An optical fiber sensor circuit

Abstract

The utility model discloses a kind of optical fiber sensor circuits, including power supply circuit module, microcontroller circuit module, optical signal transmitting circuit module, optical signal receiving circuit module and signal output circuit module.Power supply circuit module is used to convert external input power supply into stable voltage output;Microcontroller circuit module is connected with power module, for controlling the operation of optical fiber sensor;Optical signal transmitting circuit module is connected with microcontroller module and optical fiber line, for producing adjustable intensity optical signal and emitting through optical fiber line;Optical signal receiving circuit module is connected with microcontroller module and optical fiber line, for receiving the optical signal transmission through optical fiber line and converting into electrical signal output to microcontroller module;Signal output circuit module is connected with microcontroller module, for outputting working condition indicating signal, switchable NPN / PNP signal and display information.The device utilizes different module, enhances the stability and anti-interference of optical fiber sensor circuit.

Description

Technical Field

[0001] This utility model relates to the field of fiber optic sensing technology, and in particular to a fiber optic sensor circuit. Background Technology

[0002] Fiber optic sensors are devices that use the optical properties of light to measure external parameters. Their working principle is that the light beam incident from the light source is transmitted to the sensor through an optical fiber. The external parameter being measured interacts with the light signal, causing changes in the optical properties of the light, such as intensity, wavelength, frequency, phase, or polarization state, forming a modulated light signal. This signal is then returned through the optical fiber and processed by an operational amplifier circuit, ultimately being converted into a distance parameter and compared with a reference value to output a switching signal.

[0003] However, existing fiber optic sensor circuits have several problems. First, the power supply circuit suffers from insufficient heat dissipation, high ripple noise, poor voltage output stability, and a significant decrease in power efficiency after prolonged operation, affecting system reliability. Second, interference exists between different components, degrading the quality of the analog signals acquired by the fiber optic sensor. Existing fiber optic sensors typically offer only one output mode, either NPN or PNP. In practical applications, adapting to different control systems often requires changing the sensor model or adding signal conversion circuits, increasing costs and reducing system flexibility and versatility. Furthermore, the display interface often uses digital tubes, which are complex and unintuitive, making it difficult for users to quickly obtain information and resulting in a poor user experience. Finally, the light-emitting diodes (LEDs) have limited accuracy, slow sampling speed, and insufficient detection accuracy for demanding scenarios. Utility Model Content

[0004] The purpose of this invention is to provide a fiber optic sensor circuit that solves the technical problems of existing fiber optic sensors, such as severe power supply overheating, high ripple noise, single signal output mode, and insufficient optical signal acquisition accuracy.

[0005] To solve the above-mentioned technical problems, this utility model provides an optical fiber sensor circuit, comprising: The power supply circuit module includes multiple power supply circuit units, which are used to convert external input power into a stable voltage output. A microcontroller circuit module, connected to the power supply module, is used to control the operation of the fiber optic sensor; An optical signal transmitting circuit module, connected to the microcontroller module and the optical fiber, includes a transmitting tube and a driving circuit, used to generate an adjustable intensity optical signal and transmit it through the optical fiber; An optical signal receiving circuit module, connected to the microcontroller module and the optical fiber, includes a light receiving tube and an operational amplifier circuit, used to receive optical signals transmitted through the optical fiber and convert them into electrical signals for output to the microcontroller module; The signal output circuit module is connected to the microcontroller module and is used to output working status indication signals, switchable NPN / PNP signals, and display information.

[0006] Furthermore, the power supply circuit module includes a DC-DC step-down unit, a first linear regulator unit, and a second linear regulator unit; The DC-DC step-down unit includes a DC-DC step-down chip, three diodes, a first protection wire, a first light-emitting diode, and a first transistor; The first diode, the first protective wire, and the first resistor are connected in series, and one end of the series connection is connected to the power supply voltage. One end of the second diode is connected between the first diode and the first protective wire, and connected to the third power supply; the other end is grounded. One end of the first capacitor is connected to the other end of the series connection of the first diode, the first protective wire, and the first resistor, and is connected to the first power supply; the other end is grounded. The first pin of the DC-DC step-down chip is connected to the sixth pin through the second capacitor. The second pin is grounded. The fourth pin is connected to the other end of the series connection between the first diode, the first protective wire, and the first resistor through the third resistor. The fifth pin is connected to the other end of the series connection between the first diode, the first protective wire, and the first resistor. The sixth pin is also connected to one end of the inductor. One end of the third diode is connected between the sixth pin of the DC-DC step-down chip and the inductor, and the other end is grounded; The source of the first transistor is connected to the other end of the inductor to form the first branch, the drain is grounded, and the gate is connected to the analog power supply. One end of the second resistor is connected to the first branch, and the other end is connected to one end of the sixth resistor, the other end of which is grounded. The third pin of the DC-DC step-down chip is connected between the second resistor and the sixth resistor, and is connected to the first branch via the third capacitor; One end of the fourth capacitor is connected to the first branch and to the second power supply, while the other end is grounded; One end of the fourth resistor is connected to the first branch, and the other end is grounded through the first light-emitting diode; One end of the fifth capacitor and the fifth resistor are both connected to the first branch, and the other end of each is connected to one end of the seventh resistor, the other end of which is grounded.

[0007] Furthermore, the first linear voltage regulator unit includes a first linear voltage regulator chip, an eighth resistor, a sixth capacitor, and a seventh capacitor; The first pin of the first linear regulator chip is connected to a 5V analog power supply through an eighth resistor, the second pin is grounded, and the third pin is connected to the analog power supply. A 5V analog power supply is also connected to one end of the sixth capacitor and one end of the seventh capacitor, and the other end of the sixth capacitor and the seventh capacitor are both grounded; The second linear regulator unit includes a second linear regulator chip; The first pin of the second linear regulator chip is connected to the analog power supply, the second pin is grounded, the third pin is connected to the analog power supply, and the fifth pin is connected to one end of the ninth resistor to form the second branch; The other end of the ninth resistor is connected to a 3.3V analog power supply; The analog power supply is also connected to one end of an eighth capacitor, and the other end of the eighth capacitor is grounded. The second branch is also connected to one end of the tenth resistor, the ninth capacitor, the tenth capacitor and the eleventh capacitor respectively. The other ends of the tenth resistor, the ninth capacitor, the tenth capacitor and the eleventh capacitor are all grounded. One end of the ninth capacitor is also connected to a 3.3V power supply. The 3.3V analog power supply is also connected to one end of the twelfth capacitor and the other end of the ninth resistor, and the other end of the twelfth capacitor is grounded.

[0008] Furthermore, the microcontroller circuit module includes a controller chip, an empty pin, a twelfth resistor, a fourteenth resistor, a thirteenth capacitor, a fourteenth capacitor, a fifteenth capacitor, and a seventeenth capacitor; The first pin of the controller chip is connected to a 3.3V power supply, and the sixth pin is grounded through the fourteenth resistor and the unused pin. The seventh pin of the controller chip is connected to a 3.3V power supply through the twelfth resistor and is also grounded through the fourteenth capacitor; The eighth pin of the controller chip is connected to analog ground; The ninth pin of the controller chip is connected to a 3.3V analog power supply and is also grounded through the fifteenth capacitor; The controller chip's 24th pin is connected to a 3.3V power supply and is also grounded through the 17th capacitor; The controller chip's 48th pin is connected to a 3.3V power supply and is also grounded through the 13th capacitor; The controller chip's 23rd, 44th, and 47th pins are all grounded.

