Micro-pressure optical measurement system and method based on Michelson interferometer and smart phone

Abstract

The invention discloses a micro-pressure optical measurement system and method based on a Michelson interferometer and a smart phone. The micro-pressure optical measurement system comprises the Michelson interferometer, a hydraulic lever secondary displacement zooming module and a smart phone sensing module. According to the system, the liquid level height difference caused by weak pressure is scaled step by step and converted into nanoscale displacement of a movable reflecting mirror of an interferometer, so that interference fringes are caused to move. The optical sensor of the intelligent mobile phone is used for automatically recording and accurately counting stripe changes, a linear quantitative relation between the stripe change ring number and the pressure is established, and high-precision and automatic measurement of the millinewton-level weak pressure is achieved. The method has the advantages of low cost, simplicity and convenience in operation, high anti-interference capability and the like, and greatly expands the application scenes of the Michelson interferometer and the smart phone in physics teaching and scientific research.

Description

Technical Field

[0001] This invention belongs to the field of flat motor housing technology, and specifically discloses a micro-pressure optical measurement system, method and device based on a Michelson interferometer and a smartphone. Background Technology

[0002] Micro-pressure measurement plays a crucial role in cutting-edge technologies such as biomedicine, materials science, and microelectromechanical systems (MEMS) device testing. Currently, mainstream micro-pressure sensors mainly include capacitive, piezoresistive, and resonant types. While these sensors each have their own advantages, they generally suffer from some inherent drawbacks. For example, they are susceptible to electromagnetic interference from the environment, the measurement signal drifts significantly due to temperature changes, and their manufacturing costs increase dramatically under high precision and large range requirements, limiting their widespread adoption in certain applications.

[0003] To overcome the shortcomings of traditional electrical sensors, optical measurement methods offer an effective alternative. The Michelson interferometer is a classic and extremely precise optical interferometer. Its basic principle is to use amplitude division to split a beam of light into two paths, which interfere when they meet again after propagating along different paths. By accurately measuring the movement or "swallowing" of the interference fringes caused by minute changes in optical path difference, nanometer-scale displacement changes can be inferred. In traditional physics teaching and experiments, the Michelson interferometer is often used to measure the Young's modulus of metallic materials or the wavelength of lasers. However, these traditional experimental methods mostly rely on direct observation and manual counting of changes in interference fringes. This approach is not only prone to introducing large subjective errors, but also causes observer fatigue and cannot handle rapid and numerous fringe changes, which greatly limits its measurement efficiency and accuracy.

[0004] To achieve automated measurement, some studies have attempted to use CCD cameras, photoelectric sensors, and other devices to replace the human eye in detecting and counting stripes. However, these automated improvement schemes typically require specialized image acquisition cards, complex signal processing circuits, and specially developed host computer software. This makes the entire measurement system complex and costly, hindering its widespread application in routine teaching and low-cost scientific research.

[0005] In recent years, with the rapid development of information technology, the performance of smartphones has been greatly improved and they have become widely used globally. Today's smartphones integrate various high-precision sensors, such as ambient light sensors for automatically adjusting screen brightness, and also possess powerful data processing and computing capabilities. This makes it possible to develop them into portable, multi-functional measurement tools. Utilizing the built-in optical sensors of smartphones to detect changes in light intensity, combined with their powerful processors for data analysis, holds promise for combining high-precision optical measurement principles with convenient smart terminal technology. Therefore, developing a micro-pressure measurement solution that combines high precision, low cost, and ease of operation to meet the growing needs of scientific research and teaching has become an urgent technical problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing weak pressure measurement technologies and provide a micro-pressure optical measurement system and method based on a Michelson interferometer and a smartphone. Specifically, this invention aims to solve the following technical problems: 1. Existing capacitive and piezoresistive micro-pressure sensors are susceptible to electromagnetic interference, suffer from temperature drift, and are expensive to manufacture at high precision. 2. Traditional teaching and experimental methods using Michelson interferometers rely excessively on human observation and manual counting of interference fringes, resulting in large subjective errors, fatigue, and inability to process fast or large amounts of data. 3. Existing automated improvement schemes using CCD cameras or photoelectric sensors typically require specialized image acquisition cards, signal processing circuits, and host computer software, leading to complex and costly systems that are difficult to popularize in general teaching and low-cost research.

