Underwater multichannel acoustic emission system for fish movement control

Abstract

The present invention relates to an underwater multi-channel acoustic radiation system for controlling fish movement by utilizing the auditory response characteristics of fish to induce attraction or avoidance responses. The system consists of a channel that plays low-frequency attraction and avoidance sounds via an MP3 module, and a PWM-based channel that generates high-frequency or ultrasonic stimuli in real time; each channel is radiated independently through electrically and mechanically separated underwater transducers. A central controller (e.g., ESP32) can control multiple slave units by ID via BLE, timers, remote controls, or RS485 wired communication methods, while autonomous units that do not require communication operate by repeatedly radiating sound sources according to a set cycle based on an internal battery. The housing is designed with a structure that either embeds the transducer internally or connects it externally via a waterproof connector, ensuring excellent durability and water resistance, and can be mounted on various platforms such as drones, boats, marine buoys, and fixed structures. The present invention provides an eco-friendly underwater acoustic technology capable of effectively controlling fish movement in various underwater environments, such as fishing inducement, protection of industrial facilities, and attraction of fishing grounds, without the need for large structures.

Description

Technology Field

[0001] The present invention relates to a technology for controlling the movement of fish using acoustic stimuli underwater. More specifically, the invention relates to an underwater multi-channel acoustic radiation system capable of inducing fish to move in a specific direction or move away from sensitive areas in response to stimuli by radiating avoidance stimuli (such as killer whale calls, low-frequency tones, low-frequency white noise, etc.) and attraction stimuli (such as riffle sounds, school feeding sounds, low-frequency repetitive tones, etc.) into the water through separate channels. The present invention is applicable to various fisheries applications, such as protecting aquaculture farms, inducing fish capture, protecting marine structures, and managing the marine environment. Background Technology

[0002] Conventional fish trapping methods generally involve the fixed installation of large guiding nets, such as angled nets or drop nets, to attract or block fish.

[0003] However, this method has the problem that construction and dismantling costs are high because large-scale structures must be laid in the ocean, and the induction effect is limited depending on the direction of currents, seabed topography, and the migratory characteristics of fish species.

[0004] Furthermore, large quantities of fish are flowing into industrial facilities such as power plants, nuclear power plants, and fish farms through seawater intakes, causing recurring operational issues such as reduced efficiency of cooling water systems, equipment failures, and screen damage.

[0005] In fact, cases of damage caused by the influx of fish are continuously being reported at the Kori Nuclear Power Plant, Wolseong Nuclear Power Plant, and Hadong Thermal Power Plant.

[0006] Accordingly, there is a growing need for environmentally friendly and flexible response technologies that can effectively control fish access without the need for physical structures.

[0007] According to recent research, low-frequency sounds of orcas, low-frequency white noise in the 100–300 Hz range, and low-frequency pulse sounds can induce predator avoidance or psychological avoidance responses in fish, and it has been confirmed that utilizing these can control the movement paths of fish without physical barriers.

[0008] However, most existing acoustic radiation systems are limited to repeatedly playing a fixed single frequency, and their practical field applicability is limited due to the difficulty in adapting to response characteristics of different fish species or various underwater installation environments.

[0009] In particular, although technology utilizing attraction responses has potential applications in fishing grounds and fish farms, multi-channel underwater acoustic radiation systems combining attraction and avoidance functions have not yet been commercialized. Prior art literature

[0010] Korean Patent Publication No. 10-2144792 (Registration Date: August 10, 2020) The problem to be solved

[0011] The present invention aims to overcome the limitations of existing fish guidance methods that rely on fixed guidance nets or physical structures, and to implement an active response technology that induces fish movement or causes them to avoid specific areas solely through low-frequency acoustic stimulation radiated underwater, without the need to install physical devices.

[0012] The main objective is to realize an underwater multi-channel acoustic-based fish response control system that reflects the auditory response characteristics of fish, is configured to selectively emit attraction sounds (riffle sounds, school feeding sounds, repetitive low-frequency tones, etc.) and avoidance sounds (orca calls, low-frequency white noise, low-frequency pulses, or impact sounds, etc.) depending on the situation, and allows for the flexible control of various operating methods, such as BLE, RS485, and autonomous repetitive playback, to suit the field environment.

