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Design of Intelligent Inductive Security System Based on Wireless Sensor Network
Available online at www.sciencedirect.com
Energy Procedia
Energy Procedia (2011) 000–000 Energy00Procedia 12 (2011) 718 – 725 www.elsevier.com/locate/procedia
ICSGCE 2011: 27–30 September 2011, Chengdu, China
Design of Intelligent Inductive Security System Based on Wireless Sensor Network Xiaoyan Caia*, Aina Hub, Ruyou Liuc b
a School of Information Engineering, Huanghe Science and Technology College, Zhengzhou, 450006 China Communication Engineering Department, Huanghe Science and Technology College, Zhengzhou, 450006 China c China Northeast General Municipal Engineering Design and Research Institute, Changchun, 130021 China
Abstract The current security monitoring system for transformer substation has several disadvantages, such as wiring issues, high cost of installation and maintenance and poor mobility. In order to solve these problems, this article proposes a solution that is intelligent inductive security system based on wireless sensor networks. Among this system the microwave sensors act as inductive terminals and form a multi-hop, self-organizing network through wireless communication. It will integrate data collection, alarm and remote control with characteristics of real-time, safe and reliable quality.
© 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of University of Electronic © 2011and Published by Elsevier Selection and/or peer-review under responsibility of ICSGCE 2011 Science Technology of ChinaLtd. (UESTC). Keywords: Wireless sensor network, microwave sensors, security system.
1. Introduction The security of electric power substations is not only related to the social production and life, but also related to people's lives and property. The traditional monitoring systems usually adopt the wired method, which normally has wiring issues and requires rewiring if the device has to be changed. Furthermore, too many wires affect the building’s outward appearance, the costs of installation and maintenance are generally high, and the poor mobility of the system makes upgrade and maintenance inconvenient and time consuming. Therefore, a combination with wireless communications, mobile computing and selforganization network technology, micro-electromechanical systems (MEMS) gives birth to a new intelligent network for information collection, transmission and processing—wireless sensor network [1], which has advantages in monitoring the target in the sensor monitoring area [2-8].
* Corresponding author. Tel.: +86-13503458600. E-mail address: cxy@ hhstu.edu.cn.
1876-6102 © 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of University of Electronic Science and Technology of China (UESTC). doi:10.1016/j.egypro.2011.10.097
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Xiaoyan Cai Cai et et al. al. // Energy Energy Procedia 00 12 (2011) 000–000 718 – 725 Xiaoyan
The intelligent inductive security system based on wireless sensor network described in this article is an alarm system combining data collection, alarm, and remote control in one set with excellent performance of real-time, safety and reliability. It not only saves the labor cost but also is featured with wiring free and thus results in easy installation. Therefore it is suitable for military restricted zones, substation and so on. 2. System Structure This system includes inductive terminal, data communication network, console, and monitoring center. The system structure is shown in Fig. 1.
Fig.1. System structure
The inductive terminal is mainly responsible for processing the information collected by microwave perception module. After calculation and process, the inductive terminal will inform the alarm module to implement alarm, and at the same time it will upload alarm condition information to the data communications network. The data communication network is a wireless self-organization network composed of multiple WSN nodes, in charge of data receipt and delivery, console commands for transmission, etc. Specifically, the WSN nodes mainly receive information from sensing terminal, for example, receiving the sensation if there were a person approaching the area, and receiving the commands from the console. The console receives the data transmitted from the front terminal and displays the onthe-scene situation on the console screen, and then sends the information to the monitoring center through the wired or wireless manner. 3. Hardware Design The hardware structure is shown in Fig. 2. It includes four modules, which are sensor, processor, communication and alarm and power supply. The system adopts microwave detectors as sensors to collect invasion information in the monitoring area. The high-performance ATmega1281 processor is responsible
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Xiaoyan Cai et al. / Energy Procedia (2011) 718 – 725 000–000 Xiaoyan Cai et al. / Energy12Procedia 00 (2011)
for storing and processing of the data collected and sent together with information from other nodes. The communication module employs AT86RF231 chips for wireless communication with other sensor nodes, exchanging control messages, sending and receiving collected data. The acousto-optic alarm is applied to inform the personnel on a timely basis to take actions as soon as possible in exceptional circumstances, in order to reduce risks and avoid disastrous consequences. The power supply module provides the required energy for the entire system by using the solar. Alarm Module
Sensor Module
Microprocessor Module
Communication Module
Power Supply Module
Fig.2. Hardware structure
3.1. Power supply Module The power supply is the heart of the system and its quality affects the reliability of the system directly, therefore the design of power system is a key part of the entire system. The system uses the solar power which avoids the complicated traditional wiring, marked by no pollution, easy maintenance, long life, abundant resource and high cost performance. The output terminal of solar panels is connected with the regulator LM1117-5 whose voltage remains 8.4V by adjusting RW so as to charge two 4.2V lithium batteries of series connection. A diode is added at the output terminal of LM1117 to prevent the current backflow. The circuit is shown in Fig. 3. Since microwave sensor’s operating voltage is 5V, so the voltage of both ends of the battery should keep 5V by regulators while the node working voltage is 3.3V requiring stabilizing the 5V voltage at 3.3V. LM1117
Solar panels 12 v
100UF
RW
500
+ 47UF
Battery
Fig.3. Power module
3.2. Sensor Module The sensor node is responsible for collecting the information from around monitoring area. The sensors adopted in this system are GH100 microwave mobile sensor consisting of dielectric oscillator (DRO) and a pair of micro strip antennas with microwave frequency of 10.525 GHz. The schematic and the product are shown in Fig.4.and Fig.5, respectively.
