Project 2 - Measuring distance of an object using ultrasonic sensor (HC-SR04)
CIRCUIT :
CODE :
/*
* project2.c
*
* Created: 24-04-2023 22:06:29
* Author : Divya
*/
#define F_CPU 8000000UL // define the crystal frequency
#include
#include
#include
#include
#include
#define LCD_Data_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 LCD data port
#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 function
void LCD_Char (char); // LCD data write function
void LCD_Init (void); // LCD Initialize function
void LCD_String (char*); // Send string to LCD function
void LCD_String_xy (char,char,char*); // Send row, position and string to LCD function
void LCD_Command (char cmd) // LCD command write function
{
LCD_Data_Port = cmd; // Write command data to LCD data port
LCD_Command_Port &= ~((1< LCD_Command_Port |= (1< _delay_us(1); LCD_Command_Port &= ~(1< _delay_ms(3); // Wait little bit } 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_us(1); LCD_Command_Port &= ~(1< _delay_ms(1); // Wait little bit } void LCD_Init (void) // LCD Initialize function { LCD_Command_Dir |= (1< LCD_Data_Dir = 0xFF; // Make LCD data port direction as o/p _delay_ms(20); // LCD power up time to get things ready, it should always >15ms LCD_Command (0x38); // Initialize 16X2 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 function { int i; for(i=0;str[i]!=0;i++) // Send each char of string till the 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; 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; // Turn on Pull-up LCD_Init(); LCD_String_xy(1, 0, "Ultrasonic"); sei(); // Enable global interrupt TIMSK = (1 << TOIE1); // Enable Timer1 overflow interrupts TCCR1A = 0; // Set all bit to zero Normal operation while(1) { /* Give 10us trigger pulse on trig. pin to HC-SR04 */ PORTA |= (1 << Trigger_pin); _delay_us(10); PORTA &= (~(1 << Trigger_pin)); TCNT1 = 0; // Clear Timer counter TCCR1B = 0x41; // Capture on rising edge, No prescaler TIFR = 1< TIFR = 1< /*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< TIFR = 1< TimerOverflow = 0; // Clear Timer overflow count while ((TIFR & (1 << ICF1)) == 0); // Wait for falling edge count = ICR1 + (65535 * TimerOverflow); // Take count /* 8MHz Timer freq, sound speed =343 m/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); } } OUTPUT : 