Multi-parameter smartphone portable optical fiber sensor for simultaneously detecting refractive index and liquid level and operation method of multi-parameter smartphone portable optical fiber sensor

Abstract

The invention relates to the technical field of portable detection equipment, in particular to a multi-parameter smartphone portable optical fiber sensor for simultaneously detecting refractive index and liquid level and an operation method, and adopts the following technical scheme: the multi-parameter smartphone portable optical fiber sensor comprises a terminal, a shell, a first sensor, a second sensor, a first container and a second container, the shell is detachably connected to the terminal; the terminal is used for triggering the first sensor and the second sensor to detect the refractive index of the liquid in the first container and the liquid level of the liquid in the second container. The first sensor and the second sensor can be triggered through one terminal (such as a smart phone), measurement of the liquid refractive index and the liquid level can be completed at the same time, different terminal devices do not need to be operated respectively, the measurement process is effectively simplified, the measurement efficiency is greatly improved, and the method is particularly suitable for scenes where multiple parameters need to be rapidly obtained.

Description

Technical Field

[0001] The present application relates to the technical field of portable detection equipment, and in particular to a multi-parameter smartphone portable optical fiber sensor for simultaneously detecting refractive index and liquid level and an operating method thereof. Background Art

[0002] In many fields such as industrial production, biomedicine, and environmental monitoring, the refractive index and liquid level of liquids are two crucial parameters. Their accurate measurement is directly related to production quality control, the reliability of experimental results, and process safety.

[0003] Currently, measuring the refractive index of liquids typically requires a dedicated refractometer. These instruments are often large, complex to operate, expensive, and lack portability, making them difficult to meet the needs of rapid on-site testing. Liquid level measurement, on the other hand, relies heavily on level gauges. Common types include float, capacitance, and ultrasonic. These level gauges also have their limitations. For example, float-type gauges are easily affected by liquid viscosity, capacitance-type gauges are significantly affected by ambient temperature, and ultrasonic-type gauges can lose accuracy under complex working conditions.

[0004] Crucially, existing technologies often measure refractive index and liquid level independently, requiring separate measurement devices and terminals. This results in a cumbersome measurement process, requiring the transport of multiple instruments, increasing equipment costs and portability. Furthermore, issues such as calibration discrepancies between terminals and data transmission delays can affect measurement efficiency and data consistency, making it difficult to achieve rapid, simultaneous, and accurate monitoring of liquid parameters.

[0005] In scenarios where convenient measurement is crucial, such as field testing and mobile laboratories, how to efficiently and accurately measure both the refractive index and level of liquids using a single terminal has become a pressing technical challenge. This is to simplify the measurement process, reduce equipment costs, and improve measurement efficiency and data reliability. Summary of the Invention

[0006] In order to solve the problems mentioned in the above background technology, the present application provides a multi-parameter smartphone portable optical fiber sensor and an operating method for simultaneously detecting refractive index and liquid level.

[0007] The present application provides a multi-parameter smartphone portable optical fiber sensor for simultaneously detecting refractive index and liquid level and an operating method thereof, which adopts the following technical solution: comprising a terminal, a housing, a first sensor, a second sensor, a first container, and a second container; The housing is detachably connected to the terminal; The first sensor and the second sensor are both connected to the housing; The first sensor is disposed in the first container and is used to detect the refractive index of the liquid in the first container; The second sensor is disposed in the second container and is used to detect a liquid level of the liquid in the second container; The terminal is used to trigger the first sensor and the second sensor to detect the refractive index of the liquid in the first container and the liquid level of the liquid in the second container.

[0008] Optionally, the first sensor includes a first illumination fiber and a first optical fiber; The first optical fiber and the first illumination fiber are intertwined with each other and are arranged in the second container, and the intertwined first optical fiber and the first illumination fiber extend to the bottom wall of the second container; The first optical fiber and the first illumination fiber are entangled with each other and arranged vertically.

