sensor

Abstract

To provide a sensor that can automatically grasp the layout relationship.SOLUTION: A sensor includes a sensing unit that detects an article moving on a route, a receiving unit that receives identification information of other sensors transmitted from other sensors that have detected the article, and a control unit that stores the most recently received identification information of the other sensor in a storage unit in accordance with the detection of the article by the sensing unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to sensors. [Background technology]

[0002] Patent Document 1 discloses a sensor network in which a plurality of sensors are arranged in a mesh pattern and wirelessly communicate with each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-244756 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a sensor network that detects items moving along a path such as a conveyor belt, it is useful for a user to specify the placement of sensors in order to identify defects, such as items not moving properly.

[0005] However, when there are a large number of sensors, there is a problem in that it is time-consuming to manually store the layout relationships of the sensors in the sensors.

[0006] Non-limiting examples of the present disclosure contribute to providing a sensor that can automatically determine its positional relationship. [Means for solving the problem]

[0007] One embodiment of the present disclosure is a sensor having a sensing unit that detects an object moving on a path, a receiving unit that receives identification information of another sensor that detected the object transmitted from the other sensor, and a control unit that stores the most recently received identification information of the other sensor in a memory unit in response to the detection of the object by the sensing unit.

[0008] One embodiment of the present disclosure includes a sensing unit that detects an item moving on a path, a receiving unit that receives identification information of another sensor that is transmitted when the other sensor detects the item, a memory unit that stores upstream identification information of the adjacent sensor upstream, and a control unit that turns on after a first time has elapsed after receiving identification information that matches the upstream identification information and turns off after a second time has elapsed.

[0009] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. Effect of the Invention

[0010] According to an embodiment of the present disclosure, the layout relationship of sensors can be automatically understood.

[0011] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 illustrates an example of the configuration of a sensor network according to the present disclosure. [Diagram 2] A diagram showing an example of a sensor block configuration [Diagram 3] FIG. 13 is a diagram showing an example of a table stored in a memory unit of a sensor. [Figure 4] 1 is a timing chart illustrating an example of operation in a sensor calibration mode. [Diagram 5] 1 is a timing chart illustrating an example of the operation of a sensor in normal mode. [Figure 6]1 is a flowchart showing an example of the operation of a first sensor. [Figure 7A] 11 is a flowchart showing an example of the operation of a second sensor. [Figure 7B] 11 is a flowchart showing an example of the operation of a second sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

[0014] It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0015] Fig. 1 is a diagram showing an example of the configuration of a sensor network 1 according to the present disclosure. As shown in Fig. 1, the sensor network 1 includes sensors 11, 21, 22, and 23. The sensors 11, 21, 22, and 23 communicate with each other using wireless communication. For the wireless communication, for example, wireless communication such as Wi-Fi (registered trademark) or Bluetooth (registered trademark) may be used.

[0016] 1 shows a conveyor belt 41 and an article 51 transported by the conveyor belt 41 in addition to the sensor network 1. The conveyor belt 41 transports the article 51, for example, in a factory or a logistics warehouse. The conveyor belt 41 transports the article 51, for example, at a determined speed (constant speed).

[0017] In the example of Fig. 1, belt conveyor 41 transports article 51 in the direction of arrow A1. Therefore, article 51 passes in front of sensors 11, 21, 22, and 23 in that order. Note that, hereinafter, the direction of arrow A1 in the transport direction of article 51 may be referred to as downstream. The direction opposite to the direction of arrow A1 may be referred to as upstream.

[0018] The sensors 11, 21, 22, and 23 are, for example, photoelectric sensors driven by batteries. Therefore, the sensors 11, 21, 22, and 23 do not require wiring for power supply and communication. The sensors 11, 21, 22, and 23 are assigned their own identification information (ID), for example, as shown in A to D of FIG.

[0019] The sensors 11, 21, 22, and 23 are arranged along the belt conveyor 41 (along the conveying path of the article 51). The sensors 11, 21, 22, and 23 detect the passage of the article 51 flowing on the belt conveyor 41, and monitor whether the article 51 is being properly conveyed on the belt conveyor 41. The sensors 11, 21, 22, and 23 may, for example, issue an alarm when it is determined that the article 51 is not being properly conveyed.

[0020] When the sensors 11, 21, 22, and 23 detect the passage of the article 51, they broadcast passage detection information indicating that the article 51 has passed. The sensors 11, 21, 22, and 23 receive the broadcasted passage detection information. Note that the passage detection information may include the passage time when the article 51 passed.

[0021] The sensors 11, 21, 22, and 23 are divided into a first sensor and a second sensor. For example, among the sensors 11, 21, 22, and 23, the sensor 11 that detects the article 51 first is defined as the first sensor. In other words, among the sensors 11, 21, 22, and 23, the sensor 11 that is disposed at the beginning of the conveying path is defined as the first sensor. The sensors 21, 22, and 23 other than the first sensor are defined as the second sensors.

[0022] The number of sensors is not limited to the example in Fig. 1. For example, the number of second sensors may be one or more.

[0023] Fig. 2 is a diagram showing an example of a block configuration of the sensor 21. As shown in Fig. 2, the sensor 21 has a control unit 61-1, a communication unit 62-1, a sensing unit 63-1, a power supply unit 64-1, and a storage unit 65-1.