[0009] Furthermore, the signal output circuit module includes an LED indicator circuit, which includes a second light-emitting diode, an eleventh resistor, and a thirteenth resistor; The first end of the second light-emitting diode is connected to the second pin of the controller chip through the eleventh resistor, the second end is grounded, the third end is connected to the third pin of the controller chip through the thirteenth resistor, and the fourth end is grounded.

[0010] Furthermore, the transmitting tube and driving circuit include a first connector, a first single-channel analog switch, a second single-channel analog switch, a third single-channel analog switch, a first operational amplifier, and a second transistor; The first pin of the first connector is connected to the collector of the second transistor, the second pin is connected to the second power supply through the nineteenth resistor, and the second pin is also grounded through the twenty-eighth capacitor; The base of the second transistor is grounded through the twenty-second resistor, and the emitter is grounded through the twenty-third resistor; The first pin of the first single-channel analog switch is connected to the emitter of the second transistor, the second pin is grounded through the twenty-ninth capacitor, the third pin is grounded, the fourth pin is connected to the tenth pin of the controller chip, and the fifth pin is connected to a 3.3V power supply. The first pin of the third single-channel analog switch is grounded through the twenty-ninth capacitor, the second pin is grounded through the thirtieth capacitor, the third pin is grounded, the fourth pin is grounded through the twenty-sixth resistor, and the fifth pin is connected to a 3.3V power supply. The fourth pin of the third single-channel analog switch is also connected to the sixteenth pin of the controller chip. The first pin of the second single-channel analog switch is grounded through the thirty-third capacitor, the second pin is connected to the second pin of the memory chip, the third pin is grounded, the fourth pin is grounded through the twenty-fifth resistor, and the fifth pin is connected to a 3.3V power supply. The fourth pin of the second single-channel analog switch is also connected to the tenth pin of the controller chip. The first pin of the first operational amplifier is connected to the seventeenth pin of the controller chip through the twenty-fourth resistor, the second pin is grounded, the third pin is connected to the fourth pin through the forty-fourth capacitor, the fourth pin is also grounded through the twenty-first resistor and the thirty-third capacitor, the fifth pin is connected to a 3.3V power supply, and the third pin of the first operational amplifier is grounded through the thirtieth capacitor; The second pin of the first operational amplifier is also connected to the thirty-first resistor and the thirty-second resistor, respectively.

[0011] Furthermore, the light-receiving tube and operational amplifier circuit include a second connector, a third transistor, a second operational amplifier, and a fourth diode; The first pin of the second connector is connected to one end of the thirty-fifth resistor, and the second pin is grounded; The other end of the thirty-fifth resistor is grounded through the forty-second capacitor and is also connected to one end of the thirty-third resistor; one end of the thirty-third resistor is also grounded through the forty-first capacitor, and the other end of the thirty-third resistor is connected to a 5V analog power supply. The first pin of the second operational amplifier is connected to the sixth pin through the thirty-fourth capacitor and the twenty-seventh resistor. The second pin is connected between the first pin and the thirty-fifth resistor of the second connector through the thirty-second resistor and the thirty-seventh capacitor. The third pin is connected to one end of the thirty-fourth resistor. The fourth pin is grounded. The fifth pin is connected to the other end of the thirty-fourth resistor. The seventh pin is connected to one end of the thirtieth resistor. The eighth pin is connected to a 5V analog power supply. The eighth pin is also grounded through the thirty-eighth capacitor. A 35th capacitor and a 29th resistor are also connected between the first and second pins of the second operational amplifier, respectively. The other end of the thirty-fourth resistor is connected to one end of the thirty-sixth resistor and one end of the forty-third capacitor. The other end of the thirty-sixth resistor is connected to a 5V analog power supply, and the other end of the forty-third capacitor is grounded. The third pin of the second operational amplifier and the thirty-fourth resistor are respectively connected to one end of the fortieth capacitor and the thirty-seventh resistor, and the other end of the fortieth capacitor and the thirty-seventh resistor is grounded. One end of the fourth diode is connected between the twenty-seventh resistor and the sixth pin of the second operational amplifier, and the other end is grounded; A 31st resistor and a 39th capacitor are also connected between the sixth pin and the seventh pin of the second operational amplifier, respectively. The other end of the thirtieth resistor is connected to the drain of the third transistor via the thirty-sixth capacitor. The source of the third transistor is connected to a 3.3V power supply, and the gate is connected to the eleventh pin of the controller chip. A twenty-eighth resistor is also connected between the drain and source of the third transistor.

[0012] Furthermore, the signal output circuit module includes an NPN / PNP signal output circuit; the NPN / PNP signal output circuit includes a first dual transistor array and a second dual transistor array; The first pin of the first dual transistor array is grounded, the second pin is connected to the second pin of the second dual transistor array, the third pin is connected to the twenty-second pin of the controller chip, the fourth pin is grounded, the fifth pin is connected to the fifth pin of the second dual transistor array, and the sixth pin is connected to the twenty-second pin of the controller chip. The first pin of the second dual transistor array is grounded through the forty-first resistor, the second pin is connected to the twenty-seventh pin of the controller chip through the fortyth resistor, the third pin is connected to the fifth pin of the second dual transistor array through the thirty-eighth resistor, the fourth pin is connected to the third power supply, the fifth pin is also connected to the third power supply through the thirty-ninth resistor, and the sixth pin is connected to the base of the fourth transistor. The emitter of the fourth transistor is connected to the fifth pin of the second dual transistor array, and the collector is connected to the collector of the fifth transistor via the seventh diode. The base of the fifth transistor is connected to the twenty-first pin of the controller chip through the forty-second resistor, the emitter is grounded through the forty-fourth resistor, and the emitter is also connected to the second pin of the second dual transistor array through the forty-third resistor. The collector of the fourth transistor is also connected to one end of the second protection wire, and the other end of the second protection wire is connected to one end of the fifth diode and the sixth diode, respectively. The other end of the fifth diode is connected to the third power supply, and the other end of the sixth diode is grounded.

[0013] Furthermore, the signal output circuit module also includes an OLED display circuit, which includes an OLED display screen, a third connector, and a fourth connector; The OLED display is connected to the third connector. The first pin of the third connector is connected to the positive power supply VPP, the second pin is connected to the bias voltage VCOMH, the third pin outputs the reference current, the fourth pin is connected to the seventeenth pin of the controller chip, the fifth pin is connected to the sixteenth pin of the controller chip, the sixth pin is connected to the twenty-fifth pin of the controller chip, the seventh pin is connected to the forty-fifth pin of the controller chip, the eighth pin is connected to the twenty-sixth pin of the controller chip and grounded through the fifteenth resistor, the ninth pin is connected to a 3.3V power supply, the tenth pin is grounded, the eleventh pin is connected to a 3.3V power supply and grounded through the sixteenth capacitor, the twelfth pin is connected to the thirteenth pin through the twenty-second capacitor, and the fourteenth pin is connected to the fifteenth pin through the eighteenth capacitor. The positive voltage is grounded through the twentieth and eleventh capacitors, respectively. The bias voltage is grounded through the nineteenth capacitor; The reference current is grounded through the sixteenth resistor; The first pin of the fourth connector is grounded, the second pin is connected to a 3.3V power supply, the third pin is connected to the forty-second pin of the controller chip, the fourth pin is connected to the forty-third pin of the controller chip, the fifth pin is connected to the forty-fifth pin of the controller chip, the sixth pin is connected to the twenty-fifth pin of the controller chip, and the seventh pin is connected to the twenty-sixth pin of the controller chip.

