CN102789691A - Detecting method and detecting system of flow and speed of vehicles - Google Patents
Detecting method and detecting system of flow and speed of vehicles Download PDFInfo
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- CN102789691A CN102789691A CN2012102981239A CN201210298123A CN102789691A CN 102789691 A CN102789691 A CN 102789691A CN 2012102981239 A CN2012102981239 A CN 2012102981239A CN 201210298123 A CN201210298123 A CN 201210298123A CN 102789691 A CN102789691 A CN 102789691A
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Abstract
The invention discloses a detecting method and a detecting system of flow and speed of vehicles. The detecting method of the flow and speed of vehicles comprises the following steps: two pyroelectric infrared sensors which are connected with a single chip are arranged above a road or on sides of the road at a certain spacing distance along a length direction of the road, and the two pyroelectric infrared sensors are located on the same plane; a pulse signal is output to the single chip when a vehicle is detected to drive in by the first pyroelectric infrared sensor, a timer disposed in the single chip starts to time, meanwhile, the single chip adds one to number of flow of vehicles; a pulse signal is output to the single chip when the vehicle is detected to drive in by the second pyroelectric infrared sensor, the timer stops timing; and the speed of the vehicle is calculated by the single chip according to the distance between the two pyroelectric infrared sensors as well as time calculated by the timer, and then the number of flow of vehicles and the speed of the vehicle are sent to a display for displaying. In comparison with the prior detecting method, the detecting method disclosed by the invention is simple and accurate in detection, and has important practical significance to traffic control.
Description
Technical field
The present invention relates to vehicle flowrate and speed of a motor vehicle detection technique field, specifically be meant the detection method and the system of a kind of vehicle flowrate and the speed of a motor vehicle.
Background technology
In city management and safeguarding, the management of traffic route is particularly important with construction, reasonably arranges road both can guarantee the needs of people's routine work life, can guarantee that again Community health develops in an orderly manner, reaches the effect of getting twice the result with half the effort.The detection of the vehicle flowrate and the speed of a motor vehicle is the foundation of intelligent traffic administration system; It is the important indicator of analyzing road conditions; In system, occupy critical role, can be assessment congestion in road situation, detailed data are provided; All have great significance for judging and avoid the road congestion situation, monitoring timely and accurately for relieving traffic congestion, formulate the road reformation scheme.
Traffic flow detection system is exactly a kind of system that vehicle flowrate is added up and write down, and utilizes it can realize the effective and rational control and management to road traffic.At present, the method and system that the relevant magnitude of traffic flow detects are a lot, but all exist operation calculation method complicated, or the assay device structures complicated problems, are unfavorable for popularizing, promoting.
Summary of the invention
Technical matters to be solved by this invention provides a kind of simple to operate, and the pyroelectric infrared sensor that utilizes that accuracy rate is high is measured the detection method and the system of the vehicle flowrate and the speed of a motor vehicle.
The present invention is such realization, and the detection method of a kind of vehicle flowrate and the speed of a motor vehicle may further comprise the steps:
Two pyroelectric infrared sensors that are connected with a single-chip microcomputer are separated certain distance along the link length direction be installed on road top or side, and said two pyroelectric infrared sensors are in the same plane;
Output pulse signal to said single-chip microcomputer when first pyroelectric infrared sensor detects a vehicle and sails into, the single-chip microcomputer built-in timer picks up counting, and said single-chip microcomputer adds 1 to the counting of vehicle flowrate simultaneously;
Output pulse signal to said single-chip microcomputer when second pyroelectric infrared sensor detects above-mentioned vehicle and sails into; Said timer stops timing; Behind the said vehicle speed of Time Calculation that calculates according to the distance between said two pyroelectric infrared sensors and said timer by said single-chip microcomputer, will count and the speed of a motor vehicle is delivered to said display demonstration.
Before behind the pulse signal of described pyroelectric infrared sensor output, sending into described single-chip microcomputer, further comprising the steps of:
Described pulse signal is carried out at a distance from straight amplification, compares the step of Screening Treatment.
When described second pyroelectric infrared sensor did not detect above-mentioned vehicle and sails into, the counting of said single-chip microcomputer turned back to original state.
The present invention also aims to provide the detection system of a kind of vehicle flowrate and the speed of a motor vehicle, comprise that two are separated pyroelectric infrared sensor, a single-chip microcomputer and the display that certain distance is installed on road top or side; Described two pyroelectric infrared sensors are used to detect to be exported a pulse signal respectively when vehicle sails into and sends into said single-chip microcomputer; Said single-chip microcomputer is used for calculating vehicle according to described pulse signal and calculates the speed of a motor vehicle through number and calculating and according to vehicle through the time of said two pyroelectric infrared sensors, the distance of described two pyroelectric infrared sensors, and sends into said display and show.
The detection system of the described vehicle flowrate and the speed of a motor vehicle comprises a signal processor, is used for the pulse signal of described pyroelectric infrared sensor output is carried out at a distance from directly amplifying, compare the described single-chip microcomputer of Screening Treatment reason back input.