[0013] In addition, one of the important problems that the present invention aims to solve is to provide the system with structural flexibility to adapt to various installation environments, such as surface / underwater buoy types, capture net fixed types, and drone or boat-mounted types, and to implement a modular housing structure, integrated control system, and optimized power configuration so that the user can easily install and operate it on-site. means of solving the problem

[0014] The present invention relates to an underwater multi-channel acoustic radiation system capable of actively controlling the movement path of fish or inducing and blocking them from a specific area by radiating multi-channel acoustic stimuli for attracting and avoiding fish that respond to the auditory sensitivity frequency bands of fish underwater.

[0015] The underwater acoustic radiation system of the present invention includes the following components.

[0016] 1. Central controller

[0017] Microcontrollers such as the ESP32 are

[0018] It stores low-frequency acoustic signals, such as lure sounds or killer whale sounds, on an SD card or internal memory, and directly outputs them via the DFPlayer Mini module,

[0019] The PWM-based tone generation circuit can be optionally configured and utilized for specific experiments or high-frequency stimulation tests.

[0020] The controller interacts with external devices via BLE-based wireless communication or RS485 wired communication and is typically installed on the water surface or on a buoy-type platform.

[0021] 2. Acoustic radiation module

[0022] The low-frequency radiator emits sound sources for the purpose of attraction (bubble sounds, prey sounds, etc.) or avoidance (killer whale calls, white noise, etc.), and

[0023] The high-frequency radiating unit can be configured to selectively output a tone of 3 kHz or higher or ultrasonic stimulation.

[0024] The two channels are completely electrically and physically separated and operate independently, and can operate in parallel within a single system.

[0025] 3. Amplification Circuit

[0026] The output of each channel is amplified via a Class-D amplifier (e.g., TPA3116D2) or a small, low-power amplifier (e.g., PAM8403D2) and optimized to match the transducer's impedance and output specifications. The amplifier can be optionally configured depending on the installation purpose.

[0027] 4. Transducer Structure

[0028] The low-frequency transducer can be configured to emit sound for attraction or avoidance purposes in the range of 300 Hz to 3 kHz, and the high-frequency transducer can be selectively configured to emit tones of 3 kHz or higher or ultrasonic stimulation when necessary.

[0029] The two transducers consist of two-channel independent structures that are electrically and structurally separated.

[0030] 5. Housing and Waterproof Structure

[0031] The housing of this system is designed to be modular to accommodate various installation environments (e.g., drones, boats, marine buoys, rope-mounted types, etc.), and ensures the waterproof performance and structural durability required for underwater operation.

[0032] The placement of transducers can be configured in the following two ways depending on the operational purpose.

[0033] (1) Built-in structure: A method of radiating sound without external exposure by fixing the transducer directly inside the housing.

[0034] This structure offers excellent durability against external impacts and underwater exposure environments, and is advantageous for structural simplification and integrated operation.

[0035] (2) External connection type structure: The transducer is placed outside the housing, a waterproof connector is fixed inside the housing, and the transducer cable is routed out through a waterproof gland or sealing treatment.

[0036] This method is suitable for cases requiring high-output acoustic radiation or transducer replacement.

[0037] The housing is made of a material that meets a waterproof rating of IP67 or higher, and additional cushioning material or waterproof gel may be applied to protect the internal circuit.

[0038] In addition, it includes a fixed bracket or a detachable mounting adapter, allowing for flexible installation in various locations (water surface, underwater, vertical structures, etc.).

[0039] These housing and waterproof structures can be commonly applied in various operating environments, such as drone types, boat types, fixed capture net types, industrial facility protection, and fishing site installation types, and can simultaneously ensure scalability and ease of maintenance depending on the selectable transducer placement method.

[0040] 6. Operational Control Method

[0041] The lure sound is continuously radiated, and

[0042] Avoidance stimuli (ultrasonic or killer whale sounds) can be selectively emitted via various control interfaces, such as timers, remote controls, and BLE apps.

[0043] Control methods can be diversified to include dial switches, BLE, WiFi, LoRa, RS485, etc., allowing for flexible operation depending on field conditions.

[0044] 7. Diversification of capture induction strategies

[0045] The lure sound emitter is fixedly installed at the entrance or inside the capture net, and

[0046] A dual induction strategy is possible to block the fish's reverse escape by emitting an outer avoidance stimulus after a certain period of time has elapsed.

