Sonsivri

I was trying to make a PIC-PIC (18F452) communication using the Radiotronix RF modules, i tryied everything, changing bps in the picc, changing wires, inverting the outputs, everything.  There is only one thing that i have'nt tryed & it is tu use encoder and decoder.

I hope somebody can help me.

RF modules are very complex things when not used with an encoder-decoder pair. I guess you are using the uarts of the pics for communication and this is not a good method as the baud rate could be too high for RF frequency to transmit. And don't think that decreasing the baud rate can solve the problem it may NOT! So I suggest u use another communication protocol and be sure that the pics communicate without the modules at first. Then be sure that the modules communicate with each other also. Then join the two OR use an encoder-decoder pair like PT2262-PT2272 or similar.

Regards...

IF you post more information on the RF modules, links, part numebrs, etc.
Then it may be easier to assist you.

Theres many different RF modules, from simple circuit that modulates bits with no extra support (and thus you need encoders or redunan cy in the pic) to full blown serial transmitters that you feed serial data and it takes care of everything.

Try RF chips from Nordic (nRF24L01) or Chipcon (CC1100, CC2400). You transfer the data through SPI and they handle all the rest.

The nordic chips I have found to be the best all around units.

The major big thing, they can (in the proper mode) do the re-transmission and crc of the data for you.
That is, you dont have to worry about lost data, or errors in the data, the ic's take care of it.

Theyr also very low cost, under $5

RF Chips 2272 remote and receiver

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=130159555920&ssPageName=STRK:MESE:IT

Most of the RF modules work with low baud rate RS232 serial communication if a long RF output received to set auto gain adjustment of the receiver before sending serial data. I have tested this for a hand made simple 433 Mhz modules set and for some other commercial types.

According to me the best way to send data through RF modules is pulse width coded data. Serial communication fails when a to many zero values send as zero to RF output. So the automatic gain control of the receiver module increases the gain and when following RF pulse as one arrives to the receiver, its output saturates and timing or syncronisation is lost. Superheterodyne type crystal controlled receivers has better performance for adjusting gain control so serial RS232 data can be directly transferred.

hello
u specify me the language u are using?
baud rate for both the pic of tx & rx should be equal.usally the RF modules supports from 300bps to 2400bps .u can speed up to 3600bps.if u are using roton basic then try the below commands.

transmitter.
SerOut TX,16884  ,[ "NCS", 200 ]
reciver.

SerIn RX,16884 ,[ Wait("NCS"),REC]

in above two statementstransmitter sends NCS then data 200.
in the reciever  the serin state ment waits until ncs is recieved and if data presented will be placed in the variable.
i think it may help u.

Try Aurel modules XTR903-A8 ,it work very fine just put only a serial data.

Not sure which units you are using but Radiotronics have good documentation on products.

Try the links below, it may help.

h**p://www.radiotronix.com/products/proddb.asp?ProdID=196
h**p://www.radiotronix.com/datasheets/datasheets/WI232FHSS-250-R_25-RUsersManualrev1_0_0.pdf

Cheers!
 

5$ RF module from HOPERF (china) - based on Integration Associates IA4421 transeiver chip

http://www.hoperf.com/rf_fsk.asp

I have used it.

can you help something on TI rfid


Posted on: February 04, 2008, 11:39:47 11:39 - Automerged

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thanks

Good morning
    See this site. He has many good examples
http://www.rogercom.com/

i have used low cost rf modules in communication projects using 8051 uC, the best baud rate working at 300 bps, but you must bias the receiver circuit by sending a prefix characters (10 or more) before sending the actual data to ensure good results

has anyone tried the rf modules available from jaycar before? i was thinking of getting some

Try with the RABBIT2000, it's a good model with a lot of appliances

Nordic nRF24L01 the best choice.
2.4GHz
up to 2Mbps data rate
900nA in power down
Chipcon has greater consumption.

hi.look hier: www.lprs.co.uk/?trycdp

The xbee module are a good choice

what do you  think about the laipac modules?, the ones that  work on 433mhz

If you want high speed then do not use 433 Mhz, its max is 4800 or so.We have tried it.
The 2.4 Ghz is the best, zigbee is the most safest, but it has sam problems with Wifi.

I just had a look at Jaycar but couldn't find anything other than the RFID stuff. Which modules are you talking about?

That said, while I haven't tried any of their RF stuff, and looking at the responses you've had already, a question springs to mind. What application are you looking at employing the RF module in?

There are a lot of stable, cheap RF transmitters and receivers that work down around the 433MHz range. Depending on how much data you need to transmit at any given time, these are a really easy to use solution for most data logging type applications.

I built a simple project a few years ago to send back data from my green house. It was about 100' from my workshop and with a cheap whip antenna at each end was able to tx/rx data reliably under all sorts of conditions. There was no interference from WiFI, microwaves, lightning etc.

In the end, it will come down to what you want to use it for however. To get a better answer, maybe you could link to the module(s) you're looking at and share a little more about what type of project you have in mind :)

EDIT: My bad :P    I was replying to Jader's reply #15 thinking that it was the original post  ::) What a n00b lol. I'm going to go and administer myself a stern beating now.

thank you all, the module I am thinking to buy is this one  http://www.laipac.com/easy_434_eng.htm

     I want it  to send  commands  to control little  robot  maybe,litle cars, and  stuff like that , this would be my first projects mixing Pic and Rf, thanks  , what do you think about that module?, thanks for your  help ahead, regards.

could  someone  upload a simple schematic  of the connection  of a  pic  with the laipac  module  I did  post  ahead?, thanks you all !

hello folks, here is  the schematic to implement  communication with the pic and  the RF module of laipac,Enjoy!