Detection device and detection program

Abstract

To detect the presence or absence of a nearby person with higher accuracy.SOLUTION: A detection device includes a non-contact sensor and a determination section. The non-contact sensor measures a capacitance value varying in response to the entry of an object into an electric field. The determination section determines whether there is a nearby person on the basis of an amount of change in the capacitance value measured by the sensor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a detection device and a detection program. [Background technology]

[0002] For example, there are times when it is necessary to check the current usage status and past usage history (hereinafter collectively referred to as "usage status") of desks and seats, such as desks in a workspace of a free address office and seats in a restaurant, from a remote location. Conventionally, there are desks equipped with motion sensors, for example, that enable such checking of the usage status of desks and seats from a remote location. Motion sensors can detect the presence or absence of a person approaching the desk or seat. However, when a desk equipped with a motion sensor is newly introduced to an office, restaurant, etc., it is often necessary to completely replace the equipment and systems including the desk, which results in a large cost. In order to suppress such an increase in introduction costs, a method of retrofitting an IoT device equipped with an infrared motion sensor to an existing desk can be considered. However, infrared sensors have the characteristic of being vulnerable to temperature fluctuations. Therefore, in a method using an infrared motion sensor, false detection occurs due to the influence of heat from air conditioners or sunlight coming in through a window, and the accuracy of detecting the presence or absence of a person approaching the desk or seat may decrease.

[0003] In order to prevent such a decrease in detection accuracy, a method of retrofitting an IoT device equipped with a capacitance sensor instead of an infrared sensor on an existing desk is conceivable. In general, in a method of detecting a person using a capacitance sensor, the presence or absence of a person nearby is determined based on the magnitude of the absolute value of the measured capacitance value. More specifically, in general, in detecting a person using a capacitance sensor, if the absolute value of the capacitance value is equal to or greater than a predetermined threshold, it is determined that a person nearby exists. On the other hand, if the absolute value of the capacitance value is less than a predetermined threshold, it is determined that a person nearby does not exist. However, in general, the initial value of the capacitance value varies greatly depending on the material and thickness of the desk on which the IoT (Internet of Things) device equipped with the capacitance sensor is attached. Therefore, the appropriate threshold value varies depending on the location on which the IoT device equipped with the capacitance sensor is attached. In addition, the capacitance value changes significantly not only when a person nearby exists, but also when an object is placed near the desk or when a chair is moved. Therefore, in such a conventional method, the absolute value of the capacitance value may exceed the predetermined threshold even if no person nearby exists. This can result in false positives, reducing the accuracy of detecting whether or not someone is near a desk or seat. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4816713 [Patent Document 2] Patent No. 5585793 [Patent Document 3] JP 2017-54376 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a detection device and a detection program that can detect the presence or absence of a person in the vicinity with higher accuracy. [Means for solving the problem]

[0006] The detection device according to the embodiment includes a non-contact sensor and a determination unit. The non-contact sensor measures a capacitance value that changes in response to an object entering an electric field. The determination unit determines whether or not a person is present in the vicinity based on the amount of change in the capacitance value measured by the sensor. [Brief description of the drawings]

[0007] [Figure 1] 1 is an external view showing an overall configuration of an occupancy detection device 1 according to an embodiment. [Diagram 2] 2 is a diagram showing an internal configuration of a board storage unit 12 of the seat occupancy detection device 1 of the embodiment. FIG. [Diagram 3] 1 is a diagram showing an example of installation of an occupancy detection device 1 according to an embodiment. [Figure 4] 4 is a diagram showing an example of a change in capacitance value measured by the seat occupancy detection device 1 according to the embodiment. FIG. [Diagram 5] 4 is a flowchart showing the operation of the seat presence detection device 1 according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a detection device and a detection program according to an embodiment will be described with reference to the drawings.

[0009] The overall configuration of the presence detection device 1 of the embodiment will be described. The presence detection device 1 of the embodiment is an example of the detection device of the present invention. The presence detection device 1 is an IoT device equipped with a capacitance type proximity sensor. However, the presence detection device 1 is not limited to an IoT device, and may be, for example, a standalone device or a device equipped with a communication interface connected to a network by wire. The capacitance type proximity sensor can detect the presence or absence of a nearby object by measuring a capacitance value using an electric field and capturing a change in the measured value. The presence detection device 1 is attached to, for example, a desk. The presence detection device 1 detects the presence or absence of a person using a desk or a seat (hereinafter collectively referred to as a "desk, etc.") in a non-contact manner. The presence detection device 1 is connected to a network wirelessly and transmits information indicating the detection result to an external device via the network. The external device here is, for example, a server that collects information indicating the usage status of a desk, etc.

