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

Answer:-

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

CODE:-

/*
* project2.c
*
* Created: 01-06-2022 09:53:19
* Author : mehul
*/

#include <avr/io.h> //preprocessor
#define F_CPU 16000000ul //defining cpu clock frequency
#include <util/delay.h> //preprocessor
#include <avr/interrupt.h> //preprocessor
#include <string.h>//preprocessor
#include <stdlib.h>//preprocessor

#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<<RS)|(1<<RW)); //make RS low and RW low
lcd_command_port|= (1<<EN); //high to low transition on EN
_delay_ms(1); //delay
lcd_command_port&=~(1<<EN); //clear bit
_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<<RW); //make RW low(write)
lcd_command_port|=((1<<EN)|(1<<RS)); //make RS high and high to low tnasition
_delay_ms(1); //delay
lcd_command_port&=~(1<<EN); //clear bit
_delay_ms(1); //delay
}

void lcd_init(void) //lcd initialize function
{
lcd_command_dir|= (1<<RS)|(1<<RW)|(1<<EN); //lcd command port direction as output
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; //variable declaration
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); //command of first row and required position <16
else if (row == 2)
lcd_command((pos & 0x0f)|(0xC0)); //command of second row and required position<16
lcd_string(str); //call lcd string function
}

#define trigger_pin PA0 //trigger pin
int TimerOverFlow = 0; //variable declaration

ISR(TIMER1_OVF_vect)
{
TimerOverFlow++; //increment timer overflow count
}

int main (void) //main function
{
char string[10]; //variable declaration
long count; //variable declaration
double distance; //variable declaration

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

lcd_init(); //function called for lcd initialization
lcd_string_xy(1,0,"ultrasonic"); //function called

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); //set bit
_delay_ms(10); //delay
PORTA &=(~(1<< trigger_pin)); //clear bit

TCNT1 = 0; //clear timer counter
TCCR1B = 0x41; //capture on rising edge,no pre scaler
TIFR = 1<<ICF1; //clear ICP flag
TIFR = 1<<TOV1; //clear timer overflow flag

/*calculate width of echo by input capture(icp)*/

while ((TIFR & (1<<ICF1)) == 0); //wait for rising edge
TCNT1 = 0; //clear timer counter
TCCR1B = 0x01; //capture on falling edge , no prescaler
TIFR = 1<<ICF1; //clear ICP flag
TIFR = 1<<TOV1; //clear timer overflow flag
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; //calculate distance

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

OUTPUT WINDOW:-

INPUT PULSE:- HIGH, DISTANCE:-60.38CM

Goals:

• Measured the distance of an object using Ultrasonic Distance Sensor (HC-SR04)
• Used the Input Capture Mode to measure the distance.

Key Highlights of the Project:

• Measured the distance travelled by the wave to the object and gets bounced back from the object to sensor which helps to know the distance.
• Measured the Pulse width using Input Capture Mode and got the value.

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:

We got the Knowledge on Ultrasonic sensor (HC-SR04) to measure the distance travelled by wave to the object, the hardware connection of Atmega32 and HC-SR04 and how to use input capture mode of Timer1.