[0009] Optionally, the second sensor includes a second illumination fiber and a second optical fiber; The end of the second optical fiber extends into the first container and is entangled with the second illumination fiber; The second optical fiber and the second illumination fiber that are entangled with each other are distributed in a ring shape and laid horizontally in the second container.

[0010] Optionally, the vertically arranged first lighting fiber is led out from the bottom of the inner wall of the second container and separated from the upper opening of the second container, and the first lighting fiber is connected to the second lighting fiber.

[0011] Optionally, a vernier caliper is further included. After being fixed, the vernier caliper is parallel to the first optical fiber and the first illumination fiber that are entangled with each other, and the first sensor is connected to the vernier caliper.

[0012] Optionally, the housing includes a light source connection port, a second camera connection port, and a first camera connection port; The light source connection port is connected to the first lighting fiber, and the second camera connection port and the first camera connection port are connected to the second optical fiber and the first optical fiber respectively.

[0013] Optionally, the terminal includes at least two cameras and a light-emitting unit; The two cameras correspond to the second camera connection port and the first camera connection port respectively, and the light emitting portion corresponds to the light source connection port.

[0014] Another aspect of the present invention provides a multi-parameter smartphone portable optical fiber sensor for simultaneously detecting refractive index and liquid level and an operating method thereof, comprising the following steps: detachably connecting the housing to the terminal, ensuring that the terminal is connected to the first sensor and the second sensor; Installing a first sensor in a first container and installing a second sensor in a second container; activating the first sensor and the second sensor through the terminal, triggering the first sensor to detect the refractive index of the liquid in the first container, and the second sensor to detect the liquid level of the liquid in the second container; The two cameras of the terminal are used to capture the optical signal output of the first sensor and the second sensor respectively, wherein the optical signal of the first sensor is used for refractive index analysis, and the optical signal of the second sensor is used for liquid level analysis; The captured optical signal is processed on the terminal, and the refractive index of the liquid in the first container and the liquid level of the liquid in the second container are calculated and output.

[0015] Preferably, the method further comprises the following steps: Before triggering the first sensor and the second sensor, a light source is provided by the light emitting portion of the terminal, and the light source is transmitted to the first lighting fiber and the second lighting fiber through the light source connection port of the housing; Configure the parameters of the terminal's two cameras, including ISO sensitivity and exposure time, to optimize the capture of optical signals output by the first and second optical fibers; During the detection process, the refractive index of the liquid in the first container is detected based on the change in coupling power caused by the change in refractive index by using a vertical structure in which the first optical fiber and the first illumination fiber are intertwined. The liquid level in the second container is detected based on the change in coupling power caused by the change in liquid level by using a ring-shaped horizontal structure in which the second optical fiber and the second illumination fiber are intertwined. The captured optical signal is analyzed in real time through the terminal to generate numerical results of refractive index and liquid level, which are stored in the terminal for subsequent query.

[0016] Preferably, the method further comprises the following steps: Before the detection begins, the first sensor is fixed using a vernier caliper, with the vernier caliper being parallel to the winding structure of the first optical fiber and the first illumination fiber to ensure the position stability of the first sensor in the first container; During the detection process, recording environmental parameters of the liquids in the first container and the second container, including temperature and liquid type, and correlating the environmental parameters with the detection data; Analyze the light signals from the first sensor and the second sensor, extract the grayscale pixel value of each frame using MATLAB or other signal processing software, and calculate the total light intensity; According to the total light intensity, the normalized intensity change of the refractive index and the normalized intensity change of the liquid level are calculated respectively, wherein the refractive index change is based on the air reference intensity, and the liquid level change is based on the zero liquid level reference intensity; The calculated refractive index and liquid level results are presented to the user through the terminal's display interface, and the results can be transmitted to a remote device via a wireless module for further analysis.

