A lettuce atomized cultivation system and its control method

Abstract

This invention provides a lettuce atomized cultivation system and its control method, including a control unit, an image acquisition unit, an atomization rack, an atomization box, a supply unit, and a low-frequency nuclear magnetic resonance spectrometer. Plasma nozzles are connected to the supply unit and the control unit, respectively. A temperature sensor and an axial flow fan are connected to the control unit. The axial flow fan is installed on the body of the atomization box. The plasma nozzles are used to convert nitrogen molecules in the air inside the atomization box into nitrogen-containing compounds and to ionize oxygen in the air to generate ozone. The high voltage generated by the plasma nozzles during operation ionizes the air, converting nitrogen molecules in the air that are not easily absorbed by lettuce into nitrogen-containing compounds that can be absorbed by lettuce, thus playing a nitrogen-fixing role. This promotes the absorption of water and nutrients by the lettuce roots. The ionization of oxygen in the air to generate trace amounts of ozone has a bactericidal and disinfecting effect on the lettuce roots, allowing the lettuce to grow healthily.

Description

Technical Field

[0001] This invention belongs to the field of agricultural engineering, and in particular relates to a lettuce atomization cultivation system and its control method. Background Technology

[0002] Aeroponics is currently one of the most practical cultivation methods for plants. Roots are suspended in the air, allowing for free growth, abundant oxygen, and particularly well-developed root systems. It also provides water and nutrients directly, offering the most suitable, abundant, and direct supply of water, fertilizer, and air. This significantly improves the quality and quantity of production, greatly reducing the input of labor, fertilizer, water, and pesticides. It facilitates three-dimensional, vertical cultivation, increasing planting efficiency per unit area several times over. Furthermore, it reduces pests and diseases by more than 75%, enabling pesticide-free, pest-free production. This is more economical than soil cultivation, significantly lowering agricultural input costs. Therefore, aeroponics is currently the most promising and promising technology in horticultural production and research, unmatched by any other cultivation method, and is a major development project and highly efficient agricultural technology for future greenhouse cultivation.

[0003] However, current aeroponics technology simply adjusts the spraying time and volume based on data collected by sensors, neglecting the impact of nutrient deficiencies in plant growth. This leads to slow growth and even wilting. Furthermore, ignoring the effects of water stress on the root and crown system also results in slow growth or even wilting and rotting. Finally, the lack of attention to nitrogen fixation in plant roots and the application of sterilization and disinfection slows down the absorption of water and nutrient solutions, potentially causing plant death and hindering growth. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the aforementioned technical problems. To this end, the present invention provides a lettuce atomization cultivation system and its control method, which facilitates the healthy and rapid growth of lettuce.

[0005] This invention utilizes neural network recognition technology, thermal imaging technology, and low-frequency nuclear magnetic resonance technology to solve the problem of slow growth or even wilting of lettuce caused by nutrient deficiency and water stress. It employs plasma spraying technology to convert nitrogen molecules in the air inside the aeroponic box that are not easily absorbed by lettuce into nitrogen-containing compounds that can be absorbed by lettuce, thereby fixing nitrogen and promoting the absorption of water and nutrient solution by the lettuce roots. In addition, the oxygen in the air is ionized by high-voltage electricity to produce trace amounts of ozone. Using ozone to replace pesticides for sterilization and disinfection can reduce costs, protect the environment, and ensure the healthy and rapid growth of lettuce.

[0006] The objective of this invention is achieved through the following approach.

[0007] The technical solution of the present invention is: a lettuce atomization cultivation system, including a control unit, an image acquisition unit, an atomization rack, an atomization box, a supply unit, and a low-frequency nuclear magnetic resonance spectrometer;

[0008] The control unit is connected to the image acquisition unit, the aeroponic box, the supply unit and the low-frequency nuclear magnetic resonance spectrometer respectively. The aeroponic box is installed on the aeroponic rack and the supply unit is connected to the aeroponic box.

[0009] The aeroponic chamber includes a temperature sensor, an axial fan, and a plasma nozzle. The plasma nozzle is connected to the supply unit and the control unit, respectively. The temperature sensor and the axial fan are connected to the control unit. The temperature sensor is used to detect the temperature inside the aeroponic chamber and transmit it to the control unit. The axial fan is installed on the chamber body of the aeroponic chamber. The plasma nozzle is used to spray the nutrient solution from the supply unit onto the lettuce, convert nitrogen molecules in the air inside the aeroponic chamber into nitrogen-containing compounds, and ionize oxygen in the air to produce ozone.

[0010] The image acquisition unit is used to acquire images of lettuce leaves and thermal images of lettuce leaves or roots on the aeroponic box. The image acquisition unit transmits the acquired lettuce leaf images and thermal images to the control unit. The control unit preprocesses the acquired lettuce leaf images and transmits the preprocessed lettuce leaf images to the neural network. The neural network determines the type of missing element for each lettuce leaf and classifies the lettuce leaves accordingly. The control unit controls the supply unit to configure the corresponding element nutrient solution according to the missing element of each category of lettuce leaves and delivers the nutrient solution to the plasma nozzle. The control unit controls the plasma nozzle to move under the lettuce of that category and controls the plasma nozzle to deliver the configured nutrient solution. The nutrient solution is atomized and sprayed onto the roots of the target lettuce. The control unit extracts temperature data from the acquired thermal images. At the corresponding time when the thermal images are acquired, samples of lettuce leaves or roots are taken. The moisture content of the lettuce leaf or root samples is detected by a low-frequency nuclear magnetic resonance spectrometer, and the moisture content data is transmitted to the control unit. The control unit processes the temperature data and moisture content data. When the moisture content drops below a preset value within the set temperature difference range, the control unit records the initial temperature value within that temperature difference. The temperature sensor detects the temperature inside the aeroponic chamber. When the temperature sensor detects that the temperature inside the aeroponic chamber is higher than the initial temperature value recorded by the control unit, the control unit turns on the axial fan.

[0011] In the above scheme, the aeroponic box also includes a guide rail, which is installed inside the box body. The plasma nozzle is installed on the guide rail, and a motor is installed on the guide rail to drive the plasma nozzle to slide on the guide rail.

