Grain fungaltoxin content detection device

Abstract

The utility model discloses a grain fungaltoxin content detection device which comprises a cylindrical main shell and a circular truncated cone-shaped lighting bin located at the lower end of the main shell, a spectrum detection device is arranged in the main shell, the small opening end of the lighting bin is fixedly connected with the main shell, and an objective table is assembled at the large opening end of the lighting bin. A power supply circuit is arranged at the bottom of the objective table; light source groups with multiple wavelengths are uniformly arranged along the circumference of the bottom of the objective table; every two light sources with the same wavelength are arranged in a central symmetry manner; the power supply circuit comprises an adjustable constant-current circuit and a boost driving circuit, the input end of the boost driving circuit is connected with an input power supply, the input end of the adjustable constant-current circuit is connected with a boost driving signal of the boost driving circuit, and the light sources are connected in series and then connected to the output end of the adjustable constant-current circuit; the power supply circuit drives the light source group to emit light to irradiate a sample, so that the spectrum detection device can collect spectrum images of the sample under different single-wavelength light sources, and the device is simple in structure and convenient to use.

Description

Technical Field

[0001] The utility model relates to the technical field of grain detection instruments, in particular to a grain mycotoxin content detection device. Background Art

[0002] Mycotoxins are secondary metabolites produced by some fungi during their growth process that are prone to cause pathological changes and physiological abnormalities in humans and animals, and are highly toxic to humans and animals. Since mycotoxins contaminate a wide range of grains, such as wheat, barley, corn, oats, sorghum, rye, rice, and products related to these grains, reliable mycotoxin detection technology is necessary to detect the mycotoxin contamination level in grains and determine whether the toxin content meets the relevant limit standards.

[0003] Traditional food physical and chemical testing methods are to detect fungal toxins by physically crushing samples, chemical extraction, and chemical reaction coloring, which have the disadvantages of long detection cycles, low accuracy, sample damage, and environmental pollution. Multispectral imaging, as an emerging detection technology, generally benefits all mankind and is often used in various industries, especially in the field of food testing. It is increasingly widely used, which is of great help to mankind and is conducive to the healthy and safe production of related industries and the stable development of the trading market.

[0004] When using multispectral imaging technology to detect grain, it is necessary to use a light source to emit light to illuminate the sample to be tested to collect spectral images of the sample under different light intensities. The stability and reliability of the light source is crucial to the multispectral imaging effect and helps to achieve rapid detection of spectral responsiveness. Utility Model Content

[0005] The technical problem to be solved by the utility model is how to stably and reliably provide a light source with multiple wavelengths for a seed sample, which helps to obtain high-quality spectral images of the seed sample under different single-wavelength light sources.

[0006] The utility model solves the above technical problems through the following technical means:

[0007] A device for detecting the mycotoxin content in grains is proposed. The device comprises: a cylindrical main shell and a truncated cone-shaped lighting chamber located at the lower end of the main shell, a spectrum detection device is arranged inside the main shell, a small-mouth end of the lighting chamber is fastened to the main shell, a loading platform is mounted on the lower end surface of the large-mouth end of the lighting chamber, a power supply circuit is arranged inside the loading platform, and a light source group with multiple wavelengths is evenly arranged along the bottom circumference, and every two light sources with the same wavelength are arranged symmetrically in the center; the loading platform is used to carry grain seed samples;

[0008] The power supply circuit includes a boost drive circuit and an adjustable constant current circuit, the input end of the boost drive circuit is connected to an input power supply, the input end of the adjustable constant current circuit is connected to a boost drive signal output by the boost drive circuit, and each of the light sources is connected in series to the output end of the adjustable constant current circuit.