[0047] This structure can be operated in conjunction with rope-type fixing systems, drone recovery devices, etc.

[0048] 8. Installation and Application Environment

[0049] This system can be effectively applied in various marine environments such as the following.

[0050] Fishing inducement (purse seine, net)

[0051] Protection of industrial facilities (water intakes, power plants, marine purification facilities, etc.)

[0052] Ecosystem Conservation and Environmental Assessment

[0053] Inducing concentration of fish in fishing grounds and fish farms

[0054] The present invention can be operated as an active system capable of controlling fish movement solely through acoustic stimulation without the need for a fixed structure. Effects of the invention

[0055] According to the present invention, by radiating lure sounds and avoidance sounds in multiple channels according to the auditory response characteristics of fish, the movement path of fish can be actively controlled without physical structures, thereby allowing for excellent effects in terms of improving fishing efficiency and protecting industrial facilities.

[0056] In particular, by independently controlling major stimulus sounds such as orca calls, attracting sounds, and low-frequency white noise through a 2-channel structure that is electrically and physically separated, customized operation tailored to the response characteristics of each fish species or environment is possible.

[0057] In addition, PWM-based high-frequency output means or ultrasonic stimulation can be selectively configured as needed, allowing it to be adapted to specific fish groups or experimental purposes.

[0058] This system can be flexibly combined with various operating methods, such as drones, boats, marine buoys, and fixed installations.

[0059] A 2-channel structure with transducers separated into low-frequency and high-frequency types prevents interference between acoustic stimuli and enables clear and selective stimuli delivery.

[0060] In addition, the waterproof housing can be designed to either house the transducer internally or connect it externally via a waterproof connector, allowing it to accommodate various installation methods and offering excellent ease of maintenance.

[0061] Depending on the purpose, the amplification circuit can be configured as a small low-power amplifier (such as the PAM8403) or in a non-amplification mode, making it suitable for operation in low-power environments such as nearby fishing spots or fixed-type catch nets.

[0062] Since it can be replaced with a high-output Class-D amplifier if necessary, flexible circuit configuration is possible depending on the installation purpose.

[0063] In addition, through a strategy of continuously emitting lure sounds and conditionally selectively emitting avoidance sounds, fish are lured by a lure sound emitter fixed at the entrance of the capture net, and

[0064] A complex induction strategy is realized by driving the target into the capture net by emitting avoidance stimuli from the periphery after a certain point in time.

[0065] This strategy enables effective fishing using only small nets, without the need for large guiding nets.

[0066] Furthermore, this system is applicable to various fisheries and industrial environments as follows.

[0067] Inducing fish school concentration and response at fishing grounds, fish farms, fisheries research institutes, etc.

[0068] Protection of industrial facilities such as power plant water intakes, ports, and purification facilities

[0069] Marine ecosystem conservation and eco-friendly fish control

[0070] Due to this technical flexibility and adaptability to installation environments, the present invention has great potential to be utilized as a general-purpose underwater acoustic stimulation system suitable for various purposes. Brief explanation of the drawing

