remote control using PICs and RF module problem

[nettigerman]

HI every one; this is my first thread

iam building up a remote control using two pic for the transmitter and the recevier with a RF module

iam using the UART of each PIC along with the transmitter or the receiver modules to send and receive the data

i send 8 bytes of data with 2400 bit/s as a baudrate

when using a wire instead of the RF modules it works very fine
but when using the modules it doesnot work at all

i have checked that the received data from the module isnot correct

so could any body tell me the problem, is it the bad rate should I increase it or what

and thanks for help

 

[Nigel Goodwin]

You can't send plain RS232 over a wireless link in that way, check my wireless modules PIC tutorial for an explanation and solution.

 

[nettigerman]

no you have got it wrong iam sending bits from on pic to another not from pc ta a pic

but i will check ur tutorial also
thanks for ur care

 

[Nigel Goodwin]

no you have got it wrong iam sending bits from on pic to another not from pc ta a pic

I never mentioned a PC?, my tutorials are PIC to PIC.

 

[nettigerman]

dear NIGEL

i have locked at ur tutorial it is quite nice and i learned much

but in a different thread u said that using a usart with those RF modules are not a good idea beacus those modules are AC coupled so u cant send a long high as it will give a zero

i know that when the pic is not transmitting it keeps the tx pin high which give a low at the receiver module

but what if i first used a wake up byte with 9 bit of data just to make the uart receiver synchronize right with the data being transmitted and then continue the with transmitting the 8 bit data i used to send before

i will keep the uart of the receiver in 8 bit mode and the transmitter the wake up will be 9 bit mode lets say i send 0xAA with the 9 bit is high, lets say the baud rate is 9600 bit/s

i hope that u understood me well and thanks for ur effort

i will try to make a diagram fast with my thought of the transmitted data so that u could understans me easier

 

[Nigel Goodwin]

dear NIGEL

i have locked at ur tutorial it is quite nice and i learned much

but in a different thread u said that using a usart with those RF modules are not a good idea beacus those modules are AC coupled so u cant send a long high as it will give a zero

i know that when the pic is not transmitting it keeps the tx pin high which give a low at the receiver module

AC coupling.

but what if i first used a wake up byte with 9 bit of data just to make the uart receiver synchronize right with the data being transmitted and then continue the with transmitting the 8 bit data i used to send before

Still no good, because you would need a constant flow of data, and losing the link would just swamp it with random data.

If you want to try and use the UART, then do as my tutorial mentions and fit a hardware inverter in both transmitter and receiver. While it's not as good as using Manchester routines, it may make it workable.

 

[nettigerman]

ok i got the message i will try to understand the manchester code well from ur tutorials then

thanks again

 

[Aeddon]

hi mr nigel goodwin,
i am newbie to micro controller
i actually have a problem doing a asm code using lm35dz to get value and get it to display it on lcd module, do you have a sample asm to spare?

 

[Chippie]

hi mr nigel goodwin,
i am newbie to micro controller
i actually have a problem doing a asm code using lm35dz to get value and get it to display it on lcd module, do you have a sample asm to spare?

You should look at Nigel's website for his tutorials





and start a new thread rather than hijacking this one....

 

[7star]

The transmitter module accepts serail data at a maximum of 2400 bps.They are directly interface to a microcontroller.at the Rx end ,the receiver microcontroller receives the signal via the Rf reciever module,decodes the serial data and reproduce the original data.