[0017] In summary, this application has the following beneficial technical effects: The present invention can trigger the first sensor and the second sensor through a terminal (such as a smartphone) to simultaneously complete the measurement of the liquid refractive index and liquid level, without the need to operate different terminal devices separately. This effectively simplifies the measurement process and greatly improves measurement efficiency. It is particularly suitable for scenarios where multiple parameters need to be quickly obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the front side of the embodiment of the present application; Figure 2 It is a partial schematic diagram of an embodiment of the present application; Figure 3 is a schematic diagram of the three-dimensional structure of the first illumination fiber and the first optical fiber in an embodiment of the present application; Figure 4 is a schematic diagram of the three-dimensional structure of the second optical fiber and the second illumination fiber in an embodiment of the present application; Figure 5 Schematic diagram of the torsion structure in the embodiment of the present application; Figure 6 It is an information graph collected by the terminal in the embodiment of the present application.

[0019] Reference numerals: 1. Shell; 11. Light source connection port; 11. Light source connection port; 12. Second camera connection port; 13. First camera connection port; 2. Terminal; 21. Light-emitting portion; 22. Camera; 3. First lighting fiber; 4. Second optical fiber; 5. First optical fiber; 6. First container; 7. Second container; 8. Second lighting fiber. DETAILED DESCRIPTION

[0020] The following is combined with Figure 1-5 This application is described in further detail.

[0021] The embodiments of the present application disclose a multi-parameter smartphone portable optical fiber sensor for simultaneously detecting refractive index and liquid level.

[0022] See also Figures 1 to 4 The present invention relates to a multi-parameter smartphone portable optical fiber sensor for simultaneously detecting refractive index and liquid level, aiming to achieve convenient and efficient liquid parameter detection.

[0023] The sensor primarily consists of a terminal 2, a housing 1, a first sensor, a second sensor, a first container 6, and a second container 7. The housing 1 is detachably connected to the terminal 2, facilitating installation and removal, portability, and maintenance. The first and second sensors are both securely connected to the housing 1 and positioned within the first and second containers 6 and 7, respectively, each performing its own function: detecting the refractive index and liquid level of the liquid within the corresponding container. Terminal 2, serving as the control and data acquisition center for the entire system, triggers the first and second sensors to accurately detect the refractive index of the liquid within the first container 6 and the liquid level within the second container 7.

[0024] The first sensor includes a first illumination fiber 3 and a first optical fiber 5. In order to optimize the sensing performance, the first optical fiber 5 and the first illumination fiber 3 are intertwined with each other (the specific connection method is to wind them in a spiral twisting manner), and are vertically arranged in the second container 7, and the intertwined parts extend all the way to the bottom wall of the second container 7. This vertical arrangement and winding structure can effectively increase the propagation path and interaction area of ​​light in the liquid, and improve the sensitivity to changes in the refractive index of the liquid. In addition, a vernier caliper is also provided. After the vernier caliper is fixed, it remains parallel to the intertwined first optical fiber 5 and the first illumination fiber 3, and the first sensor is connected to the vernier caliper. The setting of the vernier caliper can be used to accurately adjust the position of the first sensor in the liquid to ensure the accuracy and consistency of the measurement.

[0025] When light is transmitted through first illumination fiber 3 into the liquid in second container 7, the coupling and transmission pattern between first optical fiber 5 and first illumination fiber 3 changes due to the different refractive indices of the liquids. First optical fiber 5 transmits the received light signal to a subsequent detection unit, which analyzes the changes in the light signal to accurately calculate the refractive index of the liquid.

[0026] The second sensor consists of a second illumination fiber 8 and a second optical fiber 4. The end of the second optical fiber 4 extends into the first container 6 and is intertwined with the second illumination fiber 8. The intertwined second optical fiber 4 and second illumination fiber 8 form a circular arrangement and are laid horizontally within the second container 7. This horizontal, circular arrangement enables omnidirectional sensing of liquid level changes, improving the accuracy and reliability of liquid level detection.

[0027] As the liquid level in first container 6 rises or falls, it gradually covers or exposes the intertwined second optical fiber 4 and second illumination fiber 8 (specifically, they are twisted in a helical pattern). This change in liquid level causes changes in the transmission loss of light between the second optical fiber 4 and the second illumination fiber 8. The second optical fiber 4 transmits the optical signal with this change in transmission loss to a subsequent detection unit. By analyzing this optical signal loss, accurate liquid level information can be derived.