[0012] In the above scheme, the aeroponic box also includes a planting basket, a sponge, a negative ion generator, a planting board, a nutrient solution return pipe, and a nutrient solution collection bucket;

[0013] The planting board is installed on the box, and the planting board has planting holes. The box has a nutrient solution return port. Planting baskets and sponges are installed in the planting holes. A negative ion generator is installed on the planting board, and the nutrient solution collection tank is connected to the nutrient solution return port through a nutrient solution return pipe.

[0014] In the above scheme, the plasma nozzle includes a high-voltage generator, which includes a metal cap, two piezoelectric ceramics, a phosphor bronze sheet, a high-voltage lead, a first striking mechanism, a second striking mechanism, a first spring, a second spring, and a housing.

[0015] The piezoelectric ceramic, phosphor bronze sheet, first striking mechanism, second striking mechanism and first spring are all installed inside the housing. The phosphor bronze sheet is placed between two piezoelectric ceramics. One end of the high voltage lead is connected to the phosphor bronze sheet and the other end is led out of the housing. One end of the second striking mechanism is installed on the piezoelectric ceramic. The other end of the second striking mechanism is connected to one end of the first striking mechanism through the first spring, so that the first striking mechanism can slide along the inner wall of the housing under the elastic force of the first spring. The other end of the first striking mechanism is equipped with a second spring.

[0016] In the above scheme, the image acquisition unit includes an RGB camera and a thermal imaging camera;

[0017] The RGB camera is mounted on the aeroponic rack and is located above the aeroponic box. The RGB camera is used to capture images of lettuce leaves on the aeroponic box.

[0018] Thermal imaging cameras are used to capture thermal images of lettuce leaves or roots.

[0019] In the above scheme, the supply unit includes a diaphragm pump, several nutrient solution tanks, a nutrient solution mixing tank, a metering pump, a water tank, and an air compressor;

[0020] The diaphragm pump is installed on the aeroponic rack. The diaphragm pump is connected to the nutrient solution mixing tank and the plasma nozzle respectively. The nutrient solution tank and the water tank are connected to the nutrient solution mixing tank respectively. Metering pumps are installed on the pipelines connecting the nutrient solution tank and the water tank to the nutrient solution mixing tank. There are several metering pumps. The nutrient solution mixing tank and the air compressor are connected to the plasma nozzle respectively. The nutrient solution mixing tank is equipped with a stirring assembly.

[0021] In the above solution, the control unit includes a Raspberry Pi, a computer, and a relay;

[0022] The computer is used to process the data acquired by the image acquisition unit and the low-frequency nuclear magnetic resonance spectrometer, and to transmit the processing results to the Raspberry Pi.

[0023] The Raspberry Pi is connected to a computer and a relay, which is connected to a plasma nozzle, a metering pump, a stirring assembly, a diaphragm pump, an air compressor, a motor, and an axial fan. The temperature sensor is connected to the computer.

[0024] The above solution also includes plant growth lights;

[0025] The plant growth light is installed on the aeroponic rack, located above the aeroponic box.

[0026] A control method for a lettuce atomized cultivation system includes the following steps:

[0027] The image acquisition unit is used to acquire images and thermal images of lettuce leaves on the aeroponic box, and the image acquisition unit transmits the acquired images and thermal images to the control unit respectively;

[0028] The control unit preprocesses the acquired images and transmits the preprocessed images to the neural network. The neural network determines the type of missing elements in each lettuce leaf and classifies the lettuce leaves accordingly. The control unit controls the supply unit to configure the corresponding nutrient solution according to the missing elements in each category of lettuce leaves and delivers the nutrient solution to the plasma nozzle. The control unit controls the plasma nozzle to move under the lettuce of that category and controls the plasma nozzle to spray the nutrient solution from the supply unit onto the lettuce, convert nitrogen molecules in the air inside the aeroponic box into nitrogen-containing compounds, and ionize oxygen in the air to produce ozone.

[0029] The above scheme also includes the following steps:

[0030] The control unit extracts temperature data from the acquired thermal images. At the corresponding time when the thermal images are acquired, samples of lettuce leaves or roots are taken. The moisture content of the lettuce leaf or root samples is detected by a low-frequency nuclear magnetic resonance spectrometer, and the moisture content data is transmitted to the control unit. The control unit processes the temperature data and moisture content data. When the moisture content drops below a preset value within a set temperature difference range, the control unit records the initial temperature value within that temperature difference. The temperature sensor detects the temperature inside the aeroponics chamber. When the temperature sensor detects that the temperature inside the aeroponics chamber is higher than the temperature value recorded by the control unit, the control unit turns on the axial fan.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] 1. The high voltage generated by the plasma nozzle of this invention ionizes the air, converting nitrogen molecules in the air that are not easily absorbed by lettuce into nitrogen-containing compounds that can be absorbed by lettuce, thereby fixing nitrogen and promoting the absorption of water and nutrients by the lettuce roots. The ionization of oxygen in the air produces trace amounts of ozone, which has a bactericidal and disinfecting effect on the lettuce roots, allowing the lettuce to grow healthily.

[0033] 2. The plasma nozzle of this invention is installed on a guide rail and can be moved to the area below the roots of the lettuce to be sprayed with liquid. It atomizes the prepared nutrient solution and sprays the atomized liquid onto the roots of the target lettuce, thereby irrigating the target lettuce and ensuring that lettuce of various nutrient deficiencies can fully obtain the required elements, thus ensuring the healthy growth of lettuce.

[0034] 3. This invention uses a neural network to determine the type of element deficiency in lettuce. Based on the deficiency type, a raspberry pie controls a metering pump to prepare a relatively high concentration of nutrient solution. Then, a plasma nozzle sprays the nutrient solution onto the corresponding lettuce plants. The plasma spraying technology is used to fix nitrogen and sterilize. A negative ion generator is used to accelerate the growth of lettuce. Thermal imaging technology and a low-frequency nuclear magnetic resonance spectrometer are used to detect the temperature and water content of lettuce leaves or roots. This prevents lettuce from being affected by water stress, which can hinder the absorption of water and nutrient solution, leading to slow growth or even wilting and rotting. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall lettuce atomization cultivation system according to one embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the structure of an aeroponic box according to one embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of a low-frequency nuclear magnetic resonance imaging (NMR) instrument according to an embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram showing the connection between the relay module and other devices according to one embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of an image acquired by a thermal imaging camera according to an embodiment of the present invention.

