Tobacco leaf moisture content detection system

Abstract

The invention relates to a tobacco leaf moisture content detection system and method, a TYPE-C5V or 3.7 V lithium battery is used for supplying power, and after being powered on, the system is automatically initialized and a WiFi hotspot is created. After a hot spot is connected, the system enters a calibration mode, a zero reference is established through a short-circuit electrode clamp, and recalibration is prompted if the resistance value is abnormal. After calibration is completed, the system is switched to a measurement mode, and two options of rapid detection and continuous detection are provided. After the electrode clamp is in contact with a tobacco leaf, the constant-voltage and voltage-dividing resistance measuring circuit works, the 24-bit ADC sampling circuit performs high-precision sampling, and the microcontroller converts a resistance value into a moisture content percentage. In the rapid detection mode, measurement is completed within 1-2 seconds, and a result is displayed; in the continuous detection mode, data are displayed in real time and trend analysis is carried out. All the modules work cooperatively, it is ensured that the detection process is non-destructive, high in precision and intelligent, and an efficient solution is provided for tobacco leaf moisture content detection.

Description

Technical Field

[0001] This invention belongs to the field of tobacco leaf testing technology, and in particular relates to a tobacco leaf moisture content testing system. Background Technology

[0002] Moisture content of tobacco leaves is a key indicator affecting tobacco quality and processing technology. Accurate and rapid moisture content detection is of great significance for the storage, transportation, grading, and processing of tobacco leaves. Commonly used methods for detecting the moisture content of tobacco leaves include gas chromatography, near-infrared spectroscopy, and Karl Fischer-furnace method. However, these methods are time-consuming, have a small measurement range, and are difficult to intuitively reflect the moisture distribution on the surface of tobacco leaves.

[0003] Traditional methods for determining the moisture content of tobacco leaves primarily employ the drying method and the Karl Fischer method. While the Karl Fischer method is the most specific and accurate method for determining moisture content among various chemical methods, and has been adopted as the standard method for moisture determination in many substances, it requires the consumption of chemical reagents, all containers must be dried, and the reagent becomes ineffective if 6g of water is mixed into 1L of Karl Fischer reagent during preparation and storage. The method is also complex and can cause some environmental pollution. Although the drying method is relatively simple to operate, many substances are unstable under heating conditions, and the detection time is relatively long, failing to meet the needs for rapid detection.

[0004] Near-infrared spectroscopy, a technology developed in recent years, has been widely used in tobacco leaf testing. Near-infrared spectroscopy analysis is a green analysis technology that is environmentally friendly and does not require chemical reagents, as it involves simple sample pretreatment. However, the equipment used in this technology is expensive, and it requires the establishment of complex spectral databases and calibration models. Furthermore, it is prone to errors when changing tobacco varieties or when the leaves have poor expansibility.

[0005] Plants are living organisms and are dielectrics between conductors and insulators. Water content is the most important factor affecting the dielectric properties of plants. Water content detection based on resistance method has advantages such as simple equipment, low cost and fast response. However, the traditional resistance method has limited measurement accuracy and is easily affected by contact resistance and environmental factors.

[0006] Furthermore, existing moisture content testing equipment generally suffers from insufficient data recording and management functions. Most can only perform single measurements and display instantaneous results, lacking historical data storage, trend analysis, and remote monitoring capabilities, thus failing to meet the requirements of modern tobacco processing for end-to-end quality traceability and intelligent management. At the same time, these devices have relatively fixed functions and poor scalability, making it difficult to upgrade or customize them to meet the needs of different application scenarios. Therefore, existing technologies still have significant shortcomings in improving the speed, accuracy, intelligence, and system scalability of tobacco moisture content testing. Summary of the Invention

[0007] (a) Purpose of the invention To overcome the above shortcomings, the purpose of this invention is to provide a tobacco leaf moisture content detection system to solve the aforementioned technical problems.