[0009] Furthermore, the adjustable constant current circuit includes a three-terminal voltage regulator adjustment chip of model LM317L, the input terminal VI of the three-terminal voltage regulator adjustment chip is connected to the power supply after the boost drive, the output terminal VO of the three-terminal voltage regulator adjustment chip is connected to the variable resistor RV added in this design, and the capacitor C2 is connected in series between the other end of the variable resistor RV and the input end of the voltage regulator adjustment chip. The capacitor C2 is only used for test voltage filtering of a separate debugging module and can be omitted in the module connection because the boost drive circuit already has filtering; the adjustment terminal ADJ of the three-terminal voltage regulator adjustment chip is used for additional output current adjustment and connected to the constant current output to the load end.

[0010] Further, the boost drive circuit includes an MC34063 chip, a pin SWC of the MC34063 chip is connected to one end of an energy storage inductor L, a pin DRC of the MC34063 chip is connected to the other end of the energy storage inductor L via a resistor R, a pin IPK of the MC34063 chip is respectively connected to the other end of the resistor R, and forms a current limiting protection with the resistor RSC, and the other end of the resistor RSC is connected to the power supply end of the MC34063 chip for peak current sampling;

[0011] The pin SWC of the MC34063 chip is also connected to the anode of the diode D1, the cathode of the diode D1 is grounded via the filter capacitor CO, the voltage sampling terminal CINV / COMP of the MC34063 chip is grounded via the resistor R1, a variable resistor RV1 designed to be connected in series between one end of the resistor R1 and one end of the filter energy storage capacitor CO, a capacitor C1 is connected in series between the other end of the resistor R1 and the resistor R, and the pin CT of the MC34063 chip is connected to the timing capacitor;

[0012] The diode D1 and the filter energy storage capacitor CO serve as the output end of the boost driving circuit to output the boost driving signal.

[0013] Furthermore, the light source is an LED lamp.

[0014] Further, the light source group includes light sources having wavelengths of 470nm, 505nm, 525nm, 570nm, 590nm, 630nm, 645nm, 660nm, 700nm, 780nm, 850nm, 870nm, 890nm, 910nm, 940nm and 970nm.

[0015] Further, the spectrum detection device includes a photoelectric sensor module and an image collector, and the photoelectric sensor module includes an InGaAs photodiode, a photoelectric signal amplification circuit and an AD signal acquisition circuit;

[0016] The output of the InGaAs photodiode is connected to the AD signal acquisition circuit via the photoelectric signal amplification circuit, and the output of the AD signal acquisition circuit is connected to the image collector.

[0017] Furthermore, a spectroscopic element and a lens are arranged inside the main housing. The spectroscopic element is arranged on the reflected light path of the seed sample, and the lens is arranged on the outgoing light path of the spectroscopic element.

[0018] Furthermore, the light splitting element is arranged at the bottom of the lighting chamber using a high-pass filter.

[0019] Furthermore, an observation window is provided on the side wall of the main shell, and a display screen is embedded in the observation window.

[0020] Further, a lens is arranged at the top opening of the main housing;

[0021] Furthermore, an image collector is arranged above the top opening of the main shell, and the image collector adopts a CCD camera.

[0022] The advantages of the utility model are:

[0023] (1) The utility model provides a truncated cone-shaped illumination chamber, and assembles a stage at the large end of the illumination chamber, arranges a power supply circuit and a light source group at the bottom of the stage, and the light source group is composed of light sources with multiple wavelengths evenly arranged along the circumference of the bottom of the stage, and every two light sources with the same wavelength in the light source group are arranged symmetrically to the center. During detection, the power supply circuit is used to provide input current to the light source group to drive the light sources with different wavelengths in the light source group to emit light, so that the spectral detection device can collect spectral images of seed samples under different single-wavelength light sources.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will become apparent from the following description or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a device for detecting the content of mycotoxins in grains proposed in an embodiment of the utility model;

[0026] Figure 2 This is a front view of a device for detecting the content of mycotoxins in grains proposed in an embodiment of the utility model;

[0027] Figure 3It is a side view of a device for detecting the content of mycotoxins in grains proposed in an embodiment of the utility model;