[0007] Therefore, this invention aims to combine the classic high-precision optical measurement principle with the widely adopted smart terminal technology to create a micro-pressure measurement solution that combines high precision, high sensitivity, low cost, strong anti-interference capability, and automated operation characteristics.

[0008] To achieve the above objectives, this invention discloses a micro-pressure optical measurement system based on a Michelson interferometer and a smartphone. This system uses a sophisticated mechanical design to convert the weak pressure to be measured into changes in optical path difference step by step, and uses a smartphone to realize automatic and accurate counting and data processing of interference fringe changes, ultimately achieving high-precision digital measurement of weak pressure.

[0009] This invention discloses a micro-pressure optical measurement system based on a Michelson interferometer and a smartphone, comprising: a Michelson interferometer module for generating optical path difference and forming interference fringes; a hydraulic transmission and displacement scaling module, mechanically connected to a movable mirror of the interferometer module, for converting the liquid level height difference caused by weak pressure into nanometer-level displacement of the movable mirror; and a smartphone optical sensing and data processing module, wherein the optical sensor is configured to collect the light intensity changes of the interference fringes and automatically count the number of moving rings of the fringes through a built-in program.

[0010] Preferably, the hydraulic transmission and displacement scaling module includes: a first-stage hydraulic scaling mechanism: a syringe and a graduated dropper connected by a silicone tube to form a communicating vessel; and a second-stage mechanical scaling mechanism: a lever mechanism mechanically connected between the piston of the syringe and the movable reflector of the interferometer module.

[0011] Preferably, the Kerson interferometer module includes a base, a first iron stand, and a second iron stand. A helium-neon laser, a beam expander, a beam splitter, a compensating mirror, a fixed first reflecting mirror, a second reflecting mirror, and a 1:20 lever are fixed on the base. The beam splitter and the compensating mirror are arranged parallel to each other and spaced apart. The helium-neon laser is positioned next to the beam splitter, and the second reflecting mirror and the 1:20 lever are positioned next to the compensating mirror. The first iron stand is located next to the base, and a syringe is horizontally fixed on the first iron stand. A graduated dropper is vertically fixed on the second iron stand. One end of the syringe is connected to a steel connecting rod, and the other end of the syringe is connected to the graduated dropper via a silicone tube. The second reflecting mirror contacts one end of the 1:20 lever via the steel connecting rod, and the other end of the 1:20 lever is connected to the piston handle of the syringe. The end of the syringe is connected to the graduated dropper via a silicone tube.

[0012] Preferably, the helium-neon laser is located at the beginning of the optical path, and a beam expander and a beam splitter are arranged sequentially on the optical path; the fixed first reflector is located on the optical path behind the beam splitter, and the second reflector is located on the optical path to the right of the beam splitter, so as to form two mutually perpendicular interference arms.

[0013] Preferably, the smartphone optical sensing and data processing module includes a smartphone and a phone holder; the phone holder is placed in front of the base so that the smartphone's optical sensor can face the interference pattern emitted from the beam splitter, thereby replacing the observation screen for signal acquisition.

[0014] This invention also discloses a method for micro-pressure measurement using a system, comprising the following steps: Step 1: Constructing an experimental setup, connecting a steel connecting rod to a second reflecting mirror and a 1:20 lever, connecting the left end of a syringe to the steel connecting rod and the right end to a silicone tube, connecting the other end of the silicone tube to a graduated dropper, adjusting the level to ensure the syringe is horizontal, fixing the smartphone holder, and ensuring the optical sensor is aligned with the interference pattern; Step 2: Launching the Phyphox software on the smartphone, accessing the "Original Sensor" menu to call up the optical sensor, setting the data recording mode for capturing interference. Step 3: Add a measured amount of water to the graduated dropper. Use the hydraulic pressure of the water column to move the syringe piston. The piston, through a steel connecting rod, drives the 1:20 lever and the second reflecting mirror to produce a slight displacement, changing the optical path difference of the Michelson interferometer and causing the interference fringes to "spit out" of light. The Phyphox software simultaneously records the curve of light intensity changing over time. Step 4: Read the number of peaks or troughs in the light intensity curve to determine the number of interference fringe rings ∆N. Combined with the laser wavelength λ=632.8nm, use the formula ∆d=∆N. Calculate the displacement ∆d of the second reflecting mirror using λ⁄2; Step 5: Based on the 1:20 lever displacement ratio α=20 and the displacement ratio of the graduated dropper to the syringe β=8.0847, obtained from experimental calibration, use the formula ∆h=α β Δd calculates the liquid level difference Δh in the graduated dropper; Step 6: Substitute the liquid density ρ, gravitational acceleration g, and the cross-sectional area S of the graduated dropper, and use the formula F=ρ g S ∆h is used to calculate the weak pressure F, thus completing the measurement.

