CN210804749U - Vehicle detector - Google Patents

Abstract

The embodiment of the application provides a vehicle detector, which comprises a power supply, a main control module, a plurality of isolation power supply modules, a plurality of oscillation circuit modules and a plurality of coils, wherein the power supply is connected with the main control module, the main control module is connected with the plurality of oscillation circuits, the plurality of oscillation circuit modules are connected with the plurality of isolation power supply modules, the plurality of isolation power supply modules are connected with the power supply, the plurality of coils are connected with the plurality of oscillation circuit modules, the plurality of coils are buried under the ground, the inductance value changes when a vehicle passes through, the plurality of oscillation circuit modules form an oscillation circuit to generate oscillation signals, then the main control module receives the oscillation signals output by the plurality of oscillation circuit modules and performs sampling processing for multiple times to judge whether the vehicle is on the coils, the power supply supplies power to the main control module, the plurality of isolation power supply modules supply power to the plurality of oscillation circuit modules, and the plurality of isolation power supply modules isolate the power, therefore, each path of oscillation circuit is isolated from the power supply, and the purpose of reducing crosstalk is achieved.

Description

Vehicle detector

Technical Field

The application relates to the technical field of electricity, in particular to a vehicle detector.

Background

A loop coil vehicle detector (hereinafter referred to as a vehicle detector) is a very important device in a parking lot system and a road traffic monitoring system. With the development of parking lot equipment and road traffic monitoring equipment, the requirements on the stability and accuracy of vehicle detectors are higher and higher. At present, the vehicle detector has single-path and multi-path, and some scenes need to use multi-path or use a plurality of single-path to realize, but the cost of using a plurality of single-path is higher than that of using multi-path. In addition, the multi-lane vehicle detector may have a problem of crosstalk with each other through a common power supply. At present, circuits between each path of a plurality of paths of vehicle detectors are not isolated, and share a power supply and a power supply ground, so that the problem of crosstalk is easily caused. At present, a multi-channel vehicle detector adopts a multi-channel time-sharing gating mode to avoid the problem of crosstalk, but the time-sharing gating mode greatly reduces instantaneity, cannot respond in time, and has a complex detection control algorithm.

SUMMERY OF THE UTILITY MODEL

An object of the embodiments of the present application is to provide a vehicle detector, which is used to reduce crosstalk caused by a common power source of circuits between each two circuits while implementing multi-path detection.

The embodiment of the application provides a vehicle detector, which comprises a power supply, a main control module, a plurality of isolated power supply modules, a plurality of oscillation circuit modules and a plurality of coils; the power supply is connected with the main control module and used for supplying power to the main control module; the main control module is connected with the plurality of oscillation circuit modules and is used for receiving and processing the electric signals output by the plurality of oscillation circuit modules; the plurality of isolation power supply modules are connected between the power supply and the plurality of oscillation circuit modules and used for isolating the power supply from the plurality of oscillation circuit modules; the plurality of oscillating circuit modules are connected with the plurality of coils and used for generating oscillating signals; the plurality of coils are buried under a road surface and used for detecting whether a vehicle is on the coils or not based on inductance change.

In the implementation process, the plurality of coils are buried under the ground, the inductance value changes when a vehicle passes, the oscillation circuit is connected with a plurality of oscillation circuit modules to form an oscillation circuit to generate oscillation signals, the oscillation circuit modules are connected with a plurality of isolation power supply modules, the isolation power supply modules are connected with a power supply, the isolation power supply modules isolate the power supply from the oscillation circuit modules, the isolation power supply modules supply power to the oscillation circuit modules, the isolation power supply modules receive electric energy from the power supply, the power supply is connected with a main control module, the power supply supplies power to the main control module, the main control module is connected with the oscillation circuit modules, and then the main control module receives the oscillation signals output by the plurality of oscillation circuit modules and performs sampling processing for a plurality of times to judge whether a vehicle is on a coil, so that each path of oscillation circuit is isolated from a power supply, and the purpose of reducing crosstalk is achieved.