[0028] Figure 4 It is a bottom view of a device for detecting the content of mycotoxins in grains proposed in an embodiment of the utility model;

[0029] Figure 5 It is a structural schematic diagram of an adjustable constant current circuit in an embodiment of the utility model;

[0030] Figure 6 It is a schematic diagram of the structure of the boost drive circuit in the embodiment of the utility model;

[0031] Figure 7 This is a schematic diagram of an adjustable boost constant current drive in an embodiment of the utility model;

[0032] Figure 8 This is a schematic diagram of the optical path structure of the photoelectric sensor for collecting light in the embodiment of the utility model;

[0033] Fig. 9 It is a schematic diagram of the LED free gating circuit structure in the embodiment of the utility model.

[0034] Description of reference numerals:

[0035] 1- Main housing; 2- Switch; 3- Display screen; 4- Lighting compartment; 5- LED light. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in combination with the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0037] like Figures 1 to 4 As shown, an embodiment of the utility model proposes a device for detecting the mycotoxin content in grains, the detection device comprising: a cylindrical main shell 1 and a truncated cone-shaped lighting chamber 4 located at the lower end of the main shell, the main shell 1 and the lighting chamber 4 are fastened with bolts to form a detachable structure; a spectral detection device is arranged inside the main shell 1, the small mouth end of the lighting chamber 4 is fastened to the main shell, and a stage is mounted on the lower end face of the large mouth end of the lighting chamber 4, a power supply circuit is arranged inside the stage, and a light source group with multiple wavelengths is evenly arranged along the bottom circumference, and every two light sources with the same wavelength are arranged symmetrically in the center; the stage is used to carry grain seed samples.

[0038] The power supply circuit includes a boost drive circuit and an adjustable constant current circuit. The input end of the boost drive circuit is connected to the input power supply, and the input end of the adjustable constant current circuit is connected to the boost drive signal output by the boost drive circuit. The light sources are connected in series and then connected to the output end of the adjustable constant current circuit. Figure 5 , Figure 7 The load end is shown (the drawings and ports of all circuit modules are given in the standard form of two-port networks).

[0039] In this embodiment, a truncated cone-shaped lighting chamber is provided, and a stage is installed at the large end of the lighting chamber, a power supply circuit and a light source group are arranged at the bottom of the stage, the light source group is composed of light sources with multiple wavelengths evenly arranged along the circumference of the bottom of the stage, and every two light sources with the same wavelength in the light source group are arranged symmetrically to the center. During detection, the power supply circuit is used to provide input current to the light source group to drive light sources of different wavelengths in the light source group to emit light, so that the spectral detection device can collect spectral images of seed samples under different single-wavelength light sources; and the designed detection device has a simple structure and is easy to use.

[0040] As a further preferred technical solution, Figure 5 As shown, the adjustable constant current circuit includes a three-terminal voltage regulator adjustment chip of model LM317L, and the input terminal VI of the three-terminal voltage regulator adjustment chip is connected to the boost drive signal output by the boost drive circuit; the output terminal VO of the three-terminal voltage regulator adjustment chip is connected to the designed variable resistor RV, and the other end of the variable resistor RV is connected to the current adjustment terminal ADJ to provide the required constant current source to the load (i.e., the LED lamp group).

[0041] The working principle of LM317L can be summarized as follows:

[0042] Adjustable output voltage: The output voltage of the LM317L can be adjusted between 1.2V and 37V by controlling external resistors and capacitors.

[0043] Feedback circuit: LM317L has a reference voltage circuit inside, which is usually limited to Vref = 1.25V, and the output voltage is set by the external resistor RS. When the input voltage changes, the feedback circuit adjusts the output voltage to keep it stable.

[0044] Current Regulation: When the LM317L is used as a current regulator, it can be achieved by connecting a fixed resistor between the regulation and the output. In this case, the output current of the LM317L can be calculated by the formula Io = 1.25 / RS.

