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

abinaya

#include //AVR preprocessor section
#include //delay library
#define F_CPU 16000000UL//frequency of the AVR
#include //interrupt service routine library
#include //library for strings
#include // library for the mathematical operations

#define lcd_data_dir DDRD// LCD data direction port as port d
#define lcd_command_dir DDRC//LCD command direction port as port c
#define lcd_data_port PORTD//LCD data port as port d
#define lcd_command_port PORTC////LCD command port as port c
#define EN PC2//enable signal set to port c pin 2
#define RW PC3//read/write select set to port c pin 2
#define RS PC4//register select set to port c pin 4

void lcd_cmd(char);//command write function for LCD
void lcd_char(char);//data write function for LCD
void lcd_init(void);//LCD initialization function
void lcd_string(char*);//send string to LCD function
void lcd_string_xy(char,char,char*);//sending the row, position and string to LCD function

void lcd_command(char cmd)
{
    lcd_data_port=cmd;//command data to LCD data port
    lcd_command_port&=~((1<    lcd_command_port|=(1<    _delay_ms(1);// wait for 1 millisecond
    lcd_command_port&=~(1<    _delay_ms(2);// wait for 1 milliseconds
    }/* LCD commands purpose of this function*/

    void lcd_char(char char_data)
    {
        lcd_data_port=char_data;//LCD data write function
        lcd_command_port&=~(1<        lcd_command_port|=((1<        _delay_ms(1);// wait for 1 millisecond
        lcd_command_port&=~(1<        _delay_ms(1);// wait for 1 millisecond
        }/* LCD data write function*/

        void lcd_init(void)
        {
            lcd_command_dir|=((1<            lcd_data_dir=0Xff;// LCD command port direction as output
            _delay_ms(20);// wait for 20 milliseconds
            lcd_command(0x38);//2 line and 5x7 matrix
            _delay_ms(2);
            lcd_command(0x01);//Clear LCD screen
            _delay_ms(2);
            lcd_command(0x0C);//display ON,cursor OFF
            _delay_ms(2);
            lcd_command(0x06);//increment cursor
            _delay_ms(2);
            lcd_command(0x80);//force the cursor to begin from the 1st line
            _delay_ms(2);

            }/* LCD initialization function*/

            void lcd_string(char*str)
            {
                int i;// declaring the i as int data type
                for(i=0;str[i]!=0;i++)
                {
                    lcd_char(str[i]);
                }//for string will be sent till it reaches NULL
            }// for the purpose of LCD string increment

            void lcd_string_xy(char row,char pos,char *str)
            {
                if(row==1)
                lcd_command((pos&0X0f)|(0x80));//first row and position<16>                else if(row==2)
                lcd_command((pos&0x0f)|(0xC0));//second row and position<16>                lcd_string(str);//LCD string function called
                }/* LCD string display row and position declaration function*/

                #define trigger_pin PA0//setting trigger pin as port A pin 0
                int TimeOverFlow=0;

                ISR(TIMER1_OVF_vect)
                {
                    TimeOverFlow++;//increment timeoverflow
                    }/* Interrupt service routine function*/

                    int main(void)
                    {
                        char string[10];
                        long count;
                        double distance;
                        DDRA=0X01;//Port A as output
                        PORTB=0Xff;//for turning ON internal pull_resistor
                        lcd_init();//LCD_init function called
                        lcd_string_xy(1,0,"ULTRASONIC");//displays at 1 st row 0th position
                        sei();//enable the global interrupt
                        TIMSK=(1<                        TCCR1A=0;//timer counter control register as low

                        while (1)
                        {
                            PORTA|=(1<                            _delay_ms(10);
                            PORTA&=(~(1<                            TCNT1=0;//clear the timer counter
                            TCCR1B=0X41;//no pre scalar, capture on rising
                            TIFR=1<                            TIFR=1<                            while((TIFR &(1<                            TCNT1=0;//clear the timer counter
                            TCCR1B=0X01;//capture on falling edge,no prescalar
                            TIFR=1<                            TIFR=1<                            TimeOverFlow=0;//clear timeoverflagflow count

                            while((TIFR &(1<                            count=ICR1+(65536 * TimeOverFlow);//tkae count fromt the 16MHz timer frequency, sound frequency=343m/s
                            distance=(double)count/466.47;//calcualting the distance

                            dtostrf(distance,2,2,string);//distance to string
                            strcat(string,"cm");//concatenated unit of cm
                            lcd_string_xy(2,0,"dist= ");//displays at 2nd row and 0th position
                            lcd_string_xy(2,7,string);//display the string at 2nd row ,7 th position
                            _delay_ms(200);//wait for 200 milliseconds
                        }
                    }

output