Further, the vehicle detector further comprises a plurality of photoelectric signal isolation modules; the plurality of photoelectric signal isolation modules are connected between the main control module and the plurality of oscillation circuit modules and used for isolating the electrical connection between the main control module and the plurality of oscillation circuit modules.

In the implementation process, the vehicle detector further comprises a plurality of photoelectric signal isolation modules, the photoelectric signal isolation modules are connected between the main control module and the plurality of oscillation circuit modules, the photoelectric signal isolation modules can convert electric signals output by the oscillation circuit modules and then reshape and amplify the electric signals, the electric connection isolation of the main control module and the oscillation circuit modules is achieved, and the detection of the oscillation period of the coil is more convenient.

Furthermore, the isolation power supply module comprises an input circuit submodule, an output circuit submodule and a switch-type isolation power supply; the input circuit submodule is connected with the power supply and used for receiving the electric energy of the power supply; the output circuit sub-module is connected with the plurality of oscillating circuit modules and is used for providing electric energy for the plurality of oscillating circuit modules; the switch type isolation power supply is connected between the input circuit submodule and the output circuit submodule and used for isolating the input and the output of the power supply.

In the implementation process, the isolation power supply module comprises an input circuit submodule, an output circuit submodule and a switch-type isolation power supply, the input circuit submodule receives electric energy from a power supply, the switch-type isolation power supply is connected between the input circuit submodule and the output circuit submodule to isolate the input and the output of the power supply, the output circuit submodule provides electric energy for the oscillation circuit module, and isolation of each circuit of oscillation circuit from the power supply is achieved.

Furthermore, the photoelectric signal isolation module comprises a photoelectric signal conversion circuit and an amplification shaping circuit; the photoelectric signal conversion circuit is connected between the plurality of oscillation circuit modules and the amplification shaping circuit, and is used for converting the electric signals generated by the plurality of oscillation circuit modules into optical signals and then into electric signals and sending the converted electric signals to the amplification shaping circuit; the amplifying and shaping circuit is connected with the main control module and used for amplifying and shaping the converted electric signals and sending the electric signals to the main control module.

In the above-mentioned realization process, the photoelectric signal isolation module includes photoelectric signal conversion circuit and amplification shaping circuit, photoelectric signal conversion circuit receives the signal of telecommunication of oscillation circuit module output, then photoelectric signal conversion circuit converts the signal of telecommunication into optical signal, convert the optical signal into the signal of telecommunication again, send the signal of telecommunication to amplification shaping circuit, amplification shaping circuit carries out the plastic and enlargies the signal of telecommunication, then amplification shaping circuit sends signal transmission to host system, electrical connection's isolation has been realized, the detection that makes things convenient for the oscillation cycle has been realized.

Further, the photoelectric signal conversion circuit comprises a first resistor, a first light emitting diode and a first photosensitive diode; the first resistor is connected between the first light emitting diode and the plurality of isolation power supply modules and used for providing bias current for the first light emitting diode; the first light emitting diode is connected with the plurality of oscillation circuit modules and used for converting the electric signals output by the plurality of oscillation circuit modules into optical signals; the first photosensitive diode is connected with the amplifying and shaping circuit and used for converting the optical signal into an electric signal.

In the implementation process, the photoelectric signal conversion circuit comprises a first resistor, a first light emitting diode and a first photosensitive diode, the first resistor provides bias current for the first light emitting diode, the first light emitting diode receives the electric signal output by the oscillation circuit module and converts the electric signal into an optical signal, the first photosensitive diode receives the optical signal and converts the optical signal into the electric signal, and then the electric signal is sent to the amplification shaping circuit, so that the isolation of electrical connection is realized.

Further, the amplifying and shaping circuit comprises a NAND gate and a first triode; the NAND gate is connected between the photoelectric conversion circuit and the base electrode of the first triode and is used for shaping the electric signal and sending the shaped electric signal to the base electrode of the first triode; and the collector electrode of the first triode is connected with the main control module and used for amplifying the shaped electric signal and sending the electric signal to the main control module.

