This post is to make your experience with XBEE Radios a breeze.I shall make it in 4 parts.

First part is Introduction & a little theory of XBEE Radios.In this part we shall also see the types of XBEE Radios available.

Second part is about Texas CC2500 ChipCon RF module which is a low cost XBEE like module.Link here.

Third part is about configuring & using TARANG Modules of Melange Systems.here

Final part is about original XBEE Radios from DIGI company.here

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PART 1  : Introduction to types of XBEES & Theory of operation

If you are in a hurry watch this quick reference video & move on to part 2.

XBEE RADIOs Quick Reference Guide

XBee modules are wireless Transceivers that provide wireless end-point connectivity to devices. These modules either use the IEEE 802.15.4 networking protocol  or ZIGBEE protocol for fast point-to-multipoint or peer-to-peer networking.

ZIGBEE & XBee are not the same thing. Zigbee is a protocol that defines the communication & Xbee is a type of Radio that supports the protocol like Zigbee.Note that Xbee also supports protocols like 802.15.4 & Wi-Fi.

Other modern wireless protocols are WiFi (IEEE 802.11) and Bluetooth (IEEE 802.15.1).

XBee uses the Zigbee standard or 802.15.4 protocol.

XBee 802.15.4 modules,sometimes referred to as Series 1.This protocol is known as a Low-Rate, Wireless Personal Area Network (LR-WPAN). It provides up to 250 kbps of data transfer between nodes .It is not intended for large volumes of data, such as image files.

XBee ZB modules, sometimes referred to as Series 2. Series 2 supports the full Zigbee protocol.

Firmware for Series1 is 802.15.4 point to point & that of Series 2 is ZB Zigbee mesh.

All the firmware versions of Zigbee end either in API or AT .These are methods by which your Xbee radio will talk on their serial ports.Every transfer of data requires a protocol,which has rule for communication.As you know Bluetooth is a protocol , WI-FI is a protocol.Same way ZIGBEE is a protocol and XBEE radios work according to this protocol.Xbee working on ZiGbee protocol is called Series 2.Series 2 hardware uses a microchip from Ember Networks.

If you check up the website of DIGI here, the manufacturer of original XBEEs, you can have an idea of different Protocols of XBEEs.

Series 1 and Series 2 hardware are NOT compatible with each other. If you mix & try to match it, it won’t work, not even close.The underlying chipset for Series 1 is FREESCALE & that of Series 2 is EMBER.Recently  Digi Company  has released Series 2B with an optional programmable microprocessor and compatible with Series2.

Be sure to use same type of Radios in a network.If you try to mix Series 1 & Series 2 then you will never reveal the network.

Power consumption of XBEE is 50mA at a working voltage of 3.3V.They transmit at 1mw power @ data rate of 250kbps to a range of 300Ft (XBEE Pros transmit to a range of 1Mile)

Most of the Xbee modules operate at 2.4GHz, but there are a few that operate at 900MHz.

There are regular XBees and the XBee Pros. The Pros use more power (longer range of operation, 3times that of a regular) and cost more money. You can mix and match these on the same network.

The XBee comes with a variety of antenna styles . Two of the most popular versions are the chip antenna and whip (wire) antenna.

XBee Radios have a Wire Antenna – a small wire sticking up or they have Trace antennas (chip antenna), which are printed directly to the circuit board.

The various types of XBEE Radios available in the Market are

1.  XBEE & XBEE PRO of DIGI Company

2.  TARANG Modules from Melange Systems

3.  Texas Instrument’s low cost CHIP CON module CC2500.

Image 2              tarang          cc2500

XBEE Original (DIGI Co.)               TARANG Module                Texas CC2500

Now a little bit of theory of  Zigbee networks.

This theory applies to SERIES 2 modules using Zigbee protocol.

Every Zigbee network will have a single Coordinator device which is responsible for creating the Network,handing out addresses & manages the security.Each network must be formed by a Coordinator.

Every Zigbee network will also have a Router Device or an End Device.A Router is a Zigbee Node that joins existing Networks.

End devices are stripped down versions of Router & always need a Parent device (a router or a coordinator).

Note that in Series 1 devices there is no Coordinator or Router.

ZigBee networks connect together using a layout called Topology.There are 4 major topologies Pair,Star ,Mesh & Cluster Tree.

Each XBee radio has a unique & permanent 64 bit serial number.No other Radio is assigned the same number.There is also a 16 bit address assigned to each Radio by the coordinator of the network.Xbee radios can also be assigned a human friendly name called node identifier.

Each Zigbee network creates a Personal Area Network address PAN ,a 16 bit address and there are 12 channels to be assigned for network conversation.The channel selection is handled by Xbee radios automatically.

For two Radios to communicate,the radios need to be on the same channel & have the same PAN information.The sending radio must know the receiving radio’s address.

The XBee supports both an AT and an API (Application Programming Interface) mode for sending and receiving data at your controller.

In AT Mode (Transparent Mode) just the message data itself is sent to the module and
received by the controller. It appears to be a  direct serial link between the nodes . This
mode allows simple transmission and reception of serial data. AT Commands are used to configure the XBee.

In API Mode, the programmer packages the data with needed information, such as destination address, type of packet, and checksum value. Also, the receiving node accepts the data with information such as source address, type of packet, signal strength, and checksum value.

Data may be sent in API Mode and received in AT Mode or vice-versa.

You can use Xbee radios in Transparent/Command mode or in API (Application Programming Interface) mode.Human interaction is required in the first mode ie., you need to type +++ to enter Command mode & then issue AT commands to interact with the Radio.

In API mode computers can interact with other computers without human interaction.Highly structured data is transmitted quickly & reliably in API mode.

To communicate with the XBee radio we use a serial Terminal software .The most popular ones are Teraterm , PUTTY , CoolTerm & Hyperterminal.

To configure XBEE original we use DIGI company software X-CTU

X-CTU program is the official configuration program for XBee Radios.The internal microcontroller of XBee radio runs a program called Firmware that performs & controls the functions,addressing & security of the Radio.To configure this Firmware we use X-CTU software.

To configure TARANG modules we use TMFT software from Melange Systems,Bangalore.

For configuring Texas CC2500 use SmartRF Studio .Download it from

http://www.ti.com/tool/smartrftm-studio&DCMP=hpa_rf_general&HQS=Other+OT+smartrfstudio

Note that you cannot use X-CTU to configure Tarang & that you cannot use TMFT to configure DIGI’s XBEE modules.

Read the next post of configuring & using Texas CC2500 RF Modules.

For in depth reading about XBEEs the Bible is “Building Wireless Sensors Networks” by Robert Faludi. You can buy it online from Flipkart here.

For availability of XBEE Radios and Break out Boards contact :

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