[0015] Preferably, in step 3, different volumes of water need to be added multiple times for repeated measurements. Each time, an appropriate amount of water is added, the corresponding number of interference fringe changes is recorded, the pressure value of each measurement is calculated, and compared with the theoretical pressure value calculated based on the difference in liquid level position of the graduated dropper to evaluate the measurement deviation.

[0016] Preferably, in step 6, the cross-sectional area S of the graduated dropper is calculated by the inner diameter of the graduated dropper, and the inner diameter is measured using an indirect method with an accuracy of 0.1 mm.

[0017] Preferably, the laser wavelength λ is 632.8 nm, the lever displacement ratio α is 20, the liquid surface displacement ratio β is 8.0847, the liquid is water, and its density ρ is 1000 kg / m³. 3 The acceleration due to gravity g is taken as 9.8 m / s². 2 .

[0018] Preferably, step b is repeated multiple times, with different volumes of liquid added each time. The number of interference fringe changes is recorded each time, and the pressure measurement value is calculated. This value is then compared with the theoretical pressure value calculated based on the difference in liquid level position using a graduated dropper to assess the measurement deviation.

[0019] Preferably, the cross-sectional area S of the graduated dropper in step f is calculated by measuring the inner diameter of the graduated dropper using an indirect method, and the inner diameter measurement accuracy is retained to 0.1 mm.

[0020] Compared with existing technologies, this invention produces significant beneficial effects through its unique system configuration and measurement method: First, this invention possesses extremely high measurement accuracy and sensitivity. This effect stems from the core measurement principle employed by the system: utilizing a Michelson interferometer and a stable laser wavelength as the benchmark for precise measurement. The nanometer-level displacement of the movable mirror is directly calculated through the change in the number of interference fringe rings, fundamentally guaranteeing nanometer-level accuracy in displacement measurement. More importantly, the invention's unique hydraulic and lever-based two-stage displacement scaling module, through hydraulic transmission and the step-by-step scaling of the lever mechanism, converts a macroscopic and easily controlled change in liquid level height into a microscopic displacement of the mirror. This ingenious mechanical scaling design enables the system to respond to millinewton-level pressure changes, thereby achieving extremely high measurement sensitivity.

[0021] Secondly, this invention achieves extremely low manufacturing costs and broad applicability. Its core advantage lies in its innovative use of readily available smartphones and their built-in optical sensors, combined with corresponding software applications, to replace the expensive dedicated CCD cameras, image acquisition cards, and host computer software of traditional solutions. Simultaneously, other components of the system, such as syringes, graduated droppers, levers, and iron stands, are all standard and inexpensive laboratory equipment. This configuration significantly lowers the barrier to entry for building high-precision pressure measurement systems, making them not only suitable for scientific research but also easier to promote and popularize in teaching environments.

[0022] Furthermore, this invention possesses strong anti-interference capabilities. On one hand, the system employs the principle of optical interferometry for measurement, which is inherently unaffected by environmental electromagnetic interference, fundamentally superior to capacitive and piezoresistive electrical sensors. On the other hand, the constructed hydraulic and lever transmission system, particularly the fluid transmission component, effectively dampes and filters high-frequency mechanical vibrations, significantly suppressing the influence of external environmental vibrations on the measurement. This physical filtering mechanism ensures the stability of measurements and the reliability of results under ordinary experimental conditions.

[0023] Furthermore, this invention achieves a high degree of automation and intelligence in the measurement process. By utilizing a smartphone application, the system can automatically capture the light intensity and time curves corresponding to changes in interference fringes, and can automatically identify the number of peaks or troughs to determine the number of fringe rings through algorithms. This technical feature completely replaces the traditional method that relies on human observation and manual counting, avoiding subjective errors and visual fatigue. It makes the data acquisition and processing objective, efficient, and accurate, highly consistent with the trend of intelligent development in modern experimental techniques.