[0008] (II) Technical Solution To achieve the above objectives, the technical solution provided in this application is as follows: A tobacco leaf moisture content detection system includes electrode clips, a constant voltage divider resistance measurement circuit, a 24-bit ADC sampling circuit, a microcontroller control circuit, and a power supply circuit. The electrode clips are used to hold tobacco leaves and establish an electrical connection; The constant voltage divider resistance measurement circuit includes a 2.5V constant voltage circuit and a standard resistor. The blade resistance value is calculated by measuring the voltage divider on the resistor to be measured. The 24-bit ADC sampling circuit performs high-precision sampling of the voltage signal; The microcontroller control circuit processes the sampled data and accurately converts the resistance value into water content based on the relationship between plant resistance and water content using a built-in resistance-water content algorithm. The microcontroller control circuit integrates WiFi wireless communication functionality, enabling data display and device control via a web page.

[0009] Preferably, the resistance-moisture content algorithm is based on a mathematical model showing a negative correlation between plant resistance and water content. Through preset conversion coefficients and compensation parameters, the measured leaf resistance value is converted into a corresponding water content percentage. The conversion formula is as follows: Where MC is the moisture content, R is the measured resistance value, T is the temperature compensation factor, and K is the tobacco variety correction coefficient.

[0010] Preferably, the specific steps for converting the measured leaf resistance value into the corresponding water content percentage include: The S1 resistance-moisture content algorithm receives resistance measurement data R from the 24-bit ADC sampling circuit 3; S2 calculates the temperature compensation factor T based on the built-in temperature compensation model to eliminate the influence of ambient temperature on resistance measurement. S3 determines the variety correction coefficient K based on the preset tobacco variety type to adapt to the differences in electrical resistance characteristics of different tobacco varieties. S4 uses mathematical models Calculate the corresponding moisture content percentage.

[0011] The conversion coefficients and compensation parameters were established based on experimental data from a large number of tobacco leaf samples. They cover the resistivity characteristics of common tobacco leaf varieties under different moisture contents and also have adaptive capabilities. The calculation parameters can be dynamically adjusted according to the measurement environment and sample characteristics to ensure accurate conversion within the accuracy range of 0.5%-1%.

[0012] Preferably, the conversion formula includes temperature compensation and variety correction functions, which can dynamically adjust the calculation parameters according to the measurement environment and tobacco variety characteristics. An integrated temperature sensor monitors the ambient temperature in real time and calculates a temperature compensation factor based on a preset temperature coefficient α. in For actual measured temperature, By standardizing the measured resistance value to the reference temperature, the influence of temperature changes on the resistance measurement is eliminated. The microcontroller control circuit has a built-in tobacco variety characteristic database that stores the resistance characteristic parameters of different varieties. Users can select tobacco varieties through the web interface or the system can automatically identify the variety type based on the initial resistance characteristics and determine the corresponding variety correction coefficient K. This coefficient is calculated based on the resistance ratio of the standard variety and the current variety under the same moisture content conditions, thus realizing the standardization of measurement between different varieties.

[0013] Preferably, the power supply circuit supports two power supply methods: TYPE-C 5V power supply and 3.7V lithium battery power supply. It is also equipped with a power indicator LED. When the power is on, the green LED is constantly lit to indicate that the device is working normally.

[0014] Preferably, the microcontroller control circuit creates a WiFi hotspot, and a web operation interface automatically pops up after the user device connects. The web interface has calibration function, test mode selection function and data display function.

[0015] Preferably, the electrode clip is an alligator clip structure, which is connected to the constant voltage divider resistance measuring circuit through a wire. The web interface prompts for calibration upon first use. During calibration, the electrode clip needs to be short-circuited, and normal measurement can only be performed after zero-point calibration is completed.

[0016] Preferably, the web interface provides two working modes: a fast detection mode and a continuous detection mode. The fast detection mode completes a single measurement within 1-2 seconds and directly displays the moisture content result through algorithm conversion. The continuous detection mode performs continuous measurements at set time intervals and displays the moisture content change trend through charts.

