Transmiting data by RF

Transmiting data by RF#45934

By Marian77 - Sun Apr 06, 2008 5:33 pm

- Sun Apr 06, 2008 5:33 pm #45934

Hi everyone! This is my proyect: I need to stablish an inalambric communicattion between two pics via RF. The pic of the tx will send a data encoded to the tx. The rx will receive and decode it to finally send to the second pic. I'd like to implement this with rf modules wich operate in FM or FSK, but unfortunatly they are quite expensive for my budget. But on the other hand if I choose the ones that transmit in AM or ASK I'm afraid not to get more than rubish. At last someone suggest me to try on with transceivers like TRW-2.4Ghz but I'm not sure if it's my best choice. I don't need the rx sends back to tx any message. I hope my description was enough clear. Summarising What would be my best choice AM/ASK; FM/FSK or TRW-2.4G considering costs, esay implementation and efficient?

Thanks a lot for your answers!
Marian

#45995

By ttabbal - Mon Apr 07, 2008 8:02 pm

- Mon Apr 07, 2008 8:02 pm #45995

I have the OOK TX and RX modules working fine. These are the ones I'm using. http://www.sparkfun.com/commerce/produc ... ts_id=7815

I'm using a PIC on each end to handle the data. Works pretty good for me. The encoding is pretty simple. I just send a data byte followed by it's compliment (0xFF - data). It keeps the receiver DC balanced and is easy to debug. I also send a few bytes of data before the main payload to sync up the UART and such. I can show you some simple code to build the packet if you want.

Another option if you want FSK is the hopeRF modules. They are pretty cheap and seem to work well. I haven't had the chance to get a PCB made to test the ones I have though. I've just read good reviews and the specs look reasonable. I'm using the RFM12B from http://futurlec.com/Radio.shtml. $8.90/ea.

------ Travis