[0024] Finally, the system design of this invention has good scalability. Although the embodiments of this invention are mainly aimed at liquid pressure measurement, its core technical solution is to convert a pressure source into a measurable displacement. Therefore, by adapting the components that serve as the pressure input end, such as replacing them with a sealed gas pressure chamber or a platform that applies minute forces, this system can also be applied to measure micro-pressures of gases or minute forces in solids, providing a novel, low-cost, and high-precision measurement solution for fields such as materials mechanical property research. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments disclosed in this invention, the accompanying drawings of the embodiments will be briefly described below. These drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0026] Figure 1 This is a schematic diagram (front view) of the overall device of the micro-pressure optical measurement system provided in one embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram (top view) of the overall device of the micro-pressure optical measurement system provided in one embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the curve of interference light intensity changing over time, recorded using a smartphone application, in one embodiment of the present invention.

[0029] Figure 4 This is a linear fitting relationship diagram between the pressure to be measured and the number of rings of the interference fringes, plotted based on experimental data in one embodiment of the present invention.

[0030] Figure 5 This is a schematic diagram of the experimental principle of one embodiment of the present invention, illustrating the collaborative working principle of optical path, hydraulic transmission and mechanical scaling.

[0031] Figure 6 This is a schematic diagram of the lever assembly of a micro-pressure optical measurement system provided in one embodiment of the present invention. In the diagram: 1. Helium-neon laser; 2. Beam expander; 3. Beam splitter; 4. Compensator; 5. First reflecting mirror; 6. Second reflecting mirror; 7. Observation screen; 8. 1:20 lever; 9. Steel connecting rod; 10. Syringe; 11. Silicone tubing; 12. Graduated dropper; 13. First iron stand; 14. Second iron stand; 15. Base; 16. Power supply; 17. Mobile phone holder; 18. Level; 19. Smartphone A; 20. Smartphone B; 21. Pin; 22. Return spring; 23. Lever spring. Detailed Implementation

[0032] The technical solutions (including preferred technical solutions) of the present invention will be further described in detail below with reference to the accompanying drawings and by way of listing some optional embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] This invention provides a micro-pressure optical measurement system based on a Michelson interferometer and a smartphone, such as... Figure 1 and Figure 2As shown, it includes a helium-neon laser 1, a beam expander 2, a beam splitter 3, a compensating mirror 4, a first reflecting mirror 5, a second reflecting mirror 6, an observation screen 7, a 1:20 lever 8, a steel connecting rod 9, a syringe 10, a silicone tube 11, a graduated dropper 12, a first iron stand 13, a second iron stand 14, a base 15, a power supply 16, a mobile phone holder 17, a level 18, a smartphone A19, a pin 21, a return spring 22, and a lever spring 23, as well as a smartphone B20 for data display. The helium-neon laser 1, beam expander 2, beam splitter 3, compensating mirror 4, fixed first reflecting mirror 5, second reflecting mirror 6, and 1:20 lever 8 are fixed on the base 15. In terms of optical path layout, the beam splitter 3 and compensating mirror 4 are arranged parallel and spaced apart. The helium-neon laser 1 is located on one side of the incident light path of the beam splitter 3, while the compensating mirror 4, second reflecting mirror 6, and 1:20 lever 8 together form a movable interference arm located on one side of its transmission light path. A helium-neon laser 1 and a beam expander 2 are arranged on the left side of beam splitter 3, and a second reflector 6 and a 1:20 lever 8 are arranged on the right side of compensating mirror 4. A first reflector 5 is arranged above beam splitter 3 and compensating mirror 4, and a mobile phone holder 17 and a smartphone A19 are arranged below beam splitter 3 and compensating mirror 4.

[0035] The mobile phone holder 17 and the steel connecting rod 9 of the present invention are arranged around the core area where the beam splitter 3 and the compensating mirror 4 are located. The mobile phone holder 17 is located directly in front of the optical path of the beam splitter 3 and is used to support the smartphone to receive and record interference signals; while the steel connecting rod 9 is located in the movable interference arm, to the right rear of the compensating mirror 4, and serves as a mechanical transmission element connecting the second reflecting mirror 6 and the 1:20 lever 8.

