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

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

Aim:

To get experienced with Ultrasonic sensor (HC-SR04) usage by measuring the distance travelled by wave to the object and also to implement the hardware connection of Atmega328p and HC-SR04 interfaces by using input capture mode of Timer1 and hence to display the results in LCD.

Tools used:

PC with Microchip studio & SimulIDE

Program:

/*
 * project2.c
 *
 * Created: 04-11-2022 16:52:11
 * Author : Kavitha
 */ 

#include <avr/io.h>
#define F_CPU 16000000L
#include <util/delay.h>
#include "avr/interrupt.h"
#define lcdport PORTB
#define rs_high PORTD|=(1<<0);
#define rs_low PORTD&=~(1<<0);
#define en_high PORTD|=(1<<1);
#define en_low PORTD&=~(1<<1);
unsigned int tov=0,count, distance;
void lcd_command(unsigned char cmd);
void lcd_data(unsigned char data);
void lcd_init();
void cursorpos(char x, char y);
void lcd_out(char x, char y, char *str);
void lcd_print(char row, char coloumn, unsigned int value, int digits);

int main(void)
{
	DDRB=0xff;		//Port B as output
	DDRD |=(0<<6);	//PortD pin 6 as input from echo pin of sensor
	DDRC |=(1<<0);	//PortC.0 as output
	sei();			//Enable global interrupt
	lcd_init();
	TCCR1A=0x00;	//Normal Mode
	TIMSK|=(1<<2);
	
	while(1)
	{
		PORTC|=(1<<0);//Trigger Sensor
		_delay_us(10);
		PORTC&=~(1<<0);
		
		TCCR1B=0x41;	//ICF Enable
		TCNT1=0;
		TIFR=(1<<ICF1);
		TIFR=(1<<TOV1);
		tov=0;
		while((TIFR&(1<<ICF1))==0);  //chech timer overflow condition
		TCNT1=0;
		TCCR1B=0x01;
		TIFR=(1<<ICF1);
		TIFR=(1<<TOV1);
		tov=0;
		while((TIFR&(1<<ICF1))==0);
		count = ICR1 + (65535 * tov); //calculate the count for time taken
		distance = (unsigned int)count /932.87;  //sensor datasheet formula
		lcd_print(1,1,distance,4);
		lcd_out(1,6,"cm");
	}
}
ISR(TIMER1_OVF_vect)
{
	tov++;
}

void lcd_cmd(unsigned char cmd)
{
	lcdport=cmd;
	rs_low;
	en_low;
	_delay_ms(1);
	en_high;
}

void lcd_data(unsigned char data)
{
	lcdport=data;
	rs_high;
	en_low;
	_delay_ms(1);
	en_high;
}

void lcd_init()
{
	lcd_cmd(0x38);_delay_ms(5);
	lcd_cmd(0x02);_delay_ms(5);
	lcd_cmd(0x01);_delay_ms(5);
	lcd_cmd(0x0c);_delay_ms(5);
	lcd_cmd(0x06);_delay_ms(5);
	lcd_cmd(0x80);_delay_ms(5);
	lcd_cmd(0xC0);_delay_ms(5);
}

void cursorpos(char x, char y)
{
	if((x<1||x>2)||(y<1||y>16))
	{
		x=1;
		y=1;
	}
	if(x==1)
	lcd_cmd(0x7F+y);
	else
	lcd_cmd(0xbf+y);
}

void lcd_out(char x,char y, char *str)
{
	cursorpos(x,y);
	while(*str)
	{
		lcd_data(*str);
		str++;
	}
}
void lcd_print(char row, char coloumn, unsigned int value, int digits)
{
	unsigned int temp,unit,tens,hundred,thousand,million;
	unsigned char flag=0;
	if(row==0||coloumn==0)
	{
		cursorpos(1,1);
	}
	else
	{
		cursorpos(row,coloumn);
	}
	if(digits==5|| flag==1)
	{
		million=value/10000+48;
		lcd_data(million);
		flag=1;
	}
	if(digits==4 || flag==1)
	{
		temp = value/1000;
		thousand = temp%10 +48;
		lcd_data(thousand);
		flag=1;
	}
	if(digits==3 || flag==1)
	{
		temp = value/100;
		hundred = temp%10 +48;
		lcd_data(hundred);
		flag=1;
	}
	if(digits==2 || flag==1)
	{
		temp = value/10;
		tens= temp%10 +48;
		lcd_data(tens);
		flag=1;
	}
	if(digits==1 || flag==1)
	{
		unit = value%10 + 48;
		lcd_data(unit);
	}
	if(digits>5)
	{
		lcd_data('e');
	}
}

Output:

Simulation Result:

Conclusion:

Thus using MIcrochip & simulIDE tools Ultrasonic sensor (HC-SR04) was successfully connected with Atmega328p for measuring the distance of the object, using input capture mode of Timer1 and hence results were displayed in LCD.