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Xiaoyan Cai et et al. al. / Energy Energy Procedia 00 12 (2011) 000–000 718 – 725 Xiaoyan
Fig.4. Schematic diagram
Fig.5. Products diagram
This mobile detector is low cost, non-contact, low powered, high sensitivity, compact and free from the influence of heat, noise, humidity, aerial currents, dust and other ambient factors. Thus it is suitable for harsh environment particularly. Since the output intensity of the sensor signal output is related to the reflection intensity of emission energy, usually on microvolt level, an amplifier with high gain and low frequency is needed to process the signal so that it can be handled by the processor. Amplifier circuit is shown in Fig. 6. Amplified signal is shown in Fig. 7. 3.3. Processor Module and Communication Module The processor is responsible for receiving the alarm signal and controlling, coordinating each functional module to work normally. It also responds to alarm information including information record, on-site alarm, remote communications alarm etc. ATmega1281 produced by Atmel Corporation is a kind of 8-bit microcontroller with low energy consumption and abundant resources greatly. This chip provides internal 256KB Flash memory, 8KB SRAM data memory (which can be expanded to 64KB by external connections) and 4KB EPROM memory. The chip also has 8/16 channels of 10-bit ADC, two 8-bit and four 16-bit hardware timing/counter, four 8-bit PWM channels, programmable watchdog timer and onchip oscillator, on-chip analog comparator, 2/4 programmable serial USART, 51/86 programmable I/O port lines, SPI, I2C bus interface. Both of JTAG programming and ISP programming are applicable for this chip. Besides the normal work pattern, ATmega1281 also has 6 kinds of sleep patterns: idle mode, ADC noise-suppressing mode, electricity-saving mode, power-down mode, standby mode and extended standby mode. Therefore ATmegal281 [9] is very suitable for low energy consumption situation.
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Xiaoyan al. / Energy Procedia 12 (2011) 718 – 725 Xiaoyan Cai et Cai al. /etEnergy Procedia 00 (2011) 000–000 +5
R2 100k
+5 C1 105
C3 100u
GND
GND
_
C2
IF R1 12k
R4 330k
_
4.7u
C6
+
GH100
R3 100k
GND
LM324
C4 2.2nF GND
C5 4.7u
R6
R5
10K
1M
4.7u
R7
+
LM324
OUT
8.2k C7 2.2nF R8 100K
Fig.6.Amplifier circuit
1.5m waveform
3m waveform
Fig.7. IF waveform amplified
The wireless communication module adopts AT86RF231 as wireless transceiver chip with low power consumption, low voltage and SPI interface. This chip is also in compliance with 2.4GHZ IEEE802.15.4.standard [10]. AT86RF231 is connected with the ATmega1281 processor through the SPI interface and executes data reading and writing through the serial output (MOSI) and serial input (MISO). The reading and writing function is controlled by the serial clock (SCK). The connection between processors and peripheral devices are shown in Fig. 8.
Fig.8. Processors and peripheral devices connection graph
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Xiaoyan Cai Cai et et al. al. // Energy Energy Procedia 00 12 (2011) 000–000 718 – 725 Xiaoyan
3.4. Alarm Module The alarm modules include on-site alarm and remote alarm, both using the acousto-optic alarm. The on-site alarm uses a buzzer and LED lights to achieve the function. The buzzer and LED are connected with the processor’s I/O port while buzzer needs a transistor as a driver. When someone invades, the buzzer and LED lights will be controlled by raising the I/O port level. At the same time, remote alarm will be realized when alarm information is transmitted to the backstage and displayed on the screen. 4. Software Design After establishing the network, terminals (microwave intrusion detector nodes) request to join it and then collect data periodically. As shown in Fig. 7, the amplitude and frequency of the amplified intermediate frequency signal are related to the object’s moving speed and distance. Furthermore, the change of amplitude is more obvious than that of frequency when the object is moving and it’s easier to detect amplitude than frequency. For the reasons given above, this system only detects its amplitude and runs analog-to-digital conversion for the amplitude of IF signal by using the A/D channel of microcontroller. Alarm event will be recognized when the magnitude detected is higher than the threshold. The processor will send out alarm and transfer the intrusion information to the monitoring center. Software design flow chart is shown in Fig. 9. Initialization network Initialization success？ Y build a network
Node to join
？
N
Y collect data Threshold comparison
Have invaders or not？
N
Y alarm Send to monitoring center to display
Fig.9. Software flow charts
5. Experimental Analysis and Test Results Fig.10. shows the experimental setup conducted. Sensing terminal is set on column at the height of 2.6 m from the ground level, as shown in Fig. 10 (a). Let the angel of the triangular bracket be α. The sensing distance is 3m with α = 30º; when α = 45º, the sensing distance is 6.6 m. Experimental test image is shown in Fig.10 (b) and (c). Experimental results as shown in Fig. 11.