[0014] Furthermore, it also includes a button control circuit, which includes multiple button units, each of which includes a switch and a filter capacitor; The first pin of the switch is connected to the button signal output terminal and is also grounded through the filter capacitor; the second pin of the switch is grounded. The button signal output terminal is connected to the pin of the controller chip.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: This invention achieves coordinated operation of multiple functional modules, including power management, signal acquisition and processing, signal output, and human-machine interaction, through an integrated modular design. The power supply module employs a hybrid power supply method combining a DC-DC step-down unit and a linear regulator, effectively reducing ripple noise and improving power efficiency. The optical signal transmitting circuit module outputs adjustable intensity optical signals through a driver circuit, while the optical signal receiving circuit module converts the optical signal into a high-quality electrical signal through an operational amplifier circuit, improving measurement accuracy. The signal output circuit module supports switchable NPN / PNP signal output, enhancing the system's flexibility and adaptability to meet the needs of different application scenarios. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the connection of each module of the fiber optic sensor circuit in one embodiment of the present invention; Figure 2 This is a circuit diagram of the power supply circuit module in one embodiment of the present invention; Figure 3 This is a circuit diagram of the microcontroller circuit module and the LED indicator circuit in one embodiment of the present invention; Figure 4 This is a circuit diagram of the transmitting tube and driving circuit in one embodiment of the present invention; Figure 5 This is a circuit diagram of the light-receiving tube and operational amplifier circuit in one embodiment of the present invention; Figure 6 This is a circuit diagram of an NPN / PNP signal output circuit in one embodiment of the present invention; Figure 7This is a circuit diagram of an OLED display circuit in one embodiment of the present invention; Figure 8 This is a circuit diagram of the button control circuit in one embodiment of the present invention; Figure 9 This is a circuit diagram of the communication interface circuit in one embodiment of the present invention.

[0017] Reference numerals: U1, DC-DC step-down chip; U2, first linear regulator chip; U3, second linear regulator chip; U4, controller chip; U5, memory chip; U6, first connector; U7, first single-channel analog switch; U9, second single-channel analog switch; U10, third single-channel analog switch; U8, first operational amplifier; U11, second connector; FPC1, third connector; H1, fourth connector; U12, second operational amplifier; D1, first diode; D2, second diode; D3, third diode; D4, fourth diode; D5, fifth diode; D6, sixth diode; D7, seventh diode; F1, first protection wire; F2, second protection wire R1-R19, Resistors 1-19; R21-R44, Resistors 21-44; NC, Unused pin; C1-C22, Capacitors 1-22; C23-C26, Filter capacitors; C27-C44, Capacitors 27-44; SW1-SW4, Switches; L1, Inductor; LED1, First LED; LED2, Second LED; Q1, First transistor; Q2, Second transistor; Q3, Third transistor; Q4, First dual transistor array; Q6, Second dual transistor array; Q5, Fourth transistor; Q7, Fifth transistor; VPP, Positive power supply; VCOMH, Bias voltage; IREF, Reference current. Detailed Implementation

[0018] Based on the teachings of this specification, those skilled in the art can form new technical solutions by combining different implementation methods without creating technical contradictions. Such variations should be considered to fall within the protection scope of this patent.

[0019] The following is a more detailed description of a fiber optic sensor circuit according to the present invention, with reference to the schematic diagrams illustrating preferred embodiments. It should be understood that those skilled in the art can modify the present invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the present invention.

[0020] The present invention will be described in more detail below by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0021] like Figures 1 to 9 As shown, this utility model embodiment proposes an optical fiber sensor circuit, including: The power supply circuit module includes multiple power supply circuit units, which are used to convert external input power into a stable voltage output.

[0022] A microcontroller circuit module, connected to the power supply module, is used to control the operation of the fiber optic sensor.

[0023] An optical signal transmitting circuit module, connected to the microcontroller module and the optical fiber, includes a transmitting tube and a driving circuit, for generating an adjustable intensity optical signal and transmitting it through the optical fiber.

[0024] An optical signal receiving circuit module, connected to the microcontroller module and the optical fiber, includes a light receiving tube and an operational amplifier circuit, used to receive optical signals transmitted through the optical fiber and convert them into electrical signals for output to the microcontroller module.

[0025] The signal output circuit module is connected to the microcontroller module and is used to output working status indication signals, switchable NPN / PNP signals, and display information.

[0026] The overall operation of the fiber optic sensor circuit relies on the coordinated operation of its various functional modules. The external input power is first converted into a stable voltage output by multiple power circuit units within the power supply module, effectively preventing performance degradation due to power efficiency attenuation. The microcontroller circuit module dynamically regulates the overall workflow in real time, improving control accuracy and response efficiency. Under the command and control of the microcontroller circuit module, the optical signal transmitting circuit module generates an adjustable intensity optical signal through the transmitting tube and driving circuit, which is then transmitted to the external environment via the optical fiber. The adjustable mechanism allows the light source to adapt to different distances and media detection conditions, enhancing the flexibility and environmental adaptability of signal transmission. After receiving the optical signal transmitted through the optical fiber, the optical signal receiving circuit module uses a receiving tube and operational amplifier circuit to convert the optical signal into an electrical signal, and precisely amplifies and suppresses noise in weak signals, effectively reducing the impact of external interference on the analog signal quality, thereby improving the accuracy and stability of signal conversion. Based on the processing results of the microcontroller circuit module, the signal output circuit module outputs a working status indication signal, a switchable NPN / PNP signal, and display information. The switching of the NPN / PNP signal between high and low levels determines whether it is a normally open or normally closed NPN output or a normally open or normally closed PNP output, enhancing the adaptability to different application scenarios and improving the flexibility of use.

[0027] This application further proposes a power supply circuit module, such as Figure 2 As shown, the power supply circuit module includes a DC-DC buck unit, a first linear regulator unit, and a second linear regulator unit. The DC-DC buck unit is responsible for quickly reducing the higher input voltage to an intermediate voltage. Due to its high conversion efficiency, DC-DC converters are suitable for handling large voltage differences, but their output contains a certain amount of switching ripple. The first and second linear regulator units further regulate the output of the DC-DC buck unit. The linear regulator unit has the advantages of low output ripple and low noise, providing clean power to analog and digital circuits with high power quality requirements. Through this two-stage conversion architecture, both high power conversion efficiency and excellent output power quality are ensured.

[0028] Specifically, such as Figure 2 As shown, the DC-DC step-down unit includes a DC-DC step-down chip U1, three diodes, a first protection wire F1 (which can be an nSMD010 model), a first light-emitting diode LED1 (which can be an NCD0603G1 model), and a first transistor Q1 (which can be a BSS84 model).

[0029] The first diode D1, the first protective wire F1, and the first resistor R1 are connected in series, with one end of the series connection connected to the power supply voltage. One end of the second diode D2 is connected between the first diode D1 and the first protective wire F1, and connected to the third power supply VCC3; the other end is grounded. The first diode D1 provides reverse connection protection, preventing damage to the circuit when the power supply polarity is reversed. The first protective wire F1 acts as an overcurrent protection element, automatically blowing when a short circuit or overload occurs, cutting off the power input and protecting the downstream circuits. The second diode D2, in conjunction with the third power supply VCC3, provides a backup power path in case of power failure or abnormality.

[0030] One end of the first capacitor C1 is connected to the other end of the series connection of the first diode D1, the first protective wire F1, and the first resistor R1, and is connected to the first power supply VCC1. The other end is grounded. As an input filter capacitor, the first capacitor C1 can filter out high-frequency noise and transient interference in the input power supply, while providing a stable input voltage for the DC-DC step-down chip U1, preventing input voltage fluctuations from affecting conversion efficiency and output stability.