[0071] Fig. 1. Circuit diagram of an ESP32-based underwater multi-channel acoustic radiation system A circuit diagram showing the connection relationships and signal flow between the ESP32 controller, DFPlayer Mini module, PWM-based tone generation circuit (optional configuration), amplifier circuit (PAM8403 or Class-D), and low-frequency and high-frequency transducers. Fig. 2. Conceptual diagram of a drone-mounted acoustic guidance system An operational concept diagram for guiding fish in a specific direction by mounting the acoustic radiation system of the present invention on a drone and radiating downward sound from above the water surface. Fig. 3. Configuration diagram of a rope-type multi-channel guidance system A conceptual diagram illustrating a multi-channel operating structure that radiates time-difference-based acoustic stimulation by suspending multiple slave units at regular intervals from a fixed rope installed on the surface or underwater. Fig. 4. Acoustic radiation algorithm flowchart A flowchart illustrating the flow of a control algorithm including fish species selection, frequency setting, radiation period setting, time difference output, termination or restart conditions, etc. Fig. 5. Conceptual diagram of a boat-mounted acoustic guidance system A conceptual diagram of a small boat equipped with a transducer on the front or side to radiate sound horizontally or downward at a close distance to the water surface to guide fish in a specific direction. Fig. 6. Conceptual diagram of a conventional bicornuate mesh structure An explanatory diagram illustrating the structure of a conventional fixed fishing method consisting of a wing-type guiding net and a capture net. Fig. 7. Conceptual diagram of the capture structure when the present invention is applied. A conceptual diagram of a complex strategy illustrating a structure that drives fish using only lure sound emission and avoidance stimulus emission, and captures them through a small V-shaped net. Fig. 8. Conceptual diagram of avoidance guidance A structural conceptual diagram illustrating the response of fish to evade in the opposite direction by radiating orca sounds and selected high-frequency stimuli in sensitive areas such as around industrial facilities. Fig. 9. Conceptual diagram of attraction induction A conceptual diagram illustrating a strategy of continuously emitting low-frequency attracting sounds to concentrate and guide fish to a specific location. Fig. 10. Conceptual diagram of capture induction by avoidance response after lure. A conceptual diagram illustrating a dual induction strategy that concentrates a school of fish around a capture net using a lure sound, and then guides them into the net by emitting an evasion sound. Fig. 11. BLE and RS485-based communication control structure diagram A structure in which a central controller (ESP32) receives commands from user devices via BLE and individually controls multiple underwater slave units (ID1~IDn) via RS485 wired communication. Each unit operates based on ID and is utilized for real-time or time-delayed radiation. Fig. 12. Configuration diagram of an autonomous sound-attracting unit A structural diagram illustrating the configuration of a battery-embedded unit capable of operating without communication, consisting of an MP3 module, an amplifier (PAM8403 or Class-D), a transducer, a waterproof housing, etc., and an autonomous operation concept that repeatedly emits an attractive sound according to a set cycle. Specific details for implementing the invention

[0072] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0073] FIGS. 1 to 12 are conceptual diagrams for explaining the configuration and operation method of an underwater multi-channel acoustic radiation system according to the present invention.

[0074] 1. System Configuration

[0075] The underwater multi-channel acoustic radiation system of the present invention is composed of the following components.

[0076] ① ESP32 microcontroller (100)

[0077] ② DFPlayer MP3 module (110)

[0078] ③ PWM output section (120)

[0079] ④ Amplification module (140)

[0080] ⑤ Transducer connection terminal (150)

[0081] ⑥ Low frequency / high frequency underwater transducer (160)

[0082] Description by function:

[0083] Low-frequency sounds (e.g., killer whale sounds, lure sounds) are stored in MP3 or WAV format on an SD card or internal memory and are directly played back through the DFPlayer MP3 module.

[0084] The PWM circuit is optionally configured and can generate tones of 3 kHz or higher, or ultrasonic stimulation for experiments targeting specific fish species in real time.

[0085] Each output signal is transmitted to the corresponding transducer through a channel-specific independent amplification circuit and radiated underwater.

[0086] ※ Depending on the installation purpose, the amplifier can be configured as a compact amplifier (e.g., PAM8403) or a high-output Class-D amplifier (e.g., TPA3116D2).

[0087] Transducer Structure:

[0088] Low-frequency transducer: Attractive / repellent acoustic radiation in the 300Hz–3kHz band

[0089] High-frequency transducer: A configuration capable of selectively radiating tones of 3 kHz or higher or ultrasonic stimulation.

[0090] The two transducers are configured as a 2-channel structure that is completely electrically and physically isolated and follow a universal design that can be built inside the housing or connected externally through a waterproof connector.

[0091] 2. Controller and Communication Structure

[0092] The central controller of this system consists of an ESP32 microcontroller and connects wirelessly to a smartphone app via BLE (Bluetooth Low Energy) or Wi-Fi.

[0093] The central controller is interconnected with multiple underwater slave units (ID1~IDn) via RS485-based wired communication, and each slave unit is configured to be individually controlled based on its unique ID.

[0094] The RS485 communication line and power line are configured as a single integrated cable, and a DC-DC converter is built into each slave unit to stably convert and supply the input power (e.g., 12V) according to the circuit requirements.

[0095] The conversion voltage can be set to 3.3V, 5V, 9V, etc., depending on the device configuration.