[0045] Specifically, in this embodiment, a 15V test excitation source is added to the input end. Within the input current range of LM317L (such as 50mA), it can output a constant current of 100mA to 1A (acceptable output voltage 1.2V to 37V) with a small error. This is because LM317L, as a low-power device of LM317, uses three-stage linear voltage regulation. As the adjustment pin current Iadj, pin 3 (ADJ) only outputs a current of about 50μA. The current Io output by the load test end (LED lamp group):

[0046] Io=Is+Iadj=Vref / RS+Iadj

[0047] Where Is is the output current of the LM317L chip output terminal (out), I adj To adjust the pin (ADJ) current;

[0048] Within the allowable error range, the output current Io is approximately:

[0049] Io=Is=1.25 / RS

[0050] Therefore, the required 20mA constant current source can be obtained by limiting RS=62.5Ω. In this embodiment, RS is replaced by a variable resistor RV (maximum resistance 125Ω), so that the constant current source (0-40mA) can be freely adjusted.

[0051] The advantage of this constant current circuit is that it not only realizes stable control of the input current, but also utilizes the characteristics of three-stage linear voltage regulation to design variable resistors to achieve adjustable constant current value. Different from the most common BJT constant current source circuit, this circuit does not have the on-voltage requirement of the BJT constant current source circuit (the on-voltage requirement is lower) to achieve adjustable output current, which optimizes the shortcomings of BJT that are easy to be broken down and have large temperature effects. It is more free and reliable and reduces the energy consumption requirements of the power supply drive.

[0052] As a further preferred technical solution, Figure 6 As shown, the boost drive circuit includes an MC34063 chip, the pin SWC of the MC34063 chip is connected to one end of the energy storage inductor L, the pin DRC of the MC34063 chip is connected to the other end of the energy storage inductor L via a resistor R, the pin IPK of the MC34063 chip is respectively connected to the other end of the resistor R, and forms a current limiting protection with the resistor RSC, and the other end of the resistor RSC is connected to the power supply end of the MC34063 chip for peak current sampling;

[0053] The pin SWC of the MC34063 chip is also connected to the anode of the diode D1, the cathode of the diode D1 is grounded via the filter capacitor CO, the voltage sampling terminal CINV / COMP of the MC34063 chip is grounded via the resistor R1, a variable resistor RV1 is designed to be connected in series between one end of the resistor R1 and one end of the filter capacitor CO, a capacitor C1 is connected in series between the other end of the resistor R1 and the resistor R, and the pin CT of the MC34063 chip is connected to the timing capacitor;

[0054] The diode D1 and the filter capacitor CO serve as the output end of the boost driving circuit to output the boost driving signal.

[0055] Specifically, the boost drive circuit is based on the power chip MC34063, the positive power terminal V+ and the negative power terminal V- are internal switches, the emitter lead SWE of the switch tube Q1 is connected to the power supply to ensure that the switch tube Q1 inside the chip is turned on; pin 1 (i.e. SWC) is connected to the collector lead of the internal switch tube Q1 and the energy storage inductor L to ensure that the collector is turned on; pin 3 (i.e. CT) is connected to the timing capacitor; pin 5 (i.e. CINV / COMP) is used as the comparator inverting input terminal / output voltage sampling terminal; pin 7 (i.e. IPK) is connected to the peak current sampling terminal and the internal oscillator; pin 8 (i.e. DRC) is the collector lead of the internal switch tube Q1 and the switch tube Q2.

[0056] The internal comparator reference source voltage of the MC34063 power chip is 1.25V: Vout = 1.25*(1+RV1 / R1). The operating parameters of the circuit are: operating frequency 33kHz; theoretical output current value 50mA; theoretical ripple voltage value 100mV(pp); theoretical peak current IPK = 360mA.

[0057] Preferably, the protection diode D1 may be a voltage regulator diode.