Described signal processor includes:
At a distance from straight amplifying circuit, be used for the pulse signal of described pyroelectric infrared sensor output is carried out behind straight the amplification, exporting the comparison module circuit to;
The comparison module circuit is used for comparing at a distance from straight pulse signal and the threshold voltage that amplifies said, but inputs to said single-chip microcomputer after filtering out said single-chip microcomputer processing signals.
Described comparison module circuit comprises a window comparator circuit and a digital regulation resistance, and described digital regulation resistance is by said Single-chip Controlling, the threshold voltage of using when being used to control the said window comparator circuit comparison Screening Treatment signal of adjustment.
Described display is a LCD display.
The present invention through the information of vehicles output pulse signal that utilizes two pyroelectric infrared sensor collections of separating certain distance and pass through to single-chip microcomputer; Calculating vehicle by single-chip microcomputer according to described pulse signal calculates vehicle speed through the time and delivers to the display demonstration through number and according to distance between described sensor and vehicle; Thereby accomplish measurement, realized that real-time demonstration detects and the demonstration vehicle flowrate and the speed of a motor vehicle the wagon flow quantitative statistics and the speed of a motor vehicle; Simultaneously, the inventive method is simple, detects accurately.
Description of drawings
Fig. 1 is the vehicle flowrate that provides of the embodiment of the invention and the detection method synoptic diagram of the speed of a motor vehicle;
Fig. 2 is the structure principle chart of the detection system of the vehicle flowrate that provides of the embodiment of the invention and the speed of a motor vehicle;
Fig. 3 is the circuit theory diagrams of the pyroelectric infrared sensor that provides of the embodiment of the invention;
The pyroelectric infrared sensor output Signal Processing process flow diagram that Fig. 4 embodiment of the invention provides;
Fig. 5 is the circuit theory diagrams at a distance from straight amplifying circuit that the embodiment of the invention provides;
Fig. 6 is the circuit theory diagrams of the digital regulation resistance that provides of the embodiment of the invention;
Fig. 7 is the circuit theory diagrams of the window comparator circuit that provides of the embodiment of the invention;
Fig. 8 is the display circuit schematic diagram of the display that provides of the embodiment of the invention;
Fig. 9 is the synoptic diagram of the display interface of the display that provides of the embodiment of the invention;
The circuit theory diagrams of the single-chip microcomputer storer that Figure 10 embodiment of the invention provides;
Figure 11 is the process flow diagram of single-chip microcomputer external interrupt INT 1 control program that provides of the embodiment of the invention
Figure 12 is the process flow diagram of single-chip microcomputer external interrupt INT 0 control program that provides of the embodiment of the invention;
Figure 13 is the process flow diagram of the single-chip microcomputer inquiry control program that provides of the embodiment of the invention;
Figure 14 is the process flow diagram of the regulating system detection sensitivity that provides of the embodiment of the invention.
Embodiment
Below in conjunction with accompanying drawing and embodiment the present invention is further specified.
The present invention through the information of vehicles output pulse signal that utilizes two pyroelectric infrared sensor collections of separating certain distance and pass through to single-chip microcomputer; Calculating vehicle by single-chip microcomputer according to described pulse signal calculates vehicle speed through the time and delivers to the display demonstration through number and according to distance between described sensor and vehicle; Thereby accomplish measurement, realized that real-time demonstration detects and the demonstration vehicle flowrate and the speed of a motor vehicle the wagon flow quantitative statistics and the speed of a motor vehicle.
The present invention is such realization, and the detection method of a kind of vehicle flowrate and the speed of a motor vehicle may further comprise the steps:
Two pyroelectric infrared sensors that are connected with a single-chip microcomputer are separated certain distance along the link length direction be installed on road top or side, and said two pyroelectric infrared sensors are in the same plane;
Output pulse signal to said single-chip microcomputer when first pyroelectric infrared sensor detects a vehicle and sails into, the single-chip microcomputer built-in timer picks up counting, and said single-chip microcomputer adds 1 to the counting of vehicle flowrate simultaneously;
Output pulse signal to said single-chip microcomputer when second pyroelectric infrared sensor detects above-mentioned vehicle and sails into; Said timer stops timing; Behind the said vehicle speed of Time Calculation that calculates according to the distance between said two pyroelectric infrared sensors and said timer by said single-chip microcomputer, will count and the speed of a motor vehicle is delivered to said display demonstration.
Before behind the pulse signal of described pyroelectric infrared sensor output, sending into described single-chip microcomputer, further comprising the steps of:
Described pulse signal is carried out at a distance from straight amplification, compares the step of Screening Treatment.
In the embodiment of the invention, the external storer of establishing of described single-chip microcomputer.
When described second pyroelectric infrared sensor did not detect above-mentioned vehicle and sails into, the counting of said single-chip microcomputer turned back to original state.