[0017] Preferably, an SD card storage interface is also provided for storing the original measurement data and the converted moisture content data. When no SD card is inserted, the system saves the latest 100 measurement records.

[0018] Preferably, the measuring positions of the electrode clips are at both sides of the widest part of the cross-section of the tobacco leaf, ensuring good electrical contact with the leaf surface.

[0019] A method for detecting the moisture content of tobacco leaves, specifically including the following steps: Step 1: Connect the power supply. The power indicator LED will light up and remain constantly lit. Step 2: After the microcontroller control circuit is powered on, it performs a 5-second initialization, activates the WiFi module, creates a passwordless hotspot, and starts the web server program; Step 3: After the external device connects to the WiFi hotspot, the microcontroller pushes the web operation interface to the client, and the system enters calibration mode; Step 4: The web interface sends a command to short-circuit the electrode clips. After the electrode clips are short-circuited, the constant voltage divider resistance measuring circuit detects a near-zero resistance signal. Step 5: The 24-bit ADC sampling circuit samples the signal, and the microcontroller establishes a zero-point reference based on the sampling results to complete the calibration. If the resistance value is abnormal, the calibration is repeated. Step 6: After calibration, the web interface displays a tobacco variety selection menu, including options for Yunyan 87, K326, Hongda, or other common varieties. The user selects the corresponding tobacco variety, and the microcontroller loads the correction coefficient K and related resistance characteristic parameters of the variety from the built-in database. At the same time, the system activates the temperature sensor, starts to monitor the ambient temperature in real time, and calculates the temperature compensation factor T. After the settings are completed, the web interface displays two modes: fast detection and continuous detection. Step 7: After the electrode clips contact the two sides of the widest part of the cross-section of the tobacco leaf, the constant voltage divider resistance measuring circuit works. The 2.5V constant voltage circuit provides a stable voltage and forms a voltage divider circuit. Step 8: The 24-bit ADC sampling circuit performs high-precision sampling of the voltage divider signal and transmits the data to the microcontroller; Step 9: In rapid detection mode, the microcontroller controls the measurement process, runs the resistance-moisture content conversion algorithm, completes the measurement within 1-2 seconds, and transmits the result to the web interface for display; Step 10: In continuous detection mode, the microcontroller cyclically controls the operation of each module at preset time intervals, and the measurement data is displayed in real time and trend analysis is performed; Step 11: The microcontroller is responsible for data storage management. When an SD card is detected, it stores data to the SD card. When no SD card is detected, it enables memory storage mode and retains the latest 100 records.

[0020] Beneficial effects: 1. High measurement accuracy: It adopts the constant voltage divider resistance measurement principle combined with 24-bit ADC sampling and dedicated conversion algorithm, avoiding the influence of ammeter internal resistance and contact resistance interference. Through a precise resistance-moisture content conversion model, the measurement accuracy reaches 0.5%-1%, which is significantly better than the traditional resistance method.

[0021] 2. Precise Algorithm Conversion: Built-in dedicated resistance-moisture conversion algorithm, based on a scientific relationship model between plant resistance and water content, can accurately convert resistance measurements into moisture content percentage, eliminating the errors and complexity of manual conversion.

[0022] 3. Simple and quick operation: No chemical reagents or complicated pretreatment are required. It can be operated by connecting via WiFi hotspot. The rapid detection is completed in 1-2 seconds and the moisture content result is automatically displayed, which greatly improves the detection efficiency.

[0023] 4. High level of intelligence: It integrates WiFi communication and web interface, supports wireless operation and real-time data display, and has automatic calibration and multiple test modes, providing a user-friendly experience.

[0024] 5. Comprehensive data management: Supports continuous monitoring and historical data recording, and displays the trend of moisture content changes intuitively through charts, facilitating quality traceability and process control.