[0058] As described above, the output and input of the boost driving circuit and the adjustable constant current circuit are connected to obtain an adjustable boost constant current source for power supply amplification and adjustable control. Figure 7 As shown, the current source can be used to stably drive the LED, and the gating of LED drivers of different wavelengths needs to be implemented through a gating circuit module, such as Fig. 9 As shown:

[0059] The four-bit 16-to-1 selection module is mainly controlled by a 74HC4067 multiplexing chip. It has a common signal input terminal X, five control terminals (low-level effective enable terminal EN, high and low bit control signal DCBA) and sixteen selection output lines (X0~X15); the principle and structure of the selection module circuit are very simple. The four control signals DCBA are effective at high levels. As the high-to-low bit connection switch in the binary system, it can control the selection of the sixteen output lines X0~X15 from 0000~1111, thereby outputting the signal in X.

[0060] Connecting the adjustable boost constant current source to the gating circuit X, i.e. the input end, can achieve stable LED gating emission.

[0061] As a further preferred technical solution, the light source adopts an LED lamp, which has the characteristics of high luminous efficiency, small size and long life.

[0062] As a further preferred technical solution, the light source group includes light sources having wavelengths of 470nm, 505nm, 525nm, 570nm, 590nm, 630nm, 645nm, 660nm, 700nm, 780nm, 850nm, 870nm, 890nm, 910nm, 940nm and 970nm.

[0063] In this embodiment, LED lamps with 16 wavelengths are arranged at the bottom of the stage, and every two LED lamps with the same wavelength are placed diagonally, that is, 32 LED lamps are evenly arranged along the circumference of the bottom of the stage, so as to provide light sources with multiple wavelengths for the seed samples.

[0064] As a further preferred technical solution, the spectrum detection device includes a photoelectric sensor module and an image collector, and the photoelectric sensor module includes an InGaAs photodiode, a photoelectric signal amplification circuit and an AD signal acquisition circuit;

[0065] The output of the InGaAs photodiode is connected to the AD signal acquisition circuit via the photoelectric signal amplification circuit, and the output of the AD signal acquisition circuit is connected to the image collector.

[0066] It should be noted that the light source group emits near-infrared light to illuminate the seed sample to be tested, and the photodiode collects the signal reflected by the seed sample to be tested to complete the photoelectric conversion, and the photoelectric signal amplification circuit converts the uA-level weak current signal into a mV-level voltage signal, which is converted into a digital signal through the AD signal acquisition circuit and then sent to the image acquisition device.

[0067] The photodiode used in this embodiment is a semiconductor element composed of a PN structure, and also has the characteristic of unidirectional conduction. The photodiode works under the action of reverse voltage. When there is no light, the reverse current is very weak, called dark current; when there is light, the reverse current quickly increases to tens of microamperes, becoming photocurrent. The greater the intensity of light, the greater the reverse current. The change of light causes the change of photodiode current, thereby realizing the conversion of optical signal into electrical signal.

[0068] As a further preferred technical solution, Figure 8 As shown, a spectroscopic element and a lens are also arranged inside the main housing. The spectroscopic element is arranged at the bottom of the lighting chamber using a high-pass filter, and a lens is arranged at the top opening of the main housing;

[0069] Preferably, the light splitting element is a high-pass filter.

[0070] In this embodiment, the spectroscopic element is provided to filter out noise wavelengths, and then the light reflected by the sample to be tested is focused onto the photodiode through a focusing lens.

[0071] As a further preferred technical solution, an image collector is arranged at the top opening of the lighting chamber, and the image collector adopts a CCD camera.

[0072] As a further preferred technical solution, Figure 1 As shown, a switch 2 is provided in the middle of the side wall of the main shell for controlling the start and shut down of the device, and a display screen 3 is embedded in the observation window for connecting a CCD camera to display the photoelectric data received by the camera.