[0028] The vertically arranged first illumination fiber 3 is led out from the inner bottom of the second container 7 and out of the upper opening of the second container 7. The first illumination fiber 3 is interconnected with the second illumination fiber 8. This interconnected structure allows light from the light source to pass through the first illumination fiber 3 and the second illumination fiber 8 in sequence, providing a stable light source for the first and second sensors.

[0029] The housing 1 is provided with a light source connection port 11, a second camera connection port 12, and a first camera connection port 13. The light source connection port 11 is connected to the first lighting fiber 3 for receiving an external light source (such as a mobile phone flashlight). The second camera connection port 12 and the first camera connection port 13 are connected to the second optical fiber 4 and the first optical fiber 5, respectively, for transmitting the optical signals collected by the first and second sensors to the camera of the terminal 2 for image acquisition and analysis.

[0030] Terminal 2 is equipped with at least two cameras 22 and a light-emitting unit 21. The two cameras 22 precisely correspond to the second camera connection port 12 and the first camera connection port 13, respectively, ensuring accurate capture of images formed by the optical signals transmitted from the first and second sensors. The light-emitting unit 21 corresponds to the light source connection port 11. When the terminal 2's own illumination function is needed to provide light for the sensor, light can be introduced into the first illumination fiber 3 through the light source connection port 11, thereby providing illumination for the entire sensor system.

[0031] The first lighting fiber 3 and the second lighting fiber 8 are the same lighting fiber and correspond to the light emitting portion 21 . The terminal 2 only needs one light emitting portion 21 to realize the supply of light source.

[0032] It is worth noting that the multi-parameter smartphone portable fiber optic sensor of the present invention, through structural design and fiber optic arrangement, can efficiently and accurately detect the refractive index and liquid level of the liquid at the same time. In combination with a smartphone, it has convenient data collection, transmission and analysis functions, and has broad application prospects.

[0033] The fiber optic sensor is capable of measuring liquid level and refractive index (RI) simultaneously and is fully integrated into a smartphone platform serving as the terminal 2. The sensor design is based on a connected first illumination fiber 3 and a second illumination fiber 8, wherein two independent twisted regions form coupling regions for liquid level detection and refractive index sensing, respectively. The smartphone's built-in flashlight serves as a light source, and its dual-camera system independently records the optical responses of the first sensor and the second sensor. This fiber optic sensor uses the functionality of two cameras 22 for the first time to overcome the decoupling challenges in simultaneous multi-parameter detection. In terms of liquid level detection, the system demonstrates a measurement range of 0-100 mm, a resolution of 0.007 mm, and a sensitivity of 0.0102% / mm. For refractive index sensing, the system achieves a measurement range of 1.333–1.361 RIU with a resolution of 1.03×10 -4 RIU, with a sensitivity of 102% / RIU. The underlying sensing mechanism is based on optical coupling modulation, which is affected by the change in the refractive index of the coupling region. This fiber optic sensor not only simplifies the sensor fabrication process, such as complex steps such as tapering or grating writing, but also ensures reliable, high-resolution performance in a compact and field-deployable format. This approach shows great potential in practical applications such as chemical processing, environmental monitoring, and industrial automation.

[0034] Notably, the sensing function is achieved by intentionally introducing controlled perturbations within the coupling region. This unconventional approach challenges standard assumptions in coupled-mode theory. The sensor is fabricated using a simple yet effective method, whereby a localized coupling region is formed by helical twisting of two polymer optical fibers. This twisted region serves as a functional sensing probe. By cascading multiple twisted sections within a single fiber, multiple sensing regions can be realized within a single fiber structure.

[0035] Another embodiment of the present application discloses a method for operating a multi-parameter smartphone portable optical fiber sensor for simultaneously detecting refractive index and liquid level.

