Electronic level detection and control device based on salient point type electrode and conductive liquid

Abstract

The invention belongs to the technical field of level detection devices, and particularly relates to an electronic level detection and control device based on a salient point type electrode and conductive liquid, the electronic level detection and control device comprises a sensor unit, a signal processing unit and an output unit, the sensor unit comprises a sealed cavity and a salient point type electrode array, the sealing cavity is in a long strip shape, the two ends of the sealing cavity are slightly higher than the center of the sealing cavity, the salient point type electrode array is arranged on the inner surface of the top of the sealing cavity, the salient point type electrode array is composed of conductive salient points which are arranged in a discrete mode and insulated from one another, and conductive liquid is packaged in the sealing cavity. When the cavity inclines, the number of the salient point electrodes covered by the conductive liquid is changed in a step-type positive correlation mode, accurate and step-type change of loop resistance is caused, resistance change of the sensor unit is detected through the constant voltage source voltage division circuit, and continuous electric signals or digital signals proportional to the inclination angle are output through ACD sampling and microprocessor resolving. And the method has extremely high linearity and stability.

Description

Technical Field

[0001] This invention belongs to the field of horizontal detection and sensor technology, specifically referring to an electronic horizontal detection and control device based on a convex electrode and a conductive liquid. Background Technology

[0002] Horizontal leveling is a fundamental requirement in fields such as construction, engineering machinery, and equipment installation. Currently, horizontal leveling devices on the market can be mainly categorized as follows: 1. Bubble Level: This type of level works by placing an air bubble in a transparent tube filled with liquid. The level is determined by visually observing the bubble's position relative to the scale. This device relies entirely on manual reading, cannot output electrical signals, cannot be integrated into automated systems, and is inefficient and prone to introducing errors.

[0003] 2. Electronic Tilt Sensor (MEMS): Its core is a microelectromechanical system (MEMS) chip, which measures angle by detecting changes in physical quantities such as capacitance and resistance of internal microstructures under the influence of gravity. This type of sensor is highly accurate and powerful, but it is also expensive, complex in structure, and has high environmental requirements. It is not economical in many cost-sensitive and harsh environmental applications and is considered to have "excessive performance".

[0004] 3. Mercury switch: Mercury and electrodes are encapsulated in a sealed glass tube. The fluidity and conductivity of mercury are used to trigger a tilt switch. Its core drawback is its limited functionality; it can only provide a "on" or "off" switching signal and cannot measure specific tilt angles or directions, nor can it provide a continuous signal proportional to the tilt angle, making precise control difficult. Summary of the Invention

[0005] To address the aforementioned challenges, this invention provides an electronic level detection and control device based on convex electrodes and a conductive liquid. It can provide intuitive indication like a traditional level and output a continuous electrical or digital signal proportional to the tilt angle. It can be directly used in automated control systems to achieve automatic level detection, alarm, and control, while maintaining the characteristics of simple structure and low cost.

[0006] To achieve the above functions, the technical solution adopted by this invention is as follows: An electronic level detection and control device based on convex electrodes and conductive liquid includes a housing. The housing integrates a sensor unit, a signal processing unit, and an output unit. The sensor unit is electrically connected to the signal processing unit via wires. The sensor unit includes a sealed cavity, a convex electrode array, and a common plane reference electrode. The sealed cavity is elongated, and its bottom forms a V-shaped cross-section along its length, with its center line being the lowest point. It rises to both sides at a 2.5° inclination angle. This design ensures that in a horizontal state, the conductive liquid accumulates at the lowest point of the center of the sealed cavity due to gravity. When tilting occurs... The conductive liquid flows upward along the inclined slope. By reasonably designing the slope angle, the threshold angle at which the sensor begins to respond can be accurately set, and the linearity of its angle-resistance change curve can be optimized. The convex electrode array is set on the top inner surface of the sealed cavity, and the convex electrode array is composed of discretely arranged, mutually insulated conductive convex electrodes, which are connected in series outside the sealed cavity. The sealed cavity is encapsulated with conductive liquid. The conductive liquid, together with the conductive convex electrodes and the common plane reference electrode, forms an electrical path. The common plane reference electrode is a continuous conductive strip set at the bottom or side of the sealed cavity, which is spatially opposite to all the conductive convex electrodes. Its function is to provide a common reference terminal for the current loop.