[0025] 6. High scalability: It reserves software and hardware interfaces, and can add threshold alarms, automatic control and other functions as needed to adapt to different application scenarios.

[0026] 7. Non-destructive testing: Measurements can be completed with slight contact of the electrode clips without damaging the blades, and the same sample can be tested repeatedly.

[0027] 8. High portability: Supports lithium battery power supply, and the miniaturized design of the device is suitable for on-site and mobile testing needs. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of the invention.

[0029] Example 1 This invention provides a tobacco leaf moisture content detection system, comprising electrode clips, a constant voltage divider resistance measurement circuit, a 24-bit ADC sampling circuit, a microcontroller control circuit, and a power supply circuit. The electrode clips are used to hold tobacco leaves and establish an electrical connection; The constant voltage divider resistance measurement circuit includes a 2.5V constant voltage circuit and a standard resistor. The blade resistance value is calculated by measuring the voltage divider on the resistor to be measured. The 24-bit ADC sampling circuit performs high-precision sampling of the voltage signal; The microcontroller control circuit processes the sampled data and accurately converts the resistance value into water content based on the relationship between plant resistance and water content using a built-in resistance-water content algorithm. The microcontroller control circuit integrates WiFi wireless communication functionality, enabling data display and device control via a web page.

[0030] Preferably, the resistance-moisture content algorithm is based on a mathematical model showing a negative correlation between plant resistance and water content. Through preset conversion coefficients and compensation parameters, the measured leaf resistance value is converted into a corresponding water content percentage. The conversion formula is as follows: Where MC is the moisture content, R is the measured resistance value, T is the temperature compensation factor, and K is the tobacco variety correction coefficient.

[0031] Preferably, the specific steps for converting the measured leaf resistance value into the corresponding water content percentage include: The S1 resistance-moisture content algorithm receives resistance measurement data R from the 24-bit ADC sampling circuit 3; S2 calculates the temperature compensation factor T based on the built-in temperature compensation model to eliminate the influence of ambient temperature on resistance measurement. S3 determines the variety correction coefficient K based on the preset tobacco variety type to adapt to the differences in electrical resistance characteristics of different tobacco varieties. S4 uses mathematical models Calculate the corresponding moisture content percentage.

[0032] The conversion coefficients and compensation parameters were established based on experimental data from a large number of tobacco leaf samples. They cover the resistivity characteristics of common tobacco leaf varieties under different moisture contents and also have adaptive capabilities. The calculation parameters can be dynamically adjusted according to the measurement environment and sample characteristics to ensure accurate conversion within the accuracy range of 0.5%-1%.

[0033] Preferably, the conversion formula includes temperature compensation and variety correction functions, which can dynamically adjust the calculation parameters according to the measurement environment and tobacco variety characteristics. An integrated temperature sensor monitors the ambient temperature in real time and calculates a temperature compensation factor based on a preset temperature coefficient α. in For actual measured temperature, By standardizing the measured resistance value to the reference temperature, the influence of temperature changes on the resistance measurement is eliminated. The microcontroller control circuit has a built-in tobacco variety characteristic database that stores the resistance characteristic parameters of different varieties. Users can select tobacco varieties through the web interface or the system can automatically identify the variety type based on the initial resistance characteristics and determine the corresponding variety correction coefficient K. This coefficient is calculated based on the resistance ratio of the standard variety and the current variety under the same moisture content conditions, thus realizing the standardization of measurement between different varieties.

[0034] Preferably, the power supply circuit supports two power supply methods: TYPE-C 5V power supply and 3.7V lithium battery power supply. It is also equipped with a power indicator LED. When the power is on, the green LED is constantly lit to indicate that the device is working normally.

[0035] Preferably, the microcontroller control circuit creates a WiFi hotspot, and a web operation interface automatically pops up after the user device connects. The web interface has calibration function, test mode selection function and data display function.

