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Topic: 350Mhz RF Remote. I know there is 315mhz and 433mhz. (Read 7 times) previous topic - next topic

Retroplayer

Here is a page that explains differential driving without appearing more complex than it really is:

http://www.linear.com/product/LTC1690

Typically the datasheets make these things look intimidating, but they aren't really. The most important thing is to match your impedence on either side. A cat5 cable is designed for 100ohm impedence. On the differential transmission side, you split this as 50 ohm for each line. At the receive side, you place a 100 ohm resistor across the pair. You drive one twisted pair for each differential signal. D is the data you want to send, and R is the data you want to receive.

Mysticle31

Differential driving is really good to know.  I would have tested on the bench, hooked it up in a semi-permanent installation to test and said WTF?

I think I found a better way to wire my project. 

This relay says it can learn 315mhz codes. 
http://www.ebay.com/itm/315-DC-12V-Single-Channel-Learning-Code-Wireless-Remote-Control-Relay-/261157962603?pt=LH_DefaultDomain_0&hash=item3cce3a436b

I could then put these in/near my small home (I'm betting they will be in range) and wire to my gates/gerage door and control them with one 315mhz transmitter on the Arduino.  It would just depend on which code it broadcasts, right?  Just want to conform I'm on the right track before I start buying stuff. 

Its either that or I play with the remote relays that are on different channels, but I think different code would be better/more reliable.  Wouldn't I need a bunch of different channel transmitters if I had different channel remote relays?

Retroplayer

The "transmitter" should just be thought of as a wire. What you put into it, comes out of the receiver. That's all. The channels, house codes, and all the rest of that comes from the encoder on these remotes. But, since you are using the arduino, YOU are the encoder and have complete control over all of that. So, no... you would use only one 315Mhz module for all 315Mhz remotes, one 350MHz module for all 350Mhz remotes, etc... Your code handles the channels, housecodes, etc...

The rfswitch library I link you to handles all of that. You send whatever you want over the RF module.

There is nothing locking the actual radio module to specific channels, etc... all of that is done in the encoder. Check out the datasheets for a PT2262 attached. Nearly all of these remotes use this or some clone of this.

Mysticle31

Ohh.  Thank you.  That means that rotating codes could be a possibility if I learned how to use that IC to it's potential?

Can I play with the transmitters with just a computer for the moment, or do I need the Arduino right now too?  I've got multiple computers with serial ports.  What I cant seem to find is the equivalent of the library or an app that can tell the transmitter what to do. Windows, Linux.  I dont care.

Incredible!  Possibilities are limited only by ones imagination and programming abilities.

I was under the impression that channel was a slight change in frequency?  I read the RC-Switch manual and missed that part.

Retroplayer

I am not aware of any software on the computer that allows you to play with these modules. If you are handy with visual basic, you could progran something, I'm sure. But easier to just create a sketch, include that RF-Switch library, connect the data line to one of your pins on the arduino, and play with the examples included in that library. I just noticed that it is missing a nice example for setting commands from the serial port. I could write an example up for you, but I am probably not going to have time to do it this weekend. It would be useful to me in future project as well, so I will do it as soon as I have the time. In the meantime, I suggest just playing around with it.

You won't be using that encoder IC, but the datasheet helps explain how the protocol works. The RC-Switch library is meant to emulate that IC.

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