Zigbee Wireless Technology

Abstract

During the past three decades, the world has seen significant changes in the technologies industry. There have been some remarkable aspects to the rapid growth in wireless technologies and engineers across many disciplines are becoming interested in wireless communication, However, the introduction of Zigbee technology make wireless technologies more challenging for home automation and sensor networking such as lightning, heating etc. This task focuses on generic wireless data acquisition system based on zigbee sensor and zigbee controllers which are built up using jennic JN5121 zigbee modules.

CHAPTER 1: Introduction to Wireless Technology

Probably one of the most fascinating technologies in industry today is the wireless technology. It's becoming a wireless world over the past few years, discovering of moving data wirelessly has been a major challenge in many companies around the world and there are a lot of developments in wireless technologies and most companies these days venture into it basically to reduce the cost of equipment, easy installation, simpler engineering, reduction in material needed and most importantly, to ensure good delivery of data. There are some few wireless technologies that can be used to achieve this, but the most recent low power supply, cheap and reliable wireless technology is called 'Zigbee'.

The history of wireless communications is nothing new. Since the early days of civilization, various forms of communication took place without the advantage of physical connectivity or technology. In tribal jungle environments, drums were a primary means of communicating. As message senders beat on either drums or hollowed out logs, the reverberating sounds were interpreted at the other end. In many situations, the drumbeat would travel only at a limited distance, so various relay points were needed. The first receiver would acknowledge the sender's message through a series of return drumbeats, and then relay the same message to the next receiver. This limited form of transmission met the need but was subject to a lot of noisy interference and misunderstanding. Therefore, the message was sent over and over again to minimize potential errors in interpretation. The method was crude and it worked. But wireless communication is more than communicating through drumbeat or hollowed out logs.

Zigbee is a next generation wireless technology and it provides two or more way communication link between devices. The origin word of the Zigbee derived from the way honey bees communicate the location of the new found food source. This technique used by the honey bees referred to as the Zigbee Principle, whereby the bees dances in a zigzag pattern to share some important information such as the location, distance, and direction of a newly discovered food source to their fellow member. Zigbee technology standard built on IEEE 802.15.4 specification and IEEE is US based standard body. The features of this wireless connectivity standard allow Zigbee based products to be installed easily and cost effectively, its built -in intelligence, and flexibility allow networks to be easily adapted to changing needs by adding, removing or moving network devices. It also increases productivity by introducing mobility, flexibility and fast network access. Zigbee improves the functionality of wireless technology by offering flexible; widen network topologies with an incorporated system and routing intelligence to make it possible for easy installation and high flexibility to failure. Zigbee wireless technology also integrate listen before talk and thorough security actions that control them to co exist with other wireless technologies like Bluetooth and WIFI that operates at the same operating environment. Zigbee technology is perfect for sensing and controlling rate at which energy being consumed for home automation such as lightning, heating, air conditioning and now that the whole world very much worried with rising energy costs, which have increased 4X in the last 25 30years, it is now obvious that Zigbee technology is more and more sight as a foremost technology to facilitate reducing the cost in home automation and commercial buildings through smart energy products. On the other hand, Zigbee technology has important role to play as the world prepare to reduce the energy usage because of the global warming. For instance, Zigbee used in home automation, lightning control and refrigeration control, all these application let Zigbee enabled meters to correspond and manage Zigbee enabled devices in the home and the users will have choice of taking voluntary actions during demand/ response time to decrease their personal usage by turning off electrical devices and this not only lessen the peak load on the utility grid but also helps home users make quick decisions on their energy use. Therefore, Zigbee technology regards as green technology as it focuses on green issue. Zigbee technology has greater features when compared with other existing wireless methods like WIFI, Bluetooth, Infrared, and WiMaX. Zigbee has high level wireless communication protocol using a very low power supply and it provides an exceptionally dependable data delivery to all devices attached to it.

The features of wireless connectivity allow zigbee based devices to be in power saving mode when it is not used. That means, devices attached to zigbee like sensors can be powered and this make them self controlled and lessen the installation costs.

Important of Wireless Technologies:

i. Flexibility: this is one of the vital advantages of wireless technology compared to a wired connection.

ii. It is portable

iii. Wearable

iv. Performance

v. Low power

vi. Sensors.

The main objective of this project as follows;

1.1. The aim of this project is to develop a generic wireless data acquisition system based on Zigbee sensor boards and Zigbee controllers, which are built up using jennic JN5121 IEEE802.15.4/Zigbee modules, JN5121 Z01 M00 and this involves writing two C code, one for wireless End Device and the other as a wireless Co ordinator. Note: The Zigbee End Device is a device with no routing capability, Zigbee Co ordinator is a device with routing capability that initiates the network and Zigbee router is a device that also has the routing capability.

The design tasks of this project is divided into 3

The first task has two operation using two sensor boards and the main objectives of these includes. Writing a C code for End Device to read the measurement of the temperature/humidity and the light level (absolute values) sensors and send them to the Co ordinator wirelessly through RS232 link of a PC, the second tasks involve writing a Co ordinator C code to receive the data from the End Device, calibrate them and send them to a local PC via the RS232 link.

