JP2004173554A - Apparatus for preventing theft of cultured fish and shellfish - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for preventing theft of cultured fish and shellfish, which is inexpensive and does not require continuous monitoring by a monitor and avoids a malfunction by waves and birds. <P>SOLUTION: The apparatus for preventing theft of cultured fish and shellfish comprises using an infrared sensor 13 at a sensor part for detecting an intruder, etc., and the Internet mail utilizing specific small electric power radio transceivers 31-35 and 41-45 in a means of communication between an alarm display part 30 at the sea side and an alarm display part 40 at the land side and a cell phone network as a remote monitoring apparatus 32. The detection time of the infrared sensor 13 is monitored by a control part 38 to prevent a malfunction by the influence of waves and birds. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for preventing the cultivation of cultured fish and shellfish, and in particular, monitors the approach of an intruder or a suspicious boat (hereinafter referred to as an intruder or the like) to a cage of cultured fish or shellfish installed in the sea or the like, and theft of the cultured fish and shellfish. The present invention relates to an anti-theft device for cultured fish and shellfish which detects and prevents theft.
[0002]
[Prior art]
In order to prevent the theft of cultured fish and shellfish, monitoring with an infrared camera or a high-sensitivity camera has been conventionally performed. A surveillance device, a surveillance control unit, a surveillance system, and an aquaculture surveillance system that disclose such a surveillance camera with a movable structure and display the surveillance status of a surveillance unit on a monitor screen are disclosed (for example, see Patent Document 1). .).
[0003]
Further, as a method other than monitoring by a monitoring camera, a seafood theft prevention device that generates an alarm by combining a sensor that detects that a culture container storing fish and shellfish is lifted and a wireless device is disclosed ( For example, see Patent Document 2.) Furthermore, a security system for preventing the abalone from being cultured using an air pipe net has been disclosed (for example, see Patent Document 3).
[0004]
[Patent Document 1]
JP 2001-321005 A (pages 8-9, FIG. 1-FIG. 2).
[Patent Document 2]
JP-A-8-235454 (pages 2 to 4, FIGS. 1 to 3).
[Patent Document 3]
JP-A-2002-27861 (pages 2 to 3, FIG. 1).
[0005]
[Problems to be solved by the invention]
However, the conventional camera-based monitoring system described above has the following problems. First, the size of the device is increased, resulting in a higher price. Generally, infrared cameras and high-sensitivity cameras are more expensive than ordinary video cameras. Further, when the terrain of the farm to be monitored is complicated, the number of places where the camera becomes a blind spot increases, and it is necessary to increase the number of monitoring cameras to be installed, which further increases the price.
[0006]
Secondly, in monitoring by a camera, it is necessary to constantly monitor the monitoring camera while moving it with human eyes. Therefore, in long-term monitoring, there is a high possibility that the discovery of the theft is delayed due to reduced concentration or carelessness. Become. In the related art disclosed in Patent Document 1 described above, the detection state of an abnormal object or the like is monitored by combining a monitor that displays a monitoring state and a control computer. However, according to this method, the size of the apparatus is further increased as compared with the case where only the monitoring camera is used, and the price increases. Also disclosed is a method of monitoring underwater with a sensor that detects an abnormality when a cutting external force or the like is applied to a cage (or a gauge) for aquaculture or a sensor that detects cutting or the like of a hanging member. I have. However, it is difficult to detect a cutting external force or the like below the water surface, which also increases the price. Further, in the method of detecting the cutting of the member, once the member is cut, the member must be installed again, and the maintenance cost increases.
[0007]
The method using a sensor for detecting that the culture container is lifted up disclosed in Patent Document 2 described above can be used in the case of a small basket for pearl pearl culture and the like. However, an actual cultured fish cage is a large container having a side of about 12 meters, and is not pulled up to be stolen for cultured fish. Therefore, it is difficult to apply the monitoring to theft of such cultured fish. Further, when these sensors are used for small cages such as for pearl cultivation, sensors must be attached to each cage, which increases the price. Further, in the security system for preventing the abalone cultured abalone from being stolen using the air pipe net disclosed in Patent Document 3 described above, when the abalone cultured basket is cut or removed, pressurized air passing through the air pipe leaks out, and the air pressure is reduced. This is a method of operating the detector by lowering it. In this method, since the air pipe must be stretched in all directions, initial costs are increased. Further, even when the car is actually cut, maintenance costs such as repairs increase.