[0073] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0074] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0075] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A device for detecting the content of mycotoxins in grains, characterized in that: The detection device comprises: a cylindrical main shell and a truncated cone-shaped lighting chamber located at the lower end of the main shell, a spectrum detection device is arranged inside the main shell, the small end of the lighting chamber is fastened to the main shell, and a stage is installed on the lower end surface of the large end of the lighting chamber, a power supply circuit is arranged inside the stage, and a light source group with multiple wavelengths is evenly arranged along the bottom circumference, and every two light sources with the same wavelength are arranged symmetrically at the center; the stage is used to carry grain seed samples; The power supply circuit includes a boost drive circuit and an adjustable constant current circuit, the input end of the boost drive circuit is connected to an input power supply, the input end of the adjustable constant current circuit is connected to a boost drive signal output by the boost drive circuit, and each of the light sources is connected in series to the output end of the adjustable constant current circuit.

2. The device for detecting the mycotoxin content in grain according to claim 1, characterized in that: The adjustable constant current circuit includes a voltage stabilizing adjustment chip of model LM317L, the input terminal VI of the voltage stabilizing adjustment chip is connected to an input power supply, the output terminal VO of the voltage stabilizing adjustment chip is connected to one end of a variable resistor RV, a capacitor C2 is connected in series between the other end of the variable resistor RV and the input end of the voltage stabilizing adjustment chip, and the adjustment terminal ADJ of the voltage stabilizing adjustment chip is connected to a load end.

3. The device for detecting the mycotoxin content in grain according to claim 1, characterized in that: The boost drive circuit includes an MC34063 chip, wherein a pin SWC of the MC34063 chip is connected to one end of an energy storage inductor L, a pin DRC of the MC34063 chip is connected to the other end of the energy storage inductor L via a resistor R, a pin IPK of the MC34063 chip is respectively connected to the other end of the resistor R and one end of the resistor RSC, and the other end of the resistor RSC is connected to the positive power supply terminal V+ of the MC34063 chip; The pin SWC of the MC34063 chip is also connected to the anode of the diode D1, the cathode of the diode D1 is grounded via the capacitor CO, the voltage sampling terminal CINV / COMP of the MC34063 chip is grounded via the resistor R1, a variable resistor RV1 is connected in series between one end of the resistor R1 and one end of the capacitor CO, a capacitor C1 is connected in series between the other end of the resistor R1 and the resistor R, and the pin CT of the MC34063 chip is connected to a timing capacitor; Each of the light sources is connected in series between the cathode of the diode D1 and the other end of the capacitor CO.

4. The device for detecting the mycotoxin content in grain according to claim 1, characterized in that: The light source is an LED lamp.

5. The device for detecting the content of mycotoxins in grains according to claim 1, characterized in that: The light source group includes light sources having wavelengths of 435nm, 450nm, 470nm, 505nm, 525nm, 570nm, 590nm, 630nm, 645nm, 660nm, 700nm, 780nm, 850nm, 870nm, 890nm, 910nm, 940nm and 970nm.

6. The device for detecting the mycotoxin content in grains according to claim 1, characterized in that: The spectrum detection device includes a photoelectric sensor module and an image collector, and the photoelectric sensor module includes an InGaAs photodiode, a photoelectric signal amplification circuit and an AD signal acquisition circuit; The output of the InGaAs photodiode is connected to the AD signal acquisition circuit via the photoelectric signal amplification circuit, and the output of the AD signal acquisition circuit is connected to the image collector.

7. The device for detecting the mycotoxin content in grains according to claim 6, characterized in that: A beam splitter element and a lens are also arranged inside the main housing. The beam splitter element is arranged at the bottom of the lighting chamber using a high-pass filter, and a lens is arranged at the top opening of the main housing.

8. The device for detecting the mycotoxin content in grains according to claim 7, characterized in that: The light splitting element adopts a high-pass filter.

9. The device for detecting the mycotoxin content in grains according to claim 1, characterized in that: An observation window is provided on the side wall of the main shell, and a display screen is embedded in the observation window.

10. The device for detecting the content of mycotoxins in grains according to claim 6, characterized in that: An image collector is arranged at the top opening of the main housing, and the image collector adopts a CCD camera.

Images