[0040] Figure 6 This is a cross-sectional schematic diagram of a plasma nozzle according to an embodiment of the present invention.

[0041] Figure 7 This is a front view of a high-voltage generating device that generates vortex impeller impact according to an embodiment of the present invention.

[0042] Figure 8 This is a side view of a high-voltage generating device that generates vortex impeller impact according to an embodiment of the present invention.

[0043] Figure 9 This is a schematic diagram of the adjusting plunger structure according to one embodiment of the present invention.

[0044] Figure 10 This is a line graph of temperature and moisture content according to one embodiment of the present invention.

[0045] In the diagram: 2-Raspberry Pi; 3-Display screen; 4-Computer; 5-Relay; 7-Plant growth light; 9-RGB camera; 11-Diaphragm pump; 12-First nutrient solution tank; 13-Nutrient solution mixing tank; 14-Second nutrient solution tank; 15-Aeroponic rack; 16-Aeroponic box; 17-Metering pump; 18-Water bucket; 19-Planting basket; 20-Sponge; 21-Negative ion generator; 22-Guide rail; 23-Planting hole; 24-Planting board; 25-Temperature sensor; 26-Axial flow fan; 27-Plasma nozzle; 28-Nutrient solution return port; 29-Nutrient solution return pipe; 30-Nutrient solution collection tank; 32-Thermal imaging camera; 33-Low-frequency nuclear magnetic resonance spectrometer; 34-Air inlet sleeve; 35-Water inlet sleeve. 36-Sealing ring; 37-Liquid inlet; 38-Adjustable base; 39-Positioning screw; 40-Stepped rectifier; 41-High voltage generator; 4101-Metal cap; 4102-Piezoelectric ceramic; 4103-Phosphor bronze sheet; 4104-High voltage lead; 41051-First striking mechanism; 41052-Second striking mechanism; 4106-Second spring; 4107-Housing shell; 42-Rotating vortex impeller; 43-Second base; 44-Bearing; 45-Stepped resonant tube; 46-Adjusting plunger; 4601-Actuator; 4602-Plunger body; 4603-Fixed shaft; 47-Clamping nut; 48-Fixed cap; 49-Laval valve core; 50-Air inlet; 51-Air compressor. Detailed Implementation

[0046] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0047] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "front," "rear," "left," "right," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0048] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] Figure 1 , 2 Figures 3, 5, 6, and 7 show a preferred embodiment of the lettuce atomization cultivation system, which includes a control unit, an image acquisition unit, an atomization rack 15, an atomization box 16, a supply unit, and a low-frequency nuclear magnetic resonance spectrometer 33.

[0050] The control unit is connected to the image acquisition unit, the aeroponic box 16, the supply unit and the low-frequency nuclear magnetic resonance spectrometer 33 respectively. The aeroponic box 16 is installed on the aeroponic rack 15 and the supply unit is connected to the aeroponic box 16.

[0051] The interior of the aeroponic chamber 16 includes a temperature sensor 25, an axial fan 26, and a plasma nozzle 27. The plasma nozzle 27 is connected to the supply unit and the control unit, respectively. The temperature sensor 25 and the axial fan 26 are connected to the control unit. The axial fan 26 is installed on the chamber of the aeroponic chamber 16. The plasma nozzle 27 is used to convert nitrogen molecules in the air inside the aeroponic chamber 16 into nitrogen-containing compounds, and is also used to ionize oxygen in the air to produce ozone.

[0052] The image acquisition unit is used to acquire images and thermal images of lettuce leaves on the aeroponic box 16. The image acquisition unit transmits the acquired images and thermal images to the control unit. The control unit preprocesses the acquired images and transmits the preprocessed images to the neural network. The neural network determines the type of missing element for each lettuce leaf and classifies the lettuce leaves accordingly. The control unit controls the supply unit to prepare the corresponding element nutrient solution according to the missing element of each category of lettuce leaves and delivers the nutrient solution to the plasma nozzle 27. The control unit controls the plasma nozzle 27 to move under the lettuce of that category and controls the plasma nozzle 27 to atomize the prepared nutrient solution. The liquid is sprayed onto the root of the target lettuce; the control unit extracts temperature data from the acquired thermal image, and samples the lettuce leaves or roots at the corresponding time when the thermal image is acquired. The water content of the lettuce leaf or root samples is detected by the low-frequency nuclear magnetic resonance spectrometer 33, and the water content data is transmitted to the control unit. The control unit processes the temperature data and water content data. When the water content drops below a preset value within the set temperature difference range, the control unit records the initial temperature value in that temperature difference. The temperature sensor 25 detects the temperature inside the aeroponic box 16. When the temperature sensor 25 detects that the temperature inside the aeroponic box 16 is higher than the temperature value recorded by the control unit, the control unit turns on the axial fan 26.

[0053] Preferably, the aeroponic chamber 16 further includes a guide rail 22, which is installed inside the chamber. The plasma nozzle 27 is installed on the guide rail 22, and a motor is installed on the guide rail 22 to drive the plasma nozzle 27 to slide on the guide rail 22.

[0054] Preferably, the aeroponic box 16 further includes a planting basket 19, a sponge 20, a negative ion generator 21, a planting board 24, a nutrient solution return pipe 29, and a nutrient solution collection bucket 30. The sponge 20 is used to fix the lettuce, and the nutrient solution collection bucket 30 is used to collect the nutrient solution that has not been absorbed by the roots of the lettuce, while preventing excess nutrient solution from accumulating in the box.