[0010] The presence detection device 1 of the embodiment is a self-capacitance type capacitance sensor. However, the capacitance type is not limited to the self-capacitance type, and other types may be used. The presence detection device 1 includes a capacitance sensing IC (Integrated Circuit) connected to the electrodes, and a board having a function of transferring information as an IoT sensor. The presence detection device 1 outputs a signal to the electrodes, and calculates a capacitance value based on the change. The presence detection device 1 further calculates the amount of change in the calculated capacitance value, and detects the presence or absence of a person approaching a desk or the like based on the accumulated value of the calculated amount of change.

[0011] The following provides a more detailed explanation of an example of the configuration of the presence detection device 1. Fig. 1 is an external view showing the overall configuration of the presence detection device 1 according to an embodiment. As shown in Fig. 1, the presence detection device 1 includes an electrode unit 11 and a substrate storage unit 12.

[0012] The electrode section 11 includes a copper foil tape 111 and an insulating tape 112. The copper foil tape 111 is used as an electrode that the seat occupancy detection device 1 includes.

[0013] Generally, a printed circuit board such as an FPC (Flexible Printed Circuit) may be used as the electrode. On the other hand, the seating detection device 1 of the embodiment uses a copper foil tape 111 that can be produced in a simpler manufacturing process than an FPC. This allows the seating detection device 1 of the embodiment to keep the production cost of the electrodes lower, and also the price of the device itself lower.

[0014] Furthermore, in order to perform non-contact object detection using a capacitance-type proximity sensor, the electrodes must be sufficiently large. In general, the size of an electrode using an FPC is approximately 2 to 3 cm wide, and the length can be extended to any length. On the other hand, when a copper foil tape 111 is used as an electrode, the length can be made any length in both the vertical and horizontal directions. Therefore, in the embodiment of the occupancy detection device 1 using the copper foil tape 111, electrodes of any size and shape can be easily formed.

[0015] It should be noted that copper wire or the like may be used instead of the copper foil tape 111. However, since the copper foil tape 111 has the characteristics that it can be formed thinner than copper wire and can be easily attached to a desk or the like, it is preferable to use the copper foil tape 111.

[0016] The insulating tape 112 covers the copper foil tape 111 to prevent leakage or electric shock. For example, the copper foil tape 111 is covered by being sandwiched between two insulating tapes 112. One of the two insulating tapes 112 is further covered by, for example, an adhesive tape. This makes it possible to easily install the occupancy detection device 1 at any desired location, such as on the top plate of a desk or the underside of a drawer.

[0017] Fig. 2 is a diagram showing an internal configuration of the board storage unit 12 of the presence detection device 1 of the embodiment. As shown in Fig. 2, the board storage unit 12 is composed of an upper surface part 121 to which the electrode unit 11 is fixed, and a lower surface part 122 to which a board 123 is built in. The board 123 is composed of a capacitance sensing IC (Integrated Circuit) 124 and a communication interface 125.

[0018] The capacitance sensing IC 124 is connected to the copper foil tape 111 of the electrode unit 11, and generates an electric field for object detection by the copper foil tape 111. The capacitance sensing IC 124 calculates a capacitance value. The capacitance sensing IC 124 further calculates a change amount of the calculated capacitance value, and detects the presence or absence of a person approaching a desk or the like based on a cumulative value of the calculated change amount. The capacitance sensing IC 124 outputs information indicating the detection result to the communication interface 125. Generally, since IoT devices are required to operate with low power consumption, the capacitance sensing IC 124 measures the charge at intervals of, for example, about 10 seconds.

[0019] The communication interface 125 connects to a network and transfers information, thereby causing the occupancy detection device 1 to function as an IoT sensor. The communication interface 125 wirelessly connects to the network and transmits information indicating the detection result output from the capacitive sensing IC 124 to an external device via the network.

[0020] The communication interface 125 can use a communication method defined by any wireless communication standard. For example, when low power consumption is the objective, a communication method defined by a wireless communication standard such as Bluetooth Low Energy or EnOcean can be used. Also, when high-speed communication is the objective, a communication method defined by a wireless communication standard such as IEEE802.11ac, which is a wireless LAN (Local Area Network) standard, can be used. Also, when long-distance communication is the objective, a communication method defined by a wireless communication standard such as LoRa or Wi-Fi HaLow can be used.

[0021] Fig. 3 is a diagram showing an example of installation of the presence detection device 1 of the embodiment. As shown in Fig. 3, the presence detection device 1 is attached to the underside of the top plate of the desk 2, for example, by the above-mentioned adhesive tape covering the insulating tape 112. This allows the presence detection device 1 to detect the thighs or the upper arms that are on the desk 2 of a person who is seated on a chair (not shown) and using the desk 2.