[0036] The external mechanical hydraulic drive device consists of a first iron frame 13 and a second iron frame 14 and their components. The first iron frame 13 is placed next to the base 15, and the syringe 10 is horizontally fixed on it. The graduated dropper 12 is vertically fixed on the second iron frame 14.

[0037] As attached Figure 6 As shown, this invention discloses a hydraulically driven lever and slide rail actuation system. This system achieves precise scaling and transmission of the micrometer-level displacement output from the hydraulic system to a second reflector, resulting in nanometer-level displacement. The transmission chain of this invention consists of: a hydraulic transmission assembly, a lever assembly, and a second reflector. The hydraulic transmission assembly (whose output end is...) Figure 6 The telescopic rod 9 in the middle converts the change in liquid pressure into a linear displacement of the telescopic rod (piston rod). The lever assembly 8 receives the displacement from the telescopic rod 9 and uses the lever principle to perform mechanical scaling (displacement reduction).

[0038] The second reflector 6 of the present invention is mounted on a slide rail system and pushed by the other end of the lever assembly 8 to achieve the final, precise displacement along the optical path.

[0039] To achieve smooth and precise linear motion, the second reflector 6 is fixed to a mounting plate. This mounting plate is connected to a slider, which can slide freely on a guide rail arranged along the optical path. This ensures that the movement of the second reflector 6 is strictly linear, avoiding measurement errors caused by angular deflection. A pin 21 parallel to the optical path is fixed to the mounting plate. The tip of this pin maintains precise contact with one end of the lever assembly 8. The thrust of the lever is transmitted to the entire reflector mounting plate through this pin, thereby driving the movement of the second reflector. To allow space for the movement of the pin 21, corresponding clearance holes are provided on the limiting plate at the end of the guide rail. To enable the system to automatically return to the initial position after the external force is removed and to eliminate backlash, a lever spring 23 is provided in the system. A reset spring 22 for resetting the reflector is connected between the reflector mounting plate and the fixed limiting plate. Its function is to always provide a pulling force to the mounting plate opposite to the lever thrust. When the hydraulic pressure decreases and the lever thrust weakens, the spring will pull the second reflector and the entire sliding assembly back to the initial position.

[0040] The lever assembly 8 of this invention rotates about a rotation axis perpendicular to the optical path. One end (long lever arm end) contacts the telescopic rod 9 from the hydraulic system, and the other end (short lever arm end) contacts the ejector pin 21 on the reflector mounting plate. A lever spring 23 connects the lever 8 and the reflector mounting plate. The function of the lever spring 23 is to provide a slight tension to the lever, ensuring it always reliably presses against the telescopic rod 9 and the ejector pin 21. This works in conjunction with the return spring 22 to ensure that all contact points in the entire transmission chain (telescopic rod and lever, lever and ejector pin) are rigidly connected, completely eliminating displacement transmission errors and delays that may be caused by mechanical backlash, and guaranteeing extremely high system response sensitivity and repeatability.

[0041] As the liquid level in the upstream dropper rises, the pressure in the hydraulic chamber increases, pushing the telescopic rod 9 out. The telescopic rod pushes one end of the lever 8, causing it to rotate around the axis of rotation. The other end of the lever, with a reduced displacement, pushes the second reflector and its sliding assembly forward along the guide rail via the ejector pin 21. This forward displacement overcomes the tension of the reflector return spring 22 and the lever spring 23. When the liquid level drops and the pressure decreases, the resultant force of the two springs pushes the entire system precisely back to its original position in the opposite direction.

[0042] The second reflector 6 of this invention contacts the short arm end of the 1:20 lever 8 via a steel connecting rod 9; the long arm end of the 1:20 lever 8 is connected to the piston handle of the syringe 10, thereby converting the swing of the lever into the linear motion of the piston. In the hydraulic section, the nipple at the front end of the syringe 10 is connected to the lower end of the graduated dropper 12 via a silicone tube 11, forming a complete communicating vessel system for transmitting hydraulic changes within the graduated dropper to the syringe piston.

[0043] The optical platform of this invention belongs to the prior art. It includes a helium-neon laser 1, a beam expander 2, a beam splitter 3, a compensating mirror 4, a first reflecting mirror 5, a second reflecting mirror 6, and a 1:20 lever 8, all of which are securely fixed on a base 15. The helium-neon laser 1 is located to the left of the beam expander 2; the beam splitter 3, the compensating mirror 4, and the second reflecting mirror 6 are arranged sequentially on its right optical path; the first reflecting mirror 5 is located behind the beam splitter 3.

