The design of wireless remote intelligent home system based on zigbee and GPRS

Microsoft Word 016 doc Proceedings of ICCTA2011 THE DESIGN OF WIRELESS REMOTE INTELLIGENT HOME SYSTEM BASED ON ZIGBEE AND GPRS Fuxing Yang1, Chanyuan Liu1, Zhongcai Pei2, Zhiyong Tang2 1 College of Au.

Proceedings of ICCTA2011

THE DESIGN OF WIRELESS REMOTE

INTELLIGENT HOME SYSTEM BASED ON ZIGBEE

AND GPRS

Fuxing Yang1, Chanyuan Liu1, Zhongcai Pei2, Zhiyong Tang2

1 College of Automation, Beijing University of Posts andTelecommunication, Bejing 100876, China

2 School of Automation Science and Electrical Engineering, BeiHang University, Beijing 100191, China yangfx@bupt.edu.cn, liuchanyuan87@126.com, pzc68@yahoo.com.cn, zyt_76@yahoo.com.cn

Abstract

Intelligent home is an important application of

wireless sensor network This paper introduces a

remote wireless acquisition and control system

based on Zigbee and GPRS The system is a star

network and includes environment monitoring

sensors, intelligent appliances, terminal acquisition

and control nodes, family gateway and data display

platform This system is low cost, low power

consumption, more flexible to deploy and the

coverage is very large The whole system not only

can acquisition the environmental data and display

them, but also can remotely query and control, the

experiment show a good remote alarm and control

ability The control system includes manually

control mode and automatically control mode This

paper introduces the composition and structure of

the system, design of hardware and software are

also described In the design process, the energy

efficiency has been focused on

Keywords: Wireless network, Zigbee, GPRS,

Intelligent Home System

1 Introduction

Intelligent home system, also called intelligent

home LAN, is a diverse structure net which comes

up with modern family living style Intelligent

home control system can be summarized as a

control network Various intelligent household

appliances connect with each other in the network

The interconnection is the basis of data

communication Intelligent control is the

fundamental of home automation and home

intelligent

Zigbee is a new short-rang, low-rate wireless sensor

technology, which is a cross between tag

technology and Bluetooth wireless technology It

used to be called for HmeRF Lite or FireFly

wireless technology, mainly used for short-range

wireless connection It has its own standards

Zigbee is based on the IEEE8.2.15.4, which is a

standard of the IEEE wireless network working

group, known as IEEE8.2.15.4 technical standard

With the development of modern wireless communication technology and automatic control technology, especially zigbee technology, we have

a new way to get and process information Intelligent home system emerges in this situation Through the analysis of wireless sensor network, intelligent home system is established based on zigbee and GPRS The paper is organized as follows: Section 2 gives the overall system architecture, practical scheme Hardware and software design is presented in Section 3 and Section 4 respectively In the design process, we will focus on energy efficiency The Section 5 summarizes the results

2 System architecture

2.1 Network topology

Wireless sensor network configuration is divided into peer” and “master-slave” “peer-to-peer” mode is the communication between any two nodes and connections All wireless nodes and access nodes are connected in “master-slave” mode Access node undertakes the work of wireless management and wired network connection Master-slave mode is the ideal low-power network configuration

The Zigbee devices can be divided into full function devices (FFD) and reduced function devices (RFD) The FFD device can work as a Zigbee coordinator or router, but the RFD device can only be the Zigbee end device

Zigbee network topology is varied, the main three kinds as follows: star network, cluster tree network and mesh network Star network is appropriate for small scale, low complexity and easy connection system Intelligent home system is simple and low power Taking into account the network cost and reliability, the star network is the best choice The star network topology is shown in Figure 1