[0031] The first pin of the DC-DC step-down chip is connected to the sixth pin through the second capacitor C2. The second pin is grounded. The fourth pin is connected to the other end of the series connection of the first diode D1, the first protective wire F1 and the first resistor R1 through the third resistor R3. The fifth pin is connected to the other end of the series connection of the first diode D1, the first protective wire F1 and the first resistor R1. The sixth pin is also connected to one end of the inductor L1.

[0032] One end of the third diode D3 is connected between the sixth pin of the DC-DC step-down chip U1 and the inductor L1, and the other end is grounded. As a freewheeling diode, the third diode D3 provides a freewheeling path for the current in inductor L1 during the turn-off period, preventing the reverse electromotive force generated by inductor L1 from damaging the switch and improving energy conversion efficiency.

[0033] The source of the first transistor Q1 is connected to the other end of the inductor L1, forming the first branch. Its drain is grounded, and its gate is connected to the analog power supply AVCC. The output current is adjusted by controlling the conduction state of the first transistor to achieve startup or overcurrent protection functions. One end of the second resistor R2 is connected to the first branch, and the other end is connected to one end of the sixth resistor R6, the other end of which is grounded. The third pin of the DC-DC step-down chip U1 is connected between the second resistor R2 and the sixth resistor R6, and is connected to the first branch via the third capacitor C3. One end of the fourth capacitor C4 is connected to the first branch and to the second power supply VCC2, while the other end is grounded. The fourth capacitor C4 acts as an output filter capacitor, further filtering out ripple in the output voltage.

[0034] One end of the fourth resistor R4 is connected to the first branch, and the other end is grounded through the first LED1. The first LED1 serves as a power indicator, lighting up when the DC-DC step-down unit is operating normally, providing the user with a clear indication of the power status. The fourth resistor R4 limits the current flowing through the LED, preventing excessive current from damaging it. One end of both the fifth capacitor C5 and the fifth resistor R5 is connected to the first branch, and the other end is connected to one end of the seventh resistor R7, the other end of which is grounded. The fifth capacitor C5, the fifth resistor R5, and the seventh resistor R7 form an additional filter network, further reducing high-frequency noise in the output voltage and providing a cleaner power supply for circuits with strict power ripple requirements. This multi-stage filtering design effectively suppresses the interference of switching noise generated by the DC-DC converter on analog circuits.

[0035] In this embodiment, the first linear voltage regulator unit includes a first linear voltage regulator chip U2, an eighth resistor R8, a sixth capacitor C6, and a seventh capacitor C7.

[0036] The first pin of the first linear regulator chip U2 is connected to a 5V analog power supply AVCC via an eighth resistor R8, the second pin is grounded, and the third pin is also connected to the analog power supply AVCC. The 5V analog power supply AVCC is also connected to one end of the sixth capacitor C6 and the seventh capacitor C7, respectively, and the other ends of both capacitors C6 and C7 are grounded. The sixth capacitor C6 and the seventh capacitor C7 serve as output filter capacitors, filtering out noise in different frequency ranges. Typically, the sixth capacitor C6 is a large-capacity electrolytic capacitor used to filter out low-frequency ripple and provide energy storage; the seventh capacitor C7 is a small-capacity ceramic capacitor used to filter out high-frequency noise. The parallel connection of these two capacitors provides good filtering performance over a wide frequency range.

[0037] In this embodiment, the second linear voltage regulator unit includes a second linear voltage regulator chip U3.

[0038] The first pin of the second linear regulator chip U3 is connected to the analog power supply AVCC, the second pin is grounded, the third pin is connected to the analog power supply AVCC, and the fifth pin is connected to one end of the ninth resistor R9, forming the second branch. The other end of the ninth resistor R9 is connected to the 3.3V analog power supply AVCC. As a series resistor at the output, the ninth resistor R9 improves load regulation and transient response, while also providing some overcurrent protection.

[0039] The analog power supply AVCC is also connected to one end of the eighth capacitor C8, the other end of which is grounded. The eighth capacitor C8 provides filtering and energy storage for the input of the second linear regulator chip U3, maintaining a stable input voltage when the load current changes rapidly and preventing input voltage fluctuations from affecting the normal operation of the regulator chip. The second branch is also connected to one end of the tenth resistor R10, the ninth capacitor C9, the tenth capacitor C10, and the eleventh capacitor C11, the other ends of which are all grounded. One end of the ninth capacitor C9 is also connected to a 3.3V power supply. The 3.3V analog power supply AVCC is also connected to one end of the twelfth capacitor C12 and the other end of the ninth resistor R9, the other end of which is grounded. Through the synergistic effect of multiple filtering capacitors, the output quality of the 3.3V analog power supply AVCC is fully guaranteed.

[0040] Through the design of the power supply circuit module, this application effectively suppresses ripple noise in the power output, improves the stability of the voltage output, and enhances the reliability of high-precision signal processing of the fiber optic sensor under long-term operation.

[0041] In this embodiment, as Figure 3 As shown, the microcontroller circuit module includes a controller chip U4, an unused pin NC, a twelfth resistor R12, a fourteenth resistor R14, a thirteenth capacitor C13, a fourteenth capacitor C14, a fifteenth capacitor C15, and a seventeenth capacitor C17.

[0042] The first pin of the controller chip U4 is connected to a 3.3V power supply, and the sixth pin is grounded through the fourteenth resistor R4 and the unused NC pin. The seventh pin of the controller chip U4 is connected to a 3.3V power supply through the twelfth resistor R12 and is also grounded through the fourteenth capacitor C14. The eighth pin of the controller chip U4 is connected to analog ground AGND. The ninth pin of the controller chip U4 is connected to a 3.3V analog power supply AVCC and is also grounded through the fifteenth capacitor C15. The twenty-fourth pin of the controller chip U4 is connected to a 3.3V power supply and is also grounded through the seventeenth capacitor C17. The forty-eighth pin of the controller chip U4 is connected to a 3.3V power supply and is also grounded through the thirteenth capacitor C13. The twenty-third, forty-fourth, and forty-seventh pins of the controller chip U4 are all grounded.

[0043] The controller chip U4 typically uses a 32-bit ARM core microcontroller with rich peripheral interfaces and powerful data processing capabilities. The unused pin NC is a reserved test point or debugging interface. Grounding it via the fourteenth resistor R14 provides a defined voltage level, preventing interference or controller malfunction caused by a floating pin. The fourteenth capacitor C14 provides a reset delay or debouncing function. At power-on, the capacitor charges to delay the establishment of the reset signal, releasing the reset state only after the controller chip U4's power supply stabilizes, avoiding malfunctions caused by voltage fluctuations during power-on. The eighth pin of the controller chip U4 is connected to analog ground AGND. Separating analog and digital grounds is an important means of reducing interference from digital circuit noise to analog circuits. The eighth pin serves as an analog ground reference, providing a clean ground reference for analog functional modules such as the analog-to-digital converter (ADC) inside the controller, improving the accuracy of analog signal acquisition. Each power supply pin is equipped with an independent decoupling capacitor, providing transient current locally, suppressing power supply noise, and improving anti-interference capability and operational stability.

[0044] In this embodiment, the signal output circuit module includes an LED indicator circuit, which includes a second light-emitting diode (LED2), an eleventh resistor (R11), and a thirteenth resistor (R13). The first terminal of the second light-emitting diode (LED2) is connected to the second pin of the controller chip U4 through the eleventh resistor (R11), and the second terminal is grounded. The third terminal is connected to the third pin of the controller chip U4 through the thirteenth resistor (R13), and the fourth terminal is grounded.

