Hi, these crude carrier-only type RF modules can be bought very cheaply now from a number of online suppliers. (usually 433 MHz and 315 MHz modules).

I did some testing of the modules and show how to use them for simple USART comms between micro-micro or micro-PC USB.

I also tested the burst times and recover times etc, and tested transmitting a low frequency for people who might want to use these modules without microcontrollers.

This kind of thing comes up from time to time on the forum, and although there are quite a few online projects using these modules those projects are usually pretty sketchy, usually just a schematic and some code.

I've tested the modules a little bit more indepth, and hopefully this may be of use to others.

Also I show a simple new data protocol to get much higher speed data transfer (and more data reliability). Source code is provided for that in C.

The project can be seen here;
http://www.romanblack.com/RF/cheapRFmodules.htm

 

Thanks, Roman, I bought some of these modules years ago, only to realize I had no idea how to use them. After reading through your post, I'm thinking of digging those things out again.

 

That was a good write up.

 

Thanks guys.

Even without a microcontroller they seem to work fine with a pulsed input. So someone could use a 555 timer to modulate the transmittter at a certain frequency, and just a simple analogue circuit to detect that frequency at the receiver.

I know the "microcontroller" side can tend to put people off.