[0055] The planting board 24 is installed on the box body, and the planting board 24 is provided with planting holes 23. The box body is provided with a nutrient solution return port 28. The planting holes 23 are equipped with planting baskets 19 and sponges 20. The negative ion generator 21 is installed on the planting board 24. The nutrient solution collection tank 30 is connected to the nutrient solution return port 28 through the nutrient solution return pipe 29.

[0056] like Figure 7 , 8 As shown in Figure 9, preferably, the plasma nozzle 27 includes a high-voltage generator 41, which includes a metal cap 4101, two piezoelectric ceramics 4102, a phosphor bronze sheet 4103, a high-voltage lead wire 4104, a first striking mechanism 41051, a second striking mechanism 41052, a first spring, a second spring 4106, and a housing 4107.

[0057] The piezoelectric ceramic 4102, phosphor bronze sheet 4103, first striking mechanism 41051, second striking mechanism 41052 and first spring are all installed inside the outer casing 4107. The phosphor bronze sheet 4103 is placed between the two piezoelectric ceramics 4102. One end of the high voltage lead 4104 is connected to the phosphor bronze sheet 4103, and the other end is led out of the outer casing 4107. One end of the second striking mechanism 41052 is installed on the piezoelectric ceramic 4102, and the other end of the second striking mechanism 41052 is connected to one end of the first striking mechanism 41051 through the first spring, so that the first striking mechanism 41051 can slide along the inner wall of the outer casing 4107 under the elastic force of the first spring. The other end of the first striking mechanism 41051 is equipped with a second spring 4106.

[0058] Preferably, the image acquisition unit includes an RGB camera 9 and a thermal imaging camera 32;

[0059] The RGB camera 9 is mounted on the aeroponic rack 15 and is located above the aeroponic box 16. The RGB camera 9 is used to capture images of lettuce leaves on the aeroponic box 16.

[0060] The thermal imaging camera 32 is used to capture thermal images of lettuce leaves or roots.

[0061] Preferably, the supply unit includes a diaphragm pump 11, several nutrient solution tanks, a nutrient solution mixing tank 13, a metering pump 17, a water tank 18, and an air compressor 51.

[0062] The diaphragm pump 11 is installed on the aeroponic rack 15. The diaphragm pump 11 is connected to the nutrient solution mixing tank 13 and the plasma nozzle 27 respectively. The nutrient solution tank and the water tank 18 are connected to the nutrient solution mixing tank 13 respectively. The pipelines connecting the nutrient solution tank and the water tank 18 to the nutrient solution mixing tank 13 are equipped with metering pumps 17. There are several metering pumps 17. The nutrient solution mixing tank 13 and the air compressor 51 are connected to the plasma nozzle 27 respectively. The nutrient solution mixing tank 13 is equipped with a stirring assembly.

[0063] Preferably, the control unit includes a Raspberry Pi 2, a computer 4, and a relay 5;

[0064] The computer 4 is used to process the data acquired by the image acquisition unit and the low-frequency nuclear magnetic resonance spectrometer 33, and transmit the processing results to the Raspberry Pi 2.

[0065] The Raspberry Pi 2 is connected to the computer 4 and the relay 5. The relay 5 is connected to the plasma nozzle 27, the metering pump 17, the stirring assembly, the diaphragm pump 11, the air compressor 51, the motor and the axial fan 26. The temperature sensor 25 is connected to the computer 4.

[0066] Preferably, it also includes a plant growth lamp 7;

[0067] The plant growth light 7 is installed on the aeroponic rack 15, located above the aeroponic box 16.

[0068] In one embodiment of the present invention, preferably, when the moisture content drops by more than 0.5g in a certain temperature difference, the control unit records the initial temperature value in the temperature difference, the temperature sensor 25 detects the temperature inside the aeroponic box 16, and when the temperature sensor 25 detects that the temperature inside the aeroponic box 16 is higher than the temperature value recorded by the control unit, the control unit turns on the axial fan 26.

[0069] In one embodiment of the present invention, preferably, the temperature difference is set to 4°.

[0070] In one embodiment of the present invention, preferably, the RGB camera 9 takes a picture every 3 minutes.

[0071] Preferably, the image processing system on the computer 4 performs preprocessing on the image, including grayscale processing, grayscale transformation, binarization, filtering, region localization, and feature extraction. The processed image is then imported into the ResNet 50 neural network model. After identification, the type of nutrient deficiency in the lettuce is determined, the lettuce leaves are located, and the color, size, and edge shape of the lettuce leaves are extracted.

[0072] Preferably, the plasma nozzle 27 generates plasma. The high-energy electrons generated by the plasma can break down the strong N≡N bond at room temperature and pressure, making it a highly efficient and energy-saving nitrogen fixation technology. Plasma nitrogen fixation technology converts nitrogen molecules N₂ in the air into absorbable nitrogen-containing compounds NO. X , NH3, etc.

[0073] Plasma synthesis of NO X The two paths for NO in the code are:

[0074]

[0075] Equation 2: N2*+O→NO*+N

[0076] Equation 3: N² + e → N²* → N + N

[0077] N + O₂ → NO + O Equation 4

[0078] Reaction equations 1 and 2 directly synthesize NO under high pressure and low nitrogen-to-oxygen ratio conditions; reaction equations 3 and 4 synthesize NO by dissociating N2 under low pressure and low nitrogen-to-oxygen ratio conditions. Then, [further processes will occur].

[0079] The following reactions:

[0080] e + H₂O → OH⁻ + H⁺ + e

[0081] O + NO + M → NO2 + M

[0082] O + NO₂ + M → NO₃ + M

[0083] N + H → NH

[0084] NH + H → NH2

[0085] NH2 + H → NH3

[0086] In humid air plasma, NO X It can further react with OH to produce HNOX:

[0087] NO + OH → HNO₂

[0088] NO2 + OH → HNO3

[0089] By using plasma nitrogen fixation technology, nitrogen molecules N2 in the air that are not easily absorbed are converted into the aforementioned nitrogen-containing compounds that can be absorbed, allowing lettuce roots to better absorb nitrogen, thereby promoting the absorption of water and nutrients by the lettuce roots and making the lettuce grow faster.