[0007] As a preferred embodiment of the present invention, the signal processing unit includes a constant voltage source and a microcontroller. The constant voltage source is disposed inside the housing and is used to provide a stable operating voltage to the measurement circuit composed of a conductive liquid and a convex electrode array. The microcontroller is disposed inside the housing and has a built-in analog-to-digital converter.

[0008] As a preferred embodiment of the present invention, the output unit is connected to a microcontroller, and the output unit includes a display screen or an industrial PLC for displaying the tilt angle and direction, and outputting control signals.

[0009] As a preferred embodiment of the present invention, the conductive bump electrodes in the bump electrode array have a diameter of 0.5-1.0 mm, a height of 0.1-0.3 mm, a spacing of 1.5-2.5 mm, and a quantity of 20-50, arranged in a single-column linear arrangement or a double-column differential arrangement.

[0010] Compared with the prior art, the present invention achieves the following beneficial effects by adopting the above structure: 1. By adopting a discrete convex electrode array, the surface tension of the conductive liquid can be effectively broken, making the contact state between the liquid and the electrode a clear and stable set of "point contacts". This fundamentally eliminates the contact instability caused by the "liquid bridge" phenomenon, ensuring accurate judgment of the electrical contact state and thus obtaining a stable and reliable measurement signal. 2. The core sensor unit has a simple structure and does not require expensive MEMS chips and complex signal conditioning circuits. The main cost is concentrated in the general-purpose microcontroller and display components. It can not only intuitively indicate the level status, but also output continuous analog or digital signals. It can be used as a measuring instrument or directly as a feedback sensor for the control system to realize multiple functions such as switch alarm and proportional control. 3. Measurement accuracy can be flexibly improved by increasing the density and arrangement of the convex electrodes to meet the needs of different application scenarios; 4. The output signal depends on the change in the number of precisely countable contact points, and extremely high linearity and accuracy can be obtained after simple calibration; 5. The slender cavity and the internal micro-flow limiting structure work together to effectively dampen harmful liquid sloshing. At the same time, the protrusions, as rigid structures, will not deform due to vibration, ensuring signal stability under harsh working conditions. Attached Figure Description

[0011] Figure 1 This is an overall system block diagram of an electronic level detection and control device based on a convex electrode and a conductive liquid proposed in this invention. Figure 2 This is an overall perspective view of an electronic level detection and control device based on a convex electrode and a conductive liquid proposed in this invention. Figure 3 This is a cross-sectional view of an electronic level detection and control device based on a convex electrode and a conductive liquid, as proposed in this invention.

[0012] The components include: 1. Housing; 2. Sensor unit; 201. Sealed cavity; 202. Raised electrode array; 203. Common plane reference electrode; 204. Conductive raised electrode; 205. Conductive liquid; 3. Signal processing unit; 301. Constant pressure source; 302. Microcontroller; and 4. Output unit. Detailed Implementation

[0013] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The invention will be further described in detail below with reference to the accompanying drawings.

[0015] like Figures 1-3 As shown, the present invention provides an electronic level detection and control device based on a convex electrode and a conductive liquid. The device is integrated into a rectangular shell 1. The shell 1 is made of aluminum alloy and the surface of the shell 1 is anodized, which provides good corrosion resistance and electromagnetic interference resistance. The interior of the shell 1 is divided into three independent installation areas by an insulating partition, which are used to fix the sensor unit 2, the signal processing unit 3 and the output unit 4 respectively. The units are electrically connected by shielded wires, and the wire connection is sealed with heat shrink tubing to prevent external interference from affecting signal transmission.