[0036] Preferably, the electrode clip is an alligator clip structure, which is connected to the constant voltage divider resistance measuring circuit through a wire. The web interface prompts for calibration upon first use. During calibration, the electrode clip needs to be short-circuited, and normal measurement can only be performed after zero-point calibration is completed.

[0037] Preferably, the web interface provides two working modes: a fast detection mode and a continuous detection mode. The fast detection mode completes a single measurement within 1-2 seconds and directly displays the moisture content result through algorithm conversion. The continuous detection mode performs continuous measurements at set time intervals and displays the moisture content change trend through charts.

[0038] Preferably, an SD card storage interface is also provided for storing the original measurement data and the converted moisture content data. When no SD card is inserted, the system saves the latest 100 measurement records.

[0039] Preferably, the measuring positions of the electrode clips are at both sides of the widest part of the cross-section of the tobacco leaf, ensuring good electrical contact with the leaf surface.

[0040] A method for detecting the moisture content of tobacco leaves, specifically including the following steps: Step 1: After receiving TYPE-C 5V power or 3.7V lithium battery power, the power supply circuit provides a stable power supply to the entire system, and the power indicator LED will light up and remain constantly lit.

[0041] Step 2: After power-on, the microcontroller control circuit initializes for 5 seconds, activates the built-in WiFi module, automatically creates a passwordless hotspot, and starts the web server program.

[0042] Step 3: When an external device connects to the WiFi hotspot, the microcontroller control circuit automatically pushes the web operation interface to the client.

[0043] Step 4: The system first enters calibration mode, and the web interface issues a command to short-circuit the electrode clips. When the two clips of the electrode clips are short-circuited, the constant voltage divider resistance measuring circuit 2 detects a signal close to zero resistance.

[0044] Step 5: The 24-bit ADC sampling circuit samples this signal, and the microcontroller control circuit establishes a zero-point reference based on the sampling results to complete system calibration. If an abnormal resistance value is detected, the microcontroller control circuit will issue a recalibration command through the web interface until the zero-point calibration is successful.

[0045] Step 6: After calibration, the web interface displays a tobacco variety selection menu, including options for Yunyan 87, K326, Hongda, or other common varieties. The user selects the corresponding tobacco variety, and the microcontroller loads the correction coefficient K and related resistance characteristic parameters of the variety from the built-in database. At the same time, the system activates the temperature sensor, starts to monitor the ambient temperature in real time, and calculates the temperature compensation factor T. After the settings are completed, the web interface displays two modes: fast detection and continuous detection. Step 7: After the electrode clip 6 makes electrical contact with the two sides of the widest part of the cross-section of the tobacco leaf, the constant voltage divider resistance measuring circuit starts to work. Its 2.5V constant voltage circuit provides a stable voltage, and the standard resistor and the leaf resistance form a voltage divider circuit.

[0046] Step 8: The 24-bit ADC sampling circuit 3 performs high-precision sampling of the voltage divider signal and transmits the sampled data to the microcontroller control circuit.

[0047] Step 9: In the fast detection mode, the microcontroller control circuit controls the entire measurement process: the constant voltage divider resistance measurement circuit completes the resistance measurement, the 24-bit ADC sampling circuit samples the signal, and the microcontroller control circuit 4 runs the built-in resistance-moisture content conversion algorithm to convert the resistance value into a moisture content percentage. The whole process is completed within 1-2 seconds, and the result is transmitted to the web interface for display via the WiFi module.

[0048] Step 10: In continuous detection mode, the microcontroller control circuit controls each module to work in a cycle according to a preset time interval. Each measurement data is not only displayed in real time, but is also processed into a chart format for trend analysis.

[0049] Step 11: The microcontroller control circuit 4 is also responsible for data storage management. When an SD card is detected inserted into the SD card storage interface, both the original resistance data and the converted moisture content data are stored on the SD card. When no SD card is detected, the system automatically enables the memory storage mode and retains only the latest 100 measurement records.