[0024] The control unit 61-1 controls the entire sensor 21. The control unit 61-1 may be configured with a processor such as a CPU (Central Processing Unit) or a DSP (Digital signal Processor). The control unit 61-1 may also have a timer function.

[0025] The communication unit 62-1 uses wireless communication such as Wi-Fi or Bluetooth to communicate with the sensors 11, 22, and 23. The communication unit 62-1 may be composed of a receiving unit that receives a signal and a transmitting unit that transmits a signal.

[0026] The sensing unit 63-1 detects the passage of an article 51 traveling on the belt conveyor 41. For example, the sensing unit 63-1 may emit light and receive reflected light, and detect the passage of an article 51 based on the received light.

[0027] The power supply unit 64-1 supplies power to each part of the sensor 21. The power supply unit 64-1 supplies power to each part of the sensor 21 using a battery such as a primary battery or a secondary battery. Note that the power supply unit 64-1 may supply power in a wired or wireless manner.

[0028] The storage unit 65-1 stores a program for the control unit 61-1 to operate. The storage unit 65-1 also stores data for the control unit 61-1 to perform calculation processing or data for the control unit 61-1 to control each unit. The storage unit 65-1 may be configured with a storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, and a HDD (Hard Disk Drive).

[0029] The sensors 11, 22, and 23 also have a block configuration similar to the block configuration shown in Fig. 2. Therefore, the first sensor may be used as the second sensor, and the second sensor may be used as the first sensor.

[0030] Hereinafter, the control units of the sensors 11, 22, and 23 may be referred to as control units 61-0, 61-2, and 61-3. The communication units of the sensors 11, 22, and 23 may be referred to as communication units 62-0, 62-2, and 62-3. The sensing units of the sensors 11, 22, and 23 may be referred to as sensing units 63-0, 63-2, and 63-3. The power supply units of the sensors 11, 22, and 23 may be referred to as power supply units 64-0, 64-2, and 64-3. The memory units of the sensors 11, 22, and 23 may be referred to as memory units 65-0, 65-2, and 65-3.

[0031] Fig. 3 is a diagram showing an example of a table stored in the storage unit 65-1 of the sensor 21. As shown in Fig. 3, the table TB1 has a column for a sensor ID and a column for a previous sensor ID.

[0032] The sensor ID field stores the ID of the sensor 21. B shown in FIG.

[0033] The previous sensor ID field stores the ID of the sensor that is disposed immediately before the sensor 21 on the conveying path (in the conveying direction of the article 51).

[0034] 1, the sensor disposed immediately before sensor 21 is sensor 11. In other words, the sensor immediately upstream of sensor 21 is sensor 11. Therefore, the ID of sensor 11 is stored in the previous sensor ID field of table TB1. A shown in FIG. 3 indicates the ID of sensor 11.

[0035] The sensor immediately upstream of sensor 22 (the sensor immediately before on the transport path) is sensor 21. Therefore, the ID of sensor 21 is stored in the previous sensor ID field of storage unit 65-2 for sensor 22.

[0036] Moreover, the sensor immediately upstream of the sensor 23 is the sensor 22. Therefore, the ID of the sensor 22 is stored in the previous sensor ID of the storage unit 65-3 of the sensor 23.

[0037] There is no sensor upstream of the sensor 11 arranged at the beginning of the transport path. Therefore, for example, information indicating that no sensor exists may be stored in the previous sensor ID of the storage unit 65-0 of the sensor 11.

[0038] The following describes the operations of the sensors 11, 21, 22, and 23. The sensors 11, 21, 22, and 23 each have a calibration mode and a normal mode of operation.

[0039] In the calibration mode, the sensors 11, 21, 22, and 23 recognize the locations of the sensors 11, 21, 22, and 23. For example, each of the sensors 11, 21, 22, and 23 recognizes the previous sensor ID. That is, each of the sensors 11, 21, 22, and 23 recognizes the sensor that is one sensor upstream on the transport path.

[0040] In the normal mode, the sensors 11, 21, 22, and 23 detect the articles 51 traveling on the belt conveyor 41 and monitor whether the articles 51 are being properly transported on the belt conveyor 41. In addition, the sensing parts of the sensors 11, 21, 22, and 23 operate in an on-off manner.

[0041] First, an example of operation in the calibration mode will be described. Fig. 4 is a timing chart illustrating an example of operation in the calibration mode of the sensors 11, 21, 22, and 23. The horizontal axis in Fig. 4 indicates time.

[0042] Timing A11a indicates an on-period of the sensing unit 63-0 of the sensor 11. Timing A11b indicates an on-period of the sensing unit 63-1 of the sensor 21. Timing A11c indicates an on-period of the sensing unit 63-2 of the sensor 22. Timing A11d indicates an on-period of the sensing unit 63-3 of the sensor 23.

[0043] Timing A12a indicates the communication timing of the sensor 11. Timing A12b indicates the communication timing of the sensor 21. Timing A12c indicates the communication timing of the sensor 22. Timing A12d indicates the communication timing of the sensor 23.

