Speed measurement using Moc 7811

Anybody help to me.
I had Moc 7811 ic.
I want do a project using that component,like speed measure and line follower. can you give any circuit for that components

The above program for speed measuring the motor, through the interrupt and lcd display..
anybody help to me
the following code are correct or not?



#include<reg51.h>

sfr lcdout =0x90; //P2
sbit rs =0x85;// P0.5
sbit rw =0x86;
sbit en =0x87;

void Init_LCD();
void lcdcmd(unsigned int val);
void lcddata(unsigned char*);
void lcddata1(unsigned int);
void delay();
void count();
void Display( unsigned int val);
void Display1( unsigned int val);
//void display(unsigned int);
unsigned int cnt,disp,j,V;
unsigned char aray[]={'0','1','2','3','4','5','6','7','8','9'};


void main()
{
unsigned int i; V=0;
Init_LCD();
lcdcmd(0x83);
lcddata("MOTOR SPEED");
disp=0;
while(1)
{

cnt=0;
for(i=0;i<600;i++) {count();}


// disp=cnt; //display(disp);
//lcdcmd(0xC5);
// lcddata1(98);

loop:if(P3_0==1) goto loop;
}



}


void count()
{

TMOD=0x01;
TH0=0x3C;
TL0=0xB0;
while(TF0==0) { if(P0_0==0){cnt++;} else V++; }
TF0=0;
TR0=0;

Display(cnt);
//Display1(V);

}


void Init_LCD()
{
lcdcmd(0x38);
lcdcmd(0x0C);
lcdcmd(0x01);
}
void lcdcmd(unsigned int val)
{
lcdout=val;
rs=0;
rw=0;
en=1;
delay();
en=0;
}

void lcddata(unsigned char *t)
{
while(*t)
{
lcdout=*t++;
rs=1;
rw=0;
en=1;
delay();
en=0;
}
}

void lcddata1(unsigned int d)
{
lcdout=d;
rs=1;
rw=0;
en=1;
delay();
en=0;
}

void delay()
{
for(j=0;j<1000;j++);
}
void Display( unsigned int val)
{
unsigned int l,m,z;
l=val%10;
m=(val/10)%10;
z=(val/100)%10;
lcdcmd(0xC6);
lcddata1(aray[z]);
lcdcmd(0xC7);
lcddata1(aray[m]);

lcdcmd(0xC8);
lcddata1(aray[l]);


}
void Display1( unsigned int val)
{
unsigned int l,m,z;
l=val%10;
m=(val/10)%10;
z=(val/100)%10;
lcdcmd(0xCA);
lcddata1(aray[z]);
lcdcmd(0xCB);
lcddata1(aray[m]);

lcdcmd(0xCC);
lcddata1(aray[l]);


}