[0090] Preferably, the plasma nozzle 27 generates a high voltage to ionize some of the oxygen in the aeroponic box 16, causing oxygen molecules to decompose and polymerize into ozone. The generated trace amount of ozone has a bactericidal and disinfecting effect on the roots of lettuce, ensuring the healthy growth of lettuce.

[0091] Preferably, the aeroponic box 16 is equipped with a negative ion generator 21. The negative ions generated by the ion generator 21 help maintain the acid-base balance of the lettuce roots, thereby promoting lettuce growth.

[0092] Preferably, lettuce is deficient in nitrogen, phosphorus, potassium and other elements.

[0093] Preferably, the Raspberry Pi 2 used is a Raspberry Pi 4B from the Chuanglubo brand, equipped with a display screen 3, which needs to be connected to the network. All collected data is stored in the SD card that comes with the Raspberry Pi. The display screen 3 can be programmed and connected to the network. The Raspberry Pi 2 connects to the network through the Raspberry Pi display screen 3.

[0094] like Figure 4 The diagram shows the connection between the relay module of this invention and other devices. Relay 5's K1 section, pin 2 connects to the axial fan 26, and pin 4 connects to the air compressor 51. K2 section, pin 2 connects to the axial fan 26. The wiring method for K3 is the same as for K2. K4 section, pin 2 connects to the diaphragm pump 11, pin 3 connects to the power supply, and pin 4 connects to the metering pump 17. The connections for K4, K5, and K6 are the same. Relay 5's left side pins 1 and 2 connect to the positive and negative terminals of the power supply, and pins 3, 4, 5, 6, 7, 8, and 9 connect to the seven GPIO interfaces of the Raspberry Pi 2.

[0095] like Figure 6 As shown, preferably, the plasma nozzle 27 further includes an air inlet sleeve 34, a sealing ring 36, an adjustable base 38, a positioning screw 39, a stepped rectifier 40, a vortex impeller 42, a second base 43, a bearing 44, a stepped resonant tube 45, an adjusting plunger 46, a clamping nut 47, a fixing cap 48, and a Laval tube;

[0096] The intake sleeve 34 has an intake hole 50 at its center and a liquid inlet hole 37 on its side wall. An adjustable base 38 is connected to the outer ring of the intake sleeve 34. A positioning screw 39 is fixed to the adjustable base 38. A stepped fairing 40 and a second base 43 are fixed to the adjustable base 38 via the positioning screw 39. The intake sleeve 34 and the stepped fairing 40 form a hollow space. The Laval tube includes a liquid inlet sleeve 35 and a Laval valve core 49. The Laval tube and the fixing cap 48 are both located within the space enclosed by the cylindrical section through-hole of the intake sleeve 34 and the stepped fairing 40. One end of the fixing cap 48 is connected to the intake sleeve 34. A sealing ring 36 is provided between the liquid inlet sleeve 35 and the intake sleeve 34, and the liquid inlet sleeve 35 is fixed by the sealing ring 36. On the inner wall of the air inlet sleeve 34, the liquid inlet sleeve 35 extends into the fixed cap 48. The liquid inlet sleeve 35 is connected to the fixed cap 48 through the Laval valve core 49. There is a gap between the liquid inlet sleeve 35 and the fixed cap 48. The stepped shroud 40 is provided with a stepped groove. The high voltage generator 41 is placed in the stepped groove. The vortex impeller 42 is mounted on the stepped resonant tube 45 through the bearing 44 and is located in the stepped section of the stepped shroud 40. The vortex impeller 42 is close to the high voltage generator 41 so that the thickest edge of the blade can contact the second spring when the vortex impeller 42 rotates. One end of the stepped resonant tube 45 is connected to the second base 43 through the adjusting plunger 46. The other end of the stepped resonant tube 45 extends to the end face of the fixed cap 48.

[0097] In one embodiment of the present invention, preferably, the planting board 24 has 20 planting holes 23, each planting hole 23 having a diameter of 32 mm, and a planting basket 19 is installed in the planting hole. The planting basket 19 contains lettuce, and the roots of the lettuce are wrapped with a sponge 20 and placed in the planting basket.

[0098] In one embodiment of the present invention, preferably, the voltage of the axial fan 26 is 12V.

[0099] Preferably, the number of nutrient solution tanks is no less than two.

[0100] In one embodiment of the present invention, preferably, the nutrient solution tank includes a first nutrient solution tank 12 and a second nutrient solution tank 14. The first nutrient solution tank 12 contains nutrient solution containing macronutrients that lettuce lacks, and the second nutrient solution tank 14 contains nutrient solution containing micronutrients that lettuce lacks.

[0101] In one embodiment of the present invention, preferably, when preparing the corresponding nutrient solution, the corresponding liquids are drawn from the first nutrient solution tank 12, the second nutrient solution tank 14 and the water tank 18 in a ratio of 1:1:20 and injected into the nutrient solution mixing tank 13.

[0102] In one embodiment of the present invention, such as Figure 10 As shown, the thermal imaging camera 32 acquires thermal images of lettuce. After processing, temperature data is extracted from the acquired thermal images. At the corresponding time of thermal image acquisition, the water content of lettuce roots and leaves is detected by a low-frequency nuclear magnetic resonance spectrometer 33. A line graph is plotted between temperature data and water content, with temperature data on the X-axis and water content on the Y-axis. The line graph shows that the water content decreased by more than 0.5g under a temperature difference of 28°C to 32°C, indicating that the lettuce roots are under water stress. At this time, the absorption of water and nutrient solution by the lettuce roots is significantly weakened, and the transpiration of lettuce is strong, which significantly reduces the water content of lettuce and seriously affects the normal growth of lettuce. Therefore, it is necessary to turn on the axial flow fan 26 to cool down the lettuce roots in the aeroponic box 16, so that the lettuce roots are at a normal temperature, restore the normal absorption of water and nutrient solution, and enable lettuce to grow normally.

