CN205334734U - Traffic light intelligent control device based on singlechip - Google Patents

Abstract

The utility model discloses a traffic light intelligent control device based on singlechip, a serial communication port, include: the traffic flow detection circuit, reset circuit, clock circuit, AT89C52 singlechip to and display circuit, the display circuit includes driver MAX7219 and LED charactron, traffic flow detection circuit, reset circuit, clock circuit are connected with the AT89C52 microcontroller type end respectively, and driver MAX7219 and traffic light are connected respectively to AT89C52 singlechip output. The utility model discloses make the crossroad traffic light to go out according to crossing vehicle condition automatic adjustment is bright, slowed down traffic blocking phenomenon, use MAX7219 drive circuit to connect the LED display circuit simultaneously for it is small in quantity that the charactron occupies singlechip IO mouth, and the heavy burden that has alleviateed the singlechip makes singlechip operating time more permanent.

Description

SCM Based traffic lights intelligent controlling device

Technical field

This utility model relates to one sensor to detect vehicle flowrate, realize the technology of the automatic light on and off of traffic lights, launch in particular by infrared ray sensor, receive signal vehicle flowrate is detected, infrared ray sensor is demodulated after collecting signal, amplify, be sent to single-chip microcomputer after rectifying and wave-filtering again and process。

Background technology

Based on present intelligent transportation system, with AT89C52 for core control part, power circuit, reset circuit, crystal oscillating circuit constitutes single-chip minimum system, controls the light on and off of charactron countdown and traffic lights。Such traffic system builds, and traffic can be allowed to carry out in order, and city is current without any confusion。But this system existing defects, system can not automatically adjust traffic lights and countdown according to the practical situation of vehicle flowrate。

Summary of the invention

The purpose of this utility model is in that to design a kind of traffic system, according to how many real-time adjustment traffic lights of vehicle flowrate on road and countdown change, can really realize the intelligent transportation system of no worker monitor management。Based on the traffic system of infrared detector, detecting how many vehicle flowrates on track carrys out to adjust in real time traffic lights change, bigger improves current situation of traffic。

For realizing above-mentioned target, this utility model adopts following design:

A kind of SCM Based traffic lights intelligent controlling device, including: vehicle Flow Detection circuit, reset circuit, clock circuit, AT89C52 single-chip microcomputer, and display circuit；Described display circuit includes driver MAX7219 and LED charactron。Vehicle Flow Detection circuit, reset circuit, clock circuit are connected with AT89C52 single-chip microcomputer input respectively, and AT89C52 single-chip microcomputer outfan connects driver MAX7219 and traffic lights respectively, and driver MAX7219 is connected in series with LED charactron。Vehicle Flow Detection circuit is to adopt infrared ray sensor to launch, receive signal vehicle flowrate is detected, in infrared ray sensor, modulation pulse generator sends pulse, the modulation pulse sent, it is radiated on road, when road there being vehicle pass through, modulation pulse just reflects, demodulated, amplify, produce detection signal after rectifying and wave-filtering and send into AT89C52 single-chip microcomputer, AT89C52 single-chip microcomputer counts out the vehicle flowrate size by crossing, then LED charactron countdown and traffic light signals change are controlled according to vehicle flowrate signal and predetermined threshold value by AT89C52 single-chip microcomputer。

Wherein: described vehicle Flow Detection circuit is to adopt infrared ray sensor transmitting, reception signal that vehicle flowrate is detected, and infrared ray sensor is demodulated after collecting signal, amplifies, is sent to AT89C52 single-chip microcomputer again and processes after rectifying and wave-filtering。Described clock circuit is the crystal oscillator by a 12MHz and two circuit that 30Pf ceramic disc capacitor collectively constitutes are formed is a stable self-excited oscillator, it is provided that the clock control signal that AT89C52 single-chip microcomputer is required when properly functioning。Described reset circuit adopts automatic power-on reset circuit, this circuit is by 22 μ F electric capacity, 1000 Europe resistance are constituted, one end of electric capacity and resistance is connected on the reset input pin RST of single-chip microcomputer, and another termination power end of electric capacity, the other end ground connection of resistance, the state that single-chip microcomputer returns to current circuit as necessary。

Described LED charactron is connected in circuit with display driver, DIG0-DIG7 on driver MAX7219 cathode digital tube together drives position to connect, the SEGA-SEGGDP of charactron drives with section and is connected, and DINCLKLOAD tri-foot on driver MAX7219 is connected with any three I/O mouths of AT89C52 single-chip microcomputer。The external resistance of ISET pin of MAX7219, the peak point current that at this moment segment driver provides is about 100 times of ISET pin electric current, and the size adjusting this resistance can change display brightness。

The beneficial effects of the utility model are, have taken into account the performance of various aspects, it is achieved that traffic lights can according on road vehicle flowrate how much come the LED charactron countdown of real-time control single chip computer outfans and traffic lights light on and off。Meanwhile, being connected two parts with MAX7219 display driver between single-chip microcomputer with charactron, due to the serial data transmission of single-chip microcomputer Yu driver, save the I/O mouth of single-chip microcomputer, alleviate single-chip microcomputer and bear a heavy burden, what make that single-chip microcomputer works is more accurate。

