Program for anti-myopia desk lamp based on 51 single chip ultrasonic distance measurement

Program code 

simulation diagram

The microcontroller source program is as follows:

#include

#include

/*************************Macro definition************************/

#define uchar unsigned char

#define uint unsigned int

/************Bit definition********************************/

sbit Trig=P3^7; //Ultrasonic module trigger bit

sbit LEDRED=P1^0;

sbit LEDGREEN=P1^2;

sbit speaker=P1^7;

sbit person=P1^6;

sbit TLED = P1^5;

/************Global variable declaration************************/

uint H,T; //define global variables, H--distance, T--time

/***********Common cathode digital tube segment code table********************/

uchar a_code[]={ //Common cathode digital tube code 0~9

0x3f,0x06,0x5b,0x4f,0x66,

0x6d,0x7d,0x07,0x7f,0x6f,

/*0x77,0x7c,0x39,0x5e,0x79,

0x71*/};

/***************Delay function****************************/

void delay(uint z) //*1ms delay function

{

        uint x,y;

        for(x=z;x>0;x--)

                for(y=110;y>0;y--);

}

/*************Ultrasonic module startup function**************/

void start()

{

        Trig=1; //Pull up the trigger signal to start the ultrasonic module to emit ultrasonic waves

        _nop_(); //Delay 10us

        _nop_();

        _nop_();

        _nop_();

        _nop_();

        _nop_();

        _nop_();

        _nop_();

        _nop_();

        _nop_();

        _nop_();

        _nop_();

        _nop_();

        _nop_();

        Trig=0; //Pull the trigger signal low

}

/*****************Digital tube display function*****************/

void display(unsigned int a,unsigned int b,unsigned int c,unsigned int d)

{

    P2=0xfe;

    P0=a_code[a];

    delay(5);

    P2=0xfd;

    P0=a_code[b];

    delay(5);

        P2=0xfb;

    P0=a_code[c];

    delay(5);

        P2=0xf7;

    P0=a_code[d];

    delay(5);

}

/*********************Main function****************************/

void main()

{

          Trig=0;

         LEDRED=1;

         LEDGREEN=1;

         speaker=0;

     EA=1;

TMOD=0x19; //Timer 0 working mode:

               /*GATE=1 (Timer 0 is started by external interrupt 0 pin and TR0)

               C/T=0 (timing mode)

                                M1M0=01(16-bit timing)*/

        TH1=64580/256;

        TL1=65480%256;

        ET1=1;

        TR0=1; //Start timer 0

        EX0=1; //Open external interrupt 0

        IT0=1; //Set external interrupt 0 to falling edge trigger mode

        while(1)

{

start(); //Call the ultrasonic module start function

display(H/1000,H%1000/100,H%1000%100/10,H%10); //Call the digital tube display function

if(person==1)  

         {

                TLED=1;

                if(H<=25)

                {

                        LEDRED=0;

                        LEDGREEN=1;

                        TR1=1;

                }

                else

                {

                        LEDRED=1;

                        LEDGREEN=0;

                        TR1=0;

                }

        }

        else

        {

                TLED=0;

                LEDRED=1;

                LEDGREEN=1;

                TR1=0;

        }

}

}

/***************External interrupt 0 function****************************

The high level width of the echo output terminal is measured (when the rising edge arrives, timer 0 starts timing.

When the falling edge arrives, an external interrupt is triggered, timer 0 is turned off, timing is stopped, and distance is calculated.

************************************************************/

void int0() interrupt 0         

{

         TR0=0; //Turn off timer 0

        EX0=0; //Disable external interrupt 0

        T=(TH0*256+TL0); //Calculate the ultrasonic transmission time. The CPU uses a 12M clock, so the calculation unit is us.

         TH0=0; //Timer cleared

         TL0=0;

         H=T*0.017; //Calculate the distance in cm (Note: H=(T*17)/1000 cannot be used, as this will result in rounding)

         H=H+2;

        TR0=1; //Start timer 0

        EX0=1; // Enable external interrupt 0        

}

void time1() interrupt 3

{

        TR1=0;

        TH1=65480/256;

        TL1=65480%256;

        speaker=~speaker;

        TR1=1;

}