[0008]
[Object of the invention]
The present invention has been made in view of the above-mentioned problems of the related art, and can be constructed at a lower price than a theft monitoring system using a video camera or the like, and does not need to be constantly monitored by a human eye unlike a video camera. An object of the present invention is to provide an anti-theft device for cultured fish and shellfish.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the cultured fish and shellfish antitheft device according to the present invention employs the following characteristic configuration.
[0010]
(1) A cultured seafood antitheft device that is installed in the sea and accommodates seafood in a fish cage to prevent the fish from being stolen in the fish farming cage,
An infrared sensor for detecting that an intruder or the like has approached the aquaculture cage, a specific low-power wireless transmitter for transmitting a detection signal from the infrared sensor, and a signal transmitted from the specific low-power wireless transmitter Aquaculture comprising: an alarm device that receives a detection signal and transmits a threat signal to an intruder or the like; and a remote monitoring device that notifies the owner or the like of the culture pond that the threat signal has been transmitted. Seafood anti-theft device.
[0011]
(2) The cultured seafood theft prevention device according to (1), wherein an alarm is notified to the remote monitoring device only when a detection time of the infrared sensor has passed a predetermined time or more.
[0012]
(3) The cultured fish and seafood theft prevention device according to (1), wherein the infrared sensor is operated intermittently, and an alarm is notified to the remote monitoring device only when the detection of the intruder or the like is continuously detected.
[0013]
(4) Two infrared sensors are installed at intervals of several tens of cm, and an alarm is notified to the remote monitoring device only when the two infrared sensors detect the intruder or the like substantially simultaneously. The cultured fish and shellfish antitheft device of the above (1), (2) or (3).
[0014]
(5) The aquaculture according to any one of the above (1) to (4), wherein the remote monitoring device can receive a warning by using a mobile phone or the like, regardless of the location of the owner of the aquaculture cage. Seafood anti-theft device.
[0015]
(6) The remote monitoring device according to any of the above (1) to (5), wherein the owner of the culture cage can receive alarms, data, and the like by Internet mail using packet communication of a mobile phone or the like. Koka cultured seafood anti-theft device.
[0016]
(7) The cultured fish and shellfish theft prevention device according to any one of (1) to (6), wherein each of the culture cages operates on an independent power supply and includes a plurality of sensor units capable of transmitting a detection signal.
[0017]
(8) In a farmed seafood theft prevention device for notifying an abnormality such as the approach of an intruder to a plurality of cages containing interconnected and cultured fish and shellfish to a landside warning display unit to prevent theft,
The sacrificial rafts are provided at both ends of the connected pens to fix the plurality of pens in a substantially straight line, and each of the pens and the sacrificial raft includes a sensor and a transmitter for transmitting a detection signal of the sensor. At least one of the sacrificial rafts is provided with a seaside warning display unit including a transceiver, and notifies the detection signal of the sensor to the landside warning display unit via a transmitter of the seaside warning display unit. Prevention device.
[0018]
(9) The cultured fish and shellfish theft prevention device according to (8), wherein the sensor and the seaside warning display device are provided on a float.
[0019]
(10) The transmitter for transmitting the detection signal of the sensor to the seaside warning display device, and the communication between the seaside warning display portion and the landside warning display portion is performed by specific low-power wireless communication. Or the cultured seafood antitheft device of (9).
[0020]
(11) The above-mentioned marine-side warning display unit includes a warning indicator light and a warning sound generator that generate a threat signal by light and voice to an intruder when an abnormality is detected by the sensor. (10) The aquacultured seafood antitheft device.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the configuration and operation of a preferred embodiment of a cultured fish and shellfish antitheft device according to the present invention will be described in detail with reference to the accompanying drawings.
[0022]
FIGS. 1 to 4 show the configuration of a first embodiment of a farmed seafood antitheft device according to the present invention. FIG. 1 is an overall configuration diagram of a cultured fish and shellfish antitheft device 10 having a plurality of connected fish cages. FIG. 2 shows a detailed configuration of one of the plurality of connected cages shown in FIG. FIG. 3 shows a detailed configuration of sacrificial rafts provided at both ends of the connected fish cage in FIG. FIG. 4 is a block diagram showing a configuration of an alarm display unit provided on land.