[0050] Throughout the entire process, the various circuit modules work together: the power supply circuit ensures stable system operation, the constant voltage divider resistance measurement circuit and the 24-bit ADC sampling circuit are responsible for high-precision signal acquisition, and the microcontroller control circuit undertakes core functions such as data processing, algorithm conversion, WiFi communication and storage management, realizing non-destructive, high-precision and intelligent detection of tobacco leaf moisture content.

[0051] Example 2 This embodiment provides a tobacco leaf moisture content detection system, the structure and working principle of which are as described in Embodiment 1. It includes key components such as a power supply circuit, a microcontroller control circuit, a constant voltage divider resistance measurement circuit, a 24-bit ADC sampling circuit, a WiFi module, and an SD card storage interface, which can achieve high-precision, non-destructive detection of tobacco leaf moisture content.

[0052] Experimental conditions Environmental conditions: Temperature 30°C ± 2°C, humidity 70% ± 5%, atmospheric pressure 101.3 kPa ± 0.5 kPa.

[0053] Tobacco leaf samples: The main tobacco variety "Zhongyan 100" planted in the experimental area was selected as the test object. Tobacco leaves from the main stages of flue-cured tobacco production were selected: fresh tobacco leaves harvested in the field (A), tobacco leaves with a dry head temperature of 42℃ (yellowing stage) (B), tobacco leaves with a dry head temperature of 50℃ (color fixation stage) (C), and tobacco leaves after curing (D), for a total of 4 groups of samples. Ten tobacco leaves were randomly selected from each group at the experimental site.

[0054] Equipment: This system, standard moisture content testing instrument, drying oven, and thousandths balance.

[0055] Experimental process Calibration: Connect the system to a power source, power on the device and connect to a WiFi hotspot. Follow the instructions on the web interface to short-circuit the electrode clips to perform calibration.

[0056] Measurement: The electrode clips are clamped to both sides of the widest part of the cross-section of each tobacco leaf, and rapid and continuous tests are performed in sequence. Each type of tobacco leaf is measured 10 times.

[0057] Non-destructive testing verification: Before and after measurement, compare and observe the degree of damage to tobacco leaves caused by the instrument, and record the damage ratio.

[0058] Data recording: Record the percentage of moisture content for each measurement, and remeasure the moisture content of each tobacco leaf in the laboratory using the drying method, and record the standard moisture content value.

[0059] Experimental results Quick detection mode: Field-harvested fresh tobacco leaves (A): average moisture content 85.2% ± 1%, standard moisture content 85%, error ± 0.2%.

[0060] Tobacco leaves (B) with a dry bulb temperature of 42℃ (yellowing stage): average moisture content 67.2%±0.4%, standard moisture content 66.9%, error ±0.3%.

[0061] Tobacco leaves at a dry bulb temperature of 50℃ (during color fixation period) (C): average moisture content 50.2%±0.4%, standard moisture content 50.1%, error ±0.1%.

[0062] Cured tobacco leaves (D): average moisture content 17.1% ± 0.4%, standard moisture content 17.0%, error ± 0.1%.

[0063] Continuous detection mode: Field-harvested fresh tobacco leaves (A): The moisture content of 10 measurements fluctuated between 84.2% and 86.2%, with an average moisture content of 85.2% and a standard moisture content of 85.0%, with an error of ±0.2%.

[0064] Tobacco leaves (B) with a dry bulb temperature of 42℃ (yellowing stage): The moisture content of the 10 measured tobacco leaves fluctuated between 66.8% and 67.6%, with an average moisture content of 67.2% and a standard moisture content of 66.9%, with an error of ±0.3%.

[0065] Tobacco leaves at a dry bulb temperature of 50℃ (during color fixation period) (C): The moisture content of the 10 measured tobacco leaves fluctuated between 49.8% and 50.6%, with an average moisture content of 50.2% and a standard moisture content of 50.1%, with an error of ±0.1%.