[0096] This enables various circuit configurations based on a single power input, while simultaneously ensuring ease of installation and stability of power supply.

[0097] The central controller must be installed on a platform above the water surface, such as a buoy, drone, or boat, while the slave unit is fixedly installed underwater for operation.

[0098] This configuration takes into account the transmission and reception limitations of BLE and Wi-Fi and the characteristics of underwater communication, and enables the simultaneous securing of communication reliability and scalability of the control range through the efficient separation between ground-based control and the underwater operation system.

[0099] Meanwhile, a standalone unit operating in an environment where communication is unnecessary can be configured with a battery-based autonomous repetitive playback method.

[0100] These autonomous units repeatedly emit stored sound sources according to a set cycle or trigger condition, and can be effectively utilized in fixed installation environments such as fishing grounds, fish farms, and net entrances.

[0101] 3. Automatic frequency switching function (intelligent response-based operation)

[0102] The ESP32 controller has a database of auditory responses for each fish species pre-stored. This is loaded onto an SD card or internal memory, and for each species (e.g., red sea bream, halibut, black sea bream, etc.)

[0103] Sensitive frequency band

[0104] Attraction / Avoidance Response Characteristics

[0105] Includes output intensity / playback cycle information.

[0106] When the user simply selects an operating mode via a smartphone app or a physical dial, the system operates automatically according to preset frequencies and radiation conditions.

[0107] The operation mode can be configured according to the following criteria.

[0108] Attraction-centered mode: Repeatedly radiates low-frequency attraction sound

[0109] Avoidance-focused mode: Orca sound or white noise emission

[0110] Lure-Evasion Switch Mode: Performs lure → evasion lure strategy after a certain period of time

[0111] ※ Output of selected high-frequency stimulation (e.g., 3kHz tone or ultrasound) is also possible if necessary.

[0112] This feature enables autonomous operation and optimal response-based operation without user configuration.

[0113] 4. Representative Operational Scenario

[0114] ① Operation of fixed net → Refer to Fig. 10

[0115] A strategy of installing a lure sound emitter inside or at the entrance of a capture net to attract a school of fish, and after a certain period of time, emitting an evasion sound from the outside to drive them into the capture net.

[0116] ② Operation mounted on drones / boats → Refer to FIG. 2 and FIG. 5

[0117] Mount a controller and acoustic module on a drone / boat to radiate near the water surface or underwater.

[0118] Real-time mode switching is possible via BLE (BLE only works on the surface of the water)

[0119] ③ Operation of rope-type unit → Refer to FIG. 3 and FIG. 11

[0120] Connect multiple slave units to a rope and transmit delayed / sequentially via RS485 communication.

[0121] ④ Fixed-type operation for industrial facility protection → Refer to Fig. 8

[0122] Fixedly installed in sensitive areas such as water intakes, ports, and aquaculture farm boundaries to continuously emit avoidance sounds.

[0123] ⑤ Operation for fishing grounds and boat fishing → Refer to Fig. 12

[0124] Repeatedly radiating low-frequency induced sound with an autonomous battery unit

[0125] 5. Flexible control operation method

[0126] This system supports the following multiple control methods.

[0127] Timer

[0128] physical dial switch

[0129] BLE App Integration

[0130] Wi-Fi remote settings

[0131] RS485 wired communication

[0132] Remote control manual control

[0133] Depending on the purpose, the user

[0134] Single stimulation mode

[0135] Lure and Evasion Mixed Mode

[0136] It is selectable and can be operated in various forms such as drones, boats, fixed types, and autonomous types.

[0137] ※ Note: This system is not limited to a specific installation method and is provided as a modular platform that can be combined and expanded at the discretion of the fisherman or administrator. Explanation of the symbols