[0044] Timing A13a indicates a period during which the article 51 passes in front of the sensor 11. Timing A13b indicates a period during which the article 51 passes in front of the sensor 21. Timing A13c indicates a period during which the article 51 passes in front of the sensor 22. Timing A13d indicates a period during which the article 51 passes in front of the sensor 23.

[0045] The period during which the article 51 passes in front of the sensors 11, 21, 22, and 23 may be considered as a period during which the sensors 11, 21, 22, and 23 can detect the passage of the article 51. The article 51 may also be a test article that is sent down the belt conveyor 41 for calibration.

[0046] (1) As shown at timing A13a, the article 51 passes in front of the sensor 11. The sensor 11 detects the article 51 passing in front of the sensor 11.

[0047] The sensor 11 that detects the passage of the article 51 broadcasts the location understanding start information, the passage detection information, and the ID of the sensor 11. For example, the sensor 11 broadcasts the location understanding start information, the passage detection information, and the ID of the sensor 11 at timing A12a.

[0048] If there is a transmission delay time Tdt between detecting the passage and transmitting the passage detection information, the sensor 11 may transmit the passage detection information including information on how much the transmission was delayed from the detection start time. This allows the second sensors 21, 22, and 23 to operate taking the transmission delay time Tdt into consideration when resetting the timer.

[0049] (2) The sensors 21, 22, and 23 receive the location recognition start information, the passage detection information, and the ID of the sensor 11 broadcast by the sensor 11 at timing A12a. In response to receiving the location recognition start information, the passage detection information, and the ID of the sensor 11, the sensors 21, 22, and 23 reset a timer (for example, to 0) and start measuring time.

[0050] When the sensors 21, 22, and 23 receive the location recognition start information, they operate in the calibration mode.

[0051] (3) As shown at timing A13b, the article 51 passes in front of the sensor 21. The sensor 21 detects the article 51 passing in front of the sensor 21.

[0052] The sensor 21 that detects the passage of the article 51 stores the ID broadcast by the sensor 11 as the previous sensor ID in the memory unit 65-1. In addition, the sensor 21 that detects the passage of the article 51 stores the timer time in the memory unit 65-1. The time stored in the memory unit 65-1 indicates the time from when the article 51 passed the sensor 11 to when it passed the sensor 21.

[0053] That is, the memory unit 65-1 of the sensor 21 stores information about the sensor in front of the sensor 21 (the ID of the sensor 11) and the time from when the article 51 passes in front of the sensor 11 to when it passes in front of the sensor 21. The time stored in the memory unit 65-1 may be referred to as the delay time or transport time of the article 51 between the sensors. For example, the delay time for the sensor 21 is the time from timing A12a to timing A12b. The delay time may be determined by the second sensor 21 using the reception time of the passage detection information, the transmission delay time Tdt, and the timer time.

[0054] After storing the previous sensor ID and the delay time of the article 51 in the memory unit 65-1, the sensor 21 broadcasts the passage detection information and the ID of the sensor 21 and turns off the sensing unit 63-1. For example, the sensor 21 broadcasts the passage detection information and the ID of the sensor 21 at timing A12b, and then turns off the sensing unit 63-1 as shown at timing A11b.

[0055] Incidentally, the sensors 22 and 23 that have not detected the article 51 continue to operate the timers immediately before the timing A12b.

[0056] (4) The sensors 22 and 23 receive the passage detection information broadcast by the sensor 21 at timing A12b and the ID of the sensor 21. In response to receiving the passage detection information and the ID of the sensor 21, the sensors 22 and 23 reset their timers and start measuring time.

[0057] (5) As shown at timing A13c, the article 51 passes in front of the sensor 22. The sensor 22 detects the article 51 passing in front of the sensor 22.

[0058] The sensor 22 that detects the passage of the article 51 stores the ID broadcast by the sensor 21 as the previous sensor ID in the memory unit 65-2. In addition, the sensor 22 that detects the passage of the article 51 stores the timer time in the memory unit 65-2. The time stored in the memory unit 65-2 indicates the time from when the article 51 passes the sensor 21 to when it passes the sensor 22.

[0059] That is, in the memory unit 65-2 of the sensor 22, information on the sensor in front of the sensor 22 (the ID of the sensor 21) and the time from when the article 51 passes in front of the sensor 21 to when it passes in front of the sensor 22 are stored.

[0060] After storing the previous sensor ID and the delay time of the article 51 in the memory unit 65-2, the sensor 22 broadcasts the passage detection information and the ID of the sensor 22 and turns off the sensing unit 63-2. For example, the sensor 22 broadcasts the passage detection information and the ID of the sensor 22 at timing A12c, and then turns off the sensing unit 63-2 as shown at timing A11c.

[0061] Incidentally, the sensor 23 that has not detected the article 51 continues the timer operation immediately before the timing A12c.

[0062] (6) The sensor 23 receives the passage detection information broadcast by the sensor 22 at timing A12c and the ID of the sensor 22. In response to receiving the passage detection information and the ID of the sensor 22, the sensor 23 resets the timer and starts measuring time.

[0063] (7) As shown at timing A13d, the article 51 passes in front of the sensor 23. The sensor 23 detects the article 51 passing in front of the sensor 23.