[0103] In one embodiment of the present invention, the thermal imaging camera of the present invention processes the acquired thermal images and extracts temperature data, plots the temperature data into a line graph in sequence, and uses a low-frequency nuclear magnetic resonance spectrometer to detect the water content of lettuce roots at the corresponding time of thermal image acquisition, converting the water content data into a line graph. By correlating the temperature line graph and the water content line graph according to time, it can be seen whether the temperature is too high, causing the water content of the roots to decrease and water stress to occur, so that the axial flow fan can be turned on in time to cool the lettuce roots and ensure the healthy growth of lettuce.

[0104] Preferably, the plant growth lamp 7 is a red and blue light plant growth lamp, which is installed on the aeroponic rack 15 and located above the aeroponic box 16.

[0105] Preferably, the neural network is a ResNet 50 neural network model.

[0106] A control method for a lettuce atomized cultivation system includes the following steps:

[0107] The image acquisition unit is used to acquire images and thermal images of lettuce leaves on the aeroponic box 16. The image acquisition unit transmits the acquired images and thermal images to the control unit. The control unit preprocesses the acquired images and transmits the preprocessed images to the neural network. The neural network determines the type of missing element for each lettuce leaf and classifies the lettuce leaves accordingly. The control unit controls the supply unit to configure the corresponding element nutrient solution according to the missing element of each category of lettuce leaves and delivers the nutrient solution to the plasma nozzle 27. The control unit controls the plasma nozzle 27 to move under the lettuce of that category. The control unit controls the plasma nozzle 27 to spray the nutrient solution from the supply unit onto the lettuce, convert nitrogen molecules in the air inside the aeroponic box 16 into nitrogen-containing compounds, and ionize oxygen in the air to produce ozone.

[0108] Preferably, the following steps are also included:

[0109] The control unit extracts temperature data from the acquired thermal image. At the corresponding time when the thermal image is acquired, samples of lettuce leaves or roots are taken. The moisture content of the lettuce leaf or root samples is detected by the low-frequency nuclear magnetic resonance spectrometer 33, and the moisture content data is transmitted to the control unit. The control unit processes the temperature data and moisture content data. When the moisture content drops below a preset value within the set temperature difference range, the control unit records the initial temperature value within that temperature difference. The temperature sensor 25 detects the temperature inside the aeroponic chamber 16. When the temperature sensor 25 detects that the temperature inside the aeroponic chamber 16 is higher than the temperature value recorded by the control unit, the control unit turns on the axial fan 26.

[0110] Working process within plasma nozzle 27:

[0111] High-pressure gas enters through the air inlet 50 and travels along the inside of the water inlet sleeve 35 to the outlet of the Laval tube. Liquid enters through the liquid inlet 37. Due to the sealing ring 36 between the air inlet sleeve 34 and the water inlet sleeve 35, the liquid can only pass through the gap between the water inlet sleeve 35 and the fixing nut 48 to reach the Laval valve core 49. It then enters the Laval tube through the through hole on the Laval valve core 49. At the outlet of the Laval tube, the liquid merges with the high-pressure gas. The liquid is impacted and broken by the high-pressure gas to form large droplets, resulting in the first atomization.

[0112] Then the large droplets continue to enter the inner cavity of the stepped resonant tube 45 with the high-pressure gas. The mixture of droplets and gas undergoes a second atomization in the cavity due to the collision between the inner cavity of the stepped resonant tube 45 and the serrated inner wall of the stepped resonant tube 45 and the resonance effect of the exciter 4601.

[0113] Due to the blocking effect of the plunger body 4602, the droplets after the second atomization return along the original path in the inner cavity of the stepped resonant tube 45. After exiting the inner cavity of the stepped resonant tube 45, the droplets enter the second resonant region. The second resonant region is the internal space region formed by the combination of the groove on the end face of the fixed cap 48 and the rectifier sleeve of the stepped rectifier 40. In the second resonant region, the mixture of droplets and gas undergoes irregular oscillation, causing the droplets to undergo a third atomization.

[0114] Finally, the droplets enter the blade gaps of the vortex impeller 42 under the pressure of the droplet and gas mixture. Under the pressure of the droplet and gas mixture, the vortex impeller 42 rotates at high speed. The outermost edge of the blades of the vortex impeller 42 with unequal thickness strikes the second spring 4106 during rotation. The second spring 4106 is impacted and exerts pressure on the first striking mechanism 41051. The first striking mechanism 41051 is compressed by the pressure and impacts the second striking mechanism 41052 and the piezoelectric ceramic 4102. The piezoelectric ceramic 4102 is compressed by the impact, the polarization intensity decreases, and some adsorbed free charges are released, resulting in a discharge phenomenon. The released high voltage enters the air through the phosphor bronze sheet 4103 and the high voltage lead 4104. The droplets entering the vortex impeller 42 are transformed into plasma droplets by the high voltage. The droplets undergo a fourth atomization under the action of centrifugal force.

[0115] Finally, the droplets are sprayed from the edge of the stepped rectifier 40 and sprayed onto the roots of the lettuce, so that the droplets are evenly covered on the roots. The nitrogen in the air inside the aeroponic chamber is ionized into nitrogen-containing compounds that can be absorbed, thus playing a role in nitrogen fixation. At the same time, the oxygen in the aeroponic chamber is ionized under the action of high voltage to produce trace amounts of ozone, which plays a role in sterilization and disinfection of the roots of the lettuce.