[0044] The optomechanical and hydraulic transmission system of this invention can replace the traditional micrometer screw gauge at the second reflector 6 with a precision transmission mechanism. The second reflector 6 is connected to a lever 8 via a steel connecting rod 9. The lever 8 is preferably a 1:20 lever, with the left side of the short arm of the lever 8 in contact with or connected by a thread. The right side of the long arm of the lever 8 is connected to the piston handle of a horizontally placed syringe 10. The syringe 10 is fixed on a first iron stand 13 and its level is precisely calibrated using a level 18. The tip of the syringe 10 is connected via a silicone tube 11 to a graduated dropper 12 placed vertically on a second iron stand 14, forming a communicating vessel.

[0045] The optical data acquisition system of the present invention is positioned at the front of the system, and the smartphone A19 is fixed by the phone holder 17, with its optical sensor aligned with the direction of interference fringe emission. In some embodiments, another smartphone B20 can be placed on a table for real-time display of the data acquired and processed by the smartphone A19.

[0046] The working principle of the light in this invention is as follows: hydraulic and lever two-stage displacement scaling principle: This invention establishes a precise and quantifiable conversion chain for changes in weak pressure, small displacement, optical path difference, and interference fringes by constructing a hydraulic and lever two-stage displacement scaling system.

[0047] The first-stage hydraulic scaling applies Pascal's principle and the principle of communicating vessels, using water as a liquid medium to transmit pressure, thus avoiding errors from complex mechanical transmissions. Utilizing the significant cross-sectional area difference between the slender graduated dropper 12 and the coarse syringe 10, millimeter-level changes in liquid level within the dropper are efficiently converted into micrometer-level linear displacements of the syringe piston.

[0048] The micrometer-level displacement of the second-stage mechanical scaling piston is further reduced by a rigid 1:20 lever 8. With the help of a precise lever-arm ratio, the second reflecting mirror 6 is ultimately driven to produce a nanometer-level mirror displacement.

[0049] This two-stage displacement scaling system not only perfectly matches the interferometer's measurement range with the displacement, but also significantly reduces the impact of liquid level reading errors. At the same time, its structure can effectively suppress external mechanical vibration noise, ensuring the stability of the measurement.

[0050] This invention introduces the optical sensor of the A19 smartphone and the Phyphox software to replace traditional human observation, solving the problems of fatigue and large subjective errors associated with manual reading in Michelson interferometry experiments. Compared to solutions using CCD or photodetectors, whose image processing systems are complex and costly, this solution is extremely low-cost and easy to implement. Using the Phyphox software, changes in bright and dark fringes can be identified in real time, and the number of interferometric fringe rings ΔN can be automatically recorded, improving the counting accuracy to ±0.5 rings. The experimentally recorded "light intensity and time" data can be exported to Excel format and processed by AI tools such as DeepSeek, achieving full automation from ring counting to outputting experimental results. This frees up hands, avoids human error, and significantly improves experimental accuracy.

[0051] The present invention also discloses a method for micro-pressure measurement using the above-mentioned device, which specifically includes the following steps: Step 1: Install the Phyphox (Physical Phone Experiments) application on your smartphone, launch the application, and click "Light" in the "Original Sensor" menu to call up the optical sensor and record the changes in the brightness of the interference fringes as the liquid surface shifts. Step 2: Determine the ratio of the syringe piston displacement to the liquid level displacement of the graduated dropper using an indirect method; Step three: Add a measured amount of water to a graduated dropper. The hydraulic pressure of the water column in the dropper slowly moves the syringe piston, causing a slight displacement of the mirror. This alters the optical path difference, resulting in a periodic change in light intensity, visually appearing as continuously "ejecting" rings. The corresponding changes in interference fringes are recorded using a smartphone's optical sensor; peaks represent bright fringes, and troughs represent dark fringes. By counting the number of peaks or troughs, the number of interference fringe rings can be determined. Step four: Calculate the pressure of the descending liquid column using relevant formulas. The data can be exported and further fitted and analyzed using Excel or AI data processing tools.