Figure 1 Star networks topology

2.2 System composition

A number of environment monitoring sensors and

intelligent home appliances are connected to

terminal acquisition and control nodes through

wired or wireless way Terminal acquisition and

control nodes send data to a gateway with wireless

Meanwhile, gateway sends data to mobile base

stations through a transmission network

Transmission network is a localized network which

is responsible for the coordination of gateway node

So we use GPRS network in this system

Comparing with other options, GPRS technology is

more security and versatility Base station is a

computer connected to the internet and sends the

sensor data to data processing center It also has a

local copy of the database to cache the latest sensor

data Users can access the data center and send out

order through PC, Phone or web page The Figure 2

shows the system composition

Figure 2 System composition diagram

Different types of environmental monitoring sensor

nodes and intelligent home appliances are the

bottom of the system Several sensors compose

functional modules by simply program, such as gas

leaking detection module, fire condition detection

module and theft monitoring module The same

sensor can also be used for different purposes The

intelligent home appliance is the general household

electrical appliance with a RF module such as air

condition, TV, lamps and so on It provides a

control capability by turning on and off a relay

Terminal acquisition and control nodes have data processing and communication capability We can handle simply the data collection, particularly data fusion This handle process can greatly reduce the data traffic and energy consumption Compared with single sensor, the sensor network can change the detect targets and test contents based on user needs

Each sensing region has a gateway to collect data of sensor nodes All the gateways are connected to the upper transmission network Transmission network has strong computing power and storage capacity This network guarantees the bandwidth and reliability of communication between the gateway node and base station

Sensor network and the internet are connected through the base station The base station for the internet connection must have sufficient bandwidth and link reliability in order to avoid data loss

Finally, the data is transferred to a central database and stored Central database provides remote data services Users can access central database from any terminal, then they can view data and send control commands

3 Hardware design

3.1 Terminal nodes

Terminal nodes are the core of the wireless sensor network and the source of all information They need collection, management, storage and integration of the local information In general, terminal nodes are tiny embedded system Their data processing capability is rather poor and storage capacity is limited Power supply module is battery-powered The block diagram of a terminal node is shown in Figure 3

Figure 3 Sensor node block diagram Terminal nodes mainly use battery However, battery power is very limited and ordinary battery’s stored energy is 2.2-2.5Ah Therefore, the design of hardware and software need to firstly consider the energy efficiency

Total energy consumption in wireless sensor network is:

Total Energy Consumption=Perceived Power +

Processing Power +Send Total Energy

Consumption + Receiving Total Energy

Consumption

Table 1 Lists the energy consumption in common

operations

Table 1 Energy consumption of common operations

Sensor node operation Power consumption [nAh]

listening channel 1ms 1.250

A simulated sample 1.080

A digital sampling 0.347

Read the ADC sampling data 0.011

Read the flash data 1.111

Flash programming 83.333

Most energy is consumed by the controller and RF

Front-end Chip selection and design process

should consider to reduce the power consumption

of the node In the intelligent home system, we

should make it sleep when the sensor node needn’t

to execute collection in the current due to the low

frequency of data collection Then terminal nodes

close wireless communication module, data

acquisition module, even the calculation module in

order to save energy Sensor node circuit structure

is shown in Figure 4

RS485

ZigBee

UART

ARM Voltage

Detection

LCD

I/O Keyboard

I/O

Digital

I/O Port

Analog Input Port

Relay

Alarm

I/O PWM

Power

Module

Figure 4 Sensor node circuit structure

In hardware design, the intelligent home system

mainly includes four parts: sensor module,

processor module, wireless communication module

and energy supply module The micro control unit

for terminal node circuit is ARM9 chip

STM32F103 This chip has 32-bit flash

microcontroller based on ARM Cortex-M3 core,

256 to 512k bytes of flash memory, up to 48k bytes

of SRAM, three modes (sleep, stop and standby

modes) and supports SRAM, PSRAM, NOR and

NAND memories This chip is developed

specifically for embedded applications, so it has

quick interrupt response speed, low power

consumption and high level of integration

The CC2430 is a System-on-chip solution specifically tailored for IEEE.802.15.4 and Zigbee applications It integrates Zigbee RF front-end, microcontroller and memory CC2430 contains an 8-bit 8051 MCU, 8KB RAM, ADC, 128KB flash memory and 21 programmable I/O pins It is a cheap and low power consumption chip In the receive mode and transmit mode, the current loss is smaller than 27mA CC2430 has the capacity to change from sleep mode into active mode According to the above reasons, CC2430 is the best choice