The present invention also aims to provide the detection system of a kind of vehicle flowrate and the speed of a motor vehicle, comprise that two are separated pyroelectric infrared sensor, a single-chip microcomputer and the display that certain distance is installed on road top or side; Described two pyroelectric infrared sensors are used to detect to be exported a pulse signal respectively when vehicle sails into and sends into said single-chip microcomputer; Said single-chip microcomputer is used for calculating vehicle according to described pulse signal and calculates the speed of a motor vehicle through number and calculating and according to vehicle through the time of said two pyroelectric infrared sensors, the distance of described two pyroelectric infrared sensors, and sends into said display and show.
The detection system of the described vehicle flowrate and the speed of a motor vehicle comprises a signal processor, is used for the pulse signal of described pyroelectric infrared sensor output is carried out at a distance from directly amplifying, compare the described single-chip microcomputer of Screening Treatment reason back input.
Described signal processor includes:
At a distance from straight amplifying circuit, be used for the pulse signal of described pyroelectric infrared sensor output is carried out behind straight the amplification, exporting the comparison module circuit to;
The comparison module circuit is used for comparing at a distance from straight pulse signal and the threshold voltage that amplifies said, but inputs to said single-chip microcomputer after filtering out said single-chip microcomputer processing signals.
Described comparison module circuit comprises a window comparator circuit and a digital regulation resistance, and described digital regulation resistance is by said Single-chip Controlling, the threshold voltage of using when being used to control the said window comparator circuit comparison Screening Treatment signal of adjustment.
Described display is a LCD display.
Referring to shown in Figure 1, the figure shows the vehicle flowrate that the embodiment of the invention provides and the detection method of the speed of a motor vehicle.Two pyroelectric infrared sensors 1,2 are in the same plane, and separately certain distance is installed on suitably height and position of road top, when vehicle passes through; Produce an alternation infrared radiation signal on the sensor; Make sensor circuit produce a faint voltage signal, this signal is sent to amplification and rectification circuit, and output pulse signal is sent into single-chip microcomputer after amplifying shaping; By single-chip microcomputer count and and timing, and show that through display vehicle is through the number and the speed of a motor vehicle.
For functions such as the interruption of the main Implemented by Using Single-chip Processor of detection of vehicle flowrate and countings; Measure the mistiming that two pyroelectric infrared sensors detect for interruption, the timer of the main Implemented by Using Single-chip Processor of detection of the speed of a motor vehicle, calculate the speed of a motor vehicle according to the actual range of two pyroelectric infrared sensors.
Described two pyroelectric infrared sensors also can separate certain distance and be installed on the road side location.Can be to install, or utilize overline bridge to install, can be installed on the Width both sides of overline bridge, or be installed on the same side through support.
Shown in Fig. 1 ~ 2, the figure shows the structure of the detection system of the vehicle flowrate that the embodiment of the invention provides and the speed of a motor vehicle, for the ease of explanation, only show the part relevant with the embodiment of the invention.
In the present embodiment, described two pyroelectric infrared sensors place the overline bridge two ends respectively, and what establish that automobile touches earlier is pyroelectric infrared sensor 1, after touch and be pyroelectric infrared sensor 2.
Because automobile has high-temperature part, like engine, water tank etc., so when the automobile in the motion crossed under two pyroelectric infrared sensors, pyroelectric infrared sensor 1 can at first detect and collect signal, and produces corresponding waveform; Then signal is amplified under distortionless prerequisite; And be converted into voltage signal, again according to the threshold voltage that configures, the signal of gathering after amplifying is screened; Be initially high level; If the signal after the screening is higher than the threshold voltage value and then produces low level,,, counts negative edge when arriving if being lower than the threshold voltage value then keeps high level.
Under the original state, only let pyroelectric infrared sensor 1 open, if when detecting negative edge; Pyroelectric infrared sensor 1 is closed at once, and pyroelectric infrared sensor 2 is opened simultaneously, if pyroelectric infrared sensor 2 detects negative edge within a certain period of time; Then thinking has vehicle to cross, and counts vehicle flowrate; Meanwhile, single-chip microcomputer writes down the mistiming that two pyroelectric infrared sensors detect negative edge, and according to the mistiming calculating speed of a motor vehicle.
If pyroelectric infrared sensor 2 does not detect negative edge within a certain period of time, then can be regarded as once and disturb, and system comes back to original state.
In signal acquisition process, pyroelectric infrared sensor is placed directly over the overline bridge, point to the road of vehicle '; Detect information of vehicles and the faint electric signal of conversion output; Other disturb through elimination behind straight amplifying circuit, comparison module circuit, at last the signal that obtains are driven single-chip microcomputer and analyze and count, and analyze the waveform that produces; Parameter is handled, and formed various control signals to realize the wagon flow quantitative statistics.