In the implementation process, the amplifying and shaping circuit comprises the NAND gate and the first triode, the NAND gate receives the electric signal output by the photoelectric signal conversion circuit, shapes the electric signal, sends the electric signal to the base electrode of the first triode, the first triode amplifies the electric signal, and sends the electric signal to the main control module, so that the detection of the convenient oscillation period is realized.

Further, the oscillation circuit module comprises an oscillation circuit and an amplification circuit; the oscillating circuit is connected between the coil and the amplifying circuit, is used for generating the oscillating signal by combining with the coil and sending the oscillating signal to the amplifying circuit; the amplifying circuit is connected with the plurality of photoelectric signal isolation modules, and is used for amplifying the oscillation signal and sending the oscillation signal to the plurality of photoelectric signal isolation modules.

In the implementation process, the oscillation circuit module comprises an oscillation circuit and an amplifying circuit, the oscillation circuit is connected with the coil and combined with the coil to generate an oscillation signal, the oscillation signal is sent to the amplifying circuit, the amplifying circuit receives the oscillation signal, amplifies the oscillation signal and then sends the oscillation signal to the photoelectric signal isolation module.

Further, the oscillation circuit comprises a first capacitor, a second triode and a third triode; the first capacitor is connected between the coil and the second capacitor in parallel, the second capacitor is respectively connected with the base electrode of the second triode and the collector electrode of the third triode, the emitter electrode of the second triode is connected with the emitter electrode of the third triode, and the collector electrode of the third triode is connected with the amplifying circuit.

In the implementation process, the oscillation circuit comprises a first capacitor, a second triode and a third triode, wherein the first capacitor, the second capacitor and the coil form an oscillator to generate an oscillation signal.

Furthermore, the amplifying circuit comprises a second resistor, a third capacitor and a fourth triode; the second resistor is connected between the oscillating circuit and the base electrode of the fourth triode; the third resistor is connected between the plurality of isolated power supply modules and the collector of the fourth triode; the third capacitor is connected with the emitter and the collector of the fourth triode; and the collector electrode of the fourth triode is connected with the plurality of photoelectric signal isolation modules and used for amplifying the oscillation signal and sending the amplified oscillation signal to the plurality of photoelectric signal isolation modules.

In the implementation process, the amplifying circuit comprises a second resistor, a third capacitor and a fourth triode, the second resistor receives the oscillation signal sent by the oscillating circuit and sends the oscillation signal to a base of the fourth triode, a collector of the fourth triode is connected with the isolation power module through the third resistor to receive electric energy, and the collector of the fourth triode outputs the amplified oscillation signal and sends the amplified oscillation signal to the photoelectric signal isolation module.

Further, the amplification and shaping circuit further comprises a fourth resistor; the fourth resistor is connected between the power supply and the collector of the first triode and used for avoiding the open circuit of the collector of the first triode.

In the implementation process, the amplifying and shaping circuit further comprises a fourth resistor, the fourth resistor is connected with the power supply, and the fourth resistor is connected with the collector electrode of the first triode, so that the collector electrode of the first triode is prevented from being opened.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

Fig. 1 is a block diagram of a vehicle detector according to an embodiment of the present disclosure;

fig. 2 is a block diagram of an isolated power module according to an embodiment of the present disclosure;

fig. 3 is a block diagram of an oscillating circuit module according to an embodiment of the present disclosure;

FIG. 4 is a block diagram of another vehicle detector provided in the embodiments of the present application;

fig. 5 is a block diagram of a structure of an optoelectronic signal isolation module according to an embodiment of the present disclosure.

Icon: 10-a vehicle detector; 100-a power supply; 200-a main control module; 300-an isolated power supply module; 310-input circuit submodule; 320-an output circuit submodule; 330-switched isolated power supply; 400-an oscillating circuit module; 410-an oscillating circuit; 411-a first capacitance; 412-a second capacitance; 413-a second triode; 414-a third transistor; 420-an amplifying circuit; 421-a second resistance; 422-third resistance; 423-third capacitance; 424-fourth triode; 500-a coil; 600-a photoelectric signal isolation module; 610-a photoelectric signal conversion circuit; 611 — a first resistance; 612-a first light emitting diode; 613-a first photodiode; 620-an amplification and shaping circuit; 621-nand gate; 622 — first triode; 623-fourth resistance.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.

