XBee radio communication between PICs

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Original Assignment

Two wired PICs can communicate by RS-232. We can replace the wires with a wireless link. In this project, that wireless link will be implemented using Zigbee radio modems that use the IEEE 802.15.4 protocol. The demonstration will show two PICs talking to each other over wireless, and a PIC talking to a PC by wireless. This demonstration has the user typing in data into hyperterminal and the PIC responding. For example, the user might type "1+5 [enter]" and the PIC responds with "6".

Overview

It is common for two pics to communicate by RS-232, a wired transmission. However, it may be desirable to communicate via a wireless link. This wiki page discusses this option by using ZigBee radio modems using the IEEE 802.15.4 protocol. This will allow for two pics to communicate wirelessly as well as a pic and a PC to wirelessly communicate.

File:XBeePinOut.jpg

ZigBee is a protocol which transmits, similar to bluetooth, but uses lower frequencies (2.4 Ghz). These transmit chips, called "xbee", in comparison to bluetooth chips, are low power and low cost. The range for an XBee Pro indoors is up to 300 feet while line of site, outdoor communication is up to a mile. (XBee Manual

The XBee requires a 3.3 voltage regulator and the chip is designed to be mounted in specific sockets (See figure) (Note: These sockets don't fit in a standard bread board!)

For the pin locations, see page 7 of XBee Manual or the figure to the right.

For PIC to computer interface a program such as X-CTU needs to be used, X-CTU can be downloaded from X-CTU Site.

Circuit

Code