งานที่20 Obstacle Avoiding Robot using PIC Microcontroller

อุปกรณ์

1. PIC16F877A
2. IR Sensor (2Nos)
3. Ultrasonic Sensor (1Nos)
4. DC Gear Motor (2Nos)
5. L293D Motor Driver
6. Chaises (You can also build your own using cardboards)
7.  Power bank (Any available power source)

code

#include <xc.h>

#pragma config FOSC = HS        // Oscillator Selection bits (HS oscillator)
#pragma config WDTE = OFF       // Watchdog Timer Enable bit (WDT disabled)
#pragma config PWRTE = ON       // Power-up Timer Enable bit (PWRT enabled)
#pragma config BOREN = ON       // Brown-out Reset Enable bit (BOR enabled)
#pragma config LVP = OFF        // Low-Voltage (Single-Supply) In-Circuit Serial Programming Enable bit (RB3 is digital I/O, HV on MCLR must be used for programming)
#pragma config CPD = OFF        // Data EEPROM Memory Code Protection bit (Data EEPROM code protection off)
#pragma config WRT = OFF        // Flash Program Memory Write Enable bits (Write protection off; all program memory may be written to by EECON control)
#pragma config CP = OFF         // Flash Program Memory Code Protection bit (Code protection off)

#define _XTAL_FREQ 20000000
#define Trigger RB1 //34 is Trigger
#define Echo RB2//35 is Echo 

int time_taken;
int distance;

     
     void back_off() //used to drive the robot backward
     {
      RC4=1; RC5=0; //Motor 1 reverse
      RC6=0; RC7=1; //Motor 2 reverse  
      __delay_ms(1000);   
     }
     
     void calculate_distance() //function to calculate distance of US
     {
         TMR1H =0; TMR1L =0; //clear the timer bits
        
        Trigger = 1; 
        __delay_us(10);           
        Trigger = 0;  
        
        while (Echo==0);
            TMR1ON = 1;
        while (Echo==1);
            TMR1ON = 0;
        
        time_taken = (TMR1L | (TMR1H<<8)); 
        distance= (0.0272*time_taken)/2;        
     }
     
void main()
{
     TRISD = 0x00; //PORTD declared as output for interfacing LCD
     TRISB1 = 0; //Trigger pin of US sensor is sent as output pin
     TRISB2 = 1; //Echo pin of US sensor is set as input pin       
     TRISB3 = 0; //RB3 is output pin for LED
    
     TRISD2 = 1; TRISD3 = 1; //Both the IR sensor pins are declared as input
     TRISC4 = 0; TRISC5 = 0; //Motor 1 pins declared as output
     TRISC6 = 0; TRISC7 = 0; //Motor 2 pins declared as output
     
     T1CON=0x20;

     
     while(1)
         {
         
        calculate_distance();        
        if (distance>5)
        {
         RC4=0; RC5=1; //Motor 1 forward
         RC6=1; RC7=0; //Motor 2 forward
        }
         
        calculate_distance();   
         if (RD2==0 && RD3==1 && distance<=5) //Left sensor is blocked
         {
         back_off();
         RC4=1; RC5=1; //Motor 1 stop
         RC6=1; RC7=0; //Motor 2 forward  
         __delay_ms(500);
         }
        
        calculate_distance();   
         if (RD2==1 && RD3==0 && distance<=5) //Right sensor is blocked
         {
         back_off();
         RC4=0; RC5=1; //Motor 1 forward
         RC6=1; RC7=1; //Motor 2 stop
         __delay_ms(500);
         } 
        
        calculate_distance();   
         if (RD2==0 && RD3==0 && distance<=5)//Both sensor is open
         {
         back_off();
         RC4=0; RC5=1; //Motor 1 forward
         RC6=1; RC7=1; //Motor 2 stop
         __delay_ms(500);
         }
        
        calculate_distance();   
         if (RD2==1 && RD3==1 && distance<=5)//Both sensor is blocked
         {
         back_off(); 
         RC4=1; RC5=0; //Motor 1 reverse
         RC6=1; RC7=1; //Motor 2 stop  
         __delay_ms(1000);
         }
             
         }
}

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