Referring to fig. 1, fig. 1 is a block diagram of a vehicle detector according to an embodiment of the present disclosure. The vehicle detector can be used in parking lots and road traffic monitoring systems for detecting the passing or speed of vehicles; the vehicle detector 10 includes a plurality of power sources 100, a plurality of master control modules 200, a plurality of isolated power modules 300, a plurality of oscillator circuit modules 400, and a plurality of coils 500.

The power supply 100 is connected with the main control module 200 and is used for supplying power to the main control module 200; the main control module 200 is connected to the plurality of oscillation circuit modules 400, and is configured to receive and process the electrical signals output by the plurality of oscillation circuit modules 400; the plurality of isolated power modules 300 are connected between the power supply 100 and the plurality of oscillation circuit modules 400, and are used for isolating the power supply 100 from the plurality of oscillation circuit modules 400; the plurality of oscillation circuit modules 400 are connected to the plurality of coils 500 for generating oscillation signals; the plurality of coils 500 are buried under the road surface, and detect whether or not a vehicle is present on the coils 500 based on a change in inductance.

Illustratively, the plurality of coils 500 and the plurality of oscillation circuit modules 400 form an oscillator to generate oscillation signals, the frequency cycle of the oscillation signals changes, the plurality of oscillation circuit modules 400 send the output oscillation signals to the main control module 200 for processing, the main control module 200 receives the electric energy of the power supply 100 and works, and the plurality of isolation power supply modules 300 isolate the power supply 100 and the plurality of oscillation circuit modules 400 from each other, so that the isolation of each circuit from the power supply is realized, and the purpose of reducing crosstalk is realized.

Illustratively, the plurality of coils 500 are buried under the road surface, and when a vehicle passes over the coils 500, the inductance of the coils 500 changes, and the frequency cycle of the oscillation signal changes.

In the implementation process, the plurality of coils 500 are buried under the ground, when a vehicle passes through, the inductance changes, and the coils are connected with the plurality of oscillation circuit modules 400 to form an oscillation circuit to generate oscillation signals, the plurality of oscillation circuit modules 400 are connected with the plurality of isolated power supply modules 300, the plurality of isolated power supply modules 300 are connected with the power supply 100, the plurality of isolated power supply modules 300 isolate the power supply 100 from the plurality of oscillation circuit modules 400, the plurality of isolated power supply modules 300 supply power to the plurality of oscillation circuit modules 400, the plurality of isolated power supply modules 300 receive electric energy from the power supply 100, the power supply 100 is connected with the main control module 200, the power supply 100 supplies power to the main control module 200, the main control module 200 is connected with the plurality of oscillation circuit modules 400, then the main control module 200 receives the oscillation signals output by the plurality of oscillation circuit modules 400 and performs sampling processing for a plurality of times to judge whether the vehicle is on the coils 500, thereby realizing that each oscillation circuit module 400 is isolated, the purpose of reducing crosstalk is achieved.

In a possible implementation manner, the main control module 200 may be an MCU, the main control module 200 counts a clock source with a higher frequency by using a received oscillation signal as a gate control timer, so as to obtain a count value C, a period is calculated by the count value C, an oscillation period T of the coil 500 changes, the count value C changes, the main control module 200 obtains a filter value FV by continuously sampling a plurality of count values C, using recursive average filtering and median filtering, and then obtains a change value CH by calculating a difference value between the filter value FV and a reference value B, if a ratio of the change value CH to the reference value B is greater than or equal to a preset value, it is determined that there is a vehicle on the coil 500, otherwise, it is determined that there is no vehicle on the coil 500.