[0064] The sensor 23 that detects the passage of the article 51 stores the ID broadcast by the sensor 22 as the previous sensor ID in the memory unit 65-3. In addition, the sensor 23 that detects the passage of the article 51 stores the timer time in the memory unit 65-3. The time stored in the memory unit 65-3 indicates the time from when the article 51 passed the sensor 22 to when it passed the sensor 23.

[0065] That is, in the memory unit 65-3 of the sensor 23, information on the sensor in front of the sensor 23 (the ID of the sensor 23) and the time from when the article 51 passes in front of the sensor 22 until when it passes in front of the sensor 23 are stored.

[0066] After storing the previous sensor ID and the delay time of the article 51 in the memory unit 65-3, the sensor 23 broadcasts the passage detection information and the ID of the sensor 23 and turns off the sensing unit 63-3. For example, the sensor 23 broadcasts the passage detection information and the ID of the sensor 23 at timing A12d, and then turns off the sensing unit 63-3 as shown at timing A11d.

[0067] In this way, each of the sensors 21, 22, and 23 automatically stores the previous sensor ID in the storage unit without human intervention. Also, each of the sensors 21, 22, and 23 automatically stores in the storage unit the delay time from when the article 51 passes the previous sensor (the sensor immediately preceding the previous sensor on the upstream side) until when the article 51 passes in front of the sensor.

[0068] When broadcasting the passage detection information and the sensor ID, each of the sensors 21, 22, and 23 may turn on the transmission function of the communication units 62-1, 62-2, and 62-3. For example, each of the sensors 21, 22, and 23 may store the previous sensor ID and the timer time (the delay time of the article 51) in the storage unit, and then turn on the transmission function of the communication units 62-1, 62-2, and 62-3 to broadcast the passage detection information and the sensor ID. Then, each of the sensors 21, 22, and 23 may turn off the transmission function of the communication units 62-1, 62-2, and 62-3 after broadcasting this information.

[0069] Furthermore, as shown by timings A12a to A12d, the broadcast does not have to be performed near the center of the passing period (timings A13a to A13d) of the article 51. The broadcast may be performed after the article 51 is detected and before the article 51 arrives at the next sensor (the sensor one sensor downstream). At this time, the sensors 21, 22, and 23 may transmit the passing detection information including transmission delay information Tdt indicating how much the transmission was delayed from the detection start time.

[0070] Furthermore, the ID of the sensor that is broadcast is the ID of the sensor that detected the passage of the item 51, and may be referred to as the passage ID.

[0071] Next, an example of operation in the normal mode will be described. Fig. 5 is a timing chart for explaining an example of operation of the sensors 11, 21, 22, and 23 in the normal mode. The horizontal axis in Fig. 5 indicates time. In Fig. 5, the same reference numerals are used for the same elements as in Fig. 4. It is assumed that the previous sensor ID and delay time are stored in the memory units 65-1, 65-2, and 65-3 of the sensors 21, 22, and 23 by the calibration operation.

[0072] (1) As shown at timing A13a, the article 51 passes in front of the sensor 11. The sensor 11 detects the article 51 passing in front of the sensor 11. Note that the sensor 11 disposed at the beginning of the conveying path keeps the sensing unit 63-0 on at all times, as shown at timing A11a.

[0073] The sensor 11 that detects the passage of the article 51 broadcasts the passage detection information and the ID of the sensor 11. For example, the sensor 11 broadcasts the passage detection information and the ID of the sensor 11 at timing A12a. Note that in the normal mode, the sensor 11 does not need to broadcast the location recognition start information.

[0074] (2) The sensors 21, 22, and 23 receive the passage detection information broadcast by the sensor 11 and the ID of the sensor 11. The sensors 21, 22, and 23 compare whether the received ID of the sensor 11 matches the previous sensor ID stored in the storage units 65-1, 65-2, and 65-3.

[0075] (3) Of the sensors 21, 22, and 23, the sensor whose received ID of the sensor 11 matches the previous sensor ID stored in the memory units 65-1, 65-2, and 65-3 determines (calculates) the timing to turn on the sensing unit and the time to turn on the sensing unit (the time from when the sensing unit is turned on to when it is turned off) based on the delay time stored in the memory unit.

[0076] Therefore, the sensor 21 located one sensor behind (one sensor downstream) the sensor 11 that detected the item 51 determines the timing (Tst) and the time (Ton) for turning on the sensing unit 63-1 based on the delay time stored in the memory unit 65-1 in the calibration mode.

[0077] Note that Tst and Ton determined based on the delay time can be regarded as the time (estimated time) at which the article 51 passes in front of the sensor 21 located immediately behind the sensor 11 that detected the article 51, or a part thereof. In other words, the sensor 21 located immediately behind the sensor 11 that detected the article 51 can be regarded as determining the expected time at which the article 51 passes in front of itself based on the delay time stored in the memory unit 65-1 in the calibration mode, and determining the on-time of the sensing unit, which is the expected time or a part thereof.

[0078] A method for determining Tst and Ton will be described later. In the following, the sensor immediately behind the sensor that detected the article 51 may be referred to as a rear sensor.