[0016] Sensor unit 2 is the core detection component of the device, mainly composed of a sealed cavity 201, a convex electrode array 202, a common plane reference electrode 203, and a conductive liquid 205. The specific design and assembly method of each component are as follows: The sealing cavity 201 is integrally injection molded from PPS (polyphenylene sulfide) material. This material has high insulation, high chemical stability, and excellent mechanical strength, which can effectively prevent chemical reactions with the conductive liquid 205 and prevent external electric fields from interfering with the internal detection circuit. The sealing cavity 201 has a slender structure with a length-to-width-to-height ratio of 10:2:2, and specific dimensions of 100mm×20mm×20mm. The interior is a smooth cavity. The bottom of the sealing cavity 201 is machined into a V-shaped section along its length, with its center line being the lowest point, rising uniformly to both sides at an angle of 2.5°. To suppress vibration interference, a shallow groove array is machined on the inner wall of the top of the sealing cavity 201. The grooves are 0.2mm deep, 0.5mm wide, and 2mm apart. This can reduce the impact of vibration on the liquid position by changing the liquid flow path. The two ends of the sealing cavity 201 are permanently sealed by laser welding to ensure that there is no leakage of the internal conductive liquid 205.

[0017] The bump electrode array 202 is made of brass to form conductive bump electrodes 204. Each conductive bump electrode 204 has a diameter of 0.8 mm and a height of 0.2 mm. The spacing between adjacent conductive bump electrodes 204 is set to 2.0 mm, and a total of 30 conductive bump electrodes 204 are arranged in a double-row differential arrangement on the top inner surface of the sealed cavity 201. The two rows of electrodes are staggered, with a row spacing of 1.0 mm. The surface of each conductive bump electrode 204 is chemically plated with a nickel-gold alloy coating with a thickness of 0.05 mm, which can improve the conductivity, corrosion resistance and service life of the electrode. The conductive bump electrodes 204 are connected by the airflow inside the sealed cavity 201. The insulating grooves isolate each other, with a width of 0.3mm, ensuring no electrical connection between the conductive bump electrodes 204. The gap (0.3mm) between the conductive bump electrodes 204 is much larger than the surface tension characteristic length of the conductive liquid 205 (gallium indium tin alloy) in this environment, which can effectively prevent the liquid from crossing the gap to form a liquid bridge, ensuring that the conduction state of each conductive bump electrode 204 is independently controllable. Each conductive bump electrode 204 has an independent conductive trace integrated below it. The trace is made of copper foil and is led out from the side of the sealed cavity 201 to the external interface through a glass-metal sealing method. All conductive bump electrodes 204 are connected in series outside the cavity to form a complete detection electrode circuit.

[0018] The common plane reference electrode 203 is made of copper foil and is a continuous conductive strip with a width of 3 mm and a thickness of 0.1 mm. It is fixed to the bottom of the sealed cavity 201 with insulating adhesive and is spatially opposite to the top bump electrode array 202. The length of the conductive strip is the same as the length of the sealed cavity 201 (100 mm). The two ends of the common plane reference electrode 203 are also led out to the outside through glass-metal sealing. Its function is to provide a stable current loop common reference terminal for the entire detection circuit and ensure the electrical path consistency between each conductive bump electrode 204 and the common plane reference electrode 203.

[0019] The conductive liquid 205 is made of gallium indium tin liquid metal alloy. This alloy is liquid at room temperature, has a conductivity close to that of mercury, and is non-toxic, environmentally friendly, and chemically stable. It does not react chemically with the PPS cavity material and the nickel-gold coated electrode. The filling volume of the conductive liquid 205 is 1 / 5 of the internal volume of the cavity. The filling process is carried out in a vacuum environment to avoid the formation of air bubbles inside that may affect the detection accuracy. After filling, the filling port is sealed by laser welding to ensure that the liquid can only flow along the V-shaped profile inside the cavity.

[0020] Signal processing unit 3 includes a constant voltage source 301 and a microcontroller 302, used to convert the resistance signal output by sensor unit 2 into a digital signal and perform calculation processing: Constant voltage source 301: A high-precision linear constant voltage source 301 module is integrated into the signal processing area inside the housing 1. The input voltage is 12V, and the output is a stable 5V working voltage with a voltage ripple of less than 5mV. It can provide a stable working voltage to the measurement circuit composed of conductive liquid 205 and convex electrode array 202, avoiding the impact of voltage fluctuations on detection accuracy. The constant voltage source 301 module has a built-in overcurrent protection circuit. When a short circuit occurs in the detection circuit, it can automatically cut off the output to protect the internal components of the device from damage.

