Why Use XBee Communication Modules in R1

A Facebook friend of mine asked me why I chose the XBee modules for the R1 system. I’ll answer here so others might benefit.

There were basically three classes of wireless link technology in the running: Low cost digital radio, XBee and WiFi. I ruled out WiFi without really testing it because I was afraid the robot communications might get bogged down if someone else in the house was watching Netflix or doing a download. I don’t really have any evidence that there would be such a problem but, I didn’t want to put down the money and find out later. That left the choice between radio and XBee.

Pros for XBee

  • No special software is needed on the host computer. The PC “sees” nothing but a standard serial port.
  • No special software needed on the Arduino. Just connect the Tx and Rx pins and it’s off and running.
  • Two way communication. Many of the cheaper radio modules are one-way. R1 needs to “talk” back to the host as well.
  • Error detection and correction. I’ve seen dropped messages but, never an incorrect message.
  • XBee “looks” like a standard serial link so, I can download new Arduino firmware through the wireless link – no need to connect a programming cable. I do, however, need to press the reset button on the Aruduino – there are articles on the internet about how to do it without pressing reset.
  • More than two nodes can be involved in an XBee network. It would be possible to control multiple robots from one host computer.

Cons against XBee

  • Expensive – considering the cost of two XBee modules and two adapter boards, it’s the most expensive “part” of the system.
  • The 1mW “regular” XBee modules are unreliable when the robot is in a different room than the host computer. Several retries are often required when doing a sensor scan because of dropped data. The Pro modules may be better in this regard – I’m not sure.

That’s all. Thank You!

– Ralph

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One thought on “Why Use XBee Communication Modules in R1

  1. The main difference is, in basic RF modules like 433Mhz , no bi-directional communication is possible. No,of connections are limited upto 4. If you possibly get a 16bit encoder, decoder then 4 becomes 8. But still its a one way communication..
    These both are the main differences between ZigBee and other RF modules.
    And the rest like IEEE standard and secure communication, easier interfacing would be an extra bonus for ZigBee..
    ZigBee PRO doesn’t make a much difference between, You get more coverage that’s all it does basically

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