[0079] (4) The sensor 21 turns on the sensing unit 63-1 based on the determined Tst and Ton. For example, the sensor 21 turns on the sensing unit 63-1 as shown at timing A11b.

[0080] (5) The sensor 21 that detects the passage of the article 51 broadcasts the passage detection information and the ID of the sensor 21. For example, the sensor 21 broadcasts the passage detection information and the ID of the sensor 21 at timing A12b.

[0081] (6) The sensors 22 and 23 receive the passage detection information broadcast by the sensor 21 and the ID of the sensor 21. The sensors 22 and 23 compare whether the received ID of the sensor 21 matches the previous sensor ID stored in the storage units 65-2 and 65-3.

[0082] (7) Of the sensors 22, 23, the sensor whose received ID of the sensor 11 matches the previous sensor ID stored in the memory units 65-2, 65-3 determines the timing and the time for turning on the sensing unit based on the delay time stored in the memory unit.

[0083] Therefore, the sensor 22 immediately behind the sensor 21 that detected the article 51 determines the timing and duration for turning on the sensing unit 63-2 based on the delay time stored in the memory unit 65-2 in the calibration mode.

[0084] (8) The sensor 22 turns on the sensing unit 63-2 based on the determined Tst and Ton. For example, the sensor 22 turns on the sensing unit 63-2 as shown at timing A11c.

[0085] (9) The sensor 22 that detects the passage of the article 51 broadcasts the passage detection information and the ID of the sensor 22. For example, the sensor 22 broadcasts the passage detection information and the ID of the sensor 22 at timing A12c.

[0086] (10) The sensor 23 receives the passage detection information broadcast by the sensor 22 and the ID of the sensor 22. The sensor 23 compares whether the received ID of the sensor 22 matches the previous sensor ID stored in the memory unit 65-3.

[0087] (11) A sensor whose received ID of the sensor 22 matches the previous sensor ID stored in the memory unit determines the timing and the time for turning on the sensing unit based on the delay time stored in the memory unit.

[0088] Therefore, the sensor 23 immediately behind the sensor 22 that detected the article 51 determines the timing and duration for turning on the sensing unit 63-3 based on the delay time stored in the memory unit 65-3 in the calibration mode.

[0089] (12) The sensor 23 turns on the sensing unit 63-3 based on the determined Tst and Ton. For example, the sensor 23 turns on the sensing unit 63-3 as shown at timing A11d.

[0090] (13) The sensor 23 that detects the passage of the article 51 broadcasts the passage detection information and the ID of the sensor 23. For example, the sensor 23 broadcasts the passage detection information and the ID of the sensor 21 at timing A12d.

[0091] As described above, the sensors 21, 22, and 23 turn on the sensing units 63-1, 63-2, and 63-3 from Tst to Ton. Ton may be a constant value or may be changed according to the detection time. The detection time is the time during which the sensor detects the article 51 (the time from the start of detection to the end of detection). When Ton is changed according to the detection time, the previous sensor broadcasts the detection time of the previous sensor together with the passage detection information.

[0092] An example of a method for determining Tst and Ton will be described below. Tst may be determined by the following equations (1) and (2).

[0093] Tst = detection start time + delay time - detection time / 2 ... (1) Ton = detection time × α…(2)

[0094] Here, any value of 0<α≦1 may be used. The detection start time and detection duration can be ascertained from the passage detection information, and the delay time is stored during the calibration operation. If there is a transmission delay time Tdt, the detection start time can be calculated by subtracting Tdt from the reception time.

[0095] If the time between the transmission of wireless communication in the communication unit of a sensor and the reception of wireless communication in the communication unit of another sensor is relatively long, each sensor may take into account the delay Tdc (communication delay time) between the transmission and reception of wireless communication and set the detection start time as reception time - Tdt - Tdc. Tdc may be determined in advance by each sensor wirelessly transmitting and receiving known data. If the difference between the timer times of the wirelessly transmitting sensor and the wirelessly receiving sensor is small, the time of the wirelessly transmitting timer may be used as the detection start time.

[0096] In this manner, of the sensors 21, 22, 23, the sensing units 63-1, 63-2, 63-3 of the sensor immediately downstream of the sensor through which the article 51 has passed are turned on for a predetermined time. That is, the sensing units 63-1, 63-2, 63-3 of the sensors 21, 22, 23 operate intermittently.

[0097] Each of the sensors 21, 22, and 23 may turn on the transmission function of the communication units 62-1, 62-2, and 62-3 when broadcasting the passage detection information and the ID of the sensor 23. For example, each of the sensors 21, 22, and 23 may turn on the transmission function of the communication units 62-1, 62-2, and 62-3 after determining Tst and Ton, and broadcast the passage detection information and the sensor ID. Then, each of the sensors 21, 22, and 23 may turn off the transmission function of the communication units 62-1, 62-2, and 62-3 after broadcasting this information.

[0098] Furthermore, as shown by timings A12a to A12d, the broadcast does not have to be performed near the center of the passing period (timings A13a to A13d) of the article 51. The broadcast may be performed after the article 51 is detected and before the article 51 arrives at the rear sensor. In this case, the sensor may transmit the passing detection information including the transmission delay time Tdt as information indicating how much the transmission was delayed from the detection start time.