[0022] In addition, in the case of a desk with a drawer provided on the underside of the top board, the occupancy detection device 1 may be attached to the underside of the drawer. The occupancy detection device 1 may also be attached to the inside of the legs of the desk 2. The occupancy detection device 1 may also be installed on the side of the back panel of the desk 2 or the side of the side box of the desk 2. The occupancy detection device 1 may also be attached to something other than the desk 2, such as a side desk (not shown).

[0023] The detection algorithm used to detect the presence or absence of a person approaching the desk 2 or the like will be described below.

[0024] In the detection process by the conventional capacitance type proximity sensor, the determination is generally made based on the absolute value of the capacitance value. For example, the conventional capacitance type proximity sensor determines that there is a person nearby when the absolute value of the measured capacitance is equal to or greater than a predetermined threshold. Also, the conventional capacitance type proximity sensor determines that there is no person nearby when the absolute value of the measured capacitance is less than a predetermined threshold. However, in general, the initial value of the capacitance value varies greatly depending on the material and thickness of the desk, and the appropriate threshold value varies for each. Also, the capacitance value changes significantly even when an object other than a person approaches. This may cause false detection and reduce the detection accuracy.

[0025] In contrast, the presence detection device 1 in the embodiment detects the presence or absence of a person approaching based on the magnitude of the numerical vibration of the capacitance value, not the absolute value of the capacitance value. The magnitude of the numerical vibration here corresponds to the magnitude of the accumulated value of the change in the capacitance value for each measurement period. For example, when a moving object such as a person or an animal is approaching a capacitance-type proximity sensor, since it is difficult for the person or the animal to remain completely still, a slight movement occurs and the capacitance value fluctuates finely (numerical vibration). On the other hand, when a stationary object such as an industrial product is approaching a capacitance-type proximity sensor, the capacitance value does not change at all. The presence detection device 1 in the embodiment can detect the presence or absence of a fine change (numerical vibration) in the capacitance value by calculating the accumulated value of the change in the capacitance value. The presence detection device 1 determines the presence or absence of a person approaching a desk 2 or the like based on the accumulated value of the change in the capacitance value.

[0026] Fig. 4 is a diagram showing an example of a change in capacitance value measured by the occupancy detection device 1 of the embodiment. In the graph shown in Fig. 4, the vertical axis represents capacitance value, and the horizontal axis represents time. Each of the periods (1) to (6) shown in Fig. 4 is assumed to be sufficiently longer than a predetermined interval at which the capacitance sensing IC 124 measures the capacitance value.

[0027] For example, in the period (1) in FIG. 4, the capacitance value hardly changes. In such a case, the cumulative value of the change in the capacitance value is relatively small, so the presence detection device 1 determines that there is no person approaching the desk 2, etc. (absent). Next, in the period (2) in FIG. 4, the capacitance value increases from the previous period (1), but after the first increase, there is almost no change in the capacitance value. In such a case, the cumulative value of the change in the capacitance value is relatively small, so the presence detection device 1 determines that there is no person approaching the desk 2, etc. (absent).

[0028] When the capacitance value is increased and remains substantially constant without fluctuating as in the period (2), this may be due to, for example, something stationary being placed near the desk 2 (e.g., on or under the desk 2) or a chair being moved. In the case of a conventional capacitance-type proximity sensor that detects the presence or absence of a person nearby based on the absolute value of the capacitance value, when the capacitance value is increased as in the period (2), it is likely to be erroneously determined that a person is nearby (is seated).

[0029] Next, in the period (3) in FIG. 4, the capacitance value further increases from the previous period (2), and then fluctuates finely during the period, oscillating numerically. In such a case, the cumulative value of the change in the capacitance value becomes a relatively large value, so the presence detection device 1 determines that a person is present (occupied) near the desk 2, etc. Next, in the period (4) in FIG. 4, the capacitance value decreases from the previous period (3), but after the first decrease, the capacitance value hardly changes. In such a case, the cumulative value of the change in the capacitance value becomes a relatively small value, so the presence detection device 1 determines that a person is not present (absent) near the desk 2, etc.

[0030] 4, the capacitance value maintains a relatively small state as in the previous period (4), but fluctuates finely during the period. In this case, the cumulative value of the change in capacitance value becomes relatively large, so the presence detection device 1 determines that a person is present (occupied) near the desk 2, etc.