[0045] The second LED, LED2, is a dual-color LED with two anodes, a first terminal and a third terminal, each corresponding to a different emission color, such as red and green. By controlling the output states of the second and third pins, three display modes can be achieved: when the second pin outputs a high level and the third pin outputs a low level, the first terminal emits light to display the first color; when the second pin outputs a low level and the third pin outputs a high level, the third terminal emits light to display the second color; when both pins output a high level simultaneously, both terminals emit light simultaneously, mixing to form the third color. This design can achieve multiple status indications with a minimal number of pins and components, such as green for normal operation, yellow for detected object, and red for fault alarm. The eleventh resistor R11 and the thirteenth resistor R13 limit the current flowing through the two emission terminals, protecting the LED from damage due to excessive current and adjusting the brightness.

[0046] In this embodiment, as Figure 4As shown, the transmitting tube and driving circuit include a first connector U6, a first single-channel analog switch U7 (which can be a 74LVC1G66GW, 125 model), a second single-channel analog switch U9 (which can be a 74LVC1G66GW, 125 model), a third single-channel analog switch U10 (which can be a 74LVC1G66GW, 125 model), a first operational amplifier U8, and a second transistor Q2 (which can be a BCX56-16 model).

[0047] The first pin of the first connector U6 is connected to the collector of the second transistor Q2, and the second pin is connected to the second power supply VCC2 through the nineteenth resistor R19. The second pin is also grounded through the twenty-eighth capacitor C28. The base of the second transistor Q2 is grounded through the twenty-second resistor R22, and the emitter is grounded through the twenty-third resistor R23. The twenty-second resistor R22 provides a pull-down resistor to the base, keeping the transistor in the off state when there is no drive signal. The twenty-third resistor R23 provides negative feedback to the emitter, stabilizing the operating point and limiting the emitter current. This design prevents operating point drift caused by temperature changes and improves the stability of the drive circuit.

[0048] The first pin of the first single-channel analog switch U7 is connected to the emitter of the second transistor Q2, the second pin is grounded through the twenty-ninth capacitor C29, the third pin is grounded, the fourth pin is connected to the tenth pin of the controller chip U4, and the fifth pin is connected to a 3.3V power supply. The first single-channel analog switch U7 is used to control the operating mode or light intensity level of the emitting diode. When the tenth pin of the controller chip U4 outputs a high level, the analog switch is turned on, and the first and second pins are connected; when the output is low, the analog switch is turned off. The twenty-ninth capacitor C29 provides filtering for the switch output, reducing transient interference caused by the switching action. By controlling the on / off state of the analog switch, the emitted light intensity can be adjusted in stages or pulsed modulated.

[0049] The first pin of the second single-channel analog switch U9 is grounded through the thirty-third capacitor C33, the second pin is connected to the second pin of the memory chip U5, the third pin is grounded, the fourth pin is grounded through the twenty-fifth resistor R25, and the fifth pin is connected to a 3.3V power supply. The fourth pin of the second single-channel analog switch U9 is also connected to the tenth pin of the controller chip U4.

[0050] The second single-channel analog switch U9 is used to control the connection with the memory chip U5, which stores data that needs to be retained even when the power is off, such as the configuration parameters and calibration coefficients of the fiber optic sensor. By controlling access to the memory through the analog switch, the connection can be disconnected when reading or writing is not needed, reducing power consumption and interference.

[0051] The first pin of the third single-channel analog switch U10 is grounded through the twenty-ninth capacitor C29, the second pin is grounded through the thirtieth capacitor C30, the third pin is grounded, the fourth pin is grounded through the twenty-sixth resistor R26, and the fifth pin is connected to a 3.3V power supply. The fourth pin of the third single-channel analog switch U10 is also connected to the sixteenth pin of the controller chip U4.

[0052] The third single-channel analog switch U10 works in conjunction with the first single-channel analog switch U7 to implement more complex transmit control logic. The twenty-sixth resistor R26 provides a pull-down to the control pin, keeping the switch in a defined state when the control signal is not connected.

[0053] The first pin of the first operational amplifier U8 is connected to the seventeenth pin of the controller chip U4 through the twenty-fourth resistor R24. The second pin is grounded. The third pin is connected to the fourth pin through the forty-fourth capacitor C44. The fourth pin is also grounded through the twenty-first resistor R21 and the thirty-third capacitor C33. The fifth pin is connected to a 3.3V power supply. The third pin of the first operational amplifier U8 is grounded through the thirtieth capacitor C30. The second pin of the first operational amplifier U8 is also connected to the thirty-first resistor R31 and the thirty-second resistor R32.

[0054] The first operational amplifier U8 converts the signal output from the controller chip U4 into a voltage signal to drive the second transistor Q2. The twenty-fourth resistor R24 ​​is an input current-limiting resistor to protect the input terminal of the operational amplifier. The forty-fourth capacitor C44 and the twenty-first resistor R21 form an integrating or low-pass filter network to convert the signal into a smooth analog voltage.

[0055] In this embodiment, as Figure 5 As shown, the light receiving tube and operational amplifier circuit includes a second connector U11, a third transistor Q3, a second operational amplifier U12, and a fourth diode D4 (LM3Z5V1T1G model can be used).

[0056] The first pin of the second connector U11 is connected to one end of the thirty-fifth resistor R35, and the second pin is grounded. The second connector U11 is used to connect the optical fiber receiver head.

[0057] The other end of the thirty-fifth resistor R35 is grounded through the forty-second capacitor C42 and is also connected to one end of the thirty-third resistor R33; one end of the thirty-third resistor R33 is also grounded through the forty-first capacitor C41, and the other end of the thirty-third resistor R33 is connected to a 5V analog power supply AVCC. The thirty-fifth resistor R35 acts as the load resistor for the receiving tube, converting the photocurrent into a voltage signal. When the receiving tube receives a light signal, it generates a photocurrent, which flows through the thirty-fifth resistor R35, producing a voltage drop whose amplitude is proportional to the light intensity. The forty-second capacitor C42 and the thirty-fifth resistor R35 are connected in parallel to form a low-pass filter, filtering out high-frequency noise and smoothing the output voltage.

[0058] The first pin of the second operational amplifier U12 is connected to the sixth pin via the thirty-fourth capacitor C34 and the twenty-seventh resistor R27. The second pin is connected between the first pin of the second connector U11 and the thirty-fifth resistor R35 via the thirty-second resistor R35 and the thirty-seventh capacitor C37. The third pin is connected to one end of the thirty-fourth resistor R34. The fourth pin is grounded. The fifth pin is connected to the other end of the thirty-fourth resistor R34. The seventh pin is connected to one end of the thirtieth resistor R30. The eighth pin is connected to the 5V analog power supply AVCC and is also grounded via the thirty-eighth capacitor C38. The thirty-fifth capacitor C35 and the twenty-ninth resistor R29 are also connected between the first and second pins of the second operational amplifier U12. The second operational amplifier U12 constitutes a multi-stage amplifier circuit to amplify the weak signal output from the optical receiver. The thirty-fifth capacitor C35 and the twenty-ninth resistor R29 form a feedback network, which, in conjunction with the thirty-second resistor R32, is used to determine the gain and frequency characteristics of the operational amplifier. By selecting appropriate resistor and capacitor values, the required amplification factor and bandwidth can be achieved, maintaining a good signal-to-noise ratio while increasing the signal amplitude.