Illustratively, due to the influence of the environment, the oscillation frequency of the coil 500 may follow the change of the environment, the change is large over a long time, in order to adapt to the change of the environment, the reference value B is updated at intervals during the operation of the vehicle detector 10, the updated value of the reference value B is the average value of all sampled values in the period, and the updated sampling data of the reference value B is required to be the sampling data when the vehicle is not on the coil 500.

Referring to fig. 2, fig. 2 is a block diagram of an isolated power supply module according to an embodiment of the present disclosure, in which the isolated power supply module 300 includes an input circuit sub-module 310, an output circuit sub-module 320, and a switch-type isolated power supply 330; the input circuit sub-module 310 is connected to the power supply 100 and is configured to receive power from the power supply 100; the output circuit sub-module 320 is connected to the plurality of oscillation circuit modules 400, and is configured to provide power to the plurality of oscillation circuit modules 400; the switch-mode isolation power supply 330 is connected between the input circuit sub-module 310 and the output circuit sub-module 320 for isolating the input and output of the power supply 100.

Illustratively, the input circuit submodule 310 receives the power from the power supply 100 and transmits the power to the switch-type isolation power supply 330, and the output circuit submodule 320 receives the power from the switch-type isolation power supply 330 and outputs the power to the plurality of oscillation circuit modules 400, so as to achieve the purpose of isolating the power supply 100 from each oscillation circuit module 400.

In the implementation process, the isolation power module 300 includes an input circuit submodule 310, an output circuit submodule 320, and a switch-type isolation power supply 330, the input circuit submodule 310 receives electric energy from the power supply 100, the switch-type isolation power supply 330 is connected between the input circuit submodule 310 and the output circuit submodule 320, and isolates input and output of the power supply 100, and the output circuit submodule 320 provides electric energy for the oscillation circuit module 400, so that isolation between each circuit of the oscillation circuit module 400 and the power supply 100 is achieved.

Referring to fig. 3, fig. 3 is a block diagram of an oscillating circuit module according to an embodiment of the present disclosure, in which the oscillating circuit module 400 includes an oscillating circuit 410 and an amplifying circuit 420; the oscillating circuit 410 is connected between the coil 500 and the amplifying circuit 420, and is used for generating the oscillating signal in combination with the coil 500 and sending the oscillating signal to the amplifying circuit 420; the amplifying circuit 420 is connected to the main control module 200, and is configured to amplify the oscillation signal and send the amplified oscillation signal to the main control module 200.

Illustratively, the oscillating circuit 410 is connected with the coil 500 to form an oscillator to generate an oscillating signal, and the amplifying circuit 420 receives and amplifies the generated oscillating signal, and then sends the amplified oscillating signal to the main control module 200 for processing.

In one embodiment, the oscillation circuit 410 includes a first capacitor 411, a second capacitor 412, a second transistor 413, and a third transistor 414; the first capacitor 411 is connected in parallel between the coil 500 and the second capacitor 412, the second capacitor 412 is connected to the base of the second transistor 413 and the collector of the third transistor 414, the emitter of the second transistor 413 is connected to the emitter of the third transistor 414, and the collector of the third transistor 414 is connected to the amplifying circuit 420. The first capacitor 411 and the second capacitor 412 form an oscillator with the coil 500, and generate an oscillation signal.

In one embodiment, the amplifying circuit 420 includes a second resistor 421, a third resistor 422, a third capacitor 423, and a fourth transistor 424; the second resistor 421 is connected between the oscillating circuit 410 and the base of the fourth transistor 424; the third resistor 422 is connected between the isolated power modules 300 and the collector of the fourth transistor 424; the emitter and collector of the third capacitor 423 and the fourth triode 424 are connected; the collector of the fourth transistor 424 is connected to the main control module 200, and is configured to amplify the oscillation signal and send the amplified oscillation signal to the main control module 200.

In the implementation process, the oscillation circuit module 400 includes an oscillation circuit 410 and an amplification circuit 420, the oscillation circuit 410 is connected to the coil 500, the first capacitor 411, the second capacitor 412 and the coil 500 are combined to generate an oscillation signal, and the oscillation signal is sent to the amplification circuit 420, and the amplification circuit 420 receives the oscillation signal, amplifies the oscillation signal by the fourth triode 424, and then sends the oscillation signal to the main control module 200.