In the face of the circuit of each several part module of the present invention is former be down and the control program of single-chip microcomputer is elaborated as follows:
One, pyroelectric infrared sensor
Referring to shown in Figure 3,1 pair of power supply of capacitor C carries out filtering, and+5 V power supply flow sensor power ends get into operational amplifier U 1 behind the LPF of output terminal through resistance R 3 and capacitor C 5.
According to operational amplifier character; When sensor does not produce pulse signal; Just in-phase input end (No. 12 pin of U 1D) is when being direct current signal; The voltage of inverting input and in-phase input end equate, and this moment resistance R 4 with R 5 on do not produce electric current, the output voltage (No. 14 pins of U 1D) that computing is amplified equals the magnitude of voltage of input signal.
When sensor signal produced pulse, the voltage of in-phase input end raise suddenly, and this moment, the voltage of inverting input also increased; In the of short duration time; The voltage at capacitor C 2 two ends can not raise immediately, and at this in a flash, capacitor C 2 is equivalent to short circuit; The input voltage of in-phase input end equates with resistance R 4 voltage; Again since the electric current that flows through resistance R 5 with flow through equating of resistance R 4, so the time resistance R 5 two ends voltage be 220 times of resistance R 4 voltage, also just formed the amplification about 220 times to the input signal of in-phase input end.
Two, at a distance from straight amplifying circuit
Referring to Fig. 5, this illustrates the circuit theory at a distance from straight amplifying circuit that the embodiment of the invention provides.
Among Fig. 5, the signal that socket JP 4 sends for infrared sensor, capacitor C 7 plays the effect of isolated DC; The alternating current-direct current mixed signal of infrared sensor output is become AC signal; If capacitor C 7 capacitances are excessive, the DeGrain of isolated DC signal, the too small meeting of capacitance rising cutoff frequency; Useful signal can not normally be passed through, and can prolong the response time.
Through experiment repeatedly, 0.1 uF is suitable for the electric capacity value.Resistance R 14 discharges and recharges passage for capacitor C 7 provides, and guarantees the circuit operate as normal, and resistance is crossed conference and caused the response time long, and resistance is crossed small-signal and can be flowed directly into power supply ground and not get into amplifier, and through experiment, 100 K are suitable for the R14 value.
Pyroelectric infrared sensor imports signal into circuit, gets at a distance from straight amplifying circuit from socket JP4, but is the mixed signal of AC and DC at input end.As car under the pyroelectric infrared sensor through out-of-date, can produce a pulse, about 300 mV of peak-to-peak value, about 0.8 V of DC component.Through capacitor C 7, can the DC component of signal be filtered out, through resistance R 14,, electric capacity discharges and recharges passage for providing, guarantee the operate as normal of circuit.The in-phase input end of the signal input operational amplifier that was processed then.Because the effect of electric capacity and resistance, the DC component of signal is by elimination at this moment, and peak-to-peak value is about 50 mV.But this moment, signal amplitude was very little, needed to amplify about 50 times.In this circuit, use operational amplifier LM 324 to realize the amplification of small-signal.Resistance through changing slide rheostat can change enlargement factor.
In order to make enlargement factor is 50, and resistance is adjusted to and approximately is respectively 9.8K and 200 Ω.Peak-to-peak value is amplified to 2 V, satisfies the requirement of comparison module circuit.
Three, comparison module circuit
(1) digital regulation resistance
Digital regulation resistance is actually one by monolithic processor controlled potentiometer, and the maximum value of X 9313 is 10 K.Be digital regulation resistance by Single-chip Controlling with the key distinction of common potentiometer, electricity consumption signal controlling changes in resistance, the signal of adjusting is more accurate.The output voltage of digital regulation resistance is the dividing potential drop of the current resistance of digital regulation resistance in circuit.
As shown in Figure 6, X 9313 is a digital regulation resistance, and No. 8 pin Vcc are power supply; No. 4 pin GND ground connection; No. 5 pin VW are the voltage output pin; No. 7 pin CS are chip selection signal, ground connection; No. 2 pin UD is the rise and fall control input end, for output increases progressively, successively decreases for output during low level during high level, is controlled by single-chip microcomputer P1.1 mouth; No. 1 pin INC is a clock signal, is controlled by single-chip microcomputer P1.0 mouth; No. 3 pin VH and No. 6 pin VL are respectively high voltage input and low-voltage input, and output voltage will change between high low-voltage input.Because the resistance of digital regulation resistance is about 10K, after being connect 10 K resistance, VH meets Vcc, with ground connection behind the VL termination 20K resistance, thereby with the power supply dividing potential drop of 5 V.Through test, high voltage is 4.75 V, and low-voltage is 2.5 V, and digital regulation resistance because high low voltage range is dwindled, makes the precision of digital regulation resistance improve being equally divided into 32 parts between the high-low level.When the clock signal comes a pulse, if No. 2 pin UD connect high level, then output voltage increase high low-voltage difference 1/32, promptly be about 0.04 V; If No. 2 pin UD connect low level, then output voltage reduces by 0.04 V.