Accompanying drawing explanation

Fig. 1 is structure principle chart of the present utility model；

Fig. 2 is infrared sensor reflected signal detection workflow diagram；

Fig. 3 is the annexation figure of clocking scheme and single-chip microcomputer；

Fig. 4 be reset circuit and annexation figure；

Fig. 5 is that MAX7219 drives, LED charactron is connected figure with single-chip microcomputer。

Detailed description of the invention

Below in conjunction with accompanying drawing, this utility model is further described:

As it is shown in figure 1, SCM Based traffic lights intelligent controlling device, including vehicle Flow Detection circuit, reset circuit, clock circuit, AT89C52 single-chip microcomputer, and display circuit；Described display circuit includes driver MAX7219 and and LED charactron。Vehicle Flow Detection circuit, reset circuit, clock circuit are connected with AT89C52 single-chip microcomputer input respectively, and AT89C52 single-chip microcomputer outfan connects driver MAX7219 and traffic lights respectively, and driver MAX7219 is connected in series with LED charactron。

Traffic flow detector circuit sending signal, receives reflected signal and passes to single-chip microcomputer, and single-chip microcomputer controls the count down time of LED charactron and the light on and off of traffic lights according to the different changes of signal。Clock circuit provides the clock control signal that AT89C52 single-chip microcomputer is required when properly functioning, reset circuit adopts automatic power-on reset circuit, this circuit is by 22 μ F electric capacity, 1000 Europe resistance are constituted, one end of electric capacity and resistance is connected on the reset input pin RST of single-chip microcomputer, and another termination power end of electric capacity, the other end ground connection of resistance, the state that single-chip microcomputer returns to current circuit as necessary。The DIG0-DIG7 that LED charactron is connected in circuit on MAX7219 with display driver cathode digital tube together drives position to connect, and SEGA-SEGGDP drives with section and is connected, and DINCLKLOAD tri-foot on MAX7219 is connected with any three I/O mouths of 89C52。

As in figure 2 it is shown, what vehicle Flow Detection circuit adopted is the reflective detection technique of infrared ray sensor, infrared ray sensor critical piece is reflective detection probe, and probe is mainly made up of infraluminescence pipe and infrared receiving tube。In infrared ray sensor, modulation pulse generator sends pulse, the modulation pulse sent, it is radiated on road, when road there being vehicle pass through, modulation pulse just reflects, demodulated, amplify, produce detection signal after rectifying and wave-filtering and send into AT89C52 single-chip microcomputer, AT89C52 single-chip microcomputer counts out the vehicle flowrate size by crossing, is then controlled LED charactron countdown and traffic light signals change according to vehicle flowrate signal and predetermined threshold value by AT89C52 single-chip microcomputer。

As it is shown on figure 3, be the clocking scheme of the present embodiment, it is provided that the clock control signal that AT89C52 single-chip microcomputer is required when properly functioning。Its internal circuit follows strictly timing instructions execution work under control of the clock signal, during command operating, first CPU must take out the instruction operation code deposited in program memory, carrying out decoded operation again, last this timing circuit can produce a series of control signal and go the sequence of operations of timing instructions defined。This clock circuit is the crystal oscillator by a 12MHz and two circuit that 30Pf ceramic disc capacitor collectively constitutes are formed is a stable self-excited oscillator。The height of Induced Oscillation device frequency, the stability of agitator and the rapidity of starting of oscillation all will be determined by this crystal oscillator。And two 30pF ceramic capacitors play fine setting effect in circuit, the circuit of this design is equipped with standard time clock to single-chip microcomputer。

As shown in Figure 4, for the reset circuit of the present embodiment。Reset circuit is the state that current circuit is returned to。Its purposes and the reset button of computer are similar to, and are recalculated by zeros data。But, it is different that the open method of position restoration circuit device resets button from computer。Specifically: 1. then get started operation when power circuit starts power supply；It is manually operable when 2. needing；If 3. reset circuit is during circuit or program normal operating, can automatically carry out。

In this reset circuit, reset pin RST is connected with reset circuit by a Schmitt trigger suppressing noise。It, when the S5P2 of each machine cycle, is once gathered by the output level of Schmitt trigger by reset circuit, then just can obtain the signal of the reset operation that internal circuit needs。This utility model uses automatic power-on reset circuit, and this circuit is that resistance is constituted by components and parts electric capacity, wherein, the one end requiring this electric capacity and resistance is connected on the reset input pin of single-chip microcomputer, and another termination power end of electric capacity, the other end ground connection of resistance。It mainly works as follows: when powering on, and circuit passes through, at the RST port of single-chip microcomputer, the signal that electric capacity obtains the high level of a short time。But, this level signal is change, and electric capacity can be charged along with power supply and gradually decline by its size。Because keeping whole circuit effectively to reset, high level signal must keep the sufficient time in circuit。