Referring to fig. 4, fig. 4 is another vehicle detector provided in the embodiment of the present application, and the vehicle detector 10 further includes a plurality of optoelectronic signal isolation modules 600; the plurality of optoelectronic signal isolation modules are connected between the main control module 200 and the plurality of oscillation circuit modules 400, and are configured to isolate electrical connections between the main control module 200 and the plurality of oscillation circuit modules 400.

Illustratively, the oscillation circuit module 400 sends the generated and amplified oscillation signal to the optoelectronic signal isolation module 600, and after receiving the oscillation signal, the optoelectronic signal isolation module 600 converts the oscillation signal from an electrical signal to an optical signal, converts the optical signal to an electrical signal, realizes the isolation of electrical connection, shapes and amplifies the converted electrical signal, and sends the electrical signal to the main control module 200 for processing.

In the above implementation process, the vehicle detector 10 further includes a plurality of photoelectric signal isolation modules 600, the plurality of photoelectric signal isolation modules 600 are connected between the main control module 200 and the plurality of oscillation circuit modules 400, the plurality of photoelectric signal isolation modules 600 can convert the electrical signals output by the plurality of oscillation circuit modules 400 and then reshape and amplify, thereby realizing isolation of the electrical connection between the main control module 200 and the plurality of oscillation circuit modules 400, and realizing more convenient detection of the oscillation period of the coil 500.

Referring to fig. 5, fig. 5 is a block diagram of a structure of an optoelectronic signal isolation module according to an embodiment of the present disclosure, where the optoelectronic signal isolation module 600 includes an optoelectronic signal conversion circuit 610 and an amplifying and shaping circuit 620; the optical-electrical signal conversion circuit 610 is connected between the plurality of oscillation circuit modules 400 and the amplification shaping circuit 620, and is configured to convert electrical signals generated by the plurality of oscillation circuit modules 400 into optical signals and then into electrical signals, and send the converted electrical signals to the amplification shaping circuit 620; the amplifying and shaping circuit 620 is connected to the main control module 200, and is configured to amplify and shape the converted electrical signal and send the amplified and shaped electrical signal to the main control module 200.

Illustratively, the optical-electrical signal conversion circuit 610 receives the electrical signal sent by the oscillation circuit module 400, converts the electrical signal into an optical signal, converts the optical signal into the electrical signal, and sends the electrical signal to the amplification and shaping circuit 620, and the amplification and shaping circuit 620 receives, shapes and amplifies the electrical signal, and sends the electrical signal to the main control module 200 for processing.

In the above implementation process, the optoelectronic signal isolation module 600 includes an optoelectronic signal conversion circuit 610 and an amplifying and shaping circuit 620, the optoelectronic signal conversion circuit 610 receives the electrical signal output by the oscillation circuit module 400, then the optoelectronic signal conversion circuit 610 converts the electrical signal into an optical signal, and then converts the optical signal into the electrical signal, and sends the electrical signal to the amplifying and shaping circuit 620, the amplifying and shaping circuit 620 shapes and amplifies the electrical signal, and then the amplifying and shaping circuit 620 sends the signal to the main control module 200, thereby realizing the isolation of electrical connection, and realizing the detection of the convenient oscillation period.

In one possible implementation, the optoelectronic signal isolating module 600 may be an optical coupler 6N 137.

Illustratively, the optical-to-electrical signal conversion circuit 610 includes a first resistor 611, a first light emitting diode 612 and a first photodiode 613; the first resistor 611 is connected between the first light emitting diode 612 and the plurality of isolated power modules 300, and is used for providing a bias current for the first light emitting diode 612; the first light emitting diode 612 is connected to the plurality of oscillation circuit modules 400, and is configured to convert electrical signals output by the plurality of oscillation circuit modules 400 into optical signals; the first photodiode 613 is connected to the amplification and shaping circuit 620 for converting the optical signal into an electrical signal.

