#include <P18F458.h>
void MSDelay(unsigned int);
#define Dsensor PORTBbits.RB1
#define buzzer PORTCbits.RC7
void main(void)
  {
    TRISBbits.TRISB1 = 1;		
    TRISCbits.TRISC7 = 0;		
    while(Dsensor == 1)
      { 
        buzzer = 0;
        MSDelay(200);
        buzzer = 1;
        MSDelay(200);
      }
    while(1);			
  }
void MSDelay(unsigned int itime)
  {
    unsigned int i;
    unsigned char j;
    for(i=0;i<itime;i++)
      for(j=0;j<165;j++);
  }