Two sensor boards also used, one is used as a wireless End Device and the other as a wireless Co ordinator. It has three operations

i. In the End device, one push button is used to switch between temperature, humidity and light. When the push button is pressed, the chosen parameter needs to be not only sent to the Co ordinator via the 12C bus connection, but also sent to the OC via the serial port under name 12C data.

ii. The Co ordinator then sends the data received from 12C to the PC

iii. Both values shown on the PC (one from the End Device and the other from the Co ordinator) should be the same.

The third task of this project involves with two sensor boards (which will be used as an End Device unit and the other as a Router unit) and one Controller board (which will be used as a Co ordinator unit); the following operations must be noted

i. Writing End Device C Code to receive data from the 12C bus and send them wirelessly to the co ordinator unit

ii. Writing C code for router to receive data from the End Device and route them to the Co ordinator unit wirelessly

iii. C code to receive data from the router/End Device units and send them to the 16Mbit serial flash memory rather than a local PC.

iv. Finally, providing a menu interface using the push buttons and the 128*64 LCD screen provided with the Co ordinator to view/delete data from the memory.

1.2. Types of Wireless Technologies:

Types of wireless technologies: various wireless technologies emerged and we shall be looking at some few wireless technologies like WIFI, Bluetooth, Infrared, WiMaX and Zigbee.

1. Bluetooth Technologies; the initial approach of Bluetooth start off from an Ericsson project in 1994 and primarily designed to swap wires/cable connectivity between devices. Bluetooth technology was based on IEEE 802.15.1. It offers a short range between 1 10m and low cost connectivity between portable devices. Bluetooth operates at 2.4GHz frequency and bandwidth of 780Kbps. The low power consumption makes Bluetooth ideal for small, battery powered devices like mobile phone, printer and pocket PCs. Bluetooth allows users to connect a broad range of computing and telecommunication equipments easily without any stress and without the requirement of additional cables, this save cost of extra cables by the users. Bluetooth is poised to capitalize on the emerging market of small mobile devices that is expected to grow more than the present stage in the world of wireless technology. Bluetooth's short range (<10) is ideal for the concept of personal operating space and integrates the notion of using a device carried on the body or otherwise located within immediate reach. Bluetooth's transmission speed of 780kbps works well for transferring small to medium sized files. Bluetooth is an ideal solution for connecting the increasing number of devices designed to be held in the hand or worn on the body. These devices are being embraced by industries using mobile automation systems. For example, at a car rental facility, an employee could use a Bluetooth enabled pocket PC equipped with a bar code scanner to scan a vehicle identification number, enter mileage and fuel data, then instantly transmit a receipt to a Bluetooth enabled portable printer worn on the hip. Another important of Bluetooth, one could use the Bluetooth enabled mobile phone at a Bluetooth enabled vending machine to charge one's account and buy a drink. One of Bluetooth's greatest advantages is that it can be used completely anywhere that has at least two Bluetooth devices within a 10 m range. It is possible because Bluetooth is designed for direct point to point networking between devices and does not require proximity to infrastructure stations like signal towers or access point. Bluetooth's is being used in mobile computers, bar code laser scanners, cash registers, vending machine, GPS receivers, slide projectors, Printer, digital cameras, digital camcorder, test and measurement equipment, and LAN access points.

Review applications of Bluetooth

i. Replacing serial cables with radio links

ii. Wearable networks/WPANs

iii. Desktop/room wireless networking

iv. Hot spot wireless networking

v. Medical: transfer of measured values from training units to analytical systems, patient monitoring.

vi. Automotive: remote control of audio/video equipment, hands free telephony

2. Infrared Technologies: infrared is an invisible band of radiation that exists at the lower end of the visible electromagnetic spectrum. This type of transmission is most effective when a clear line of sight exists between the transmitter and the receiver. Infrared is a short range technology. When used indoors, it can be limited by solid objects such as doors, walls, merchandise, or racking. In addition, the lightning environment can affect signal quality. For example, loss of communication may occur because of the large amount of sunlight or background light in an environment. Fluorescent lights may also contain large amount of infrared. This problem may be solved by using high signal power and an optimal bandwidth filter, which reduces the infrared signals coming from an outside source. In an outdoor environment, snow, ice and fog may affect the operation of an infrared based system.

Advantages of Infrared

The advantages of infrared technology are relatively many and this should be continually reflected on rather than instantly ruling it out whenever a wireless connection is needed. Many industries nowadays regard infrared as an old technology, not worthy of consideration, but most engineers across the disciplines still have it in mind as an option, at least until some others wireless technologies proves beyond reasonable doubt to be better or cost effective. Some of the most important advantages of infrared are as below:

1. Cost effective

2. Easy to Install

3. Reasonably high bandwidth

4. Efficient to move from site to site

5. No licensed required

6. Immune to radio frequency interference and electromagnetic interference

7. Capable of traversing similar paths without interference

8. Installed and running in a matter of hours

9. Capable of supporting multiple standard interfaces

10. Capable of handling voice, data, video, and LAN traffic either separately or on the same system, depending on the application.

