Real-time on-line moisture content measurement sensor for forest trees

Abstract

The utility model provides a real-time on-line moisture content measurement sensor for forest trees, which comprises a cylindrical variable-diameter shell, a sleeve is arranged in the front end of the cylindrical variable-diameter shell, a main control board is inserted in the sleeve, the main control board is provided with an RS458 transceiver circuit, a main control MCU, a signal modulation circuit and a signal demodulation circuit, a groove is arranged in the middle of the sleeve, and the signal demodulation circuit is arranged in the groove. The two ends of the sleeve are respectively surrounded by a copper ring, the two copper rings form a capacitor, the capacitor is respectively and electrically connected with the signal modulation circuit and the signal demodulation circuit, the signal modulation circuit and the signal demodulation circuit are respectively and electrically connected with the master control MCU, the master control MCU is electrically connected with the RS458 transceiver circuit, and the RS458 transceiver circuit is electrically connected with the RS458 transceiver circuit. And the output end of the RS458 transceiver circuit is connected with a traditional collector through a coaxial cable. The device can be installed in a forest tree body and is used for long-term on-line monitoring of moisture content change in the forest tree, and the accuracy of data is ensured by using a microwave principle FDR frequency domain reflection method.

Description

Technical Field

[0001] The utility model relates to the technical field of forest and grass monitoring, in particular to a sensor for measuring the moisture content of trees in real time online. Background Art

[0002] Moisture content monitoring methods have a long history of development, and there are many different methods for measuring moisture content in different industries. For example, agricultural soil moisture measurement methods include weighing method, tensiometer method, resistance method, neutron meter method, gamma-ray method, standing wave ratio method, optical measurement method, frequency domain reflection method, etc.

[0003] The methods for determining the moisture content of forests at home and abroad can be roughly divided into two categories: direct method and indirect method. The direct measurement method includes the drying and weighing method. The drying and weighing method is a method of measuring the moisture content of wood by drying the moisture content sample of wood until it is completely dry. It is the basic method for measuring the moisture content of wood and the most commonly used method. Its data is accurate, but it requires destructive sampling to measure, and it is impossible to remotely monitor the changes in the moisture content of forests that are constantly changing in nature. Indirect methods include electrical measurement, microwave method, optical method, and ray method. When the electrical measurement method determines the moisture content of wood, the measurement accuracy within the range of 28%-5% of the moisture content of wood is high. When the measured moisture content exceeds 28%, the measurement error is large. At the same time, when measuring online, the moisture content obtained must be converted to represent the actual moisture content of the wood. The optical method uses non-contact measurement and can only measure the moisture content on the surface of the material. The ray method has the advantages of fast detection speed, large detection range, and good penetration. It can quickly perform non-destructive detection on the distribution inside the wood, but the ray has radiation hazards and the equipment is expensive, which is not conducive to promotion and application.

[0004] Therefore, there is a need for a device that can measure the changes in moisture content in trees in real time online. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a sensor for measuring the moisture content of trees in real time online, so as to solve the problems existing in the prior art.

[0006] In order to solve the above technical problems, the utility model provides a sensor for real-time online measurement of moisture content of forest trees, comprising a cylindrical variable diameter shell, a sleeve is arranged in the front end of the cylindrical variable diameter shell, a main control board is inserted in the sleeve, the main control board has an RS458 transceiver circuit, a main control MCU, a signal modulation circuit and a signal demodulation circuit, a groove is arranged in the middle of the sleeve, a copper ring is respectively surrounded at both ends of the sleeve, and the two copper rings form a capacitor, the capacitor is electrically connected to the signal modulation circuit and the signal demodulation circuit respectively, the signal modulation circuit and the signal demodulation circuit are electrically connected to the main control MCU respectively, the main control MCU is electrically connected to the RS458 transceiver circuit, the output end of the RS458 transceiver circuit is connected to a coaxial cable, the coaxial cable extends from the end of the cylindrical variable diameter shell to the outside of the cylindrical variable diameter shell, and the cylindrical variable diameter shell is encapsulated with epoxy resin.

[0007] Preferably, the overall length of the cylindrical variable diameter housing is 155 mm and the wall thickness is 1.5 mm.

[0008] Preferably, the cylindrical variable diameter shell includes a detection section, a transition section and a variable diameter section arranged at the front end, the detection section has a diameter of 10 mm and a length of 125 mm, the transition section has a length of 10 mm, and the variable diameter section has a diameter of 20 mm and a length of 10 mm.