[0099] Furthermore, the ID of the sensor that is broadcast is the ID of the sensor that detected the passage of the item 51, and may be referred to as the passage ID.

[0100] 6 is a flowchart showing an example of the operation of the first sensor. The first sensor turns off the receiving function of the communication unit and turns off the transmitting function (S11). The first sensor also turns on the sensing unit (S11).

[0101] The first sensor determines whether or not an article 51 is detected (S12).

[0102] When the first sensor determines that the article 51 is not detected ("No" in S12), the process proceeds to S11.

[0103] When the first sensor determines that it has detected the article 51 ("Yes" in S12), it measures the detection time of the article 51 (the time during which the first sensor detects the article 51) and stores it in the memory unit (S13).

[0104] The first sensor determines whether the detected article 51 is for testing (S14). Whether the article 51 traveling on the belt conveyor 41 is for testing may be determined, for example, based on the shape (length) of the detected object, or may be set in the first sensor by the user. It may also be set by communication with the communication reception function turned on in S11. The number of passing articles may be counted, and those that pass in a specified order may be set as test articles.

[0105] When the first sensor determines that the detected article 51 is for testing ("Yes" in S14), it turns on the transmission function of the communication unit and broadcasts the passage detection information including the detection time stored in S13, the passage ID (ID of the first sensor), and the position recognition start information (S15). In other words, when the first sensor determines that the detected article 51 is for testing, it operates in the calibration mode.

[0106] When the first sensor determines that the detected article 51 is not for testing ("No" in S14), it turns on the transmission function of the communication unit and broadcasts the passage detection information including the detection time stored in S13 and the passage ID (ID of the first sensor) (S16). In other words, when the first sensor determines that the detected article 51 is not for testing, it operates in the normal mode.

[0107] 7A and 7B are flowcharts showing an example of the operation of the second sensor. In the flowcharts shown in Fig. 7A and 7B, the process continues at circled numbers 1 and 2. In the following, the passage detection information includes the passage time.

[0108] The second sensor turns on the receiving function of the communication unit and turns off the transmitting function (S20). Also, the second sensor turns off the sensing unit (S20).

[0109] The second sensor determines whether or not it has received the passage detection information and the passage ID (the sensor ID broadcast by the previous sensor) (S21).

[0110] When the second sensor determines that it has received the passage detection information and the passage ID ("Yes" in S21), it further determines whether it has received location recognition start information (S22).

[0111] When it is determined that the passage detection information, the passage ID, and the location recognition start information have been received ("Yes" in S22), the second sensor turns on the sensing unit (S22a).

[0112] The second sensor resets the timer and measures time (S23). That is, when the second sensor receives the passage detection information, the passage ID, and the location recognition start information, the second sensor operates in the calibration mode.

[0113] The second sensor determines whether or not a test article 51 is detected (S24).

[0114] The second sensor that detects the test article 51 in S24 stores the time of the timer that started measuring in S23 in the memory unit as a delay time (S25). In addition, the second sensor that detects the test article 51 in S24 stores the passing ID broadcast by the other second sensor (the sensor ID of the other second sensor) in the memory unit (S25). In other words, the second sensor that detects the test article 51 in S24 stores the most recent passing ID broadcast by the other second sensor.

[0115] The second sensor updates the passage time included in the passage detection information (updated to the time when the test article 51 was detected in S24), and updates the passage ID to its own sensor ID (the sensor ID of the second sensor that detected the test article 51) (S26). In addition, the second sensor that detected the test article 51 in S24 turns off its sensing unit (S26).

[0116] The second sensor that has executed the process of S25 turns on the transmission function of the communication unit, and broadcasts the passage detection information updated in S25 and the passage ID (S27).

[0117] The second sensor that broadcasts the passage detection information and the passage ID in S27 turns off its transmission function (S28).

[0118] If the second sensor does not detect the test article 51 in S24 (No in S24), it receives the passage detection information and the passage ID broadcast by another second sensor that detected the test article 51 (S29). The second sensor that receives the passage detection information and the passage ID in S29 transitions the process to S23, resets the timer, and measures time.

[0119] The second sensor, which has determined in S21 that it has not received the passage detection information, the passage ID, and the location understanding start information ("No" in S21), enters a communication reception waiting state (between S20 and S21) (S28).

[0120] When the second sensor determines in S22 that it has not received the location recognition start information ("No" in S22), it determines whether the received passing ID matches the previous sensor ID stored in the storage unit (S31 in FIG. 7B). In other words, when the second sensor receives only the passing detection information and the passing ID, it operates in the normal mode.

[0121] If the second sensor determines that the received passing ID matches the previous sensor ID stored in the memory unit ("Yes" in S31), it determines Tst and Ton based on the passing detection information (the detection time included in the passing detection information) and the delay time stored in the memory unit (S32).

[0122] The second sensor updates the passage time included in the passage detection information (to the time when the sensing unit detected the item 51) and updates the passage ID to its own sensor ID (the sensor ID of the second sensor that detected the test item 51) (S33).

[0123] The second sensor turns on the transmission function of the communication unit, and broadcasts the passage detection information updated in S33 and the passage ID (S34).

