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

ABINAYA INBAMANI MAM (LIVE BATCH)

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

  #include <avr/io.h>
  #define F_CPU 8000000UL
  #include <util/delay.h>
  #include <string.h>
  #include <stdlib.h>
  
  #define LCD_Date_Dir DDRD //define LCD data port direction
  #define LCD_Command_Dir DDRC //Define LCD command port direction register
  #define LCD_Data_Port PORTD //Define LCD data port
  #define LCD_Command_Port PORTC //
  #define EN PC2 // define Enable signal pin
  #define RW PC3 //Define read/write signal pin
  #define RS PC4 //define register select (data reg./command reg.) signal pin
  
  void LCD_Command(char); //lcd command write funtion
  void LCD_Char(char); //lcd data write function
  void LCD_Init(void); //lcd initialize function
  void LCD_String(char*); //send string to lcd funtion
  void LCD_String_xy(char,char,char*); //send row position and string to lcd funtion
  
  void LCD_Command (char cmd) // lcd command write funtion
  {
  	LCD_Data_Port=cmd; // write command daata to lcd data port..
  	LCD_Command_Port&=~((1<<RS)|(1<<RW)); //RS low (command reg.) RW low (write)
  	LCD_Command_Port|=(1<<EN); // high to low transition on EN
  	_delay_ms(1);
  	LCD_Command_Port&=~(1<<EN);
  	_delay_ms(2); // wait little bit
  	
  }
  
  void LCD_Char(char char_data) //LCD data write function
  {
  	LCD_Data_Port = char_data; //write data to lce data port
  	LCD_Command_Port &=~(1<<RW); //RW low (write)
  	LCD_Command_Port |=((1<<EN)|(1<<RS)); //RS high (data reg). high to low transis=tion on EN
  	_delay_ms(1);
  	LCD_Command_Port &=~(1<<EN);
  	_delay_ms(1); //wait little bit
  }
  
  void LCD_Init(void)
  {
  	LCD_Command_Dir|=(1<<RS)|(1<<RW)|(1<<EN); //LCD COmmand port direction as o/p
  	LCD_Date_Dir =0xFF; //lcd data port direction as o/p
  	
  	_delay_ms(20); // lcd power up time to get things ready its always >15ms
  	LCD_Command(0x38); //initialize 16*2 lcd in 8bit mode
  	LCD_Command(0x0C);//display on, cursor off command
  	LCD_Command(0x06);//auto increment cursor
  	LCD_Command(0x01);//clear lcd command
  	LCD_Command(0x80); //8 is for first line and 0 is for 0th position
  }
  void LCD_String(char *str) // send string to lcd fun
  {
  	int i;
  	for (i=0;str[i]!=0;i++) //send each char of string til null
  	{
  		LCD_Char(str[i]);
  	}
  }
  void LCD_String_xy(char row,char pos,char *str)
  {
  	if(row==1)
  	LCD_Command((pos & 0x0F)|0x80); // command of 1st row and required position<16
  	else if (row==2)
  	LCD_Command((pos &0X0F)|0XC0); // 2ND ROW AND REQUIRED POSITION<16
  	LCD_String(str); //LCD string fun
  }
  #define Tigger_pin PA0 // trigger pin
  int timeroverflow =0;
  ISR (TIMER1_OVF_vect)
  {
  	timeroverflow++; // TIMER OVERFLOW COUNT
  }
  int main(void)
  {
  	char string[10];
  	long count;
  	double distance;
  	
  	DDRA = 0X01; //trigger pin as output
  	PORTB =0xFF; // turn on pull up
  	LCD_Init();
  	LCD_String_xy(1,0,"ultrasonic");
  	
  	//sei(); // global interrupt
  	TIMSK =(1<<TOIE1);// ENABLEE TIMER1 OVERFLOW INTERRUPTS
  	TCCR1A = 0; // SET ALL BIT TO ZERO NORMAL OPERATION
  	
  	while (1)
  	{
  		PORTA |=(1<< Tigger_pin);
  		_delay_ms(10);
  		PORTA &=(~(1<<Tigger_pin));
  		
  		TCNT1=0; //clear timer counter
  		TCCR1B =0x41; //rising edge, no prescaler
  		TIFR = 1<<ICF1; //clear icp flag //input capture flag
  		TIFR = 1<<TOV1; //clear timer overflow flag
  		
  		while ((TIFR &(1<<ICF1)) == 0); // wait for rising edge
  		TCNT1=0; //clear timer counter
  		TCCR1B=0x01;//on falling edge,no prescaler
  		TIFR=1<<ICF1; //clear icp flag (i/p capture flag
  		TIFR=1<<TOV1;// clear timer overfloer flag
  		timeroverflow =0; // clear timer overflow count
  		
  		while((TIFR &(1<<ICF1))==0); // Wait for fallling edge
  		count = ICR1+(65535*timeroverflow); // take count
  		// 8MHZ timer freq, sound speed=343m/s
  		distance = (double) count/466.47;
  		
  		dtostrf(distance,2,2,string); //distance to string
  		strcat (string,"cm"); //concat unit i e. cm
  		LCD_String_xy(2,0,"Dist= ");
  		LCD_String_xy(2,7,string); //print distance
  		_delay_ms(200);
  		
  	}
  }
  
  
  ​