The parameter of digital regulation resistance is selected very important, and it directly influences the reliability of device.Threshold value is too high, and then sensitivity is low, though undesired signal suppresses to some extent to external world; But the responding ability to signal weakens, even can not respond, if threshold value is too low then highly sensitive; Interference rejection capability weakens to external world, as long as there is the undesired signal input in the external world, then just might produce maloperation.X9313 has 32 resistance values, and resistance value can be controlled through external digital signal, and the resistance value that chooses is stored in the storer, but recall.
(2) window comparator circuit
When pyroelectric infrared sensor detected vehicle, the vehicle infrared radiation that will surveyed and receive by sensor was transformed into faint voltage signal, outwards output after the FET in being contained in sensor amplifies.Because sensor possibly produce the output signal to the interference of photo-thermal and other objects, so add window comparator circuit, signal is screened, and improves the precision of measuring.
The signal that pyroelectric infrared sensor sends will be provided with quiescent point earlier after amplifying circuit amplifies signal, to satisfy the requirement of window comparator circuit.
Signal after at first will amplifying connects capacitor C 8 and removes flip-flop, with the resistance of resistance R 4 and 19 two 100 K of resistance R, inserts like Fig. 7 then, makes the direct current quiescent point be enhanced 2.5 V.The value of resistance must be enough big, otherwise useful signal is disappeared.The output terminal of this signal and digital regulation resistance is inserted voltage comparator.In this circuit, voltage comparator adopts the integrated computing of LM324 to amplify chip (U3B among Fig. 7), and through the sensitivity of reference voltage regulator potentiometer regulating circuit, just investigative range.
When not having vehicle to get into, No. 6 pin voltage of operational amplifier are about 2.5 V; The voltage that the adjusting digital regulation resistance makes No. 5 pins is a little more than 2.5 V, and this moment, No. 7 pins were output as high level.When vehicle got into investigative range, infrared sensor output detecting voltage made inverse output terminal voltage be higher than the voltage of in-phase input end after amplifying, and output end voltage saltus step at this moment is a low level, produces negative edge, thereby triggers singlechip interruption.Because operational amplifier connects negative supply, output possibly be negative value, can damage the external interrupt of single-chip microcomputer, so interpolation diode D3 and current-limiting resistance R 17 make negative voltage be no more than-0.7 V as clamping circuit, and the protection single-chip microcomputer; At last, whether signal gets into single-chip microcomputer external interrupt INT 0, be used for detecting vehicle and get into.
Four, the display circuit of display
Referring to shown in Figure 8, in the embodiment of the invention, it is power supply ground that display chip adopts 12864, No. 1 pins of serial LCD chip, and No. 2 pins are positive supply, and No. 3 pin is regulated input voltage through slide rheostat RW1, the contrast of control liquid crystal display; No. 4 pin CS are chip selection signal, and by the control of single-chip microcomputer P0.0 mouth, No. 5 pin SID are the serial data mouth, and by the control of single-chip microcomputer P0.1 mouth, No. 6 pin CLK are clock signal, are controlled by single-chip microcomputer P0.3 mouth.Among the present invention, use serial mode, No. 15 pin PSB is used for selecting to use the parallel still working method of serial, connects low level all the time; No. 16 pin NC is unsettled; No. 17 pin RET reseting pin and No. 18 pin Vout negative pressure output pin also needn't use; No. 19 pin LED_ K and No. 20 pin LED_ K are that LED-OV and backlight are anodal, connect together+5 V power supplys and ground with No. 1, No. 2 pins respectively.
Five, memory circuitry
Shown in Fig. 9 ~ 10, memory chip 24C256 is a 256K bit serial CMOS EPROM, and 32768 bytes are contained in inside.Concrete method of attachment and pin function are: No. 4 pin GND are power supply ground, and No. 8 pin Vcc are positive supply, and No. 1 pin and No. 2 pin A 0 are address input line with A 1; These pins are hardwired or do not connect, for 4 24C256 devices of the maximum addressables of unibus system, directly are changed to low level here; The address is that 00, No. 7 pin WP is write-protect, connects low level here; Close write-protect, allow device to carry out write operation, No. 6 pin SCL are serial clock input pins; Be used to produce the clock that all data of device are sent or received, by the P0.4 mouth control of single-chip microcomputer, No. 5 pin SDA are bidirectional linked list data/address signals; Be used for the transmission and the reception of all data of device, control by single-chip microcomputer P0.5 mouth.
Six. the software control flow process of single-chip microcomputer
When carrying out software design based on single-chip microcomputer, all software programs all use the C language, to reach the function that shows the vehicle flowrate and the speed of a motor vehicle.Control program comprises 2 external interrupt triggers, initialization subroutine, digital regulation resistance adjusting program and liquid crystal display program etc.
