RF Communications

RICoder

I've been looking at the RX and TX modules here at Parallax, as well as some other places (like sparkfun), and wondering what the best route to go is. The XBee looks interesting to me, but I'm not sure how well it works, and how much of a pain in the butt it is due to what looks like its own higher-level protocol. So, I have a few questions:

1) Is the XBee a transceiver?
2) Has anyone used XBee? and are they any good?
3) Is there some other option I am missing?

Because I know it will be asked:
I am working on some home-automation projects (multiple devices for multiple purposes) which will all be driven from a main server (PC). Said PC will have an RF module attached to it to communicate with RF devices, and use UDP to communicate with devices connected to the network.

Thanks in advance for advice.

sylvie369

1 - XBees are transceivers - that is, each can both transmit and receive data (I assume that's what your question was about).

2 - I have several XBee modules, all Series 1. I think they're amazing. I get good range from the "Pro" modules (and not bad from the regular one), and they're quite reliable when set up and programmed correctly. They're definitely "good", as long as you're using them for things that are appropriate.

You can use them to do the kinds of things that you're proposing, though I assume you're not expecting them to handle the UDP connections, right?

Be aware that you cannot mix Series 1 and Series 2 modules, and that the Series 2 modules require additional setup. Of course that additional setup is not that complicated, and it's the kind of thing you're going to want to learn to do on the Series 1 modules even if you go that way.

I haven't set up any kind of permanent set of devices with them yet - I'm still just playing around with the various options to learn how they work.

There is a lot of good information on how to set them up here:

www.selmaware.com/appbee/

as well as some boards that you can use to connect them to Stamp or Propeller modules.

Dgswaner

I would agree, Xbee is the way to go. They are just as easy to use as the RF modules from parallax. And more complex if you need them to be.

First I tried using the Parallax RF modules, but I wasn't too happy with them. They worked as described, they just didn't work for what I had intended (RF controlled bot via the web). I took a gamble and bought some Xbee pro modules and with some help from Peter V, and Mike Green I got them working. My main issue with Xbee is, I was making it more complex then it needed to be. in AT mode, you just use the multiserialdebug object and your done.

Definitively get a Carrier board tho.

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DGSwaner

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"When in doubt, use C4" - Jamie Hyneman, Myth Buster

Tom C

RICoder,

I just bought two of the 2mw Series 2.5 XBees from Sparkfun along with an XBee-Explorer to check them out.

You can also use a Gavitech XBee-USB converter (http://store.gravitech.us/xbtousbad.html) or·a Selmaware Solutions AppBee-Mod: http://www.selmaware.com/appbee/home.htm

I used the X-CTU application to view the XBee's firmware. They had been programmed with ZB (Not ZET 2.5) firmware and both were router/end devices.

To set up a Series 2 (2.5) network you will need to have at least one coordinator and one router/end device. A router/end device can be programmed to be a coordinator with the X-CTU application.

Two router/end devices can talk to one another without a coordinator. Here is how on the second page of this thread: http://forums.parallax.com/showthread.php?p=732590

Hope this helps.

Regards,
TCIII

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If you are going to send·a Robot·to save the world, you·better make sure it likes it the way it is!

Post Edited (Tom C) : 1/15/2009 11:29:26 PM GMT

RobotWorkshop

The Xbee modules look interesting and I eventually want to try them out myself for a few projects. In the past I have had excellent results using wireless Bluetooth modules if you just want your remote device to talk to a PC. I prefer the Class 1 devices that are rated for 100m (330 ft) and most just appear as a Serial port on the PC. No special protocol required. Many systems already support bluetooth so you just need the modules for the remote side. For that I really like the A7 engineering eb-501 modules which have logic level 3.3v and 5V connections as well as an RS-232 connection. I wrote about one of the projects that used them in the May 2008 issue of SERVO.

With the setup you asked about you could just add an eb-501 at each remote device and they will each appear as a new serial port on your server which should be easy to use.

There as several options open to you and you can think about what may be best for your application.

Hope this helps,

Robert

RICoder

I got a couple of XBees coming to me from SparkFun whenever USPS decides to drop it off. I have the boards started for a thermostat and my "server" board as well...when it gets up and running, I'll post back and let you know what I think.