Project 2 - Measuring distance of an object using ultrasonic sensor (HC-SR04)

c = b-a;                                                    // Subtract the a register from b to get the difference to store in c variable.

}

}

void trigger()//function for giving trigger pulse to the ultrasonic sensor

{

PORTC |=(1<<6);//making a high pulse

_delay_ms(15);

PORTC &=~(1<<6);//making a low pulse

 

 

}

 

void lcd_cmd(unsigned char cmd)//function for lcd command

{

rs_low;

lcdport=cmd;//writting the command on lcd

en_high;

_delay_ms(1);

en_low;

 

}

 

void lcd_data(unsigned char data)//function for writting data for lcd

{

rs_high;

lcdport=data;

en_high;

_delay_ms(1);

en_low;

 

}

void lcd_init()//function for initialising lcd

{

lcd_cmd(0x38);_delay_ms(1);

lcd_cmd(0x02);_delay_ms(1);

lcd_cmd(0x01);_delay_ms(1);

lcd_cmd(0x0c);_delay_ms(1);

lcd_cmd(0x06);_delay_ms(1);

lcd_cmd(0x80);_delay_ms(1);

 

}

void cursor_pos(unsigned int x,unsigned int y)//setting the cursor position

{

 

if((x>2||x<1) || (y>16||y<1))

{

x=1;

y=1;

 

}

if(x==1)

lcd_cmd(0x7F+y);

else

lcd_cmd(0xBF+y);

 

 

}

void lcd_print(unsigned int x,unsigned int y,unsigned char*str)//function for printing string data on lcd

//with row and coloumn as argument

 

{

unsigned int i=0;

if(x==0||y==0)

{

cursor_pos(1,1);

}

else

{

cursor_pos(x,y);

}

 

while(str[i]!=0)

{

lcd_data(str[i]);

i++;

 

}

 

}

void convert(char x,char y,int value ,int digits)//for displaying digits on screen

{

unsigned int temp;

unsigned int unit;

unsigned int tens;

unsigned int hundreds;

unsigned int thousands;

unsigned int millions;

unsigned int flag=0;

if((x==0) || (y==0))//realocating cursor position in (1,1)

cursor_pos(1,1);

else//realocating cursor position in (row,coloum)

cursor_pos(x,y);

 

 

if(digits==5 ||flag==1)

{

millions=value/10000+48;//digital value is converted into ascii value

lcd_data(millions);

flag=1;

 

 

}

if(digits==4 ||flag==1)

{

temp=value/1000;//digital value is converted into ascii value

thousands=temp%10+48;

lcd_data(thousands);

flag=1;

}

if(digits==3 ||flag==1)

{

temp=value/100;//digital value is converted into ascii value

hundreds=temp%10+48;

lcd_data(hundreds);

flag=1;

}

if(digits==2 ||flag==1)

{

temp=value/10;//digital value is converted into ascii value

tens=temp%10+48;

lcd_data(tens);

flag=1;

}

if(digits==1 ||flag==1)

{

unit=value%10+48;//digital value is converted into ascii value

lcd_data(unit);

 

}

if(digits>5)

{

lcd_print(1,1,"error");

 

}

 

 

}

 

 

 

// //////////////////////////

 

 

int main(void)

{

unsigned int period=0;

    DDRD=0xff;//making portd as output

DDRC |=(1<<5)|(1<<4)|(1<<6);

DDRB=(0<<0);//making pb0 as input

    TCCR1A=0;//configuring the timers

TCCR1B=0x41;

TIMSK1=0b00100000;//configuring TIMSK register

lcd_init();//function call for initializing the lcd

lcd_print(1,2,"DISTANCE IN CM ");//printing the distance

    while (1) 

      {

TCNT1=0;//making tcnt1 to zero

trigger();//function call to trigger the ultrasonic sensor

sei();//enabling all interrupt functionality

        period=(c/447);c//onverting to distance

convert(2,5,period,3);//displaying the distance in "cm"

  }

  

}