[0023]
First, with reference to FIG. 1, the overall configuration of the cultured fish and shellfish antitheft device 10 according to the present invention will be described. As shown in FIG. 1, a farmed seafood theft prevention device 10 according to the present invention includes a plurality of cages 11a to 11n connected to each other and arranged substantially in a straight line (hereinafter, reference numeral 11 is used for individual or multiple cages). And the sacrificial rafts 12a to 12b and the landside warning display unit 40 arranged at both ends of the fish cage 11.
[0024]
Each of the cages 11 has, for example, a size of about 12 meters on one side, is framed by an iron pipe or the like, and has a structure surrounded by a wire mesh or the like. A float made of, for example, styrene foam is attached to the periphery and floats near the sea surface. Cultured fish and shellfish are cultivated inside the wire mesh. Usually, about eight cages 11 are connected, and rafts referred to as sacrificial rafts 12a to 12b are connected to both sides of the cage 11. The sacrificial rafts 12a to 12b are fixed by anchors (not shown), and fix the plurality of cages 11 to each other.
[0025]
As shown in FIG. 2, a plurality of infrared sensors 13a to 13d are attached to each fish cage 11. Further, these infrared sensors 13 are connected to a specific low-power wireless transmission unit 20 by a cable 14. The specific low-power wireless transmitter 20 includes a specific low-power wireless transmitter 21, a storage battery 22, and a solar cell 23. That is, operating power is supplied to the specific low-power wireless transmission unit 21 of the specific low-power wireless transmission unit 20 from the storage battery 22 that stores the electromotive force of the solar cell 23.
[0026]
As shown in FIG. 3A, the sacrificial raft 12 is provided with a plurality of infrared sensors 13 a to 13 f around the raft 12, and has a seaside warning display unit 30 that generates a warning for an intruder (ship) inside. . Similarly to the fish cage 11, the plurality of infrared sensors 13 are connected to the specific low-power wireless transmission unit 20 by cables. As shown in FIG. 2, the specific low-power wireless transmission unit 20 includes a specific low-power wireless transmitter 21, a storage battery 22, and a solar battery 23.
[0027]
As shown in FIG. 3B, the seaside warning display unit 30 of the sacrificial raft 12 includes a specific low-power wireless receiver 31 having a receiving antenna, a remote monitoring device 32 having a transmitting antenna, and a specific low-power wireless transmitter 35, respectively. , A solar battery 33, a storage battery 34, an alarm indicator light 36, an alarm sound generator 37, and a control unit 38. The specific low-power wireless receiver 31 of the seaside warning display unit 30 receives an alarm signal transmitted from the specific low-power wireless transmission unit 20 of the fish cage 11 or the sacrificial raft 12.
[0028]
As shown in FIG. 4, the landside warning display section 40 includes a specific low-power radio receiver 41 and a specific low-power radio transmitter 45 each having an antenna, for example, a power supply section 42 to which AC 100 V is supplied, a warning indicator light 46, a warning. It comprises a sound generator 47 and a control unit 48.
[0029]
Next, an operation of the first embodiment of the cultured fish and shellfish antitheft device 10 according to the present invention will be described with reference to FIGS. The infrared sensor 13 is an infrared sensor that projects infrared light and determines the presence or absence of an object (a suspicious object such as an intruder or an intruding ship) in the detection range based on the reflected light. When a suspicious ship or the like approaches the fish cage 11 and enters the detection range of the infrared sensor 13, the infrared sensor 13 detects the suspicious ship or the like and the detection signal is transmitted to the specific small via the signal transmission cable 14. The power is transmitted to the specific low power radio transmitter 21 of the power radio transmission unit 20. The specific low-power wireless transmitter 21 wirelessly transmits a detection signal to the specific low-power wireless receiver 31 in the seaside warning display unit 30 and the specific low-power wireless receiver 41 in the landside warning display unit 40. I do.
