RD, is located at a distance D I from the second object 2 provided with the tag TG.

[0123] If in step S9, reading the tag TG is possible, thus, both objects 1 and 2 are in a first relative position RLPS 1 corresponding to a distance D I smaller than or equal to the read range RDRG of the reader RD.

[0124] In other words, if in step S9, reading the tag TG is possible, thus, both objects 1 and 2 are spaced by a distance D I smaller than or equal to the read range RDRG of the reader RD . Further as explained with reference to figure 4, the RSSI value may be optionally used for estimating more precisely the distance D I .

[0125] As illustrated in figure 10, if reading the tag TG is not possible in step S 10, thus, both objects 1 and 2 are in a second relative position RLPS2 corresponding to a distance D2 between both objects greater than the read range RDRG.

[0126] In other words, if in step S 10, reading the tag TG is not possible, thus, both objects 1 and 2 are spaced by a distance D2 greater than the read range RDRG of the reader RD .

[0127] Other embodiments may be implemented, in particular for application using an open / close mechanism.

[0128] More precisely, the first object 1 , in particular the smart lock, comprises indication means for delivering an indication on said relative position or said status .

[0129] Such indication means are for example a green indicator light LDG or a red indicator light LDR (figure 5) or a speaker or other means.

[0130] The first object, in particular the smart lock, may be configured to send a notification (step S I 100; figure 1 1 ) to a third object OBJ3 connected to the first object for example through NFC or the web .

[0131] The reader maybe further configured, when reading the tag is possible, to perform security check (step S 1200; figure 12) including checking an identification information ID of the tag sent by the tag and / or using cryptographical keys.

Claims

CLAIMS1. Method for determining a relative position of two objects movable relative to each other, comprising-providing one of the objects ( 1 ) with a contactless reader (RD) and providing the other object with a contactless transponder (TG) , -determining (ST9, ST 10) said relative position using a reader check whether reading the tag is possible or not.

2. Method according to claim 1 , wherein said contactless reader has a predetermined read range (RDRG), and wherein- if reading the tag is possible, the two objects are in a first relative position corresponding to a distance (D I ) between the respective antennas of the reader and the transponder smaller than or equal to said read range, and- if reading the tag is not possible, the two objects are in a second relative position corresponding to a distance (D2) between the respective antennas of the reader and the transponder greater than said read range.

3. Method for determining a status opened or closed of an open / close mechanism ( 12-20) belonging to two objects movable relative to each other, comprising-providing one ( 1 ) of the objects with a contactless reader (RD) and providing the other object (2) with a contactless transponder (TG) , -determining said status using a reader check whether reading the tag is possible or not.

4. Method according to claim 3 , wherein the mechanism has the status closed if reading the tag (TG) is possible and the status opened if reading the tag (TG) is not possible.

5. Method according to claim 4, wherein said contactless reader has a predetermined read range (RDRG), and-the open / close mechanism has the status closed when the two objects are in a first relative position corresponding to a distance between the respective antennas of the reader andthe transponder smaller than or equal to said read range, and -the mechanism has the status opened when the two objects are in a second relative position corresponding to a distance between the respective antennas of two objects greater than said read range.

6. Method according to any one of the preceding claims, wherein-said reader check whether reading the tag is possible comprises sending by the reader a request command (REQ) and receiving by the reader an answer (ANS) to said request command, and- said reader check whether reading the tag is not possible comprises sending by the reader a request command (REQ) and not receiving by the reader any answer (ANS) to said request command.

7. Method according to any one of the preceding claims, wherein the reader determines the value (RSSIV) of the Received Signal Strength Indicator-RSSI- of the communication between the tag and the reader, and said method comprises estimating a distance value by between the two objects by using the RSSI value.

8. Method according to any one of the preceding claims, wherein one ( 1 ) of the objects comprises a part of a door frame or window frame and the other object (2) comprises a part of the door or the window .

9. Method according to claim 8, wherein said other object delivers an indication on said relative position or said status .

10. Method according to claim 9, wherein said delivery includes sending a notification to a third object connected to said other object.

11. Method according to any one of the preceding claims, further comprising, when reading the tag is possible, performing by the reader security check including checkingan identification information of the tag and / or using cryptographical keys .

12. System comprising-two objects ( 1 ,2) movable relative to each other, one of the objects including a contactless reader (RD) and the other object including a contactless transponder (TG), said reader being configured to check whether reading the tag is possible or not, and-indication means (INDM) for indicating a relative position of the two objects based on said check.

13. System according to claim 12, wherein said contactless reader has a predetermined read range (RDRG), and said indication means are configured to-indicate that the two objects are in a first relative position corresponding to a distance between the respective antennas of the two objects smaller than or equal to said read range if reading the tag is possible, and-indicate that the two objects are in a second relative position corresponding to a distance between the respective antennas of the two objects greater than said read range if reading the tag is not possible.

14. System comprising-an open / close mechanism ( 12-20) belonging to two objects( 1 ,2) movable relative to each other, one of the objects including a contactless reader (RD) and the other object including a contactless transponder (TG) , said reader being configured to check whether reading the tag is possible or not, and-indication means (INDM) for indicating a status opened or closed of said open / close mechanism based on said check.

15. System according to claim 14, wherein said indication means (INDM) are configured to indicate that the mechanism has the status closed if reading the tag ispossible and the status opened if reading the tag is not possible.

16. System according to claim 15, wherein said contactless reader has a predetermined read range (RDRG), and said indication means are configured to indicate that-the mechanism has the status closed when the two objects are in a first relative position corresponding to a distance between the respective antennas of two objects smaller than or equal to said read range, and -the mechanism has the status opened when the two objects are in a second relative position corresponding to a distance between the respective antennas of two objects greater than said read range.

17. System according to any one of the claims 12 to 16, wherein- for checking whether reading the tag is possible, said reader is configured to send a request command (REQ) and to check it receives an answer (ANS ) to said request command, and- for checking whether reading the tag is not possible, said reader is configured to send a request command and to check it does not receive any answer to said request command.

18. System according to any one of the claims 12 to 17, wherein the reader is configured to determine the value (RSSIV) of the Received Signal Strength Indicator-RSSI- of the communication between the tag and the reader, and said reader is configured to estimate a distance value between the two objects by using the RSSI value.

19. System according to any one of the claims 12 to 18, wherein one of the objects comprises a part of a door frame (2) or window frame and the other object ( 1 ) comprises a part of the door or window.

20. System according to claim 19, wherein the other object comprises a smart lock ( 10) on the door ( 1 ) or the window .

21. System according to claim 19 or 20, wherein said other object comprises indication means for delivering an indication on said relative position or said status .

22. System according to any one of the claims 19 to 21 , wherein said other object is configured to send a notification to a third object connected to said other object.

23. System according to any one of the claims 12 to 22, wherein the reader is further configured, when reading the tag is possible, to perform security check including checking an identification information of the tag and / or using cryptographical keys .

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