The performance of power management module is directly related to the stability and energy consumption of the node Power supply mode is divided into 12V DC power supply and 3V battery power supply DC-DC power module must be converted the voltage to 5V because some of the sensor’s voltage is higher than 3V To further reduce energy consumption, wireless communication module wakes up from sleep mode every 10 minutes, but main chip requires power all times In the system, main chip and wireless communication module need power supply separately Power supply of terminal node is shown

in Figure 5

SOFT STAR T

NCP58 5

C +12V

SLECTER +5VD

NCP58 5 +3.3VD1

DC/DC +5VD1 +5VD

+5VD

DC/D C 3V

+12 V

Figure 5 Power supply of terminal node

3.2 The design and implement of the gateway

Gateway is the remote transmission equipment Zigbee low-speed wireless sensor network and high-speed internet network connect with each other through gateway On the Zigbee network, gateway is a network coordinator and can integrate the measurement data The data is sent to the remote mobile base stations by GPRS module after the micro-processing At the same time, the gateway receives instructions from the remote data center and sent instructions to each terminal node The micro control unit of the gateway circuit is also STM32F103 chip Zigbee module of the gateway is also CC2430 chip Gateway circuit structure is shown in Figure 6

Figure 6 Gateway circuit structure

GPRS communication module sends data (GPRS

mode) and short messages (GSM mode) using

SIM900 SIM900 and MCU connected with each

other through SPI SIM900A is a 2-frequency

GPRS module with the working frequency band

EGSM900MHZ and DCS1800MHZ Its size is

only 24mmh24mmh3mm and the lowest current

consumption is only 1.0mA in sleep mode

Meanwhile, it supports SIM card and standard

8-wire serial interface

Figure 7 shows the functional block diagram of

SIM900A and describes the main features section

Figure 7 The functional block diagram of SIM900A

4 Software design

The software of the system which is compiled

based on the basis of the MAC layer in

IEEE802.15.4 protocol, has the advantages of

simple code and flexible expansibility compared

with the public development platform provided by

Zigbee manufacturer

The sleep/wakeup work mode and time

synchronization algorithms are adopted in the

programming to keep the low power consumption

which leads to long life span of the system

4.1 Gateway workflow

Firstly we must complete system initialization includes system clock initialization, receiver buffer pool initialization, initialization of the microprocessor IO, serial initialization and RF wireless transmission initialization RF wireless transmission initialization includes hardware abstraction initialization, transceiver information configuration, transceiver state initialization, the selection of band, output power, network ID and data transfer rate Finally, we execute the enable CRC checking

Then the gateway gets into the listening state When terminal node is assigned 16-bit segment address when it asks to join the network At the same time, gateway collects data when the terminal node wakes up from sleep by the timer The data is transferred to PC management system software for data display and processing or to ARM processor through the serial port After that the data is transferred to host computer through the GPRS module Flow diagram of the gateway is shown in Figure 8

Figure 8 Flow diagram of the gateway

4.2 Gateway workflow

Firstly, we must complete system initialization as

same as the gateway After the state transition of

the wireless module, terminal node sends broadcast

packets to search the web and listens for reply

packet It sets the network short address, receives

time and wakeup parameters and enters the sleep

timer wakeup module if the terminal node receives

a response package

Terminal node follows the sleep mode—wakeup

mode—work mode—sleep mode sequence Flow

diagram of the terminal node is shown in Figure 9

Figure 9 Flow diagram of the terminal node

5 Conclusions

Innovation of this system is: Achieve real-time collection of sensor data which record home environment conditions and equipment status

Realize the remote monitoring of home state with alarm function The software of the system which is compiled based on the basis of the MAC layer in IEEE802.15.4 protocol Sleep-wake up work mode and time synchronization algorithm are adopted in the programming to keep the low power consumption Analysis of the node power consumption verifies the correctness of hardware and software

System integrated debugging results show that: The system has a good working stability and accuracy

of measurement Network nodes are very small, easy to install Have a strong advantage in low power and low cost The system has good versatility and scalability System function will be more complete by increasing the relevant sensors

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