[0030]
The operating power of the infrared sensor 13 and the specific low-power wireless transmitter 21 is supplied from the solar battery 23 via the storage battery 22. The infrared sensor 13 may be an infrared passive sensor that detects a heat source. However, since this method is easily affected by waves on the sea surface, an active infrared sensor that is not easily affected by waves is preferable. The infrared sensor 13 is attached as a waterproof structure mounted on a plastic case or the like, for example, to a framework of an iron pipe constituting the fish cage 11 or the sacrificial raft 12. In this case, the above-mentioned surrounding float becomes a rapid place such as a bird, and the infrared sensor may malfunction. This malfunction is to notify an alarm only when the detection time of the infrared sensor 13 has passed (or continued) for a predetermined time or more, to make the detection of the infrared sensor 13 an intermittent operation, and to notify the alarm only when the detection is continuous. Can be prevented.
[0031]
Normally, setting the detection time or intermittent operation of the infrared sensor 13 to about several tens of seconds is effective for preventing malfunction. However, birds can rest for long periods on the float. In this case, two infrared sensors 13 are attached to one place, and the distance between these infrared sensors 13 is set to be about the length of a bird, that is, about several tens of centimeters, and an abnormality is determined only when both infrared sensors detect an obstacle at the same time. By making the determination, it is possible to avoid or prevent a malfunction.
[0032]
As shown in FIG. 1, about eight cages 11 are connected by a rope, and during harvesting, it is common to move some of the cages 11 out of the connected cages 11. Therefore, it is preferable that the specified low-power wireless transmission unit 20 and its operation power supply be installed in each cage 11. However, the specific low-power wireless transmission unit 20 may be provided only in one specific fish cage, depending on the movement of the fish cage 11. In that case, it is preferable that the infrared sensor 13 of each cage 11 and the specific low-power wireless transmission unit 20 be connected by a waterproof connector.
[0033]
The specific low-power wireless receiver 31 of the seaside warning display unit 30 provided in the sacrificial raft 12 shown in FIG. 3 transmits from the specific low-power wireless transmitter 21 of the specific low-power wireless transmission unit 20 installed in the fish cage 11. The control unit 38 receives the detected detection signal and sends the detection signal to the control unit 38. The control unit 38 measures the detection time of the detection signal in order to prevent a malfunction caused by a bird or the like as described above. Then, an alarm signal is sent to the remote monitoring device 32, the specified low-power wireless transmitter 35, the alarm indicator 36, and the alarm sound generator 37 only when the above-mentioned detection signal continues for a predetermined time or more.
[0034]
The remote monitoring device 32 is provided with a mobile phone packet communication terminal device, and has a function of transmitting a message to a plurality of Internet mail addresses registered in advance by e-mail from the mobile phone network via the Internet. . Therefore, the remote monitoring device 32 that has received the alarm signal generates an alarm on the mobile phone of the registered owner (or the manager in charge) of the fish cage 11 or a personal computer (PC) installed at a monitoring place on land or the like. Send an email notifying that you have done so.
[0035]
In the first embodiment of the present invention, an alarm notification is transmitted by e-mail via the Internet using a packet communication terminal. In packet communication, since the system is charged for the amount of data transmitted, even if the remote monitoring device 32 is constantly operating, there is an effect that charging is not performed unless an alarm signal is input and data is transmitted. is there. If the remote monitoring device 32 is configured to operate only when the alarm signal is input, the mobile line is connected only when the alarm signal is input, and billing is performed, so that the alarm can be transmitted at a low cost recorded voice message. It is.
[0036]
Further, the warning indicator light 36 that has received the warning signal emits light and notifies the surroundings of a warning. At the same time, an alarm sound is generated by the alarm sound generator 37 to inform the surroundings (intruder) that the fish cage 11 is in the alert state, and to be able to surely give an alarm.
[0037]
On the other hand, the specified low-power wireless transmitter 35 is a wireless device for communication with the landside warning display unit 40. In the seaside warning display section 30, the presence or absence of operation cannot be confirmed on land unless the infrared sensor 13 detects an abnormality. In order to confirm that the infrared sensor 13 and the seaside warning display unit 30 are operating normally, for example, a timer is provided in the control unit 38, and a status check (health check) is transmitted periodically or a landside warning is issued. A control signal is transmitted from the display unit 40, whereby the state of the infrared sensor 13 and the seaside warning display unit 30 are transmitted to the landside warning display unit 40. The specified low power wireless transmitter 35 is also used for communication for this purpose.