[0059] The other end of the thirty-fourth resistor R34 is connected to one end of the thirty-sixth resistor R36 and the forty-third capacitor C43. The other end of the thirty-sixth resistor R36 is connected to a 5V analog power supply AVCC, and the other end of the forty-third capacitor C43 is grounded. The third pin of the second operational amplifier U12 is also connected to one end of the fortieth capacitor C40 and the thirty-seventh resistor R37, respectively, between the thirty-fourth resistor R34 and the fortieth capacitor C40. The other ends of the fortieth capacitor C40 and the thirty-seventh resistor R37 are grounded. One end of the fourth diode D4 is connected between the twenty-seventh resistor R27 and the sixth pin of the second operational amplifier U12, and the other end is grounded. The fourth diode D4 acts as a clamping protection element, limiting the voltage range of the feedback signal and preventing abnormal signals from causing excessive voltage at the operational amplifier input, which could damage the device. The thirty-sixth resistor R36 provides a pull-up or bias to the output of the operational amplifier, and the forty-third capacitor C43 filters out high-frequency noise at the output, stabilizing the output voltage.

[0060] A 31st resistor R31 and a 39th capacitor C39 are connected between the sixth and seventh pins of the second operational amplifier U12, respectively. The other end of the 30th resistor R30 is connected to the drain of the third transistor Q3 via the 36th capacitor C36. The source of the third transistor Q3 is connected to a 3.3V power supply, and its gate is connected to the 11th pin of the controller chip U4. A 28th resistor R28 is also connected between the drain and source of the third transistor Q3.

[0061] The controller chip U4 outputs a control signal through pin 11 to adjust the conduction level of the third transistor Q3, thereby changing the impedance and gain of the signal path. This design can automatically adjust the amplification factor according to the intensity of the received optical signal, reducing gain to prevent saturation under strong light conditions and increasing gain to enhance sensitivity under weak light conditions, achieving wide dynamic range optical signal detection. The entire receiving amplification circuit, through multi-stage amplification, filtering, and automatic gain adjustment, can convert weak optical signals into high-quality electrical signals, providing reliable input for subsequent processing by the microcontroller.

[0062] In this embodiment, the signal output circuit module includes an NPN / PNP signal output circuit. For example... Figure 6 As shown, the NPN / PNP signal output circuit includes a first dual transistor array Q4 and a second dual transistor array Q6. A dual transistor array is a device that integrates two transistors, featuring a compact structure and good parameter matching.

[0063] The first pin of the first dual transistor array Q4 is grounded, the second pin is connected to the second pin of the second dual transistor array Q6, the third pin is connected to the twenty-second pin of the controller chip U4, the fourth pin is grounded, the fifth pin is connected to the fifth pin of the second dual transistor array Q6, and the sixth pin is connected to the twenty-second pin of the controller chip U4.

[0064] The first pin of the second dual transistor array Q6 is grounded through the forty-first resistor R41, the second pin is connected to the twenty-seventh pin of the controller chip U4 through the fortieth resistor R40, the third pin is connected to the fifth pin of the second dual transistor array Q6 through the thirty-eighth resistor R38, the fourth pin is connected to the third power supply VCC3, the fifth pin is also connected to the third power supply VCC3 through the thirty-ninth resistor R39, and the sixth pin is connected to the base of the fourth transistor Q5.

[0065] The emitter of the fourth transistor Q5 (which can be a BC807-40, 215 model) is connected to the fifth pin of the second dual transistor array Q6, and the collector is connected to the collector of the fifth transistor Q7 via the seventh diode D7 (which can be a 1N5819HV67-F model).

[0066] The base of the fifth transistor Q7 (which can be model 2SD1782KT146R) is connected to the twenty-first pin of the controller chip U4 through the forty-second resistor R40, and the emitter is grounded through the forty-fourth resistor R44. The emitter is also connected to the second pin of the second dual transistor array Q6 through the forty-third resistor R43.

[0067] The collector of the fourth transistor Q5 is also connected to one end of the second protection wire F2. The other end of the second protection wire F2 is connected to one end of the fifth diode D5 (which can be an SMF36CA model) and the sixth diode D6 (which can be an SMF36CA model). The other end of the fifth diode D5 is connected to the third power supply VCC3, and the other end of the sixth diode D6 is grounded.

[0068] The second protective fuse, F2, acts as an overcurrent protection element, automatically blowing when the output current exceeds its rated value, protecting the output circuit and load equipment. The fifth diode, D5, is connected to the third power supply, VCC3, providing a current path in PNP output mode and also acting as a clamping protection to prevent the output voltage from exceeding the power supply voltage. The sixth diode, D6, is connected to ground, providing a current loop in NPN output mode and preventing the output voltage from falling below ground potential. This bidirectional protection design can accommodate the different current directions in both NPN and PNP output modes, providing comprehensive protection for the output circuit.

[0069] In this embodiment, the signal output circuit module further includes an OLED display circuit. For example... Figure 7 As shown, the OLED display circuit includes an OLED display screen, a third connector FPC1 (which can be model X03A10L15G), and a fourth connector H1 (which can be model PZ254V-11-07P). OLED displays have advantages such as self-illumination, high contrast, fast response speed, and wide viewing angle, and can provide clear display effects under various ambient light conditions.

[0070] The OLED display is connected to the third connector FPC1. The first pin of the third connector FPC1 is connected to the positive power supply VPP, the second pin is connected to the bias voltage VCOMH, the third pin outputs the reference current IREF, the fourth pin is connected to the seventeenth pin of the controller chip U4, the fifth pin is connected to the sixteenth pin of the controller chip U4, the sixth pin is connected to the twenty-fifth pin of the controller chip U4, the seventh pin is connected to the forty-fifth pin of the controller chip U4, the eighth pin is connected to the twenty-sixth pin of the controller chip U4 and grounded through the fifteenth resistor R15, the ninth pin is connected to a 3.3V power supply, the tenth pin is grounded, the eleventh pin is connected to a 3.3V power supply and grounded through the sixteenth capacitor C16, the twelfth pin is connected to the thirteenth pin through the twenty-second capacitor C22, and the fourteenth pin is connected to the fifteenth pin through the eighteenth capacitor C18. The positive voltage is grounded through the twentieth capacitor C20 and the twenty-first capacitor C21, the bias voltage VCOMH is grounded through the nineteenth capacitor C19, and the reference current IREF is grounded through the sixteenth resistor R16.

[0071] The positive power supply VPP connected to the first pin provides power to the pixel driver of the OLED display. This voltage is typically higher than the logic power supply to meet the driving voltage required for OLED light emission. The bias voltage VCOMH connected to the second pin is used to adjust the display contrast and brightness; adjusting this voltage optimizes the display effect. The reference current IREF output from the third pin sets the reference for the pixel drive current, and the display brightness can be adjusted via an external resistor.

[0072] The first pin of the fourth connector H1 is grounded, the second pin is connected to a 3.3V power supply, the third pin is connected to the forty-second pin of the controller chip U4, the fourth pin is connected to the forty-third pin of the controller chip U4, the fifth pin is connected to the forty-fifth pin of the controller chip U4, the sixth pin is connected to the twenty-fifth pin of the controller chip U4, and the seventh pin is connected to the twenty-sixth pin of the controller chip U4.

[0073] In this embodiment, a button control circuit is also included. For example... Figure 8As shown, the button control circuit includes multiple button units, each of which includes a switch (such as model T-TC018A-H0375-L1) and a filter capacitor. The first pin of the switch is connected to the button signal output terminal and is also grounded through the filter capacitor; the second pin of the switch is grounded. The button signal output terminal is connected to pin U4 of the controller chip.