(1) down trigger mode
Because vehicle at first can pass through pyroelectric infrared sensor 1,, have only INT 1 could accomplish counting for open mode when system is in when waiting for the state that vehicle crosses.Can design thus, the main contents of principal function are the initialization of each element and digital regulation resistance, progressively reduce digital regulation resistance voltage to suitable value, and the initial value that demonstration is set is 0.Accomplish the assignment and the demonstration of vehicle flowrate and vehicle speed initial value, get into circulation at last.
In the digital regulation resistance initialization, the output voltage of digital regulation resistance is divided into 32 lattice with the voltage of 2.5 V～3.75 V, about 0.04 V of every lattice.Because the initial output voltage of digital regulation resistance is unknown, so in initialize routine, at first the output voltage with digital regulation resistance rises to the 32nd the highest lattice, promptly 3.75 V make its decline afterwards in master routine.Requirement according to sensitivity is different, and fall is also different.For example, if descend 26 lattice, just use the 8th lattice, this moment, the threshold voltage of digital regulation resistance output was 2.5 V+0.04 V * 8=2.82 V.
(2) external interrupt INT 1 program
Referring to shown in Figure 11, the figure shows the flow process of single-chip microcomputer external interrupt INT 1 program.
After opening external interrupt INT 1, this moment, system began to wait for crossing of vehicle, when vehicle crosses pyroelectric infrared sensor 1, can produce pulse signal, and through shaping, produced negative edge, and negative edge will be identified, thereby produced external interrupt INT 1.Close external interrupt 1 this moment; Opening timing device 0; The timer initial value is set and starts timer 0, the vehicle flowrate number adds 1, opens external interrupt INT 0 and waits for that vehicle is through another pyroelectric infrared sensor; And the triggering mode of external interrupt INT 0 is set, at last the vehicle flowrate data of upgrading are sent into display and shown through the display circuit of display.
(3) external interrupt INT 0 program
Referring to shown in Figure 12, the figure shows the flow process of single-chip microcomputer external interrupt INT 0 program.
After opening external interrupt INT 0, system begins to wait for that vehicle crosses from infrared sensor 2, when vehicle crosses; Pyroelectric infrared sensor can produce pulse signal, equally through shaping, produces negative edge; Negative edge will be identified, and interrupts thereby produce INT 0.Have no progeny in the generation and close external interrupt, the timeing closing device, and with the data based formula v=s/t calculating speed of a motor vehicle in the timer register, s is that variable is wide here, the overline bridge width of promptly measuring; T is the timer measurement of measuring through the time that the crossover-passing width is consumed.The speed of a motor vehicle that calculates is sent into the variable multiplier, and the data of the vehicle speed that upgrades are sent into display and demonstration.
Referring to shown in Figure 13, master control program uses cyclic query mode, circular wait.When the P03 mouth is low level, explained that vehicle arrives, start timer, vehicle flowrate adds 1, update displayed vehicle flowrate, circular wait.When the P20 mouth becomes low level, explain that vehicle rolls away from, with distance/Time Calculation speed of a motor vehicle, the update displayed speed of a motor vehicle.
In the embodiment of the invention, digital regulation resistance is divided into 32 shelves, the output voltage range of adjustment is 2.5 V-3.75 V, and voltage is defined as the 1st grade when being 2.5 V, and voltage is defined as the 32nd grade when being 3.75 V.The regulation voltage span is 1.25V, that is to say, and one grade of the every rising of digital regulation resistance, output voltage increases 0.04V.For example, second grade of voltage is 2.5 V+0.04 V=2.54 V.The initial voltage and the pairing voltage of each grade of digital regulation resistance are set.
Through the actual test to the different time environment, find following rule: 14 o'clock in the afternoon, this moment, solar irradiation was the strongest; Ambient temperature is the highest, and digital regulation resistance tap initial position is the 6th grade, makes that threshold voltage is 2.74v; As disturbed and transfer to the 8th grade at most, threshold voltage is 2.82 V.At late 23 o'clock, digital regulation resistance tap initial position was 4 grades, and threshold voltage is 2.66v, as disturbed and transfer to the 5th grade or the 6th grade at most.
In reality was tested, the adjusting of sensitivity is trouble, and sensitivity is too high possibly to cause pulse mistake meter, and sensitivity is crossed to hang down and possibly leaked meter easily; And different time, different location, Various Seasonal, all different to the requirement of sensitivity.Therefore, must correct, reach the effect of automatic straightening sensitivity this phenomenon.
Referring to shown in Figure 15, at first the initial value of digital regulation resistance is made as very sensitively, judged whether that then the pulse mistake counts phenomenon, promptly whether do not having under the situation of car counting to have taken place.
Determination methods is following: if per 30 seconds an of road can not surpass 20 through vehicle flowrate, if the detected vehicle flowrate of system is greater than 20 in 30 seconds, explain the situation that the vehicle mistake is counted to have occurred, at this moment will reduce the sensitivity of 1 lattice.Can be adjusted to suitable sensitivity automatically by this method.
