ultrasonic distance measuring sensor using atmega32

[rahuljin]

ultrasonic distance circuit

hello,

i am using an atmega32 at 5v with 16mhz crystal. i have written the code for the ultrasonic distance measurement sensor. this is the code ---

#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>

#define lcd_port PORTD

#define LCD_EN 0x80

#define LCD_RS 0x20

unsigned int count, dist, temp, t; // Count the number of 40khz pulses, 1 pulse = 2 count

void command (char cmd)
{
        DDRD = 0xFF;
        lcd_port = ((cmd >> 4) & 0x0F)|LCD_EN;
        lcd_port = ((cmd >> 4) & 0x0F);
        _delay_ms(1);
        lcd_port = (cmd & 0x0F)|LCD_EN;
        lcd_port = (cmd & 0x0F);

       
        _delay_ms(1);
}

void datawr (char dat)
{
        lcd_port = (((dat >> 4) & 0x0F)|LCD_EN|LCD_RS);
        lcd_port = (((dat >> 4) & 0x0F)|LCD_RS);
       _delay_ms(1);
        lcd_port = ((dat & 0x0F)|LCD_EN|LCD_RS);
        lcd_port = ((dat & 0x0F)|LCD_RS);

        _delay_ms(5);
}
void lcd_reset(void)
{
        DDRD = 0xFF;
        _delay_ms(1);
        lcd_port = 0x03+LCD_EN;
        lcd_port = 0x03;
        _delay_ms(1);
        lcd_port = 0x03+LCD_EN;
        lcd_port = 0x03;
        _delay_ms(1);
        lcd_port = 0x03+LCD_EN;
        lcd_port = 0x03;
        _delay_ms(1);
        lcd_port = 0x02+LCD_EN;
        lcd_port = 0x02;
        _delay_ms(1);
}

void lcd_init (void)
{
        lcd_reset();  
         int j=0;
         char b[]={0x28,0x0C,0x06,0x80,'\0'};
         while(b[j]!='\0')
         {
           command(b[j]);
          _delay_ms(1);
            j++;
        }
}




ISR(TIMER2_COMP_vect)
{
        if((count < 4))              //send 2 pulse of 40khz
        {
                PORTB ^= (1<<0);                 //toggle the output at the PORTB.0
                count++;
                if(count == 2)           //start the timer1 for time between transmission and receive after first pulse  
                {
                        TCNT1 = 0;                  
                        TCCR1B |= (1 << CS10);
                }
                               
        }
        //x++;
}



int main(void)
{

        count = 0;
       
        DDRD = 0xFF;
       
        lcd_init();
       
        unsigned char string[] = "Distance:";
       
        for(int i=0; i<9; i++)
       
        datawr(string[i]);
       
        command(0x04);                             //To shift the cursor from right to left
       
        command(0x8D);                             //To jump to 8D position
               
        DDRB = 0x01;                       //Set PORTB.0 as output
       
        PORTB |= (0<<0);
       
        TCCR2 |= (1 << WGM21);        // Configure timer 2 for CTC mode

        TIMSK |= (1 << OCIE2);        // Enable CTC interrupt

        sei();                         //  Enable global interrupts

        OCR2   = 196;                  // 16000000/40000 = 400, therefore current frequency is 80 khz for timer interrupt

        TCCR2 |= (1 << CS20);         // Start timer at Fcpu/1

        for (;;)
        {
                if((PINB & 0x02) && (count >= 4)) // if pulse is received after sending 2 pulses
                {
                        t = 4;
                        temp = TCNT1;
                        dist = (int)((double)((temp * 0.0000125 * 34000))/2);  //calculate the distance in cm and speed of sound is 340 m/s
                        temp = dist;
                        while(t!=0)         // print the distance in four digits from right to left on lcd
                        {
                                datawr((temp%10) + 0x30);
                                temp = temp/10;
                                t--;
                        }
                        count = 0;
                }
               
                if(TCNT1 > 20000)                       //if signal does not received, reset the count and send pulse again     about 1.2ms            
                {
                        TCNT1 = 0;
                        count = 0;
                       
                }


        }
}

In proteus, i get the 2 waves of 24.80 micro seconds using the virtual oscilloscope. this is the output ---

**broken link removed**

also i am planing to use the circuit given on this site ---

http://instruct1.cit.cornell.edu/courses/ee476/FinalProjects/s2007/jjl49_mar97/jjl49_mar97/index.htm

i want to make sure that the code and circuit is correct before making the actual physical circuit.
so, please help me and correct my problems ---

1. how can i check the output(i.e. frequency) of atmega32 in oscilloscope in lab ?

2. is the circuit good for making an ultrasonic sensor ?

3. is the code correct and output is correct ? if not, please suggest a solution.

i am using a normal pair of ultrasonic transducer, given on this page ---

http://robokits.co.in/shop/index.php?main_page=product_info&cPath=11&products_id=100

also attaching proteus file.

btw, thanks

rahul

 

[Dea DeeTawakal]

Hi Rahuljin..
I'm newby..
I will make the similar system as yours..
But Ican't found the ultrasonic sensor in Proteus software..
Can you help me? thanks

Can i ask for your email address please? Thank you

 

[docdark]

i´m sory, but i´m very newbiee

how can I simulate this system on Proteus ?
I put the code(.hex) in the atmega32 and after I run the projet. But doesn´t happen anything !
It doesn´t appears anything in the LCD.

how can I simulate several distances ?

 

[docdark]

anyone ????????