[0074] Filter capacitors are used to filter out mechanical bounce caused by button presses. During the pressing and releasing process, the elasticity of the mechanical contacts causes multiple on-off cycles in a short period of time. Without debouncing, the controller may mistakenly identify this as multiple button presses. Filter capacitors smooth out the level changes during bounce through RC charging and discharging delay. The controller reads the button state only after the delay has stabilized, effectively preventing false triggering.

[0075] The button control circuit provides a human-machine interface for users, allowing them to operate the device via buttons. In each button unit, when a button is pressed, the switch closes, the first pin is grounded through the second pin, and the voltage level drops to low. The controller chip U4 detects this pin level change, recognizes the button press action, and executes the corresponding function.

[0076] This embodiment also includes a communication interface circuit. For example... Figure 9 As shown, the communication interface circuit includes a communication chip. The first, second, third, fourth, and seventh pins of the communication chip are all grounded. The fifth pin is connected to the thirty-third pin of the controller chip U4, the sixth pin is connected to the thirty-second pin of the controller chip U4, and the eighth pin is connected to a 3.3V power supply and is also grounded through a twenty-seventh capacitor. A seventeenth resistor R17 is connected between the eighth and sixth pins of the communication chip, and an eighteenth resistor R18 is connected between the eighth and fifth pins of the communication chip.

[0077] In summary, this utility model, through its integrated modular design, achieves the coordinated operation of multiple functional modules, including power management, signal acquisition and processing, signal output, and human-computer interaction. The power supply module employs a hybrid power supply method combining a DC-DC step-down unit and a linear regulator, effectively reducing ripple noise and improving power efficiency. The optical signal transmitting circuit module achieves adjustable intensity optical signal output through a driver circuit, while the optical signal receiving circuit module converts the optical signal into a high-quality electrical signal through an operational amplifier circuit, improving measurement accuracy. The signal output circuit module supports switchable NPN / PNP signal output, enhancing the system's flexibility and adaptability to meet the needs of different application scenarios.

[0078] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. An optical fiber sensor circuit, characterized by, include: The power supply circuit module includes multiple power supply circuit units, which are used to convert external input power into a stable voltage output. A microcontroller module, connected to the power supply module, is used to control the operation of the fiber optic sensor; An optical signal transmitting circuit module, connected to the microcontroller module and the optical fiber, includes a transmitting tube and a driving circuit, used to generate an adjustable intensity optical signal and transmit it through the optical fiber; An optical signal receiving circuit module, connected to the microcontroller module and the optical fiber, includes a light receiving tube and an operational amplifier circuit, used to receive optical signals transmitted through the optical fiber and convert them into electrical signals for output to the microcontroller module; The signal output circuit module is connected to the microcontroller module and is used to output working status indication signals, switchable NPN / PNP signals, and display information.

2. The fiber optic sensor circuit as described in claim 1, characterized in that, The power supply circuit module includes a DC-DC step-down unit, a first linear regulator unit, and a second linear regulator unit. The DC-DC step-down unit includes a DC-DC step-down chip, three diodes, a first protection wire, a first light-emitting diode, and a first transistor; The first diode, the first protective wire, and the first resistor are connected in series, and one end of the series connection is connected to the power supply voltage. One end of the second diode is connected between the first diode and the first protective wire, and connected to the third power supply; the other end is grounded. One end of the first capacitor is connected to the other end of the series connection of the first diode, the first protective wire, and the first resistor, and is connected to the first power supply; the other end is grounded. The first pin of the DC-DC step-down chip is connected to the sixth pin through the second capacitor. The second pin is grounded. The fourth pin is connected to the other end of the series connection between the first diode, the first protective wire, and the first resistor through the third resistor. The fifth pin is connected to the other end of the series connection between the first diode, the first protective wire, and the first resistor. The sixth pin is also connected to one end of the inductor. One end of the third diode is connected between the sixth pin of the DC-DC step-down chip and the inductor, and the other end is grounded; The source of the first transistor is connected to the other end of the inductor to form the first branch, the drain is grounded, and the gate is connected to the analog power supply. One end of the second resistor is connected to the first branch, and the other end is connected to one end of the sixth resistor, the other end of which is grounded. The third pin of the DC-DC step-down chip is connected between the second resistor and the sixth resistor, and is connected to the first branch via the third capacitor; One end of the fourth capacitor is connected to the first branch and to the second power supply, while the other end is grounded; One end of the fourth resistor is connected to the first branch, and the other end is grounded through the first light-emitting diode; One end of the fifth capacitor and the fifth resistor are both connected to the first branch, and the other end of each is connected to one end of the seventh resistor, the other end of which is grounded.

3. The fiber optic sensor circuit of claim 2, wherein, The first linear regulator unit includes a first linear regulator chip, an eighth resistor, a sixth capacitor, and a seventh capacitor; The first pin of the first linear regulator chip is connected to a 5V analog power supply through an eighth resistor, the second pin is grounded, and the third pin is connected to the analog power supply. A 5V analog power supply is also connected to one end of the sixth capacitor and one end of the seventh capacitor, and the other end of the sixth capacitor and the seventh capacitor are both grounded; The second linear regulator unit includes a second linear regulator chip; The first pin of the second linear regulator chip is connected to the analog power supply, the second pin is grounded, the third pin is connected to the analog power supply, and the fifth pin is connected to one end of the ninth resistor to form the second branch; The other end of the ninth resistor is connected to a 3.3V analog power supply; The analog power supply is also connected to one end of an eighth capacitor, and the other end of the eighth capacitor is grounded. The second branch is also connected to one end of the tenth resistor, the ninth capacitor, the tenth capacitor and the eleventh capacitor respectively. The other ends of the tenth resistor, the ninth capacitor, the tenth capacitor and the eleventh capacitor are all grounded. One end of the ninth capacitor is also connected to a 3.3V power supply. The 3.3V analog power supply is also connected to one end of the twelfth capacitor and the other end of the ninth resistor, and the other end of the twelfth capacitor is grounded.

4. The fiber optic sensor circuit of claim 1, wherein, The microcontroller module includes a controller chip, an empty pin, a twelfth resistor, a fourteenth resistor, a thirteenth capacitor, a fourteenth capacitor, a fifteenth capacitor, and a seventeenth capacitor; The first pin of the controller chip is connected to a 3.3V power supply, and the sixth pin is grounded through the fourteenth resistor and the unused pin. The seventh pin of the controller chip is connected to a 3.3V power supply through the twelfth resistor and is also grounded through the fourteenth capacitor; The eighth pin of the controller chip is connected to analog ground; The ninth pin of the controller chip is connected to a 3.3V analog power supply and is also grounded through the fifteenth capacitor; The controller chip's 24th pin is connected to a 3.3V power supply and is also grounded through the 17th capacitor; The controller chip's 48th pin is connected to a 3.3V power supply and is also grounded through the 13th capacitor; The controller chip's 23rd, 44th, and 47th pins are all grounded.

5. The fiber optic sensor circuit as described in claim 4, characterized in that, The signal output circuit module includes an LED indicator circuit, which includes a second light-emitting diode, an eleventh resistor, and a thirteenth resistor. The first end of the second light-emitting diode is connected to the second pin of the controller chip through the eleventh resistor, the second end is grounded, the third end is connected to the third pin of the controller chip through the thirteenth resistor, and the fourth end is grounded.

