51 Single Chip Microcomputer Design of traffic light system (with Proteus simulation, C program, schematic diagram, PCB, thesis and other complete data)

The design requirements
（1） utilize 51 Single chip microcomputer designs a traffic light control system , To realize the diversion of pedestrians and traffic flow . The system is mainly used at intersections , Longitudinal main road , Laterally, it is a branch road ;
（2） Lord 、 Branch roads alternate , The traffic lights on the two main roads work simultaneously , Every time the main road is green 15 second , Every time the branch road is released 10 second , The release time can be changed by pressing the key ;
（3） Every time the green light turns red , The yellow light flashes first 3 second , here , The red light remains on the other main road ;
（4） The function of traffic control at intersections is realized by pressing buttons ;
（5） The structure diagram of the whole system is given 、 Software and hardware flow chart ;

Design Overview
The east-west trunk road and the North-South branch trunk road are controlled by a group of three-color traffic lights , They are the red in the direction of the main road 、 yellow 、 Green and red in the direction of the main road 、 yellow 、 green .

Logical analysis shows that , When the main road is green , Branch roads must be red and forbidden ; After the green light , The main road enters the yellow light flashing waiting state , Branch Road red light ; After the yellow light , The main road turns red and no traffic is allowed , The branch road turns green ; After the green light on the branch road ends , The branch road enters the yellow light flashing waiting state , The main road is red , So circular .

From this process we can see that , Traffic light control is divided into 4 Status , Respectively ：S1 state , The main road is the green light , The direction of the branch road is red ;S2 state , The yellow light flashes in the direction of the main road , Branch Road red light ;S3 state , The direction of the main road is red , The direction of the branch road is green ;S4 state , The yellow light flashes in the direction of the branch road , The main road is red . These four states continue to cycle . From this we can list 4 A list of States and make 4 A flow chart of States .

The system has 4 A button , They are the setting keys , Add the key , Minus keys and traffic control keys . The setting key is used to start and confirm the setting , Adding and subtracting keys is to adjust the travel time , The traffic control key is a mandatory setting for the traffic light system .

When the system is powered on or manually reset , In the default mode, it will run according to the parameters recorded in the program before power failure . If the setting key is pressed at this time , Then enter the setting state of traffic time , The time originally recorded is displayed on the nixie tube and flashes , You can add or subtract keys to things 、 The waiting time of the north-south trunk road is modified , After the modification is completed , Press the set key to save the new parameter .

Traffic control key , Used for traffic control at intersections . There are five modes ： thing 、 Red light on the North-South main road ; Things are red , North South green light ; Things green , North south red light ; Things green , North South green light ; Things are yellow , North and south yellow lights .

Simulation circuit diagram


Schematic diagram and PCB


Physical drawing of hole board

Analysis of simulation results
In the real traffic lights , It's a vertical operation , The vertical direction is north-south ; In the simulation circuit diagram , From the front view, the vertical is something , It's the same as the real thing when viewed obliquely from the left . therefore , Physical and simulation are one-to-one correspondence ！

load “ Based on graduation 51 Single chip microcomputer traffic light design .hex” File to MCU , Click on the run , The traffic lights began to work （ The diode displays red 、 yellow 、 Green tricolor lamp ,LED Show countdown ）.

In the program, we set , The green light passing time of the east-west trunk road is 15S, The traffic time of the North-South branch road is 10S. The system automatically enters the state S1： The green light on the East-West main road is on , The red light of the North-South branch road is on .

It can be seen that , The green light passing time of the east-west trunk road is 15S, The waiting time for the red light on the North-South branch road is 15S. thing 、 North south trunk road LED count down 12S after , System entry S2 state ： The yellow light on the East-West main road flashes 3S, The red light of the North-South Branch Road .

3S after , System entry S3 state ： Red light on the East-West main road , The green light of the North-South green trunk road , The passage time is 10S. The simulation results are as follows .

7S after , System entry S4 state ： The yellow light on the north-south trunk road flashes 3S, The east-west trunk road is still red . Then enter S1 state , Keep cycling .

Press down “ Set up ” Post key , The system enters setup mode , adopt “ Add ” Key sum “ reduce ” Key to set the green light passage time of the east-west trunk road . Press again “ Set up ” key , You can set the passage time of the north-south trunk road . After setting the travel time , Press again “ Set up ” key , The system returns to the running state .