[0009] Preferably, the length of the copper ring is 20 mm, and the length of the groove is 10 mm.

[0010] Preferably, the copper ring is also connected to a thermistor for measuring the ambient temperature.

[0011] Preferably, the cylindrical variable diameter shell and the sleeve are ABS material tubes.

[0012] Compared with the prior art, the utility model has the following beneficial effects:

[0013] The sensor of the utility model is installed in the body of a tree (including living trees and dead trees in a natural state, and artificial standard wood) after drilling a hole with an electric drill. The front end of the sensor is mainly composed of two copper rings to form a capacitor, and the surrounding wood acts as a dielectric. The capacitor and the oscillator of the signal modulation circuit form a tuning circuit. Since the capacitance is proportional to the dielectric constant of the measured medium between the two levels, when the moisture in the medium (wood) increases, its dielectric constant increases accordingly, and the measured capacitance value also increases accordingly, resulting in a change in the measurement frequency. Therefore, the signal modulation circuit is controlled by the main control MCU, the signal modulation circuit transmits a sine wave to the copper ring and the signal demodulation circuit, the sine wave at the copper ring end returns to the signal demodulation circuit, and the signal demodulation circuit transmits a voltage signal to the main control MCU. The main control MCU measures the moisture content of the medium in combination with the data model and algorithm in the prior art. The RS458 transceiver circuit at the end of the sensor can be connected to a traditional collector through a coaxial cable to achieve long-term online monitoring of moisture content changes in the forest. The sensor of the utility model utilizes the microwave principle FDR frequency domain reflection method to obtain the moisture content of the wood according to the change of the frequency of electromagnetic wave propagation in the wood, thereby ensuring the accuracy of the data and being connectable to the traditional collector, with low cost and suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The sensor for measuring the moisture content of trees in real time online according to the utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0015] Figure 1 The utility model is a schematic diagram of the structure of a sensor for measuring the moisture content of trees in real time online.

[0016] Figure 2 This is a structural block diagram of the main control board of the utility model.

[0017] The description of the reference numerals is as follows.

[0018] A cylindrical variable diameter housing 1, a detection section 11, a transition section 12, a variable diameter section 13, a sleeve 2, a groove 21, a copper ring 22, a main control board 3, an RS458 transceiver circuit 31, a main control MCU 32, a signal modulation circuit 33, a signal demodulation circuit 34 and a coaxial cable 4. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0020] like Figure 1 and Figure 2As shown, the utility model provides a sensor for measuring the moisture content of forest trees in real time online, comprising a cylindrical variable diameter shell 1, a sleeve 2 is arranged in the front end of the cylindrical variable diameter shell 1, and a main control board 3 is inserted in the sleeve 2. The main control board 3 has an RS458 transceiver circuit 31, a main control MCU 32, a signal modulation circuit 33 and a signal demodulation circuit 34. A groove 21 is arranged in the middle of the sleeve 2, and a copper ring 22 is respectively surrounded at both ends of the sleeve 2. The two copper rings 22 form a capacitor, and the capacitor is electrically connected to the signal modulation circuit 33 and the signal demodulation circuit 34 respectively, and the signal modulation circuit 33 and the signal demodulation circuit 34 are electrically connected to the main control MCU 32 respectively, and the main control MCU 32 is electrically connected to the RS458 transceiver circuit 31. The output end of the RS458 transceiver circuit 31 is connected to a coaxial cable 4, and the coaxial cable 4 extends from the end of the cylindrical variable diameter shell 1 to the outside of the cylindrical variable diameter shell 1. The cylindrical variable diameter housing 1 is filled with epoxy resin throughout, and has the advantages of being waterproof, pressure-resistant and having a long service life.

[0021] The sensor of the utility model is installed in the wood body (including living wood and dead wood in natural state, and artificial standard wood) after drilling a hole with an electric drill. The front end of the sensor is mainly composed of two copper rings 22 to form a capacitor. The surrounding wood acts as a dielectric. The capacitor and the oscillator of the signal modulation circuit form a tuning circuit. Since the capacitance is proportional to the dielectric constant of the measured medium between the two levels, when the moisture in the medium (wood) increases, its dielectric constant increases accordingly, and the measured capacitance value also increases accordingly, resulting in a change in the measurement frequency. Therefore, the signal modulation circuit 33 is controlled by the main control MCU 32, and the signal modulation circuit 33 transmits a sine wave to the copper ring 22 and the signal demodulation circuit 34. The sine wave at the copper ring 22 end returns to the signal demodulation circuit 34, and the signal demodulation circuit 34 transmits a voltage signal to the main control MCU 32. The main control MCU 32 measures the moisture content of the medium in combination with the data model and algorithm in the prior art. The RS458 transceiver circuit 31 at the end of the sensor can be connected to a traditional collector through a coaxial cable 4 to achieve long-term online monitoring of the moisture content changes in the forest. The utility model uses the microwave principle FDR frequency domain reflection method to ensure the accuracy of the data, and can be connected to a traditional collector. It is low-cost and suitable for large-scale promotion and application.

