Need help to make code for Wireless PC Controlled Robot without HT12E & HT12D

[Amit Kumar]

Dear all, I have made wireless robot using HT12E & HT12D ICs. Now i have made hardware part for PC controlled wireless robot & the hardware is in working condition as i checked whatever i am pessing from keyboard, the recieving pin of atmega16 showing logic1. I used FR modules but did not use Encoder & decoder ICs. As i am transmitting data serially from the hyperterminal with RS232 interfacing using data out pin of tx section of rf module and recieving data serially on pin 14 PC0 of atmega16. On 14 pin (PC0) of atmega16 is showing logic 1 whatever i am pressing from the keyboard. But i am unable to show the logic that i require on th output. Plz help me. I am also pasting my programe that i am using.

 

 

#include<avr/io.h>

int main(void)
{
DDRB=0xFF;
PORTB=0x00;
UCSRB=(1<<RXEN);
UCSRC=(1<<UCSZ1)|(1<<UCSZ0)|(1<<URSEL);
UBRRL=0x33;
unsigned char ch;
while(1)
{
while(!(UCSRA & (1<<RXC)));
ch=UDR;
if(ch=='A')
PORTB=0x01;
else
if(ch=='B')
PORTB=0x02;
else
if(ch=='C')
PORTB=0x04;
else
if(ch=='D')
PORTB=0x08;
}
return 0;
}

[D.V.G. Krishna]

i think the problem is in the RF module

when i checked the data sheet 

i found that 434 RF module works at 1.2kb speed

so i think if we use baud rate higher than it we may get random data

 

some people say that RF moduls works on “monchester coding”

so the data must be de coded  at the reciver 

[Pinky]

salamz can u plz tell me about sallenkey low pass filter  that how does it works? what is effect of feed back network and RC network  in it . thanku

[AJISH ALFRED]

I’ve done a similar project using TWS/RWS 434 ASK. I’ve set the baud rate 1200 and everything works fine. Logic one at the receiving pin dosen’t means you are getting correct data bits. Also make sure that the receving pin is not loaded by any led indicator or such things.

[D.V.G. Krishna]

are you using MAX232 IC to convert

the rs232 logic to TTL logic ……?

as the RF module works only at TTL logic 

use a max232ic between serialport and RF transmitter module

 

 

[Author]

Posts