[0066] Cured tobacco leaves (D): The moisture content of 10 measurements fluctuated between 16.7% and 17.5%, with an average moisture content of 17.1% and a standard moisture content of 17%, with an error of ±0.1%.

[0067] Non-destructive testing verification: Before and after the measurement, no obvious damage was found in any of the leaves. The instrument did not cause any visible damage to the tobacco leaves and had no impact on the determination of the tobacco leaf purchase grade, which proved the non-destructive testing capability of this system.

[0068] Experimental conclusions This system demonstrates good accuracy, stability, and convenience under different conditions. Furthermore, through non-destructive testing, it ensures that the tobacco leaves are not damaged during the testing process, proving its superiority and practicality in real-world applications.

[0069] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0070] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tobacco leaf moisture content detection system, characterized in that, It includes electrode clips, a constant voltage divider resistance measurement circuit, a 24-bit ADC sampling circuit, a microcontroller control circuit, and a power supply circuit. The electrode clips are used to hold tobacco leaves and establish an electrical connection; The constant voltage divider resistance measurement circuit includes a 2.5V constant voltage circuit and a standard resistor. The blade resistance value is calculated by measuring the voltage divider on the resistor to be measured. The 24-bit ADC sampling circuit performs high-precision sampling of the voltage signal; The microcontroller control circuit processes the sampled data and accurately converts the resistance value into water content based on the relationship between plant resistance and water content using a built-in resistance-water content algorithm. The microcontroller control circuit integrates WiFi wireless communication functionality, enabling data display and device control via a web page.

2. The tobacco leaf moisture content detection system according to claim 1, characterized in that, The resistance-moisture content algorithm is based on a mathematical model showing a negative correlation between plant resistance and moisture content. Through preset conversion coefficients and compensation parameters, it converts the measured leaf resistance values ​​into corresponding moisture content percentages. The conversion formula is as follows: ； Where MC is the moisture content, R is the measured resistance value, T is the temperature compensation factor, and K is the tobacco variety correction coefficient.

3. The tobacco leaf moisture content detection system according to claim 2, characterized in that, The specific steps for converting the measured leaf resistance value into the corresponding water content percentage include: The S1 resistance-moisture content algorithm receives resistance measurement data R from the 24-bit ADC sampling circuit 3; S2 calculates the temperature compensation factor T based on the built-in temperature compensation model to eliminate the influence of ambient temperature on resistance measurement. S3 determines the variety correction coefficient K based on the preset tobacco variety type to adapt to the differences in electrical resistance characteristics of different tobacco varieties. S4 uses mathematical models Calculate the corresponding moisture content percentage; The conversion coefficients and compensation parameters were established based on experimental data from a large number of tobacco leaf samples. They cover the resistivity characteristics of common tobacco leaf varieties under different moisture contents and also have adaptive capabilities. The calculation parameters can be dynamically adjusted according to the measurement environment and sample characteristics to ensure accurate conversion within the accuracy range of 0.5%-1%.

4. The tobacco leaf moisture content detection system according to claim 2, characterized in that, The conversion formula includes temperature compensation and variety correction functions, which can dynamically adjust the calculation parameters according to the measurement environment and tobacco variety characteristics. An integrated temperature sensor monitors the ambient temperature in real time and calculates a temperature compensation factor based on a preset temperature coefficient α. ； in For actual measured temperature, By standardizing the measured resistance value to the reference temperature, the influence of temperature changes on the resistance measurement is eliminated. The microcontroller control circuit has a built-in tobacco variety characteristic database that stores the resistance characteristic parameters of different varieties. Users can select tobacco varieties through the web interface or the system can automatically identify the variety type based on the initial resistance characteristics and determine the corresponding variety correction coefficient K. This coefficient is calculated based on the resistance ratio of the standard variety and the current variety under the same moisture content conditions, thus realizing the standardization of measurement between different varieties.