[0124] The second sensor turns on the sensing unit in accordance with Tst and Ton determined in S32 (S35). After turning on the sensing unit, the second sensor shifts the process to S28.

[0125] The order of the operations from S33 to S35 may be changed. The second sensor may update and transmit the passage notification information and the passage ID while the sensing unit is on or before or after the sensing unit is on.

[0126] When the second sensor determines in S31 that the received passing ID does not match the previous sensor ID stored in the storage unit ("No" in S31), the second sensor shifts the process to S28.

[0127] As described above, the sensor 21 has a sensing unit 63-1 that detects an item 51 traveling on the conveyor belt 41, a communication unit 62-1 that receives sensor IDs transmitted by other sensors 11, 22, and 23 when they detect an item 51, and a control unit 61-1 that stores the other sensor IDs most recently received in a memory unit 65-1 in response to the detection of an item 51 by the sensing unit 63-1.

[0128] In this way, when the sensing unit 63-1 of the sensor 21 detects the article 51, the sensor 21 stores the most recently received sensor ID in the memory unit 65-1. That is, the memory unit 65-1 stores identification information of the sensor immediately adjacent to the sensor on the upstream side of the belt conveyor 41. Similarly, the other sensors 22, 23 forming the sensor network 1 store identification information of the sensor immediately adjacent to the sensor on the upstream side of the belt conveyor 41 in the memory units of the sensors 22, 23.

[0129] Therefore, the sensors 21, 22, and 23 can automatically understand the layout relationship of the sensors, and the user can easily understand the layout order of the sensors.

[0130] As described above, the sensor 21 has a sensing unit 63-1 that detects items 51 traveling on the conveyor belt 41, a communication unit 62-1 that receives sensor IDs transmitted by other sensors 11, 22, 23 when they detect an item 51, a memory unit 65-1 that stores identification information of the adjacent sensor upstream, and a control unit 61-1 that turns on the sensing unit 63-1 at a predetermined timing (Tst) after receiving the sensor ID and turns it off after a predetermined time (Ton) if the received sensor ID matches the identification information stored in the memory unit 65-1.

[0131] In this way, when the sensor ID transmitted by the other sensors 11, 22, 23 is the identification information of the adjacent sensor 11 on the upstream side of the belt conveyor 41, the sensor 21 turns on the sensing unit 63-1 at a predetermined timing after receiving the sensor ID of the sensor 11, and turns it off after the predetermined time. That is, the sensor 21 turns on the sensing unit 63-1 after the article 51 passes the adjacent sensor 11 on the upstream side of the belt conveyor 41, and turns it off after the predetermined time.

[0132] Therefore, the sensor 21 can reduce power consumption compared to when the sensing unit 63-1 is always on.

[0133] Note that the second sensor may receive passage detection information of the second article 51 before the arrival of the first article 51. In this case, the second sensor stores the passage detection information of the first article 51 and the passage detection information of the second article 51 in a memory unit, and turns on the sensing unit based on the respective passage detection information. That is, the second sensor may store the passage detection information of the article 51 that has not passed in a memory unit, and turn on the sensing unit based on the passage detection information stored in the memory unit.

[0134] Furthermore, the detection time in formula (1) may be 0. That is, the second sensor may turn on the sensing unit based on the passage detection information and the delay time.

[0135] Furthermore, when the first sensor is always on, it can calculate the length of the transported article 51. For example, the first sensor can calculate the length of the article 51 from the detection time and the speed of the article 51 transported by the belt conveyor 41.

[0136] The first sensor and the second sensor may broadcast the length of the article 51 calculated by the first sensor, including it in the passage detection information. The second sensor may use the length of the article 51 to determine Tst and Ton. The passage detection information may also include the start time and end time of the passage of the article 51, instead of the length of the article 51. The passage detection information may be broadcast twice, once when the passage of the article 51 starts and once when the passage of the article 51 ends.

[0137] Furthermore, the order of all sensors and the delay time from the previous sensor may be stored in one or more sensors, or may be stored in another storage device such as a server. From the stored order of all sensors and the delay time from the previous sensor, abnormalities in the transport of the item 51 may be monitored and the location where the abnormality in the transport occurs may be identified. Furthermore, if the moving speed of the item 51 is known, abnormalities in the transport may be detected based on the passage time predicted from the stored delay time and the actual passage time during operation.

[0138] The calibration mode may also be used to determine the placement of the sensor without determining the delay time.

[0139] In the above, the first sensor and the second sensor perform wireless communication, but they may perform wired communication. Even in the case of wired communication, the first sensor and the second sensor can grasp the placement of the sensors. Furthermore, the second sensor can reduce the power consumption of the wired sensor network by operating intermittently.

[0140] Furthermore, the sensing unit of the first sensor does not have to be on all the time. For example, the sensing unit of the first sensor may be turned on when a person inserts an item into the belt conveyor 41. Then, the first sensor may be turned off after detecting the item.

[0141] Furthermore, a sensor that first detects a test item may be determined as a first sensor among the multiple sensors that make up the sensor network 1. The sensor determined to be the first sensor may broadcast location recognition start information.

[0142] In this case, the multiple sensors that make up the sensor network 1 may have a location understanding flow and an item monitoring flow.