[0116] Example 1

[0117] RGB camera 9 captures images of lettuce leaves on the front of planting board 24 and transmits the images to computer 4 for image preprocessing, including region localization and feature extraction. Computer 4 uses an existing ResNet 50 neural network model to determine the nutrient deficiency type of each lettuce leaf, finding that 6 lettuce plants in the 20 planting holes 23 are deficient in nitrogen, 4 in phosphorus, and 3 in potassium, while the remaining 7 are growing normally. The 6 nitrogen-deficient lettuce plants are grouped into one group, the 4 phosphorus-deficient lettuce plants into another group, and the 3 potassium-deficient lettuce plants into a third group. The grouping results are transmitted to Raspberry Pi 2. Raspberry Pi 2 uses relay 5 to control the metering pumps 17 on the high-nitrogen nutrient solution tank 14, the micronutrient nutrient solution tank 14, and the water tank 18, respectively. Preferably, the corresponding liquids are injected into the nutrient solution mixing tank 13 at a ratio of 1:1:20. The mixing components in the nutrient solution mixing tank 13 stir the prepared nutrient solution evenly. Raspberry Pi 2 then... Relay 5 controls diaphragm pump 11 to draw prepared nutrient solution from nutrient solution mixing tank 13 and deliver it to plasma nozzle 27. Raspberry Pi 2 controls motor via relay 5 to drive plasma nozzle 27 to slide on guide rail 22 to the underside of 6 nitrogen-deficient lettuce plants. Raspberry Pi 2 controls air compressor 51 and diaphragm pump 11 via relay 5 to atomize the prepared liquid and air in plasma nozzle 27 and spray the atomized liquid out, so that the atomized liquid is absorbed by the roots of lettuce leaves on the back of planting board 24. Excess nutrient solution is sprayed into nutrient solution collection tank 30, while preventing excess nutrient solution from accumulating in the tank. Spraying for nitrogen-deficient lettuce ends when the nutrient solution in nutrient solution mixing tank 13 is used up.

[0118] Raspberry Pi 2, via relay 5, controls metering pumps 17 on the high-phosphorus nutrient solution tank 14, trace element nutrient solution tank 14, and water tank 18 to draw the corresponding liquids in a 1:1:20 ratio and inject them into the nutrient solution mixing tank 13. The mixing tank 13 is then stirred by a stirring assembly to ensure the prepared nutrient solution is homogeneous. Raspberry Pi 2, via relay 5, controls diaphragm pump 11 to draw the prepared nutrient solution from the mixing tank 13 and deliver it to the plasma nozzle 27. Raspberry Pi 2, via relay 5, controls a motor to drive the plasma nozzle. 27 Slides on guide rail 22 to the bottom of 6 phosphorus-deficient lettuce plants. Raspberry Pi 2 controls air compressor 51 and diaphragm pump 11 via relay 5 to atomize the prepared liquid and air in plasma nozzle 27 and spray the atomized liquid out. The atomized liquid is absorbed by the roots of the lettuce leaves on the back of the planting plate 24. Excess nutrient solution is sprayed into nutrient solution collection tank 30, while preventing excess nutrient solution from accumulating in the box. The spraying of phosphorus-deficient lettuce ends when the nutrient solution in nutrient solution mixing tank 13 is used up.

[0119] Raspberry Pi 2, via relay 5, controls metering pumps 17 on the potassium-concentration nutrient solution tank 14, trace element nutrient solution tank 14, and water tank 18 to draw the corresponding liquids in a 1:1:20 ratio and inject them into the nutrient solution mixing tank 13. The mixing tank 13 is then stirred by a stirring component to ensure the prepared nutrient solution is homogeneous. Raspberry Pi 2, via relay 5, controls diaphragm pump 11 to draw the prepared nutrient solution from the mixing tank 13 and deliver it to the plasma nozzle 27. Raspberry Pi 2, via relay 5, controls a motor to drive the plasma nozzle. 27 slides on guide rail 22 to the bottom of 6 potassium-deficient lettuce plants. Raspberry Pi 2 controls air compressor 51 and diaphragm pump 11 through relay 5 to atomize the prepared liquid and air in plasma nozzle 27 and spray the atomized liquid out. The atomized liquid is absorbed by the roots of the lettuce leaves on the back of the planting plate 24. Excess nutrient solution is sprayed into nutrient solution collection tank 30, while preventing excess nutrient solution from accumulating in the box. The spraying of potassium-deficient lettuce ends when the nutrient solution in nutrient solution mixing tank 13 is used up.

[0120] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0121] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A lettuce atomization cultivation system, characterized in that, It includes a control unit, an image acquisition unit, a misting rack (15), a misting box (16), a supply unit, and a low-frequency nuclear magnetic resonance spectrometer (33). The control unit is connected to the image acquisition unit, the aeroponic box (16), the supply unit and the low-frequency nuclear magnetic resonance spectrometer (33) respectively. The aeroponic box (16) is installed on the aeroponic rack (15) and the supply unit is connected to the aeroponic box (16). The aeroponic chamber (16) includes a temperature sensor (25), an axial fan (26), and a plasma nozzle (27). The plasma nozzle (27) is connected to the supply unit and the control unit respectively, and the temperature sensor (25) and the axial fan (26) are connected to the control unit. The temperature sensor (25) is used to detect the temperature inside the aeroponic chamber (16) and transmit it to the control unit. The axial fan (26) is installed on the chamber of the aeroponic chamber (16). The plasma nozzle (27) is used to spray the nutrient solution from the supply unit onto the lettuce, convert nitrogen molecules in the air inside the aeroponic chamber (16) into nitrogen-containing compounds, and ionize oxygen in the air to produce ozone. The image acquisition unit is used to acquire images of lettuce leaves and thermal images of lettuce leaves or roots on the aeroponic box (16). The image acquisition unit transmits the acquired lettuce leaf images and thermal images to the control unit. The control unit preprocesses the acquired lettuce leaf images and transmits the preprocessed lettuce leaf images to the neural network. The neural network determines the type of missing element for each lettuce leaf and classifies the lettuce leaves according to the missing element type. The control unit controls the supply unit to configure the corresponding element nutrient solution according to the missing element of each category of lettuce leaves and delivers the nutrient solution to the plasma nozzle (27). The control unit controls the plasma nozzle (27) to move to the bottom of the lettuce of that category. The control unit controls the plasma nozzle (27) to deliver the configured nutrient solution. The nutrient solution is atomized and sprayed onto the root of the target lettuce. The control unit extracts temperature data from the collected thermal image and takes samples of lettuce leaves or roots at the corresponding time of the thermal image acquisition. The water content of the lettuce leaf or root samples is detected by a low-frequency nuclear magnetic resonance spectrometer (33), and the water content data is transmitted to the control unit. The control unit processes the temperature data and water content data. When the water content drops below the preset value within the set temperature difference range, the control unit records the initial temperature value in the temperature difference. The temperature sensor (25) detects the temperature inside the aeroponic box (16). When the temperature sensor (25) detects that the temperature inside the aeroponic box (16) is higher than the initial temperature value recorded by the control unit, the control unit turns on the axial flow fan (26). The plasma nozzle (27) includes a high voltage generator (41), which includes a metal cap (4101), two piezoelectric ceramics (4102), a phosphor bronze sheet (4103), a high voltage lead (4104), a first striking mechanism (41051), a second striking mechanism (41052), a first spring, a second spring (4106), and a housing (4107). The piezoelectric ceramic (4102), phosphor bronze sheet (4103), first striking mechanism (41051), second striking mechanism (41052) and first spring are all installed inside the outer shell (4107). The phosphor bronze sheet (4103) is placed between the two piezoelectric ceramics (4102). One end of the high voltage lead (4104) is connected to the phosphor bronze sheet (4103), and the other end is led out of the outer shell (4107). One end of the second striking mechanism (41052) is installed on the piezoelectric ceramic (4102), and the other end of the second striking mechanism (41052) is connected to one end of the first striking mechanism (41051) through the first spring, so that the first striking mechanism (41051) can slide along the inner wall of the outer shell (4107) by the elastic force of the first spring. The other end of the first striking mechanism (41051) is equipped with a second spring (4106).