11. No government regulations controlling use

Disadvantages of infrared:

As we all know that there is no technology or innovation without any problems or downside. The main disadvantages of infrared are not as remarkable as the advantages, but it should be feature into the equation since the use of light based system is being used in infrared.

1. Short distance covered

2. Potential hazards of using a laser beam in an office environment

3. Negative effects of vibration on the system

4. Signal affected by snow, light, ice, fog

5. Signal cannot penetrate solid objects

6. Generally a short range technology (30 50 ft radius under ideal conditions)

7. Dirt can interfere with infrared

8. Risk of exposure to the beam from window cleansing personnel

9. Need for a clear path in a line of sight, regardless of any other condition.

10. Impaired reception of the beam because of atmospheric disturbances

WIFI Technologies; Wireless Fidelity or WIFI technologies was developed primarily for TCP/IP and designed to enhance LAN (local area network). WIFI operates at 2.4GHz. It is based on the IEEE 802.11 specification standard. It's compatibles with TCP/IP because it has high speed. WIFI is used for TCP/IP Ethernet connections interchange that involves special IP address. WIFI technologies offer a very reliable and speedy wireless connectivity and ensure some high level of security. The only disadvantage of WIFI among the existing wireless technology is that it has no application at the field level example, home automation, remotes systems and industrial control.

4. WiMaX Technologies:

Zigbee Technology: this is a low rate wireless connection developed to provide set of industrial, residential, and medical application with very low power consumption, low cost requirement, and comfortable needs for data rate and quality of service. The low power rate enables the wireless network to consume little power. Zigbee technology is a low data rate, low power consumption, low cost; wireless networking protocol targeted toward automation and remote control applications. Zigbee technology expected to provide low cost and low power connectivity for devices that need battery life as long as several months to several years but does not require data transfer rates as high as those enabled by Bluetooth. Zigbee can be implemented in mesh (peer to peer) networks larger than possible with Bluetooth. Zigbee also operates at 2.4GHz frequency.

Wireless technologies continue to develop for industrial market; however, there are several issue and challenges that must be addressed to ensure successful implementation of this wireless technology for examples like operating frequency, receiving sensitivity, operating temperature, the pins connections etc. However, different companies manufacture different type of zigbee E.g. Chipcon, Ember Corporation, MaxStream and Jennic etc.

The table below summarized the comparison of wireless technologies.

Wireless Tech	Zigbee	Bluetooth	GSM/GPRS/CDMA
Application	Monitoring, control	Wide area voice data	Cable replacement
Resources	4 32KB	16+MB	250+KB
Battery life Cycle	100 1000days	1 7	1 7
Network	Unlimited	1	7
Bandwidth	20 250(KBps)	64 128	720
Range (m)	1 100	1000+	1 10
Metrics	Reliability	Reach, quality	Cost, convenience

1.3. Application of Zigbee.

1. It is used as building Automation such as lightning control, Access control, Refrigeration Control, HVAC control.

2. It is used as industrial Automation for example temperature sensing and control, pressure sensing, flow control.

3. It is used as Home appliances and fire/CO2 alarms

4. It is used as monitoring and remote systems.

5. It is used as advanced metering infrastructure and automatic meter reading.

6. It is used in sensor data capture in embedded networks.

7. It is used in defence like battlefield monitoring and shipboard monitoring.

CHAPTER 2: Wireless Sensor Network

Introduction: Wired sensor networks have been around for quite long time or over decades, but the recent development in science and technology especially in silicon radio chips have shown the way for the introduction of Wireless sensor network that produces low cost effective chip consisting of transistors. The chips development around the world grows every time as the technology advancing and this led to the production of less expensive, low powered consumption, and smaller mechanical structures wireless sensors. In recent time, Wireless Sensor Networks have been boosted and received remarkable attention from both academia and industry because of its large range of possible applications for home automations, industrial automation, battlefield monitoring, and remotes systems.

2.1. Wireless Sensor Network.

A wireless sensor network contains a large number of tiny sensor nodes that are densely deployed either inside the phenomenon to be sensed or very close to it. A sensor node consists of sensing, data processing, and communicating components. The positions of sensor nodes need not to be engineered or predetermined. Wireless sensor network applications require wireless ad hoc networking techniques. Although many protocols and algorithms have been proposed for traditional wireless ad hoc networks, they are not well suited for the unique features and application requirements of wireless sensor networks. One of the most important constraints on sensor nodes is the low power consumption requirement. Sensor nodes carry limited, generally irreplaceable power source. Therefore, wireless sensor network protocols must face focus primarily on power conservation. They must have built in trade off mechanisms that give the end user the option of prolonging network lifetime at the cost of lower throughput or higher transmission delay.

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Zigbee Wireless Technology