[0052] In step one, the syringe 10 is calibrated to be horizontal using a level 18. By adjusting the relative positions of the first reflector 5 and the second reflector 6, the laser emitted by the helium-neon laser 1 is made to form clear interference fringes in front. At this time, the observation screen 7 can be temporarily used to assist in observation. Then, the observation screen is removed, and the smartphone A19 with Phyphox software installed is fixed on the phone holder 17. The application is launched, and "Light" is clicked in the "Original Sensor" menu to call up the optical sensor and set it to data recording mode.

[0053] In step two, the ratio β of the liquid level displacement between the graduated dropper 12 and the piston of the syringe 10 is predetermined using an indirect method. In this embodiment, β = 8.0847. A measured amount of water is added to the graduated dropper. The hydraulic pressure generated by the water column drives the syringe piston to move slowly, which in turn causes a slight displacement of the second reflecting mirror via a lever, thereby changing the optical path difference and causing the interference fringes to continuously "emerge". The Phyphox software on the smartphone A19 simultaneously records the curve of light intensity changing over time, and this curve can be displayed in real time on the smartphone B20.

[0054] In step three, step two is repeated with different amounts of water, and multiple sets of corresponding interference fringe changes are recorded. The number of rings ΔN in each change is determined based on the recorded light intensity curves. The formula is then used... Calculate the pressure F applied in each operation, and the liquid density is... The acceleration due to gravity is The cross-sectional area of ​​the graduated dropper is The laser wavelength is The lever displacement ratio of 1:20 is The ratio of the displacement of the graduated dropper to that of the syringe is The measurement results are compared with the theoretical liquid column pressure calculated by directly reading the liquid level difference to evaluate the measurement effectiveness of this device and method.

[0055] In step four, the weak pressure signal passes sequentially through the hydraulic transmission and displacement scaling module, the Michelson interferometer module, and the smartphone optical sensing and data processing module, finally outputting the measurement result. Based on multiple sets of experimental data, the fitting expression between pressure x and the number of cycles y can be determined, such as y=24722x, 0.9945 obtained in this embodiment. This linear relationship effectively verifies the accuracy and reliability of the system.

[0056] In one specific embodiment, the operation method of the present invention is as follows: Step 1: Set up the experimental setup. Connect the steel connecting rod 9 to the second reflecting mirror 6 and the 1:20 lever 8. Connect the left end of the syringe 10 to the steel connecting rod 9 and the right end to the silicone tube 11. Connect the other end of the silicone tube 11 to the graduated dropper 12. Adjust the level 18 to make the syringe 10 horizontal. Fix the smartphone bracket 17 to ensure that the optical sensor is aligned with the interference pattern. Step 2: Launch the Phyphox software on your smartphone 19, enter the "Raw Sensor" menu to call up the optical sensor, and set the data recording mode to capture the light intensity fluctuations corresponding to the changes in the brightness of the interference fringes. Step 3: Add a measured amount of water to the graduated dropper 12. Use the hydraulic pressure of the water column to move the piston of the syringe 10. The piston, through the steel connecting rod 9, drives the 1:20 lever 8 and the second reflecting mirror 6 to produce a slight displacement, changing the optical path difference of the Michelson interferometer and causing the interference fringes to "spit out" of light. The Phyphox software simultaneously records the curve of light intensity changing over time. This step requires repeated measurements with different volumes of water added each time. Each time, add an appropriate amount of water, record the corresponding number of interference fringe changes, calculate the pressure value for each measurement, and compare it with the theoretical pressure value calculated based on the liquid level difference in the graduated dropper 12 to evaluate the measurement deviation. Step 4: Count the number of peaks or troughs in the illumination intensity curve to determine the number of interference fringe rings ∆N. Combined with the laser wavelength λ = 632.8 nm, use the formula ∆d = ∆N. Calculate the displacement ∆d of the second reflecting mirror 6 using λ⁄2; Step 5: Based on the displacement ratio α=20 of the 1:20 lever 8 and the displacement ratio β=8.0847 of the graduated dropper 12 and syringe 10, obtained from experimental calibration, the formula ∆h=α is used. B ∆d is used to calculate the height difference ∆h between the liquid levels in the graduated dropper. Step 6: Substitute the density ρ of the liquid into the value of water, taking 1000. Take the gravitational acceleration g as 9.8. And the cross-sectional area S of the graduated dropper, using the formula F=ρ g S The weak pressure F is calculated using ∆h to complete the measurement. The cross-sectional area S of the graduated dropper 13 is calculated using the inner diameter of the graduated dropper 13. The inner diameter measurement uses an indirect method, with an accuracy of 0.1 mm.