[0036] See also Figures 5 and 6, the housing 1 is detachably connected to the terminal 2 (such as a smartphone) through an adapter interface, ensuring that the circuit interface of the terminal 2 is electrically connected to the signal transmission interface of the first sensor and the second sensor, and that the mechanical positioning structure of the housing 1 precisely matches the positioning groove of the outer shell of the terminal 2 to ensure connection stability. The first sensor is installed in a vertical position in the first container 6, so that the detection area of ​​the first sensor is completely immersed in the preset depth of the liquid to be tested; the second sensor is installed in a horizontal position in the second container 7, so that the annular detection structure of the second sensor maintains a preset distance from the inner wall of the second container 7 to ensure that the detection area can effectively respond when the liquid level changes. Before triggering the first and second sensors for detection, the light-emitting portion 21 (such as a built-in flash or a dedicated LED module) is activated through the system command of the terminal 2, so that the output intensity of the light source is stabilized within the preset threshold range. The light source is transmitted to the first lighting fiber 3 and the second lighting fiber 8 through the light source connection port 11 of the housing 1. Using the camera configuration module in Terminal 2, set the parameters for each of the two cameras 22: adjust the ISO sensitivity to a range of 100-800 (dynamically selected based on ambient light intensity) and the exposure time to 10-100ms. This ensures that the optical signals output by the first and second optical fibers 5 and 4 are not overexposed during imaging while maintaining a sufficient signal-to-noise ratio. Use a vernier caliper to secure the first sensor. Terminal 2 can adjust the brightness of the light-emitting unit 21 in multiple levels.

[0037] An activation command is sent via a dedicated application on Terminal 2, triggering the first sensor to enter refractive index detection mode and the second sensor to enter liquid level detection mode. When the first sensor is operating, it utilizes the vertical structure formed by the intertwining of first optical fiber 5 and first illumination fiber 3. When the refractive index of the liquid in first container 6 changes, the coupling power between the two fibers changes accordingly. The first optical fiber 5 converts this change into an optical signal for output. When the second sensor is operating, it utilizes the annular horizontal structure formed by the intertwining of second optical fiber 4 and second illumination fiber 8. When the liquid level in second container 7 changes, the length of the fiber segment immersed in the liquid changes, resulting in a change in coupling power. The second optical fiber 4 converts this change into an optical signal for output.

[0038] The two cameras 22 of terminal 2 are respectively aimed at the optical signal output ends of the first optical fiber 5 and the second optical fiber 4 to capture the optical signal output image in real time, where the first camera only receives the optical signal of the first sensor and the second camera only receives the optical signal of the second sensor to avoid cross interference.

[0039] The pre-processed light signal image is transmitted to the processing unit of terminal 2, and the grayscale pixel value of each frame image is extracted through the built-in MATLAB component or dedicated signal processing algorithm to calculate the total light intensity.

[0040] The processing unit of the terminal 2 calculates the refractive index of the liquid in the first container 6 and the liquid level of the liquid in the second container 7 according to the normalized intensity change in combination with a pre-stored calibration curve.

[0041] The calculation results are presented to the user in real time in the form of numbers and curves through the display interface of terminal 2, and are automatically stored in the storage unit of terminal 2. The storage content includes detection time, refractive index value, liquid level value, environmental parameters and original light signal image.

[0042] Users can transmit the test results to a remote device (such as a server or computer) through the wireless module (such as Wi-Fi or Bluetooth) of Terminal 2. The transmission process uses an encryption algorithm (such as AES-128) to ensure data security for further analysis.

