rf interfacing using avr atmega8

[rishiisme]

Hi everybody i am new to rf module interfacing (using AVR) and am not being able to implement it,Can anyone please suggest some solutions or guide me on how to make it work.

Circuit info
avr tx to transmitter module(433mhz)
receiver module to rx pin

i dont know what changes to make and really need a lot of help here, been stuck for days......

 

[bigdogguru]

Checkout the EDABoard group:

Embedded Wireless Networks

SubGHz/RF TX/RX Project Oriented Website Recommendations

I have already posted several links to RF TX/RX projects and more are being posted daily.

If you still need help, just let me know.

 

[rishiisme]

is it really necessary to use external crystals on xtal or can we use the internal ??? also is it required to invert the tx and rx pins

 

[ctownsend]

Download this file. Its all there.

AVR Freaks

 

[rishiisme]

i have written my own coded transmission protocol (manchester) it is working perfectly with wires. i made sure there are no continues 1s or 0s. can i, now ,send the output directly into the tx module's data pin??

 

[bigdogguru]

Yes, if your Manchester Encoding sheme is correct you should be good to go?

 

[rishiisme]

ok i ll try that then !!!

 

[bigdogguru]

OK,

Let me know the outcome.

Ciao

 

[rishiisme]

connections r fine but still not working receiving 0x00 all the time. baud rate is 1200 bps (working for wired though). am i making any conceptual mistakes???

 

[bigdogguru]

Hi,

Depending on the TX unit you may need to drive the input with a transistor.

I just posted a three part tutorial on RF TX/RX module interfacing with MCU:

RF Communication Between Microcontrollers

in the Embedded Wireless Networks Group

Check the tutorial out and I'll see what else I can think of.

 

[rishiisme]

the thing is i am not using UART i made my own protocol which works perfectly with wires
Basic idea - baudrate either 2400
1)idle bit =0
2)start bit 1
3)manchester coding
connections
MCU1 MCU2
pin D3 -> rf-tx -> antenna antenna->rf-rx->pin D3(pulled down input mode)
it works for wired this way using the pull down resistor