[0031] In the case of a conventional capacitance-type proximity sensor that detects the presence or absence of a person nearby based on the absolute value of the capacitance value, even if the capacitance value fluctuates and changes finely, as in the period (5), the absolute value of the capacitance value remains small throughout the period, so it is likely to erroneously determine that there is no person nearby (absent).

[0032] Next, in the period (6) in Fig. 4, the capacitance value has decreased from the previous period (5), but after the first decrease, the capacitance value has hardly changed. In such a case, the cumulative value of the amount of change in the capacitance value becomes relatively small, so the presence detection device 1 determines that there is no person near the desk 2 or the like (absent). Note that, if the capacitance value remains constant without any numerical fluctuation after decreasing to a value close to zero, as in the period (6), it is possible that all objects have been removed from the vicinity of the desk 2.

[0033] An example of the operation of the presence detection device 1 of the embodiment will be described below. Fig. 5 is a flowchart showing the operation of the presence detection device 1 of the embodiment. The operation of the presence detection device 1 shown in the flowchart of Fig. 5 is started, for example, when the power of the presence detection device 1 is turned on.

[0034] The capacitance sensing IC 124 calculates the capacitance value on the electrode side (ACT001). The capacitance sensing IC 124 stores the calculated capacitance value in a storage medium (not shown) provided on the substrate 23, for example (ACT002). The capacitance sensing IC 124 refers to the storage medium (not shown) and reads out the previously calculated capacitance value. The capacitance sensing IC 124 calculates the difference between the currently calculated capacitance value and the previously calculated capacitance value to calculate the amount of change in the capacitance value (ACT003).

[0035] The capacitance sensing IC 124 refers to a storage medium (not shown) and reads out the accumulated value of the amount of change in the capacitance value up to the previous time (hereinafter referred to as the "accumulated change value"). The capacitance sensing IC 124 updates the accumulated change value. For example, the capacitance sensing IC 124 multiplies the read-out accumulated change value by 0.8, multiplies the amount of change in the capacitance value calculated this time by 0.2, and adds up the two values. Then, the capacitance sensing IC 124 sets the added value as a new accumulated change value (ACT004). Note that in the first capacitance value measurement, the accumulated change value has not yet been recorded, so the measured capacitance value is recorded as it is as the accumulated change value.

[0036] The capacitance sensing IC 124 compares the accumulated change amount with a predetermined threshold value (ACTCT005). If the accumulated change amount is equal to or greater than the threshold value (ACT006·YES), the capacitance sensing IC 124 determines that a person is present (occupied) near the desk 2 or the like, and outputs information indicating that the person is present to the communication interface 125 (ACT007). On the other hand, if the accumulated change amount is equal to or greater than the threshold value (ACT006·NO), the capacitance sensing IC 124 determines that no person is present (absent) near the desk 2 or the like, and outputs information indicating that the person is absent to the communication interface 125 (ACT008). The communication interface 125 wirelessly connects to a network, and transmits information indicating the detection result obtained from the capacitance sensing IC 124 to an external device via the network.

[0037] Here, the capacitive sensing IC 124 enters a sleep state (hibernation state) (ACT009). The capacitive sensing IC 124 remains in the sleep state until a predetermined time has elapsed (ACT010·NO). When the predetermined time has elapsed (ACT010·YES), the capacitive sensing IC 124 returns from the sleep state and resumes the process from ACT001 above. After that, the process shown in the flowchart of FIG. 5 is repeatedly executed until, for example, the power supply of the seat occupancy detection device 1 is turned off.

[0038] As described above, the presence detection device 1 of the embodiment is an IoT device equipped with a capacitance-type proximity sensor. The presence detection device 1 includes an electrode unit 11 and a capacitance sensing IC 124. The capacitance sensing IC 124 generates an electric field for object detection by the electrode unit 11. The capacitance sensing IC 124 calculates a capacitance value of the electrode unit 11. The capacitance sensing IC 124 calculates a change amount of the calculated capacitance value, and detects the presence or absence of a person approaching a desk 2 or the like based on a cumulative value of the calculated change amount.

[0039] With such a configuration, the presence detection device 1 of the embodiment can detect the slightest movement even if the person standing still near the desk 2, and can detect the person without falsely detecting that the person is an immovable object such as an industrial product. This allows the presence detection device 1 to detect the presence or absence of a person standing nearby with high accuracy.

[0040] As described above, the initial value of the capacitance value generally varies greatly depending on the material and thickness of the desk on which the capacitance type proximity sensor is attached, and the appropriate threshold value varies accordingly. Therefore, in the conventional capacitance type proximity sensor, false detection may occur. On the other hand, the seat presence detection device 1 of the embodiment is configured to perform a determination based on the cumulative value of the amount of change in the capacitance value, rather than the absolute value of the capacitance value, and therefore has the advantage that the appropriate threshold value is not influenced by the material and thickness of the desk. As a result, the seat presence detection device 1 of the embodiment can reduce the occurrence of false detection.