[0022] Various modifications of this embodiment are described in detail below.

[0023] In the present invention, the overall length of the cylindrical variable diameter housing 1 is 155 mm, and the wall thickness is 1.5 mm.

[0024] In the utility model, the cylindrical variable diameter housing 1 includes a detection section 11, a transition section 12 and a variable diameter section 13 arranged at the front end, the detection section 11 has a diameter of 10 mm and a length of 125 mm, the transition section 12 has a length of 10 mm, and the variable diameter section 13 has a diameter of 20 mm and a length of 10 mm.

[0025] In the present invention, the length of the copper ring 22 is 20 mm, and the length of the groove is 10 mm.

[0026] In the present invention, the copper ring 22 is also connected to a thermistor for measuring the ambient temperature. Based on the temperature sensitivity of the material, that is, the electronic structure inside the material changes when the temperature changes, resulting in a change in resistance. The thermistor mainly converts temperature changes into electrical signals, so that the main control MCU 32 at the end of the sensor can sense and process temperature changes.

[0027] In the utility model, the cylindrical variable diameter housing 1 and the sleeve 2 are both made of ABS material.

[0028] It should be stated that the above content and specific implementation methods are intended to demonstrate the practical application of the technical solution provided by this invention and should not be interpreted as limiting the scope of protection of this invention. Those skilled in the art can make various modifications, equivalent substitutions or improvements within the spirit and principle of this invention. The scope of protection of this invention shall be subject to the attached claims.

Claims

1. A sensor for measuring the moisture content of trees in real time online, characterized in that: The invention comprises a cylindrical variable diameter housing (1), a sleeve (2) is arranged in the front end of the cylindrical variable diameter housing (1), a main control board (3) is inserted in the sleeve (2), the main control board (3) has an RS458 transceiver circuit (31), a main control MCU (32), a signal modulation circuit (33) and a signal demodulation circuit (34), a groove (21) is arranged in the middle of the sleeve (2), and a copper ring (22) is respectively surrounded at both ends of the sleeve (2), and the two copper rings (22) form a capacitor, and the capacitor is respectively connected to the signal modulation circuit (3 3) is electrically connected to the signal demodulation circuit (34), the signal modulation circuit (33) and the signal demodulation circuit (34) are electrically connected to the main control MCU (32) respectively, the main control MCU (32) is electrically connected to the RS458 transceiver circuit (31), the output end of the RS458 transceiver circuit (31) is connected to a coaxial cable (4), the coaxial cable (4) extends from the end of the cylindrical variable diameter shell (1) to the outside of the cylindrical variable diameter shell (1), and the cylindrical variable diameter shell (1) is potted with epoxy resin throughout.

2. The real-time online moisture content sensor for measuring trees as claimed in claim 1, characterized in that: The cylindrical variable diameter housing (1) has an overall length of 155 mm and a wall thickness of 1.5 mm.

3. The real-time online sensor for measuring the moisture content of trees as claimed in claim 1, characterized in that: The cylindrical variable diameter housing (1) comprises a detection section (11) arranged at the front end, a transition section (12) and a variable diameter section (13) arranged at the end, the detection section (11) having a diameter of 10 mm and a length of 125 mm, the transition section (12) having a length of 10 mm, and the variable diameter section (13) having a diameter of 20 mm and a length of 10 mm.

4. The real-time online sensor for measuring the moisture content of trees as claimed in claim 1, characterized in that: The length of the copper ring (22) is 20 mm, and the length of the groove (21) is 10 mm.

5. The real-time online sensor for measuring the moisture content of trees as claimed in claim 1, characterized in that: The copper ring (22) is also connected to a thermistor for measuring the ambient temperature.

6. The real-time online sensor for measuring the moisture content of trees as claimed in claim 1, characterized in that: The cylindrical variable diameter housing (1) and the sleeve (2) are ABS material tubes.

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