[0043] It's worth noting that when light enters the system through the input port Pin and propagates through the illumination fiber, coupled power Pout is propagated by the fiber. The output power at the first illumination fiber 3 is denoted as P0, while the output power at the first fiber 5 (for the liquid level sensor) is denoted as P1. The power transfer dynamics between the two fibers can be described by a set of coupled differential equations:

[0044] Wherein, P0(x) represents the power in the first illumination fiber 3; P1(x) represents the power in the first optical fiber 5; and represent the attenuation coefficient of the optical fiber, and is the coupling coefficient, which depends on the liquid level L and the distance x. Here, the attenuation is assumed to be equal, since the first illumination fiber 3 and the first optical fiber 5 are of the same type, and the equation expresses an intuitive and direct concept. An explanatory visualization based on power balance is shown, similar to the finite difference method applied to a length of The modified coupling coefficient Depends on the liquid level L. The coupling coefficient can be expressed as:

[0045] Where Lmax represents the maximum operating range of the sensor, represents the coupling coefficient in a dry area without liquid, This reflects the change in the coupling liquid level as it rises or falls. The boundary conditions of the system are set as follows: at the input end of the illumination fiber, P0(0) = Pin; at the starting position of the coupling fiber, P1(0) = 0. By solving these differential equations, the general solution for the power in the two fibers can be obtained: In this model, the initial power P 0 is introduced at the beginning of the illumination fiber (x = 0), and the output power Pout is measured at the end of the first fiber 5 = (x = Lmax). According to the boundary conditions of the system, the solution of the differential equation is set as follows: at the input end of the illumination fiber, P 0 (0) = Pin; at the beginning of the first fiber 5, P 1 (0) = 0, resulting in the power distribution along the fiber:

[0046] At the end point Lmax - L, where the liquid level affects the coupling, the power in the first optical fiber 5 becomes:

[0047] To determine the output power at the end of the first optical fiber 5, taking into account the fiber attenuation, the final equation for liquid level sensing is:

[0048] By substituting the value of P1 (Lmax-L), the final output power equation is:

[0049] This equation shows how the output power decreases as the liquid level L increases. In regions with high liquid absorption, the coupling coefficient β0(L) is almost negligible, so the simplified expression for the output power Pout reflects the direct effect of liquid absorption on the transmitted light.

[0050] It is worth noting that in refractive index sensing, measurements are performed after the second optical fiber 4 is bent to a radius of 8 mm. This structural change improves power coupling because the fiber's sensitivity to changes in the refractive index of the external medium increases. The bending process introduces additional losses, which are proportional to the curvature of the fiber and the refractive index of the surrounding liquid. The coupled power equation for refractive index sensing is similar to that for liquid level sensing.

[0051] However, here P2 represents the output power of the second optical fiber 4 in the refractive index detection, which includes a coupling coefficient β related to the refractive index. RI :

[0052] where P2, the refractive index-dependent coupling coefficient β RI This loss is affected by bending losses, which can be modeled as:

[0053] Where βair represents the coupling coefficient of the optical fiber in air, Δβbend (RI) represents the coupling change due to bending, where RI bend is the bending radius and RI core is the refractive index of the optical fiber core. The output power structure of RI sensing is similar to that of liquid level sensing. The output power Pout (RI) is calculated as follows:

[0054] The DualTake app was used for video recording, allowing manual adjustment of key imaging parameters such as ISO sensitivity and exposure time. Optimizing ISO is crucial for ensuring signal strength, but excessively high ISO values ​​can increase image noise and reduce measurement accuracy. ISO was set to 500. Similarly, proper shutter speed calibration is crucial for regulating light exposure and avoiding low-intensity readings, especially when using low-noise ISO settings. These parameters need to be dynamically adjusted based on environmental conditions to maintain sensing performance. After video recording, each frame was processed in MATLAB to simultaneously analyze both sensors. These videos, captured at a 9:16 aspect ratio, were acquired using two different smartphone cameras and saved as separate video files. This dual-camera approach allows both sensors to be monitored simultaneously and uninterrupted. The first sensor uses a wide-angle lens, while the second uses an ultra-wide-angle lens to optimize field of view and image clarity. Notably, the first sensor is located approximately 10 mm from its corresponding camera lens, while the second sensor is closer to the ultra-wide-angle camera. The brightest dots represent the first and second sensors, respectively. The first and second sensors are referred to as Sensor 1 and Sensor 2 in the accompanying figures.

