Accrochages

In this experiment, we managed to connect infrared LEDs to the ATTINY. The other one ( infrared receptor seem like LED) is used for read rebounding object light form a infrared led, acting as a simple proximity sensor. ( 3 feets ...)

___________________________­[ Avr Code ]__________________________

/* -----------------------------------------------------------------------
* Title:    Asynchronous data transmit input (auto timing pulse detection)
* Author:   Samuel St-Aubin (samuel.st-aubin@sympatico.ca)
* Date:     15.1.2008
* Hardware: ATtiny13
* Software: WinAVR 20060421
-----------------------------------------------------------------------*/
#define F_CPU 1200000

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

#define SD_DATAIN PB0
#define LED PB4

volatile int Data ;
char timer;
int i;
int x;

int main(void) {

GIMSK = _BV (INT0);                       // int - Enable external interrupts int0
MCUCR = _BV (ISC01);                    // int - INT0 is falling edge
sei();                                               // int - Global enable interrupts

Data = 50;

DDRB &= ~(1<<SD_DATAIN);          // use PortD for input (switches)
DDRB |= (1 << LED);                       // Set direction register output

for (;;)                                            // Main loop (endless)
{

// interrupts do the job because he's cool
}

return 0;
}

ISR (INT0_vect)                                        // Interrupt on Int0 vector
{                                       

while (bit_is_set(PINB, SD_DATAIN))     // Calculated one pulse timing
{                                                            //
_delay_ms(1);                                      //
timer++;                                               //
}                                                            //

for ( x = 0 ; x < (3 * timer); x++)            // Wait 1.5 pulse ( 3 divided by 2)
{                                                             // (.5 for half pulse synchronysing)
_delay_ms(1);                                      //
x++;                                                     // double incrementation
}                                                            //

Data = 0;                                                // Initialize data register

for (i = 0 ; i < 7 ; i++)                              // For loop 0 to 7
{                                                             //
if bit_is_set(PINB,SD_DATAIN)              // Bit detector on Sd_Data input
{                                                           //
Data ^= (1<<i);                                  // Update data register (one by one bit )
}                                                           //

for ( x = 0 ; x < timer; x++)                  // One pulse time calculation
{                                                          //
_delay_ms(1);                                   //
x++;                                                  //
}                                                         //

}

timer = (timer * 10);                         // Show result of "timer" variable 
for ( x = 0 ; x < timer ; x++ )            // 0 = 10 usec, 255 = 2550 usec
{                                                       //
PORTB ^= (1 << Piezo);                  // Inverte led bit
_delay_us (10);                              //
}

}