How to use 433Mhz CRC ?

[bianchi77]

Guys,

How can I use 433Mhz properly ? do I need CRC ?
I tried to send "a" and "b" but it seems that it's sending continously even I'm not sending at all ?
I'm using terminal (PC) for transmitter and receiver is ATMEGA128 ...with UART .

Any ideas ?
thanks

 

[jayanth.devarayanadurga]

Post code.

 

[bianchi77]

int main(void)
{
	unsigned char cmd;
	
	DDRA = 0xFF;
	DDRD = 0xFF;
	DDRB = 0xFF;
	//PORTB = 0;
	usart_init(BAUD_PRESCALE);
	usart_pstr("Wireless Doorbell V.1.0 ");
	usart_crlf();
	
	
	lcd_init();
	
	lcd_cmd(0x01);
	
	lcd_string("  Doorbell V.1.0");
	lcd_cmd(0xC0);

     tone(150);
     _delay_ms(1000);
     tone(0);
	while(1)
    {
		cmd = usart_receive();
		
		if (cmd=='a')
		  {
			   _delay_ms(1000);
			   tone(150);
			   _delay_ms(1000);
			   tone(0);
			   _delay_ms(500);
               tone(250);
               _delay_ms(1000);
               tone(0);
 			   
			  lcd_cmd(0x01);
			  lcd_string("  Door 1!");
			  
			
			 
			
		  }
		  else if (cmd=='b')
		  {
			   _delay_ms(1000);
			   tone(350);
			   _delay_ms(1000);
			   tone(0);
			   _delay_ms(500);
			   tone(450);
			   _delay_ms(1000);
			   tone(0);
			   
			  lcd_cmd(0x01);
			  lcd_string("  Door 2!");
              _delay_ms(1000);
			
			  
		  }
		 
		  
		 
		  
			  
	  
		
        
    }
}

 

[jayanth.devarayanadurga]

Post transmitter code.

 

[bianchi77]

I don't have code for transmitter, I use PC and terminal software for transmitting.....Access Port..