[0055] For each sensor, the total light intensity is calculated independently by analyzing its corresponding video. Grayscale pixel values ​​are located within predefined regions of interest (ROIs). They are extracted from each frame and aggregated to obtain the total light intensity. These regions of interest (ROIs) are manually defined based on the known position of each sensor in the video frame, ensuring accurate isolation of the active sensing area. The data of sensor one and sensor two are processed separately for each video using MATLAB, effectively eliminating any potential interference between the two sensing channels. This approach ensures reliable and isolated signal quantification during simultaneous multi-parameter sensing. The total intensity calculation formula for each sensor is:

[0056] Where Itotal represents the total intensity of sensor 1 and sensor 2, a and b are the frame sizes. The normalized intensity calculation formula for sensor 1 is: , where I0 represents the absolute intensity value of the reference zero position, and l hThe differential intensity metric used to quantify intensity changes is as follows:

[0057] When measuring changes in refractive index, the sensor is normalized by the reference intensity Iair when exposed to air (baseline medium). For a specific liquid with a refractive index n, the normalized intensity is calculated as: The differential intensity of refractive index sensing is calculated as follows:

[0058] This unified approach streamlines the analysis process and enables real-time monitoring of intensity changes at both sensor one and sensor two. To ensure measurement stability, the entire experimental setup, including the smartphone and mounting structure, remained stationary during data acquisition. This fixed configuration eliminates the need for compensatory alignment or post-processing corrections that might be required due to unintended device movement. Maintaining the stability of the setup ensures repeatable, reliable, and consistent recorded results.

[0059] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A multi-parameter smartphone portable optical fiber sensor for simultaneously detecting refractive index and liquid level, comprising a terminal (2), a housing (1), a first sensor, a second sensor, a first container (6) and a second container (7), characterized in that: The housing (1) is detachably connected to the terminal (2); The first sensor and the second sensor are both connected to the housing (1); The first sensor is arranged in the first container (6) and is used to detect the refractive index of the liquid in the first container (6); The second sensor is arranged in the second container (7) and is used to detect the liquid level of the liquid in the second container (7); The terminal (2) is used to trigger the first sensor and the second sensor to detect the refractive index of the liquid in the first container (6) and the liquid level of the liquid in the second container (7).

2. The multi-parameter portable optical fiber sensor for simultaneously detecting refractive index and liquid level according to claim 1, characterized in that: The first sensor comprises a first illumination fiber (3) and a first optical fiber (5); The first optical fiber (5) and the first lighting fiber (3) are intertwined and arranged in the second container (7), and the intertwined first optical fiber (5) and the first lighting fiber (3) extend to the bottom wall of the second container (7); The first optical fiber (5) and the first lighting fiber (3) are intertwined and arranged vertically.

3. The multi-parameter portable optical fiber sensor for simultaneously detecting refractive index and liquid level according to claim 2, characterized in that: The second sensor comprises a second illumination fiber (8) and a second optical fiber (4); The end of the second optical fiber (4) extends into the first container (6) and is entangled with the second lighting fiber (8); The second optical fiber (4) and the second lighting fiber (8) are intertwined and distributed in a ring shape and laid horizontally in the second container (7).

4. The multi-parameter portable optical fiber sensor for simultaneously detecting refractive index and liquid level according to claim 3, characterized in that: The vertically arranged first lighting fiber (3) is led out from the inner wall bottom of the second container (7) and separated from the upper opening of the second container (7), and the first lighting fiber (3) is connected to the second lighting fiber (8).

5. The multi-parameter portable optical fiber sensor for simultaneously detecting refractive index and liquid level according to claim 2, characterized in that: It also includes a vernier caliper, which is fixed parallel to the first optical fiber (5) and the first lighting fiber (3) that are entangled with each other, and the first sensor is connected to the vernier caliper.