Illustratively, the amplification and shaping circuit 620 includes a nand gate 621, a first transistor 622, and a fourth resistor 623; the nand gate 621 is connected between the photoelectric signal conversion circuit 610 and the base of the first triode 622, and is used for shaping the electrical signal and sending the shaped electrical signal to the base of the first triode 622; the collector of the first triode 622 is connected to the main control module 200, and is used for amplifying the shaped electrical signal and sending the amplified electrical signal to the main control module 200, and the fourth resistor 623 is connected between the power supply 100 and the collector of the first triode 622 and is used for preventing the collector of the first triode 622 from being opened.

In the implementation process, the optical-to-electrical signal conversion circuit 610 includes a first resistor 611, a first light emitting diode 612 and a first photodiode 613, the first resistor 611 provides a bias current for the first light emitting diode 612, the first light emitting diode 612 receives an electrical signal output by the oscillation circuit module 400 and converts the electrical signal into an optical signal, the first photodiode 613 receives the optical signal and converts the optical signal into an electrical signal, and then sends the electrical signal to the amplification shaping circuit 620, so that the electrical connection is isolated; the amplifying and shaping circuit 620 comprises a nand gate 621, a first triode 622 and a fourth resistor 623, the nand gate 621 receives an electric signal output by the first photodiode 613, shapes the electric signal and then sends the electric signal to a base of the first triode 622, the fourth resistor 623 prevents a collector of the first triode 622 from being opened, the first triode 622 amplifies the electric signal and then sends the electric signal to the main control module 200, and detection of a convenient oscillation period is achieved.

Specifically, when a vehicle is on the coil, the inductance of the coil changes, the oscillation frequency of the oscillation circuit changes, and the oscillation period changes. After the oscillation signals are subjected to amplification and shaping by the photoelectric signal isolation module, the obtained edges are very steep, after the square wave signals with very stable signal waveforms are sent to the main control module, the main control module counts a clock source with higher frequency by using the oscillation signals as a gate control timer to obtain a count value C, the period is calculated by the count value C, the oscillation period T is changed, the count value C is changed, the main control module continuously samples 100 count values C, then recursive average filtering and median filtering are used to obtain a filtering value FV, a change value CH is obtained by calculating the difference value of the filtering value FV and a reference value B, and if the ratio of the change value CH to the reference value B is larger than or equal to a preset value, a vehicle is judged to be on a coil, otherwise, no vehicle is judged. Due to the influence of the environment, the oscillation frequency can change along with the environment, the variation is small in a short time, the total change is large after a long time, in order to adapt to the change of the environment, the reference value B is updated every other period of time in the running process of the vehicle detector, the updated value of the reference value B is the average value of all sampling values in the period of time, and the updated sampling data of the reference value B is required to be sampling data when no vehicle is on a coil. In the running process of the vehicle detector, the isolation power supply module provides electric energy for the oscillation circuit module by receiving electric energy of a power supply, and the photoelectric signal isolation module performs signal conversion on oscillation signals, so that the isolation of each circuit of the oscillation circuit from the power supply and the isolation of electrical connection are realized, and the crosstalk caused by the common power supply of each circuit of the vehicle detector is greatly reduced.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented in other ways. The apparatus embodiments described above are merely illustrative, and for example, the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

In addition, functional modules in the embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Claims (10)

1. A vehicle detector is characterized by comprising a power supply, a main control module, a plurality of isolated power supply modules, a plurality of oscillation circuit modules and a plurality of coils;

the power supply is connected with the main control module and used for supplying power to the main control module;

the main control module is connected with the plurality of oscillation circuit modules and is used for receiving and processing the electric signals output by the plurality of oscillation circuit modules;

the plurality of isolation power supply modules are connected between the power supply and the plurality of oscillation circuit modules and used for isolating the power supply from the plurality of oscillation circuit modules;

the plurality of oscillating circuit modules are connected with the plurality of coils and used for generating oscillating signals;

the plurality of coils are buried under a road surface and used for detecting whether a vehicle is on the coils or not based on inductance change.