5. The tobacco leaf moisture content detection system according to claim 1, characterized in that, The power supply circuit supports two power supply methods: TYPE-C 5V power supply and 3.7V lithium battery power supply. It also has a power indicator LED. When the power is on, the green LED is constantly lit to indicate that the device is working normally.

6. The tobacco leaf moisture content detection system according to claim 1, characterized in that, The microcontroller control circuit creates a WiFi hotspot. After a user device connects, a web operation interface automatically pops up. The web interface has calibration function, test mode selection function, and data display function.

7. The tobacco leaf moisture content detection system according to claim 1, characterized in that, The electrode clip is an alligator clip structure and is connected to the constant voltage divider resistance measuring circuit via wires. The web interface prompts for calibration upon first use. During calibration, the electrode clip must be short-circuited. Normal measurement can only be performed after zero-point calibration is completed. The measurement position of the electrode clip is on both sides of the widest part of the tobacco leaf cross-section to ensure good electrical contact with the leaf surface.

8. The tobacco leaf moisture content detection system according to claim 7, characterized in that, The web interface provides two working modes: a fast detection mode and a continuous detection mode. The fast detection mode completes a single measurement within 1-2 seconds and directly displays the moisture content result through algorithm conversion. The continuous detection mode performs continuous measurements at set time intervals and displays the moisture content change trend through charts.

9. The tobacco leaf moisture content detection system according to claim 1, characterized in that, It also has an SD card storage interface for storing raw measurement data and converted moisture content data. When no SD card is inserted, the system saves the latest 100 measurement records.

10. A method for detecting the moisture content of tobacco leaves, characterized in that, A tobacco leaf moisture content detection system according to any one of claims 1-9, characterized in that it specifically includes the following steps: Step 1: Connect the power supply. The power indicator LED will light up and remain constantly lit. Step 2: After the microcontroller control circuit is powered on, it performs a 5-second initialization, activates the WiFi module, creates a passwordless hotspot, and starts the web server program; Step 3: After the external device connects to the WiFi hotspot, the microcontroller pushes the web operation interface to the client, and the system enters calibration mode; Step 4: The web interface sends a command to short-circuit the electrode clips. After the electrode clips are short-circuited, the constant voltage divider resistance measuring circuit detects a near-zero resistance signal. Step 5: The 24-bit ADC sampling circuit samples the signal, and the microcontroller establishes a zero-point reference based on the sampling results to complete the calibration. If the resistance value is abnormal, the calibration is repeated. Step 6: After calibration, the web interface displays a tobacco variety selection menu, including options for Yunyan 87, K326, Hongda, or other common varieties. The user selects the corresponding tobacco variety, and the microcontroller loads the correction coefficient K and related resistance characteristic parameters of the variety from the built-in database. At the same time, the system activates the temperature sensor, starts to monitor the ambient temperature in real time, and calculates the temperature compensation factor T. After the settings are completed, the web interface displays two modes: fast detection and continuous detection. Step 7: After the electrode clips contact the two sides of the widest part of the cross-section of the tobacco leaf, the constant voltage divider resistance measuring circuit works. The 2.5V constant voltage circuit provides a stable voltage and forms a voltage divider circuit. Step 8: The 24-bit ADC sampling circuit performs high-precision sampling of the voltage divider signal and transmits the data to the microcontroller; Step 9: In rapid detection mode, the microcontroller controls the measurement process, runs the resistance-moisture content conversion algorithm, completes the measurement within 1-2 seconds, and transmits the result to the web interface for display; Step 10: In continuous detection mode, the microcontroller cyclically controls the operation of each module at preset time intervals, and the measurement data is displayed in real time and trend analysis is performed; Step 11: The microcontroller is responsible for data storage management. When an SD card is detected, it stores data to the SD card. When no SD card is detected, it enables memory storage mode and retains the latest 100 records.

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