6. The multi-parameter portable optical fiber sensor for simultaneously detecting refractive index and liquid level according to claim 3, characterized in that: The housing (1) comprises a light source connection port (11), a second camera connection port (12) and a first camera connection port (13); The light source connection port (11) is connected to the first lighting fiber (3), and the second camera connection port (12) and the first camera connection port (13) are connected to the second optical fiber (4) and the first optical fiber (5), respectively.

7. The multi-parameter portable optical fiber sensor for simultaneously detecting refractive index and liquid level according to claim 6, characterized in that: The terminal (2) includes at least two cameras (22) and a light-emitting unit (21); The two cameras (22) correspond to the second camera connection port (12) and the first camera connection port (13) respectively, and the light-emitting portion (21) corresponds to the light source connection port (11).

8. A multi-parameter smartphone portable optical fiber sensor and operating method for simultaneously detecting refractive index and liquid level, characterized in that: The method is applied to the multi-parameter smartphone portable optical fiber sensor for simultaneously detecting refractive index and liquid level according to any one of claims 1 to 7, comprising the following steps: Removably connecting the housing (1) to the terminal (2), ensuring that the terminal (2) is connected to the first sensor and the second sensor; Installing a first sensor in a first container (6) and installing a second sensor in a second container (7); activating the first sensor and the second sensor through the terminal (2), triggering the first sensor to detect the refractive index of the liquid in the first container (6), and the second sensor to detect the liquid level of the liquid in the second container (7); Using two cameras (22) of the terminal (2) to capture optical signal outputs of the first sensor and the second sensor respectively, wherein the optical signal of the first sensor is used for refractive index analysis, and the optical signal of the second sensor is used for liquid level analysis; The captured optical signal is processed on the terminal (2), and the refractive index of the liquid in the first container (6) and the liquid level of the liquid in the second container (7) are calculated and output.

9. The multi-parameter smartphone portable optical fiber sensor for simultaneous detection of refractive index and liquid level and the operating method according to claim 8, characterized in that: The method further comprises the following steps: Before triggering the first sensor and the second sensor, a light source is provided through the light emitting portion (21) of the terminal (2), and the light source is transmitted to the first lighting fiber (3) and the second lighting fiber (8) through the light source connection port (11) of the housing (1); Configuring parameters of two cameras (22) of the terminal (2), including ISO sensitivity and exposure time, to optimize capture of optical signals output by the first optical fiber (5) and the second optical fiber (4); During the detection process, the refractive index of the liquid in the first container (6) is detected based on the change in coupling power caused by the change in refractive index by utilizing the vertical structure in which the first optical fiber (5) and the first illumination fiber (3) are intertwined. Using a ring-shaped horizontal structure in which a second optical fiber (4) and a second illumination fiber (8) are wound around each other, the liquid level in the second container (7) is detected based on the coupling power change caused by the liquid level change; The captured optical signal is analyzed in real time by the terminal (2), and numerical results of the refractive index and the liquid level are generated and stored in the terminal (2) for subsequent query.

10. The multi-parameter smartphone portable optical fiber sensor for simultaneous detection of refractive index and liquid level and the operating method according to claim 8, characterized in that: The method further comprises the following steps: Before the detection begins, a vernier caliper is used to fix the first sensor, with the vernier caliper being parallel to the winding structure of the first optical fiber (5) and the first illumination fiber (3) to ensure the position stability of the first sensor in the first container (6); During the detection process, recording environmental parameters of the liquid in the first container (6) and the second container (7), including temperature and liquid type, and associating the environmental parameters with the detection data; Analyze the light signals from the first sensor and the second sensor, extract the grayscale pixel value of each frame using MATLAB or other signal processing software, and calculate the total light intensity; According to the total light intensity, the normalized intensity change of the refractive index and the normalized intensity change of the liquid level are calculated respectively, wherein the refractive index change is based on the air reference intensity, and the liquid level change is based on the zero liquid level reference intensity; The calculated refractive index and liquid level results are presented to the user through the display interface of the terminal (2), and the results can be transmitted to a remote device through a wireless module for further analysis.

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