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

Overview of the Project: 

In this project, the implementation of code for “Measuring distance of an object using ultrasonic distance sensor (HC-SR04)

Goals:

• Measuring the distance of an object using Ultrasonic Distance Sensor (HC-SR04)
• Usage of Input Capture Mode

Key Highlights of the Project: 

• Measuring the distance travelled by the wave to the object and gets bounced back from the object to sensor.
• Measuring Pulse width using Input Capture Mode

Deliverables of this project: 

• The distance travelled by a wave to the object for which we want to measure the distance using Ultrasonic Distance Sensor (HC-SR04).
• Measuring Pulse width using Input Capture Mode of Timer 1

Expected Outcomes: 

The students will get the Knowledge on Ultrasonic sensor (HC-SR04) to measure the distance travelled by wave to the object, the hardware connection of Atmega328p and HC-SR04 and how to use input capture mode of Timer1.

CODE : 

#include
#define F_CPU 16000000ul
#include
#include
#include
#include

#define lcd_data_dir DDRD // define lcd data port direction
#define lcd_command_dir DDRC // define lcd command port direction
#define lcd_data_port PORTD //define lcd data port
#define lcd_command_port PORTC // define lcd data port
#define EN PC2 // define enable
#define RW PC3 // define read/write
#define RS PC4 // define register select

void lcd_command(char); // lcd command write function
void lcd_char(char); // lcd data write function
void lcd_init(void); // lcd initialize function
void lcd_string(char*); // send dtring to lcd
void lcd_string_xy (char,char,char*); // send row postion

void lcd_command (char cmd) // lcd command write function
{
lcd_data_port = cmd; // write command to lcd data port
lcd_command_port&=~((1< lcd_command_port|= (1< _delay_ms(1);
lcd_command_port&=~(1< _delay_ms(2); // delay provided

}
void lcd_char(char char_data) // lcd data write function
{
lcd_data_port= char_data; // write data to lcd data port
lcd_command_port&=~(1< lcd_command_port|=((1< _delay_ms(1);
lcd_command_port&=~(1< _delay_ms(1);
}
void lcd_init(void) // lcd initialize function
{
lcd_command_dir|= (1< lcd_data_dir = 0xff; //make lcd data port direction as output

_delay_ms(20); // wait
lcd_command(0x38); // 16x2 lcd 8 bit
lcd_command(0x0C); // display On
lcd_command(0x06); // auto increment cursor
lcd_command(0x01); // clear lcd command
lcd_command(0x80); // 8 is the line and 0 is oth position
}
void lcd_string(char *str) // send string to lcd function
{
int i;
for(i=0;str[i]!=0;i++) // sending each char string till tje null
{
lcd_char (str[i]); // call lcd data write
}

}
void lcd_string_xy(char row,char pos,char *str) // send string to lcd function
{
if (row == 1)
lcd_command((pos & 0x0f)|0x80);
else if (row == 2)
lcd_command((pos & 0x0f)|(0xC0));
lcd_string(str); // call lcd string function
}
#define trigger_pin PA0 // trigger pin
int TimerOverFlow = 0;
ISR(TIMER1_OVF_vect)
{
TimerOverFlow++; // increment timer overflow count
}
int main (void)
{
char string[10];
long count;
double distance;

DDRA = 0x01; // make trigger pin as output
PORTB = 0xff; // pull-up turn on

lcd_init();
lcd_string_xy(1,0,"ultrasonic");

sei(); // enable global interrupt
TIMSK = (1<< TOIE1); // enable timer 1 overflow interrupt
TCCR1A = 0; // set all bit to zero normal position

while(1)
{
PORTA |= (1<< trigger_pin);
_delay_ms(10);
PORTA &=(~(1<< trigger_pin));

TCNT1 = 0; //clear timer counter
TCCR1B = 0x41; // capture on rising edge,no pre scaler
TIFR = 1< TIFR = 1<

while ((TIFR & (1< TCNT1 = 0; //clear timer counter
TCCR1B = 0x01; // capture on falling edge , no prescaler
TIFR = 1< TIFR = 1< TimerOverFlow = 0; // clear timer overflow count

while ((TIFR & (1<< ICF1))== 0); // wait for falling edge
count = ICR1 +(65535 * TimerOverFlow); // take count
distance = (double)count/466.47;

dtostrf(distance,2,2,string); // distance to string
strcat(string,"cm"); // count unit
lcd_string_xy(2,0,"dist= ");
lcd_string_xy(2,7,string); // print distance
_delay_ms(200);
}