[0021] The microcontroller 302 uses an STM32F103 chip based on the ARM Cortex-M3 core, integrated on a custom PCB board, which is fixed to an insulating mounting base inside the housing 1. The microcontroller 302 has a built-in 24-bit Σ-Δ analog-to-digital converter (ADC) with a sampling rate of up to 1kHz, high resolution, and high sampling accuracy, enabling precise acquisition of voltage signals from the measurement circuit. The microcontroller 302's Flash memory pre-stores a "voltage-tilt angle" calibration curve, which is obtained through pre-calibration using a high-precision turntable. During calibration, the tilt angle range is set to -5° to +5°, and the corresponding voltage value is acquired every 0.1° to form a complete calibration dataset for subsequent tilt angle calculation. Simultaneously, the microcontroller 302 incorporates a moving average filtering algorithm to filter the acquired voltage signal, suppressing noise interference and improving signal stability.

[0022] The specific circuit connection of signal processing unit 3 is as follows: a high-precision, low-temperature-drift reference resistor R is connected in series with the output terminal of constant voltage source 301. ref (Resistance value 1kΩ, accuracy ±0.1%), the other end of the reference resistor is connected to the series circuit of the convex electrode array 202, and the other end of the convex electrode array 202 is connected to the common plane reference electrode 203 through the conductive liquid 205. The common plane reference electrode 203 is connected to the ground terminal of the microcontroller 302, forming a complete measurement circuit; measurement point V out Located at the connection node between the reference resistor and the convex electrode array 202, it is connected to the ADC sampling pin of the microcontroller 302 via a wire to achieve voltage signal acquisition; according to the circuit principle, the voltage at the measurement point satisfies the formula: V out = V ref *R sen / (R ref + R sen ), where V ref R is the output voltage of the constant voltage source 301. ref R is the reference resistance value. sen The total resistance of sensor unit 2 varies with the tilt angle.

[0023] Output unit 4 is connected to the I / O interface of microcontroller 302, adopting a combination of "display screen and industrial PLC", which has both display function and control signal output function: Display Screen: A 2.4-inch OLED display with a resolution of 320×240 is used. It connects to the microcontroller 302 via an SPI interface and is fixed to the pre-drilled mounting holes on the front of the housing 1. It can display the detected tilt angle (accuracy 0.01°), tilt direction (left tilt / right tilt / horizontal), and device operating status (normal / fault) in real time. The display screen has a backlight function, allowing for clear display of information in low-light environments.

[0024] Industrial PLC: A Siemens S7-200 SMART series PLC is selected, which communicates with the microcontroller 302 via an RS485 interface to receive tilt angle data and control signals output by the microcontroller 302. The PLC output is connected to an external actuator (such as a solenoid valve or stepper motor). When the detected tilt angle exceeds a preset threshold (which can be set via the microcontroller 302 software, ranging from 0.1° to 5°), the microcontroller 302 sends a control signal to the PLC. The PLC then drives the actuator to adjust the posture of the monitored equipment until it returns to a horizontal state. At the same time, the PLC has a data upload function, which can upload tilt angle data and control commands to the industrial control system to achieve remote monitoring and control.