2. The lettuce atomization cultivation system according to claim 1, characterized in that, The aeroponic box (16) also includes a guide rail (22), which is installed inside the box. The plasma nozzle (27) is installed on the guide rail (22), and a motor is installed on the guide rail (22) to drive the plasma nozzle (27) to slide on the guide rail (22).

3. The lettuce atomization cultivation system according to claim 2, characterized in that, The aeroponic box (16) also includes a planting basket (19), a sponge (20), a negative ion generator (21), a planting board (24), a nutrient solution return pipe (29), and a nutrient solution collection bucket (30). The planting board (24) is installed on the box body. The planting board (24) is provided with planting holes (23). The box body is provided with a nutrient solution return port (28). The planting holes (23) are equipped with planting baskets (19) and sponges (20). The negative ion generator (21) is installed on the planting board (24). The nutrient solution collection bucket (30) is connected to the nutrient solution return port (28) through the nutrient solution return pipe (29).

4. The lettuce atomization cultivation system according to claim 1, characterized in that, The image acquisition unit includes an RGB camera (9) and a thermal imaging camera (32); The RGB camera (9) is installed on the aeroponic rack (15) and is located above the aeroponic box (16). The RGB camera (9) is used to capture images of lettuce leaves on the aeroponic box (16). A thermal imaging camera (32) is used to collect thermal images of lettuce leaves or roots.

5. The lettuce atomization cultivation system according to claim 2, characterized in that, The supply unit includes a diaphragm pump (11), several nutrient solution tanks, a nutrient solution mixing tank (13), a metering pump (17), a water tank (18), and an air compressor (51). The diaphragm pump (11) is installed on the aeroponic rack (15). The diaphragm pump (11) is connected to the nutrient solution mixing tank (13) and the plasma nozzle (27) respectively. The nutrient solution tank and the water tank (18) are connected to the nutrient solution mixing tank (13) respectively. The pipelines connecting the nutrient solution tank and the water tank (18) to the nutrient solution mixing tank (13) are equipped with metering pumps (17). There are several metering pumps (17). The nutrient solution mixing tank (13) and the air compressor (51) are connected to the plasma nozzle (27) respectively. The nutrient solution mixing tank (13) is equipped with a stirring assembly.

6. The lettuce atomization cultivation system according to claim 5, characterized in that, The control unit includes a Raspberry Pi (2), a computer (4), and a relay (5); The computer (4) is used to process the data acquired by the image acquisition unit and the low-frequency nuclear magnetic resonance spectrometer (33) and transmit the processing results to the Raspberry Pi (2). The Raspberry Pi (2) is connected to the computer (4) and the relay (5) respectively. The relay (5) is connected to the plasma nozzle (27), the metering pump (17), the stirring assembly, the diaphragm pump (11), the air compressor (51), the motor and the axial fan (26) respectively. The temperature sensor (25) is connected to the computer (4).

7. The lettuce atomization cultivation system according to claim 1, characterized in that, It also includes plant growth lights (7); The plant growth lamp (7) is installed on the aeroponic rack (15) and located above the aeroponic box (16).

8. A control method for a lettuce atomized cultivation system according to any one of claims 1 to 7, characterized in that, Includes the following steps: The image acquisition unit is used to acquire images and thermal images of lettuce leaves on the aeroponic box (16), and the image acquisition unit transmits the acquired images and thermal images to the control unit respectively; The control unit preprocesses the acquired images and transmits the preprocessed images to the neural network. The neural network determines the type of missing elements in each lettuce leaf and classifies the lettuce leaves accordingly. The control unit controls the supply unit to configure the corresponding element nutrient solution according to the missing elements in each category of lettuce leaves and delivers the nutrient solution to the plasma nozzle (27). The control unit controls the plasma nozzle (27) to move to the bottom of the lettuce of that category. The control unit controls the plasma nozzle (27) to spray the nutrient solution from the supply unit onto the lettuce, convert nitrogen molecules in the air inside the aeroponic box (16) into nitrogen-containing compounds, and ionize oxygen in the air to produce ozone.

9. The control method for the lettuce atomization cultivation system according to claim 8, characterized in that, It also includes the following steps: The control unit extracts temperature data from the acquired thermal image. At the corresponding time of acquiring the thermal image, samples of lettuce leaves or roots are taken. The water content of the lettuce leaf or root samples is detected by a low-frequency nuclear magnetic resonance spectrometer (33), and the water content data is transmitted to the control unit. The control unit processes the temperature data and water content data. When the water content drops below the preset value within the set temperature difference range, the control unit records the initial temperature value in the temperature difference. The temperature sensor (25) detects the temperature inside the aeroponic box (16). When the temperature sensor (25) detects that the temperature inside the aeroponic box (16) is higher than the temperature value recorded by the control unit, the control unit turns on the axial flow fan (26).

Images