[0057] To make the technical solution, implementation process, and expected technical effects of the present invention clearer and more complete, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it should be clear that the following embodiments are intended to illustrate the core technology of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, based on the technical content disclosed in these embodiments, any modifications, equivalent substitutions, or improvements made by those skilled in the art without departing from the core idea of ​​the present invention should be considered to be included within the scope of protection of the present invention.

Claims

1. A micro-pressure optical measurement system based on a Michelson interferometer and a smartphone, comprising a Michelson interferometer module and a light signal receiving and processing module; the Michelson interferometer module includes a first reflecting mirror and a second reflecting mirror arranged perpendicularly to each other, and the light signal generated by the Michelson interferometer module passes sequentially through the second reflecting mirror and the first reflecting mirror before being received by the light signal receiving and processing module, characterized in that, The first reflector is fixedly mounted, and the second reflector is slidably connected to a guide rail extending along the optical path. The second reflector is connected to a lever assembly for moving it along the guide rail and a hydraulic transmission assembly for rotating the lever assembly. The hydraulic transmission assembly includes a hydraulic chamber and a telescopic rod arranged coaxially. The telescopic rod drives the lever assembly to rotate. The hydraulic chamber is connected to a dropper located above it through a pipe.

2. The micro-pressure optical measurement system based on a Michelson interferometer and a smartphone according to claim 1, characterized in that, A slider is provided on the guide rail, a mounting plate is connected to the slider, a second reflector is fixed on the mounting plate, a limit plate is provided at the end of the guide rail, and a return spring is provided between the limit plate and the mounting plate.

3. The micro-pressure optical measurement system based on a Michelson interferometer and a smartphone according to claim 2, characterized in that, The mounting plate is provided with a pin arranged parallel to the optical path, and the limiting plate is provided with a clearance hole for the pin to pass through, and the pin keeps in contact with the lever assembly.

4. The micro-pressure optical measurement system based on a Michelson interferometer and a smartphone according to claim 3, characterized in that, The lever assembly includes a rotating shaft disposed next to the limiting plate. The rotating shaft is arranged perpendicular to the optical path. A lever is hinged on the rotating shaft. The other end of the lever is connected to the telescopic rod. A spring is connected between the lever and the mounting plate.

5. The micro-pressure optical measurement system based on a Michelson interferometer and a smartphone according to claim 3, characterized in that, The optical signal receiving and processing module includes a smartphone and a phone holder; the smartphone is connected to the phone holder, and the smartphone is arranged corresponding to the first reflector.

6. A method for micro-pressure measurement using the system according to any one of claims 1 to 5, characterized in that, The process includes the following steps: Step a, applying a slight pressure to the fluid in the hydraulic transmission component to create a difference in fluid level; Step b, using the hydraulic transmission component to convert the change caused by the difference in fluid level into the input displacement of the lever component. Step c: By rotating the lever assembly, the input displacement is scaled to a nanometer-scale output displacement that drives the movable mirror in the Michelson interferometer, thereby causing the interference fringes to move; Step d: The optical sensor of a smartphone is used to automatically collect the light intensity change signal caused by the movement of the interference fringes; Step e: The collected light intensity change signal is processed to automatically count the number of changes in the interference fringes and determine the weak pressure value to be measured based on the number.

7. The method according to claim 6, characterized in that: In step a, the slight pressure is applied by adding a measured amount of liquid to a graduated dropper connected to the hydraulic transmission assembly.

8. The method according to claim 6, characterized in that: In step d, the optical sensor of the smartphone is arranged in the outgoing light path of the interferometer.

9. The method according to claim 6, characterized in that: In step e, a pre-calibrated linear relationship is established between the number of changes in the interference fringes and the weak pressure; the value of the weak pressure to be measured is calculated using this linear relationship.

10. The method according to claim 6, characterized in that: Repeat steps a to d multiple times, adding different volumes of liquid to the dropper each time. Compare the pressure measurement value calculated by this method each time with the theoretical pressure value calculated based on the volume, density, and cross-sectional area of ​​the added liquid.

Images