[0143] For example, in the placement detection flow, the sensor that first detects the test item broadcasts placement detection start information and becomes the first sensor that is always on. The other sensors become the second sensors that perform intermittent operation.

[0144] In addition, in the location recognition flow, the second sensor may receive and store the sensor ID of the previous sensor and the delay time of the item transport from the previous sensor.

[0145] In an item monitoring flow, a first sensor may be always on and a second sensor may operate intermittently.

[0146] The second sensor may determine the timing and on-time of turning on the sensing unit based on the passage detection information transmitted by each sensor when an item passes through, the passage ID, the previous sensor ID stored in the memory unit, and the delay time from the previous sensor.

[0147] In addition, the communication unit of the sensor may wirelessly transmit the broadcast information within a range that can reach nearby sensors.

[0148] Moreover, the sensor network 1 described above is a distributed system in which the sensors 11, 21, 22, and 23 operate autonomously according to a predetermined flow. The sensor network 1 can use the same hardware, which makes it easy to replace the sensors 11, 21, 22, and 23.

[0149] Furthermore, the sensors 11, 21, 22, and 23 may broadcast the sensor ID (passage ID) but may not broadcast the passage detection information. The sensors 11, 21, 22, and 23 may notify other sensors that they have detected the article 51 by broadcasting the sensor ID.

[0150] In the above-described embodiments, the notation "... part" used for each component may be replaced with other notations such as "... circuit", "... assembly", "... device", "... unit", or "... module".

[0151] Although the embodiments have been described above with reference to the drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or altered examples within the scope of the claims. It is understood that such modified or altered examples also belong to the technical scope of the present disclosure. In addition, the components in the embodiments may be arbitrarily combined within the scope of the present disclosure.

[0152] The present disclosure can be realized by software, hardware, or software in cooperation with hardware. Each functional block used in the description of the above embodiment may be realized partially or entirely as an LSI, which is an integrated circuit, and each process described in the above embodiment may be controlled partially or entirely by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip so as to include some or all of the functional blocks. The LSI may have input and output of data. Depending on the degree of integration, the LSI may be called an IC, a system LSI, a super LSI, or an ultra LSI.

[0153] The method of integration is not limited to LSI, but may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, after LSI manufacturing, a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing.

[0154] Furthermore, if a new integrated circuit technology that can replace LSI appears due to the progress of semiconductor technology or a derivative technology, it is possible to integrate the functional blocks using that technology. The application of biotechnology is also a possibility.

[0155] The present disclosure may be implemented in any type of apparatus, device, or system with communications capabilities (collectively, communications apparatus), including, but not limited to, telephones (e.g., cell phones, smartphones, etc.), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks, etc.), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices, etc.), game consoles, digital book readers, telehealth / telemedicine devices, communications-enabled vehicles or mobile conveyances (e.g., cars, planes, ships, etc.), and combinations of the above-mentioned devices.

[0156] Sensors are not limited to portable or mobile, but also include non-portable or fixed equipment, devices, and systems of any kind, such as smart home devices (appliances, lighting, smart meters or measuring devices, control panels, etc.), vending machines, and any other "Things" that may exist on an Internet of Things (IoT) network.

[0157] Communications includes data communication via cellular systems, wireless LAN systems, communications satellite systems, and the like, as well as combinations of these. Communications apparatus also includes devices, such as controllers and sensors, connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications apparatus.

[0158] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these. [Industrial Applicability]

[0159] The present disclosure is useful for sensors that detect objects moving on a path. [Explanation of symbols]

[0160] 1. Sensor Network 11,21,22,23 Sensors 41 Conveyor Belt 51 Goods 61-1 Control section 62-1 Communications Department 63-1 Sensing section 64-1 Power supply section 65-1 Storage section TB1 Table

Claims

1. A sensing unit that detects an object moving on a path; a receiving unit that receives identification information of the other sensor that detected the item, the identification information being transmitted from the other sensor; a control unit that stores in a storage unit the identification information of the other sensor most recently received in response to the detection of the object by the sensing unit; A sensor having

2. A transmitting unit that transmits identification information of the sensor when the sensing unit detects the item. The sensor of claim 1 .

3. The control unit turns off the sensing unit after the sensing unit detects the object.

3. The sensor according to claim 1 or 2.

4. The control unit is measuring a time from when the identification information of the other sensor is received until the sensing unit detects the item, and storing the time in the storage unit; A sensor according to any one of claims 1 to 3.

5. The control unit is when the identification information received by the receiving unit matches the identification information stored in the storage unit, after the receiving unit receives the identification information, the sensing unit is turned on at a predetermined timing determined based on the time, and turned off after the predetermined time. The sensor of claim 4.

6. A sensing unit that detects an object moving on a path; a receiving unit that receives identification information of the other sensor that is transmitted when the other sensor detects the item; a storage unit that stores upstream side identification information of the adjacent sensor on the upstream side; a control unit that is turned on when a first time has elapsed since receiving identification information that matches the upstream identification information, and that is turned off when a second time has elapsed since receiving the identification information; A sensor having

7. The first time period is determined based on a time period measured in advance from when the adjacent sensor detects the object to when the sensing unit detects the object. The sensor of claim 6.

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