6. The fiber optic sensor circuit as described in claim 4, characterized in that, The transmitting tube and driving circuit include a first connector, a first single-channel analog switch, a second single-channel analog switch, a third single-channel analog switch, a first operational amplifier, and a second transistor; The first pin of the first connector is connected to the collector of the second transistor, the second pin is connected to the second power supply through the nineteenth resistor, and the second pin is also grounded through the twenty-eighth capacitor; The base of the second transistor is grounded through the twenty-second resistor, and the emitter is grounded through the twenty-third resistor; The first pin of the first single-channel analog switch is connected to the emitter of the second transistor, the second pin is grounded through the twenty-ninth capacitor, the third pin is grounded, the fourth pin is connected to the tenth pin of the controller chip, and the fifth pin is connected to a 3.3V power supply. The first pin of the third single-channel analog switch is grounded through the twenty-ninth capacitor, the second pin is grounded through the thirtieth capacitor, the third pin is grounded, the fourth pin is grounded through the twenty-sixth resistor, and the fifth pin is connected to a 3.3V power supply. The fourth pin of the third single-channel analog switch is also connected to the sixteenth pin of the controller chip. The first pin of the second single-channel analog switch is grounded through the thirty-third capacitor, the second pin is connected to the second pin of the memory chip, the third pin is grounded, the fourth pin is grounded through the twenty-fifth resistor, and the fifth pin is connected to a 3.3V power supply. The fourth pin of the second single-channel analog switch is also connected to the tenth pin of the controller chip. The first pin of the first operational amplifier is connected to the seventeenth pin of the controller chip through the twenty-fourth resistor, the second pin is grounded, the third pin is connected to the fourth pin through the forty-fourth capacitor, the fourth pin is also grounded through the twenty-first resistor and the thirty-third capacitor, the fifth pin is connected to a 3.3V power supply, and the third pin of the first operational amplifier is grounded through the thirtieth capacitor; The second pin of the first operational amplifier is also connected to the thirty-first resistor and the thirty-second resistor, respectively.

7. The fiber optic sensor circuit as described in claim 4, characterized in that, The light-receiving tube and operational amplifier circuit include a second connector, a third transistor, a second operational amplifier, and a fourth diode; The first pin of the second connector is connected to one end of the thirty-fifth resistor, and the second pin is grounded; The other end of the thirty-fifth resistor is grounded through the forty-second capacitor and is also connected to one end of the thirty-third resistor; one end of the thirty-third resistor is also grounded through the forty-first capacitor, and the other end of the thirty-third resistor is connected to a 5V analog power supply. The first pin of the second operational amplifier is connected to the sixth pin through the thirty-fourth capacitor and the twenty-seventh resistor. The second pin is connected between the first pin and the thirty-fifth resistor of the second connector through the thirty-second resistor and the thirty-seventh capacitor. The third pin is connected to one end of the thirty-fourth resistor. The fourth pin is grounded. The fifth pin is connected to the other end of the thirty-fourth resistor. The seventh pin is connected to one end of the thirtieth resistor. The eighth pin is connected to a 5V analog power supply. The eighth pin is also grounded through the thirty-eighth capacitor. A 35th capacitor and a 29th resistor are also connected between the first and second pins of the second operational amplifier, respectively. The other end of the thirty-fourth resistor is connected to one end of the thirty-sixth resistor and one end of the forty-third capacitor. The other end of the thirty-sixth resistor is connected to a 5V analog power supply, and the other end of the forty-third capacitor is grounded. The third pin of the second operational amplifier and the thirty-fourth resistor are respectively connected to one end of the fortieth capacitor and the thirty-seventh resistor, and the other end of the fortieth capacitor and the thirty-seventh resistor is grounded. One end of the fourth diode is connected between the twenty-seventh resistor and the sixth pin of the second operational amplifier, and the other end is grounded; A 31st resistor and a 39th capacitor are also connected between the sixth pin and the seventh pin of the second operational amplifier, respectively. The other end of the thirtieth resistor is connected to the drain of the third transistor via the thirty-sixth capacitor. The source of the third transistor is connected to a 3.3V power supply, and the gate is connected to the eleventh pin of the controller chip. A twenty-eighth resistor is also connected between the drain and source of the third transistor.

8. The fiber optic sensor circuit as described in claim 4, characterized in that, The signal output circuit module includes an NPN / PNP signal output circuit; the NPN / PNP signal output circuit includes a first dual transistor array and a second dual transistor array. The first pin of the first dual transistor array is grounded, the second pin is connected to the second pin of the second dual transistor array, the third pin is connected to the twenty-second pin of the controller chip, the fourth pin is grounded, the fifth pin is connected to the fifth pin of the second dual transistor array, and the sixth pin is connected to the twenty-second pin of the controller chip. The first pin of the second dual transistor array is grounded through the forty-first resistor, the second pin is connected to the twenty-seventh pin of the controller chip through the fortyth resistor, the third pin is connected to the fifth pin of the second dual transistor array through the thirty-eighth resistor, the fourth pin is connected to the third power supply, the fifth pin is also connected to the third power supply through the thirty-ninth resistor, and the sixth pin is connected to the base of the fourth transistor. The emitter of the fourth transistor is connected to the fifth pin of the second dual transistor array, and the collector is connected to the collector of the fifth transistor via the seventh diode. The base of the fifth transistor is connected to the twenty-first pin of the controller chip through the forty-second resistor, the emitter is grounded through the forty-fourth resistor, and the emitter is also connected to the second pin of the second dual transistor array through the forty-third resistor. The collector of the fourth transistor is also connected to one end of the second protection wire, and the other end of the second protection wire is connected to one end of the fifth diode and the sixth diode, respectively. The other end of the fifth diode is connected to the third power supply, and the other end of the sixth diode is grounded.

9. The fiber optic sensor circuit of claim 4, wherein, The signal output circuit module also includes an OLED display circuit, which includes an OLED display screen, a third connector, and a fourth connector. The OLED display is connected to the third connector. The first pin of the third connector is connected to the positive power supply VPP, the second pin is connected to the bias voltage VCOMH, the third pin outputs the reference current, the fourth pin is connected to the seventeenth pin of the controller chip, the fifth pin is connected to the sixteenth pin of the controller chip, the sixth pin is connected to the twenty-fifth pin of the controller chip, the seventh pin is connected to the forty-fifth pin of the controller chip, the eighth pin is connected to the twenty-sixth pin of the controller chip and grounded through the fifteenth resistor, the ninth pin is connected to a 3.3V power supply, the tenth pin is grounded, the eleventh pin is connected to a 3.3V power supply and grounded through the sixteenth capacitor, the twelfth pin is connected to the thirteenth pin through the twenty-second capacitor, and the fourteenth pin is connected to the fifteenth pin through the eighteenth capacitor. The positive voltage is grounded through the twentieth and eleventh capacitors, respectively. The bias voltage is grounded through the nineteenth capacitor; The reference current is grounded through the sixteenth resistor; The first pin of the fourth connector is grounded, the second pin is connected to a 3.3V power supply, the third pin is connected to the forty-second pin of the controller chip, the fourth pin is connected to the forty-third pin of the controller chip, the fifth pin is connected to the forty-fifth pin of the controller chip, the sixth pin is connected to the twenty-fifth pin of the controller chip, and the seventh pin is connected to the twenty-sixth pin of the controller chip.

10. The fiber optic sensor circuit of claim 4, wherein, It also includes a button control circuit, which includes multiple button units, each of which includes a switch and a filter capacitor. The first pin of the switch is connected to the button signal output terminal and is also grounded through the filter capacitor; the second pin of the switch is grounded. The button signal output terminal is connected to the pin of the controller chip.

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