[0038]
Each of the components 41 to 48 of the land-side alarm display unit 40 has substantially the same function as the corresponding components 31 to 38 of the above-mentioned seaside alarm display unit 30, and operates in the same manner. The operation power of the land-side alarm display unit 40 is different from that of the sea-side alarm display unit 30. The operation power required by the power supply unit 42 uses a 100 V AC (alternating current) commercial power source that can be easily used on land. Getting power. Therefore, a solar battery or the like is unnecessary, but a rechargeable storage battery may be used in consideration of portability. Further, in this embodiment, since the specific low-power wireless communication system is adopted for communication between the infrared sensor 13 and the alarm display unit, the seaside alarm display unit 30 and the landside alarm The communication distance with the display unit 40 is limited to about 500 m to 1 km. However, it is also possible to extend the communication distance by employing a highly sensitive receiving antenna or using a relay station.
[0039]
When the landside warning display unit 40 is installed in, for example, a monitoring hut or the like, it is effective to display a warning message on a display. Also, when a monitoring room is provided in a place where the fish farm where the fish cage 11 is installed cannot be directly seen, for example, a room in the fishery cooperative, a radio wave from the specific low power radio transmitter installed in the fish cage 11 is received. Can not do it. In this case, an alarm notification mail transmitted from the remote monitoring device 32 of the seaside alarm display unit 30 via the mobile phone network via the Internet is received, and this is displayed on the monitor of the PC. This can be solved by a method such as sending a voice message.
[0040]
As described above, in the first embodiment of the present invention, an infrared sensor is used as a sensor, a specific low-power wireless system is used for communication with an alarm display unit, and a mobile phone network is used for remote monitoring. A farmed seafood theft monitoring device can be constructed. Further, by using the mobile phone network, it is possible to reliably receive the warning message wherever the owner (or manager) of the fish cage is located, and to prevent the fish and shellfish in the culture fish cage from being stolen. Furthermore, in this embodiment, since the control section performs control so that the alarm display operation is not performed with a detection signal within a certain time, malfunction of the infrared sensor due to birds or waves can be prevented.
[0041]
Next, a second embodiment of the anti-theft device for cultured fish and shellfish according to the present invention will be described with reference to FIG. The basic configuration of the second embodiment is the same as that of the above-described first embodiment, but the sensor unit is further improved. FIG. 5 is a block diagram showing the configuration of the fish cage 11 and its sensor unit. Note that the same reference numerals are used for components corresponding to the components of the above-described first embodiment for convenience of description.
[0042]
In the second embodiment shown in FIG. 5, a plurality of independent sensor units 50 a to 50 d are provided around the fish cage 11. Each of these sensor units 50 includes an infrared sensor 13, a specific low-power wireless transmitter 21, a storage battery 22, and a solar battery 23. Unlike the first embodiment, in the second embodiment, the cable 14 is not used, so that no cable installation work is required. When the fish cage 11 is large, the specific low-power wireless transmitter 21, the solar battery 23, and the storage battery 22 are inexpensive compared to the labor cost for installing the cable, so that the cost is lower than using the connection cable 14. In some cases, an anti-theft device can be constructed.
[0043]
The configuration and operation of the preferred embodiment of the cultured fish and shellfish antitheft device according to the present invention have been described above in detail. However, it should be noted that such embodiments are merely examples of the present invention and do not limit the present invention in any way. It will be readily apparent to those skilled in the art that various modifications and changes can be made in accordance with the particular application without departing from the spirit of the invention.
[0044]
【The invention's effect】
As is clear from the above description, the anti-theft device for cultured fish and shellfish of the present invention has the following practically significant effects. First, it can be constructed at a lower cost than monitoring with an infrared camera or a high sensitivity camera. The reason is that an inexpensive infrared sensor is used for the sensor section, and Internet mail using a specific low-power wireless communication and a mobile phone network is used as the communication means.
[0045]
Second, there is no need for an observer to constantly monitor. The reason is that, since Internet mail using a mobile phone line network is adopted, an alarm notification mail can be received anywhere as long as the mobile phone is within a radio wave range.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of a first embodiment of a cultured fish and shellfish antitheft device according to the present invention.