2. The vehicle detector of claim 1, further comprising a plurality of optoelectronic signal isolation modules;

the plurality of photoelectric signal isolation modules are connected between the main control module and the plurality of oscillation circuit modules and used for isolating the electrical connection between the main control module and the plurality of oscillation circuit modules.

3. The vehicle detector of claim 1, wherein the isolated power module includes an input circuit sub-module, an output circuit sub-module, and a switched isolated power supply;

the input circuit submodule is connected with the power supply and used for receiving the electric energy of the power supply;

the output circuit sub-module is connected with the plurality of oscillating circuit modules and is used for providing electric energy for the plurality of oscillating circuit modules;

the switch type isolation power supply is connected between the input circuit submodule and the output circuit submodule and used for isolating the input and the output of the power supply.

4. The vehicle detector of claim 2, wherein the optical-to-electrical signal isolation module comprises an optical-to-electrical signal conversion circuit and an amplification shaping circuit;

the photoelectric signal conversion circuit is connected between the plurality of oscillation circuit modules and the amplification shaping circuit, and is used for converting the electric signals generated by the plurality of oscillation circuit modules into optical signals and then into electric signals and sending the converted electric signals to the amplification shaping circuit;

the amplifying and shaping circuit is connected with the main control module and used for amplifying and shaping the converted electric signals and sending the electric signals to the main control module.

5. The vehicle detector of claim 4, wherein the photo signal conversion circuit comprises a first resistor, a first light emitting diode and a first photodiode;

the first resistor is connected between the first light emitting diode and the plurality of isolation power supply modules and used for providing bias current for the first light emitting diode;

the first light emitting diode is connected with the plurality of oscillation circuit modules and used for converting the electric signals output by the plurality of oscillation circuit modules into optical signals;

the first photosensitive diode is connected with the amplifying and shaping circuit and used for converting the optical signal into an electric signal.

6. The vehicle detector of claim 4, wherein the amplification shaping circuit comprises a NAND gate and a first triode;

the NAND gate is connected between the photoelectric signal conversion circuit and the base electrode of the first triode and is used for shaping the electric signal and sending the shaped electric signal to the base electrode of the first triode;

and the collector electrode of the first triode is connected with the main control module and used for amplifying the shaped electric signal and sending the electric signal to the main control module.

7. The vehicle detector of claim 2, wherein the oscillating circuit module includes an oscillating circuit and an amplifying circuit;

the oscillating circuit is connected between the coil and the amplifying circuit, is used for generating the oscillating signal by combining with the coil and sending the oscillating signal to the amplifying circuit;

the amplifying circuit is connected with the plurality of photoelectric signal isolation modules, and is used for amplifying the oscillation signal and sending the oscillation signal to the plurality of photoelectric signal isolation modules.

8. The vehicle detector of claim 7, wherein the oscillator circuit comprises a first capacitor, a second transistor, and a third transistor;

the first capacitor is connected between the coil and the second capacitor in parallel, the second capacitor is respectively connected with the base electrode of the second triode and the collector electrode of the third triode, the emitter electrode of the second triode is connected with the emitter electrode of the third triode, and the collector electrode of the third triode is connected with the amplifying circuit.

9. The vehicle detector of claim 7, wherein the amplification circuit comprises a second resistor, a third capacitor, and a fourth transistor;

the second resistor is connected between the oscillating circuit and the base electrode of the fourth triode;

the third resistor is connected between the plurality of isolated power supply modules and the collector of the fourth triode;

the third capacitor is connected with the emitter and the collector of the fourth triode;

and the collector electrode of the fourth triode is connected with the plurality of photoelectric signal isolation modules and used for amplifying the oscillation signal and sending the amplified oscillation signal to the plurality of photoelectric signal isolation modules.

10. The vehicle detector of claim 6, wherein the amplification shaping circuit further comprises a fourth resistor;

the fourth resistor is connected between the power supply and the collector of the first triode and used for avoiding the open circuit of the collector of the first triode.

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