[0025] The working process is divided into four stages: physical-to-electrical conversion, resistance-to-voltage conversion, digital processing and calculation, and output control, as detailed below: Physical-to-electrical conversion stage: When the device is horizontal, the conductive liquid 205, under the influence of gravity, accumulates at the lowest point of the center line of the V-shaped section at the bottom of the sealed cavity 201, contacting only the conductive protrusion electrode 204 at the center and the common plane reference electrode 203, forming a conductive loop. At this time, the total resistance value of the sensor unit 2 corresponds to an inclination angle of 0°. When tilted to the left, the number of loop protrusions decreases as the inclination angle increases; when tilted to the right, the number of loop protrusions increases as the inclination angle increases. When the device being tested is tilted, the conductive liquid 205 flows upward along the V-shaped slope on the tilted side, covering the corresponding number of conductive protrusion electrodes 204. Each covered conductive protrusion electrode 204 forms a conductive loop with the common plane reference electrode 203 through the conductive liquid 205. At this time, the total resistance R of the sensor unit 2... sen The series resistance value (R) corresponding to the covered conductive bump electrode 204 sen =N×r, where N is the number of covered conductive bump electrodes and r is the resistance value of a single conductive bump electrode 204 after contact with the liquid. The larger the tilt angle, the more the number of covered conductive bump electrodes 204 changes, and the greater the change in the total resistance value, thus realizing the conversion of tilt angle signal to resistance signal. Resistance-to-voltage conversion stage: The constant voltage source 301 provides a stable 5V voltage to the measurement circuit, which is converted by the reference resistor R. ref Total resistance R of sensor unit 2 sen The voltage divider effect converts the resistance signal into a voltage signal V. out The voltage signal changes linearly with the total resistance, thus completing the resistance-to-voltage conversion; Digital processing and calculation stage: The microcontroller 302 processes the voltage signal V through its built-in ADC. out Sampling is performed at a frequency of 1kHz. After sampling, the sampled data is filtered by a moving average filtering algorithm to remove noise interference. Then, the pre-stored "voltage-tilt angle" calibration curve in the Flash memory is called, and the filtered voltage signal is solved by a lookup table or polynomial fitting algorithm to obtain the accurate tilt angle value and tilt direction. Output control stage: The microcontroller 302 sends the calculated tilt angle value and tilt direction to the OLED display screen for real-time display; at the same time, it compares the tilt angle value with the preset threshold. If the tilt angle value is within the allowable range, the current state is maintained; if the tilt angle value exceeds the preset threshold, a control signal is immediately sent to the industrial PLC. The PLC drives the external actuator to adjust the posture of the detected equipment until the tilt angle is restored to the allowable range, thus realizing automatic control of the horizontal state.

[0026] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. An electronic level detection and control device based on a convex electrode and a conductive liquid (205), characterized in that: The device includes a housing (1), which integrates a sensor unit (2), a signal processing unit (3), and an output unit (4). The sensor unit (2) is electrically connected to the signal processing unit (3) via wires. The sensor unit (2) includes a sealed cavity (201), a convex electrode array (202), and a common plane reference electrode (203). The sealed cavity (201) is elongated, and its bottom forms a V-shaped cross-section along its length. Its centerline is the lowest point, and it rises to both sides at an angle of 2.5°. The convex electrode array (202) is designed with... The top inner surface of the sealed cavity (201) is placed, and the bump electrode array (202) is composed of discretely arranged, mutually insulated conductive bump electrodes (204) connected in series outside the sealed cavity (201). The sealed cavity (201) is encapsulated with a conductive liquid (205). The conductive liquid (205) combines with the conductive bump electrodes (204) and the common plane reference electrode (203) to form an electrical path. The common plane reference electrode (203) is a continuous conductive strip disposed at the bottom or side of the sealed cavity (201) and is spatially opposite to all the conductive bump electrodes (204).

2. The electronic level detection and control device based on a convex electrode and a conductive liquid (205) according to claim 1, characterized in that: The signal processing unit (3) includes a constant voltage source (301) and a microcontroller (302). The constant voltage source (301) is located inside the housing (1) and is used to provide a stable operating voltage to the measurement circuit composed of a conductive liquid (205) and a convex electrode array (202). The microcontroller (302) is located inside the housing (1) and has a built-in analog-to-digital converter.

3. The electronic level detection and control device based on a convex electrode and a conductive liquid (205) according to claim 1, characterized in that: The output unit (4) is connected to a microcontroller (302), and the output unit (4) includes a display screen or an industrial PLC.

4. The electronic level detection and control device based on a convex electrode and a conductive liquid (205) according to claim 1, characterized in that: The conductive bump electrodes (204) in the bump electrode array (202) have a diameter of 0.5-1.0 mm, a height of 0.1-0.3 mm, a spacing of 1.5-2.5 mm, and a quantity of 20-50. They are arranged in a single-column linear arrangement or a double-column differential arrangement.

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