The above only is a preferred implementation of the present invention; Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; Can also make some improvement and retouching, these improvement and retouching also should be regarded as protection scope of the present invention.
Claims (8)
1. the detection method of the vehicle flowrate and the speed of a motor vehicle is characterized in that, may further comprise the steps:
Two pyroelectric infrared sensors that are connected with a single-chip microcomputer are separated certain distance along the link length direction be installed on road top or side, and said two pyroelectric infrared sensors are in the same plane;
Output pulse signal to said single-chip microcomputer when first pyroelectric infrared sensor detects a vehicle and sails into, the single-chip microcomputer built-in timer picks up counting, and said single-chip microcomputer adds 1 to the counting of vehicle flowrate simultaneously;
Output pulse signal to said single-chip microcomputer when second pyroelectric infrared sensor detects above-mentioned vehicle and sails into; Said timer stops timing; Behind the said vehicle speed of Time Calculation that calculates according to the distance between said two pyroelectric infrared sensors and said timer by said single-chip microcomputer, will count and the speed of a motor vehicle is delivered to said display demonstration.
2. the detection method of the vehicle flowrate according to claim 1 and the speed of a motor vehicle; It is characterized in that; Before behind the pulse signal of described pyroelectric infrared sensor output, sending into described single-chip microcomputer, further comprising the steps of: that described pulse signal is carried out at a distance from straight amplification, compares the step of Screening Treatment.
3. the detection method of the vehicle flowrate according to claim 1 and 2 and the speed of a motor vehicle is characterized in that, when described second pyroelectric infrared sensor did not detect above-mentioned vehicle and sails into, the counting of said single-chip microcomputer turned back to original state.
4. the detection system of the vehicle flowrate and the speed of a motor vehicle is characterized in that, comprise two separately certain distance be installed on pyroelectric infrared sensor, a single-chip microcomputer and a display of road top or side; Described two pyroelectric infrared sensors are used to detect to be exported a pulse signal respectively when vehicle sails into and sends into said single-chip microcomputer; Said single-chip microcomputer is used for calculating vehicle according to described pulse signal and calculates the speed of a motor vehicle through number and calculating and according to vehicle through the time of said two pyroelectric infrared sensors, the distance of described two pyroelectric infrared sensors, and sends into said display and show.
5. the detection system of the vehicle flowrate according to claim 4 and the speed of a motor vehicle; It is characterized in that; Comprise a signal processor, be used for the pulse signal of described pyroelectric infrared sensor output is carried out the described single-chip microcomputer of input after directly amplifying, compare Screening Treatment.
6. the detection system of the vehicle flowrate according to claim 5 and the speed of a motor vehicle; It is characterized in that; Described signal processor includes: at a distance from straight amplifying circuit, be used for the pulse signal of described pyroelectric infrared sensor output is carried out behind straight the amplification, exporting the comparison module circuit to; The comparison module circuit is used for comparing at a distance from straight pulse signal and the threshold voltage that amplifies said, but inputs to said single-chip microcomputer after filtering out said single-chip microcomputer processing signals.
7. the detection system of the vehicle flowrate according to claim 6 and the speed of a motor vehicle; It is characterized in that; Described comparison module circuit comprises a window comparator circuit and a digital regulation resistance; Described digital regulation resistance is by said Single-chip Controlling, the threshold voltage of using when being used to control the said window comparator circuit comparison Screening Treatment signal of adjustment.
8. according to the detection system of each the described vehicle flowrate of claim 4 ~ 7 and the speed of a motor vehicle, it is characterized in that described display is a LCD display.