As you can see from the picture above , The traffic time of the east-west trunk road is changed from the original 15S Set to 16S. Can pass “ Traffic control ” key , Control the traffic light system .

part C Code

u8 Key_Scan()
{
        
    static u8 key_up=1;// Press the key to release the sign 
    if(key_up&&(Key1==0||Key2==0||Key3==0||Key4==0))
    {
    
        delay_1ms(10);// To shake  
        key_up=0;
        if(Key1==0)         return 1;
        else if(Key2==0)return 2;
        else if(Key3==0)return 3;
        else if(Key4==0)return 4;
    }
    else if(Key1==1&&Key2==1&&Key3==1&&Key4==1)
        key_up=1;       
    return 0;//  No key press 
}


uchar flag_s;
uchar menu_1;// Vertical and horizontal addition and subtraction marks 


/******************** Set function *****************/
void key_with()
{
    
    if(key_can == 4)   // Traffic control button 
    {
    
        flag_jdgz ++;
        if(flag_jdgz > 5)
            flag_jdgz = 0;  
        if(flag_jdgz == 1)   //  All the red lights are on  
        {
    
            dx_red    = 0;  // bright  
            nb_red    = 0;  // bright  
            dx_green  = 1;  // destroy 
            dx_yellow = 1;  // destroy 
            nb_green  = 1;  // destroy 
            nb_yellow = 1;  // destroy  
        }
        if(flag_jdgz == 2)   //  Things green   North south red light 
        {
    
            dx_red    = 0;  // bright  
            nb_green  = 0;  // bright 
            dx_green  = 1;  // destroy 
            dx_yellow = 1;  // destroy 
            nb_red    = 1;  // destroy  
            nb_yellow = 1;  // destroy  
        }
        if(flag_jdgz == 3)   //  North South green light   Things are red 
        {
    
            dx_green  = 0;  // bright 
            nb_red    = 0;  // bright  
            dx_red    = 1;  // destroy  
            dx_yellow = 1;  // destroy 
            nb_green  = 1;  // destroy 
            nb_yellow = 1;  // destroy  
        }
        if(flag_jdgz == 4)   //  North South green light   Things green 
        {
    
            dx_green  = 0;  // bright 
            nb_green  = 0;  // bright 
            dx_red    = 1;  // destroy  
            dx_yellow = 1;  // destroy 
            nb_red    = 1;  // destroy  
            nb_yellow = 1;  // destroy  
        }
        if(flag_jdgz == 5)   //  North and south yellow lights   Things are yellow 
        {
    
            dx_red    = 1;  // destroy  
            dx_green  = 1;  // destroy 
            nb_red    = 1;  // destroy  
            nb_green  = 1;  // destroy 
            nb_yellow = 0;  // bright  
            dx_yellow = 0;  // bright 
        }
    }
    if(key_can == 1)      // Set the key 
    {
    
        menu_1 ++;
        if(menu_1 >= 3)
        {
    
            menu_1  = 0;
        }
    }

    if(menu_1 == 1)    // Set the time of things 
    {
    
        if(key_can == 2)
        {
    
            dx_time ++ ;        // Add 1
            if(dx_time > 99)// The maximum time is 99s
                dx_time = 99;
        }
        if(key_can == 3)
        {
    
            dx_time -- ;        // reduce 1
            if(dx_time <= 5)// The minimum time is 5s
                dx_time = 5;
        }
        dis_smg[0] = DisplayOther[2] ;  // Is shown as B
        dis_smg[1] = DisplayOther[2] ;  // Is shown as B
        dis_smg[2] = smg_du[(dx_time-1) % 10] ;     // When displaying the settings of things 
        dis_smg[3] = smg_du[(dx_time-1) / 10] ; 
    }

    if(menu_1 == 2)    // Set the North-South time 
    {
    
        if(key_can == 2)
        {
    
            nb_time ++ ;        // Add 1
            if(nb_time > 99)    // The maximum time is 99s
                nb_time = 99;
        }
        if(key_can == 3)
        {
    
            nb_time -- ;        // reduce 1
            if(nb_time <= 5)// The minimum time is 5s
                nb_time = 5;
        }
        dis_smg[0] = smg_du[(nb_time-1) % 10] ; // Is shown as A
        dis_smg[1] = smg_du[(nb_time-1) / 10] ; // Is shown as A
        dis_smg[2] = DisplayOther[2] ;      // When displaying the settings of things 
        dis_smg[3] = DisplayOther[2] ;  
    }   

}

The shared resources are
（1） be based on 51 MCU traffic light system graduation design thesis complete version ;
（2）Proteus Simulation file ;
（3）Keil C Program files ;
（4） Reference material ;
（5）Visio flow chart ;
（6）PCB Documents and schematic diagrams ;
（7） Introduction and list of components ;
（8） Reference design 1： Design of traffic lights based on single chip microcomputer （ Another set of traffic light design ）

The screenshot of resources is as follows






Get the traffic light system design paper 、Proteus Simulation 、C Program 、PCB And schematic diagram 、Visio flow chart 、 A complete set of information such as component list .
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