[0041] As described above, the capacitance value changes significantly not only when there is a person nearby, but also when an object is placed near the desk or when the chair moves. As a result, the absolute value of the capacitance value may exceed a predetermined threshold even if there is no person nearby. In this case, in a conventional capacitance-type proximity sensor, a determination is made based on the absolute value of the capacitance value, so there is a possibility of false detection if there is a person nearby. On the other hand, the presence detection device 1 of the embodiment is configured to make a determination based on the cumulative value of the change in the capacitance value, rather than based on the absolute value of the capacitance value. Therefore, in the presence detection device 1 of the embodiment, if the change in the capacitance value is not accompanied by numerical vibration, it is determined that there is no person nearby. As a result, the presence detection device 1 of the embodiment determines that there is no person nearby in the case of a change in the capacitance value caused by the movement of an industrial product such as a chair, for example, and therefore the occurrence of false detection is prevented.

[0042] As described above, the presence detection device 1 of the embodiment uses the copper foil tape 111, which can be produced in a simpler manufacturing process, as the electrodes. Therefore, the presence detection device 1 of the embodiment can reduce the production cost of the electrodes and the price of the device itself. The copper foil tape 111 has the characteristic that it can be formed thinner than, for example, copper wire, and can be easily attached to the desk 2, etc. As a result, the presence detection device 1 of the embodiment can further reduce the introduction cost and installation space.

[0043] According to the above-described embodiment, the detection device includes a non-contact sensor and a determination unit. For example, the detection device is the occupancy detection device 1 in the embodiment, the non-contact sensor is the board storage unit 12 in the embodiment, and the determination unit is the capacitance sensing IC 124 in the embodiment. The non-contact sensor measures a capacitance value that changes in response to an object entering an electric field. The determination unit determines whether or not a person is nearby based on the amount of change in the capacitance value measured by the sensor.

[0044] In the above detection device, the determination unit may determine that a person is present in the vicinity when a cumulative value of the amount of change in the capacitance value over a predetermined period of time is equal to or greater than a threshold value.

[0045] In the above detection device, the determination unit may determine that a person is present in the vicinity when the capacitance value changes with numerical vibration.

[0046] The above-mentioned detection device may further include an electrode unit. For example, the electrode unit is the electrode unit 11 in the embodiment. The electrode unit generates an electric field. The electrode unit is made of a copper foil tape. For example, the copper foil tape is the copper foil tape 111 in the embodiment.

[0047] In the above-mentioned detection device, the sensor may be installed on the bottom surface of the desk top or drawer, on the side surface of the desk back panel, or on the side surface of the desk drawer. For example, the desk is desk 2 in the embodiment.

[0048] A part or all of the functions realized by the board 23 in each of the above-mentioned embodiments may be realized by a computer. In that case, a program for realizing the functions may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into a computer system and executed to realize the functions. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. The term "computer-readable recording medium" may also include a medium that dynamically holds a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, and a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client in that case. The above-mentioned program may be a program for realizing a part of the above-mentioned functions, or may be a program that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0049] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0050] 1: Occupancy detection device, 2: Desk, 11: Electrode section, 12: Board storage section, 23: Board, 111: Copper foil tape, 112: Insulating tape, 121: Upper surface section, 122: Lower surface section, 123: Board, 124: Capacitive sensing IC, 125: Communication interface

Claims

1. A non-contact sensor that measures a capacitance value that changes in response to an object entering an electric field; a determination unit that determines whether or not a person is present in the vicinity based on the amount of change in the capacitance value measured by the sensor; A detection device comprising:

2. The determination unit determines that a person is present in the vicinity when a cumulative value of the amount of change in the capacitance value over a predetermined period of time is equal to or greater than a threshold value. The detection device of claim 1 .

3. The determination unit determines that a person is present in the vicinity when the capacitance value changes with a numerical oscillation. The detection device of claim 1 .

4. The sensor includes an electrode portion for generating the electric field. Further equipped with The electrode portion is made of copper foil tape. The detection device of claim 1 .

5. The sensor is installed on the bottom surface of a desk top or drawer, on the side of a desk top panel, or on the side of a desk drawer. The detection device of claim 1 .

6. On the computer, A non-contact sensor measures the capacitance value, which changes as an object enters the electric field, Based on the amount of change in the capacitance value measured by the sensor, it is determined whether or not a person is present nearby. Detection program.

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