ZIGBEE

Contributor : Veena C.

Introduction:

Zigbee is a wireless protocol that allows small, low-cost devices to quickly transmit small amounts of data, like temperature readings for thermostats, on\off requests for light switches, or keystrokes for a wireless keyboard. It is a global specification for reliable, cost effective, low power wireless applications based on the IEEE 802.15.4 standard for wireless personal area networks (WPANs). ZigBee is targeted at RF applications that require a low data rate, long battery life, and secure networking.Zigbee is a rather new wireless technology that looks to have applications in a variety of fields. It uses low data rates technology allows for devices to communicate with one another with very low power consumption, allowing the devices to run on simple batteries for several years. Zigbee is targeting various forms of automation, as the low data rate communication is ideal for sensors, monitors, and the like. Home automation is one of the key market areas for Zigbee, with an example of a simple network.

ZigBee is designed for wireless controls and sensors. It could be built into just about anything you have around your home or office, including lights, switches, doors and appliances. These devices can then interact without wires, and you can control them all from a remote control or even your mobile phone. It allows wireless two-way communications between lights and switches, thermostats and furnaces, hotel-room air-conditioners and the front desk, and central command posts. It travels across greater distances and handles many sensors that can be linked to perform different tasks.

ZigBee works well because it aims low. Controls and sensors don't need to send and receive much data. ZigBee has been designed to transmit slowly. It has a data rate of 250kbps (kilobits per second).Because ZigBee transmits slowly; it doesn't need much power, so batteries will last up to 10 years. Because ZigBee consumes very little power, a sensor and transmitter that reports whether a door is open or closed, for example, can run for up to five years on a single double-A battery. Also, operators are much happier about adding ZigBee to their phones than faster technologies such as Wi-Fi; therefore, the phone will be able to act as a remote control for all the ZigBee devices it encounters.

ZigBee basically uses digital radios to allow devices to communicate with one another. A typical ZigBee network consists of several types of devices. A network coordinator is a device that sets up the network, is aware of all the nodes within its network, and manages both the information about each node as well as the information that is being transmitted/received within the network. Every ZigBee network must contain a network coordinator. Other Full Function Devices (FFD's) may be found in the network, and these devices support all of the 802.15.4 functions. They can serve as network coordinators, network routers, or as devices that interact with the physical world. The final device found in these networks is the Reduced Function Device (RFD), which usually only serve as devices that interact with the physical world.

References:

http://en.wikipedia.org/wiki/ZigBee

http://seminarsonly.com/Zigbee

http://ZigBee Tutorial-Reports_Com.htm