[0138] 100 central controllers (ESP32 or similar microcontrollers) 110 SD card or internal memory (audio storage device) 120 PWM output section (optional configuration, circuit for tone or ultrasonic stimulation) 130 DFPlayer Module (MP3 Playback and Low-Frequency Audio Output Module) 140 Amplification Module (PAM8403 or Class-D Amplifier, etc.) 150 Transducer Terminals (Waterproof Connector Included) 160 Underwater transducers (electrically and mechanically separated attraction / avoidance channels) 170 RS485 Driver Circuit (Transmit / Receive Interface between ESP32 and Slave) 180 RS485 communication lines (connection line between central controller and underwater device, 2-wire wearable type) 190 Slave Unit ID Control Unit (RS485 Signal Reception and ID-Specific Command Execution Circuit) 200 drone operators (downward-emitting platforms above the water surface) 300 Rope Structure (Structure for Installing Fixed Multi-Channel Radiation Units) 310a~310n slave units (individual radiation units used in rope-type units) 400 boats or vessels (mobile acoustic radiation means) 500a, 500b Left and right wing-shaped nets of conventional bicornered nets 510 Central bag net of a conventional two-sided net 600 Small V-shaped Net 10 fish (fish schools, target organisms)

Claims

Claim 1 An underwater acoustic radiation system for attracting fish or causing them to avoid a specific area comprises: an acoustic emitter (160) capable of selectively radiating one or more of a low-frequency attracting sound, an orca-based avoidance sound, and a selected high-frequency stimulus into the water; a central controller (100) controlling the output method and radiation timing of the acoustic emitter (160); and a modular housing configured to allow the acoustic emitter (160) to be installed on a drone, boat, marine buoy, or fixed structure. The acoustic emitter (160) induces an auditory response of fish to actively control the movement path of a school of fish. The acoustic emitter (160) radiates low-frequency and high-frequency sounds through electrically and mechanically separated transducers, respectively. A waterproof connector (150) is fixedly installed inside the housing, and the transducer connection cable is pulled out to the outside through a waterproof gland, or the transducer is directly embedded inside the housing. This underwater multi-channel acoustic radiation system for controlling fish movement is characterized by the structure. Claim 2 delete Claim 3 In claim 1, the central controller (100) outputs a low-frequency lure sound through a DFPlayer MP3 module (130) based on stored sound source data, and the PWM signal generation circuit (120) is optionally configured to generate a high-frequency tone or ultrasonic stimulation in real time, and the outputs of the MP3 module (130) and the PWM output unit (120) are each amplified through a corresponding amplification circuit (140) and then radiated into the water through a low-frequency or high-frequency underwater transducer (160), characterized by an underwater multi-channel acoustic radiation system for fish movement control. Claim 4 An underwater multi-channel acoustic radiation system for fish movement control, characterized in that, in claim 1, the controller (100) receives user commands from a smartphone via a BLE-based wireless communication function and is connected to a plurality of underwater slave units (310a~310n) via an RS485 driver circuit (170) and an RS485 communication line (180), and each slave unit is individually controlled based on a slave unit ID control circuit (190) according to a unique ID. Claim 5 An underwater multi-channel acoustic radiation system for fish movement control according to claim 1, characterized in that the system is operated to emit a lure sound to attract fish in fishing grounds, fish farms, fisheries research institutes, etc., or to emit an avoidance sound to prevent fish from approaching in the vicinity of power plants, ports, purification facilities, or industrial facilities. Claim 6 An underwater multi-channel acoustic radiation system for fish movement control, characterized in that, in claim 1, the sound radiator (160) is repeatedly played according to a set cycle based on a built-in battery and a stored sound source, and has an autonomous operation structure that operates independently without separate communication. Claim 7 An underwater multi-channel acoustic radiation system for fish movement control according to claim 1, comprising a composite operation method of inducing fish toward a capture net using an attracting sound and then driving the fish into the capture net by emitting an avoidance stimulus, characterized by placing a fixed attracting sound emitter at the entrance of the capture net and emitting an avoidance sound from another location. Claim 8 In claim 1, the underwater multi-channel acoustic radiation system for fish movement control is characterized in that the controller (100) automatically switches acoustic radiation conditions according to water temperature, water depth, water pressure, time, or set external conditions, adjusts the repetition interval of acoustic radiation to a random number-based cycle or a user-set profile in addition to a fixed cycle, and is configured to automatically switch between an attraction mode and an avoidance mode based on a fish species-specific auditory response database. Claim 9 An underwater multi-channel acoustic radiation system for fish movement control according to claim 1, wherein the housing includes a cushioning material or a fixing pad to protect an internal circuit from external shock or vibration, and a buoyancy control structure, and is characterized by being capable of stable operation even in underwater environments with a depth of several meters or more.

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