As it is shown in figure 5, be the present embodiment MAX7219 drive be connected figure with LED charactron。MAX7219 is compact, serial input, common cathode New LED display driver。Its a piece of chip can drive up to 87 sections of light-emitting diode displays。BCD decoder, multiplexing scanning circuit, section and digit driver is had in its sheet。The section current settings of all LED only needs a non-essential resistance。Its interface is simple, and the I/O mouth line taking CPU is few。External interface only has 3 I/O mouth lines, and a MAX7219 can connect multiple LED charactron。According to Fig. 5, the P0.0 of AT89C52 chip connects the DIN data in pin of MAX7219, and P0.1 meets the LOAD of MAX7219 and locks input pin, and P0.2 connects the CLK clock input pin of MAX7219。The common cathode of MAX7219 and LED charactron connects, and drives the light-emitting diode display of common cathode。At the external resistance of its ISET pin, the peak point current that at this moment segment driver provides is about 100 times of ISET pin electric current, and the size adjusting this resistance can change display brightness。What MAX7219 and AT89C52 chip adopted is that serial mode carries out data transmission, data lattice are 16, the serial data data when the rising edge of each CLK being sent to DIN end are latched to numeral or control in depositor, and the data of DIN end pass through shift register transmission。AT89C52 single-chip microcomputer controls the countdown of LED charactron by driver MAX7219 and requires over software programming and realize。MAX7219 and AT89C52 chip programming is broadly divided into three parts: initialization subroutine, send aobvious subprogram and data transmission。First, carry out data transmission, write subprogram according to the sequential that device transmits, transmit data here mainly by serial mode。When sending several to MAX7219, first it is that the chip select pin making MAX7219 becomes low level, then it is single Yuan value of unit (byte) of this unit to the MAX7219 number transmitted, then MAX7219 transmits the unit to deliver to and send number (byte), the chip select pin level finally making MAX7219 is drawn high (becoming high level), and such data are just latched in corresponding data memory。Again, for initializing program, mainly the display pattern of every MAX7219, display brightness, figure place showing are initialized。Finally, carry out sending writing and utilization of explicit program, be in the data register that the numerical value that will show delivers to every MAX7219 so that it is show。Realization by a series of programmings so that the information of vehicle flowrate of infrared sensor collection processes through single-chip microcomputer and is sent to driver, finally controls LED countdown。And the light on and off of traffic lights are directly controlled by single-chip microcomputer。

In sum, signal is launched by infrared sensor, reflecting through vehicle, sensor receives return signal and transmits signals to single-chip microcomputer again through a series of processing of circuit, can well realize LED countdown and the real-time change of traffic lights light on and off again through certain artificial programming。This experiment simultaneously uses MAX7219 to realize connection and the communication of single-chip microcomputer and LED charactron, and the I/O mouth greatly saving single-chip microcomputer uses so that the port of single-chip microcomputer is sufficient, improves the work efficiency of single-chip microcomputer, is truly realized intelligent transportation。

Claims (3)

1. a SCM Based traffic lights intelligent controlling device, it is characterised in that including: vehicle Flow Detection circuit, reset circuit, clock circuit, AT89C52 single-chip microcomputer, and display circuit；Described display circuit includes driver MAX7219 and LED charactron；Vehicle Flow Detection circuit, reset circuit, clock circuit are connected with AT89C52 single-chip microcomputer input respectively, and AT89C52 single-chip microcomputer outfan connects driver MAX7219 and traffic lights respectively, and driver MAX7219 is connected in series with LED charactron；

Described vehicle Flow Detection circuit is to adopt infrared ray sensor transmitting, reception signal that vehicle flowrate is detected, infrared ray sensor collect demodulated after signal, amplify, be sent to AT89C52 single-chip microcomputer again after rectifying and wave-filtering, AT89C52 single-chip microcomputer counts out the vehicle flowrate size by crossing, is then controlled LED charactron countdown and traffic light signals change according to vehicle flowrate signal and predetermined threshold value by AT89C52 single-chip microcomputer。

2. SCM Based traffic lights intelligent controlling device as claimed in claim 1, it is characterized in that, described LED charactron is connected in circuit with driver MAX7219, DIG0 to DIG7 on driver MAX7219 and LED charactron drives position to be connected, SEGA to SEGG and the DP pin of LED charactron drives position A-G and DP to be connected with the section on driver MAX7219 respectively, DIN, CLK, LOAD on driver MAX7219 tri-foot be connected with any three I/O mouths of AT89C52 single-chip microcomputer；The external resistance changing LED charactron brightness of ISET pin of driver MAX7219。

3. SCM Based traffic lights intelligent controlling device as claimed in claim 1, it is characterized in that, described clock circuit is the crystal oscillator by a 12MHz and two circuit that 30Pf ceramic disc capacitor collectively constitutes, and what this circuit was formed is a stable self-excited oscillator；Described reset circuit adopts automatic power-on reset circuit, this circuit is made up of 22 μ F electric capacity, 1000 Europe resistance, one end of electric capacity and resistance is connected on the reset input pin RST of single-chip microcomputer, and another termination power end of electric capacity, the other end ground connection of resistance。