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Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103050014A (en) * | 2012-12-11 | 2013-04-17 | 武汉智慧城市研究院股份有限公司 | Traffic speed detection system and detection method |
| CN103680155A (en) * | 2013-12-13 | 2014-03-26 | 青岛天信通软件技术有限公司 | Vehicle flow detection device |
| CN104036637A (en) * | 2014-05-28 | 2014-09-10 | 江苏科技大学 | Bluetooth-based traffic flow detection device and implementation method |
| CN104166872A (en) * | 2014-07-10 | 2014-11-26 | 中国科学院长春光学精密机械与物理研究所 | Counting pyroelectric infrared sensor-based counter |
| CN104504911A (en) * | 2013-12-25 | 2015-04-08 | 安徽宝龙环保科技有限公司 | Motor vehicle speed measuring device and speed measuring method |
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| CN104680799A (en) * | 2013-11-29 | 2015-06-03 | 青岛永通电梯工程有限公司 | Vehicle flow detection method |
| CN104916128A (en) * | 2015-04-07 | 2015-09-16 | 北京长城金点物联网科技股份有限公司 | Vehicle flow detection method and system |
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| CN107448882A (en) * | 2017-07-20 | 2017-12-08 | 华南师范大学 | A kind of vcehicular tunnel energy efficient lighting system |
| CN107958597A (en) * | 2017-12-25 | 2018-04-24 | 重庆冀繁科技发展有限公司 | Magnitude of traffic flow monitoring system |
| CN108242155A (en) * | 2016-12-23 | 2018-07-03 | 吴若父 | A kind of overspeed monitor for velocity tunnel |
| CN108399794A (en) * | 2018-02-27 | 2018-08-14 | 吉林大学 | Tunnel driving safety pre-warning system and method based on vehicle running state detection |
| CN108765980A (en) * | 2018-04-27 | 2018-11-06 | 榛硕（武汉）智能科技有限公司 | A kind of vehicle overspeed warning device and method |
| CN114463995A (en) * | 2022-01-30 | 2022-05-10 | 河南省交通规划设计研究院股份有限公司 | Wisdom traffic road bridge monitored control system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0680026B1 (en) * | 1994-04-20 | 2000-02-02 | Odetics, Inc. | Vehicular traffic monitoring system |
| JP2000298793A (en) * | 1999-04-13 | 2000-10-24 | Matsushita Electric Ind Co Ltd | In-tunnel accident detecting device |
| CN201017478Y (en) * | 2007-01-17 | 2008-02-06 | 李铮 | Self-feedback traffic signal light control device |
| CN201051310Y (en) * | 2007-06-21 | 2008-04-23 | 南京理工大学 | Millimeter wave and ultrasonic wave dual frequency traffic parameter detector with car type recognition function |
| CN101236697A (en) * | 2007-08-08 | 2008-08-06 | 中科院嘉兴中心微系统所分中心 | Wireless sensor network system and detection method utilizing huge magneto-resistance magnetic-sensing technology for detecting vehicle information |
| CN202748940U (en) * | 2012-08-21 | 2013-02-20 | 北京信息科技大学 | Infrared sensor-based vehicle-flowrate detection apparatus |
-
2012
- 2012-08-21 CN CN2012102981239A patent/CN102789691A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0680026B1 (en) * | 1994-04-20 | 2000-02-02 | Odetics, Inc. | Vehicular traffic monitoring system |
| JP2000298793A (en) * | 1999-04-13 | 2000-10-24 | Matsushita Electric Ind Co Ltd | In-tunnel accident detecting device |
| CN201017478Y (en) * | 2007-01-17 | 2008-02-06 | 李铮 | Self-feedback traffic signal light control device |
| CN201051310Y (en) * | 2007-06-21 | 2008-04-23 | 南京理工大学 | Millimeter wave and ultrasonic wave dual frequency traffic parameter detector with car type recognition function |
| CN101236697A (en) * | 2007-08-08 | 2008-08-06 | 中科院嘉兴中心微系统所分中心 | Wireless sensor network system and detection method utilizing huge magneto-resistance magnetic-sensing technology for detecting vehicle information |
| CN202748940U (en) * | 2012-08-21 | 2013-02-20 | 北京信息科技大学 | Infrared sensor-based vehicle-flowrate detection apparatus |
Non-Patent Citations (1)
| Title |
|---|
| 王捷，等: "热释电红外传感器应用与车流量检测系统", 《自动化仪表》 * |
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103050014A (en) * | 2012-12-11 | 2013-04-17 | 武汉智慧城市研究院股份有限公司 | Traffic speed detection system and detection method |
| CN104680799A (en) * | 2013-11-29 | 2015-06-03 | 青岛永通电梯工程有限公司 | Vehicle flow detection method |
| CN103680155A (en) * | 2013-12-13 | 2014-03-26 | 青岛天信通软件技术有限公司 | Vehicle flow detection device |
| CN104504911A (en) * | 2013-12-25 | 2015-04-08 | 安徽宝龙环保科技有限公司 | Motor vehicle speed measuring device and speed measuring method |
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| CN104574964A (en) * | 2015-01-09 | 2015-04-29 | 河海大学 | Pavement structure durability and dynamic traffic monitoring system |
| CN104916128A (en) * | 2015-04-07 | 2015-09-16 | 北京长城金点物联网科技股份有限公司 | Vehicle flow detection method and system |
| CN104931717A (en) * | 2015-06-13 | 2015-09-23 | 常州大学 | Instant speed measuring instrument |
| CN106228631A (en) * | 2016-07-27 | 2016-12-14 | 安徽聚润互联信息技术有限公司 | A kind of attendance system and method based on traffic information |
| CN108242155A (en) * | 2016-12-23 | 2018-07-03 | 吴若父 | A kind of overspeed monitor for velocity tunnel |
| CN107448882A (en) * | 2017-07-20 | 2017-12-08 | 华南师范大学 | A kind of vcehicular tunnel energy efficient lighting system |
| CN107958597A (en) * | 2017-12-25 | 2018-04-24 | 重庆冀繁科技发展有限公司 | Magnitude of traffic flow monitoring system |
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| CN108399794B (en) * | 2018-02-27 | 2021-03-30 | 吉林大学 | Tunnel driving safety early warning system and method based on vehicle driving state detection |
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