FIG. 2 is a detailed configuration diagram of one fish cage and a specific low-power wireless transmission unit in FIG. 1;
3 is a detailed configuration diagram of a sacrificial raft in FIG. 1, (A) is an overall configuration diagram, and (B) is a block diagram of a seaside warning display unit.
FIG. 4 is a block diagram showing a configuration of a land side warning display unit in FIG. 1;
FIG. 5 is a block diagram of a fish cage and a sensor unit of a second embodiment of the cultured fish and seafood theft prevention device according to the present invention.
[Explanation of symbols]
Reference Signs List 10 Anti-theft device for cultured fish and shellfish 11 Fish cage 12 Sacrificial raft 13 Infrared sensor 20 Specified low-power wireless transmission unit 21, 35, 45 Specified low-power wireless transmitter 22 Storage battery 23 Solar cell 30 Seaside warning display unit 31, 41 Specified low power Wireless receiver 32 Remote monitoring device 36, 46 Alarm indicator light 37, 47 Alarm sound generator 38, 48 Control unit 40 Land side alarm display unit 50 Sensor unit

Claims (11)

In a cultured seafood anti-theft device that is installed in the sea and holds fish and shellfish in a fish cage to prevent fish from being stolen in a fish cage for aquaculture,
An infrared sensor for detecting that an intruder or the like has approached the aquaculture cage, a specific low-power wireless transmitter for transmitting a detection signal from the infrared sensor, and a signal transmitted from the specific low-power wireless transmitter An alarm device for receiving a detection signal and transmitting a threat signal to an intruder, etc., and a remote monitoring device for notifying the owner of the culture cage of the occurrence of the threat signal are provided. A cultured seafood theft prevention device characterized by the above-mentioned. 2. The cultured fish and seafood theft prevention device according to claim 1, wherein an alarm is notified to the remote monitoring device only when a detection time of the infrared sensor has passed a predetermined time or more. 3. The aquacultured seafood theft according to claim 1, wherein the infrared sensor is operated intermittently, and an alarm is notified to the remote monitoring device only when the detection of the intruder or the like is continuously detected. Prevention device. Two infrared sensors are installed at intervals of several tens of cm, and an alarm is notified to the remote monitoring device only when the two infrared sensors detect the intruder or the like substantially simultaneously. 4. The anti-theft device for cultured fish and shellfish according to claim 1, 2 or 3. 5. The remote monitoring device according to claim 1, wherein a warning can be received by using a mobile phone or the like, regardless of the location of the owner of the culture pond. 6. Cultured seafood anti-theft device. 6. The remote monitoring device according to claim 1, wherein an owner or the like of the breeding cage can receive an alarm, data, or the like by Internet mail using packet communication or the like of a mobile phone. The anti-theft device for cultured fish and shellfish described in [1]. The farmed fish and shellfish theft prevention device according to any one of claims 1 to 6, wherein each of the farming cages operates with an independent power supply and includes a plurality of sensor units capable of transmitting a detection signal. In a farmed seafood theft prevention device for notifying an abnormality such as the approach of an intruder to a plurality of fish cages accommodating interconnected and cultured seafood to a landside warning display unit and preventing theft,
The sacrificial rafts are provided at both ends of the connected pens to fix the plurality of pens in a substantially straight line, and each of the pens and the sacrificial raft includes a sensor and a transmitter for transmitting a detection signal of the sensor. At least one of the sacrificial rafts includes a seaside warning display unit including a transceiver, and notifies the detection signal of the sensor to the landside warning display unit via a transmitter of the seaside warning display unit. Cultured seafood anti-theft device. The anti-theft device for cultured fish and shellfish according to claim 8, wherein the sensor and the seaside alarm display device are provided on a float. The transmitter for transmitting the detection signal of the sensor to the seaside warning display device, and communication between the seaside warning display unit and the landside warning display unit is performed by specific low-power wireless communication. 10. The cultured fish and shellfish antitheft device according to 8 or 9. The said seaside warning display part is provided with the warning indicator light and warning sound generator which generate a threat signal by light and sound with respect to an intruder when abnormality is detected by the said sensor, The alarm sound generator characterized by the above-mentioned. The anti-theft device for cultured fish and shellfish described in [1].

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