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Xiaoyan al. / Energy Procedia 12 (2011) 718 – 725 Xiaoyan Cai et Cai al. /etEnergy Procedia 00 (2011) 000–000
Columns Triangle Bracket
a
Inductive Terminal
2. 6 m
Invaders Ground Induction Distance
(a) Schematic diagram of experimental installation
(b) Laboratory experiments picture
(c) Outdoor experiments picture
Fig.10. experimental setup conducted
Fig.11. experimental result
6. Conclusion This article describes each module incorporated in the system in details with purpose to realize the real-time monitoring for remote target. The system is highly stable, compact, safe, reliable, and easy to install, and the sensors selected meet the technical requirements of power system. The entire system is assembled in hemispherical plastic shell as waterproof thus internal components can be protected to ensure high quality and excellent performance, which enable it operate normally even in outdoor harsh conditions.
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Xiaoyan Cai Cai et et al. al. // Energy Energy Procedia 00 12 (2011) 000–000 718 – 725 Xiaoyan
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References [1] Ren Fengyuan, Huang Haining, Lin Chuang. Wireless sensor networks [J]. Journal of Software .2003, 14 (7):1282 -1291. (in Chinese) [2] AKYILDIZ I, SU W, SA N K ARA S U B RA MA N IA M Y, et al. A survey on sensor networks, IEEE Communications Magazine,2002 (8) :102-114 [3] T.He,S.Krishnamurthy,J.A.Stankovic,T.F.Abdelzaher,L.Luo,R.Stoleru,T.Yan,L.Gu,J.Hui,and B. Krogh. An energy-ef cient surveillance system using wireless sensor networks. In Proc. of Intl. Conf. on Mobile Systems, Applications, and Services (MobiSys), June 2004. [4] Sun Limin. Wireless sensor networks [M]. Beijing: Tsinghua University Press .2005. (in Chinese) [5] Lin Ruizhong. Facing the target tracking wireless sensor network research [D]. Ph.D. thesis, Zhejiang University, 2005. (in Chinese) [6]
P.Dutta,M.Grimmer,A.Arora,S.Biby,andD.Culler. Design of a Wireless Sensor Network Platform for Detecting Rare,
Random, and Ephemeral Events. In IPSN’05, 2005. [7] V.A.Petrushin,GangWei,O.Shakil,D.Roqueiro,andV.Gershman,Multiple-Sensor Indoor Surveillance System Computer and Robot Vision, the 3rd Canadian Conference, June 2006. [8] M.Waelchli, P.Skoczylas, M.Meer, and T. Braun, Distributed Event Localization and Tracking with Wireless Sensors, 5th International Conference on Wired/ Wireless Internet Communications (WWIC’07), Coimbra, Portugal, May 23-25. [9] Atmel Corporation. ATmega640/1280/1281/2560/2561 Preliminary [DB / OL]. [2009-10]. Http://www.atmel.com [10] Atmel Corporation. AT86RF231 [DB/OL]. [2009-09]. http: // www. atmel.com
725
Energy Procedia
Energy Procedia (2011) 000–000 Energy00Procedia 12 (2011) 718 – 725 www.elsevier.com/locate/procedia
ICSGCE 2011: 27–30 September 2011, Chengdu, China
Design of Intelligent Inductive Security System Based on Wireless Sensor Network Xiaoyan Caia*, Aina Hub, Ruyou Liuc b
a School of Information Engineering, Huanghe Science and Technology College, Zhengzhou, 450006 China Communication Engineering Department, Huanghe Science and Technology College, Zhengzhou, 450006 China c China Northeast General Municipal Engineering Design and Research Institute, Changchun, 130021 China
Abstract The current security monitoring system for transformer substation has several disadvantages, such as wiring issues, high cost of installation and maintenance and poor mobility. In order to solve these problems, this article proposes a solution that is intelligent inductive security system based on wireless sensor networks. Among this system the microwave sensors act as inductive terminals and form a multi-hop, self-organizing network through wireless communication. It will integrate data collection, alarm and remote control with characteristics of real-time, safe and reliable quality.
© 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of University of Electronic © 2011and Published by Elsevier Selection and/or peer-review under responsibility of ICSGCE 2011 Science Technology of ChinaLtd. (UESTC). Keywords: Wireless sensor network, microwave sensors, security system.
1. Introduction The security of electric power substations is not only related to the social production and life, but also related to people's lives and property. The traditional monitoring systems usually adopt the wired method, which normally has wiring issues and requires rewiring if the device has to be changed. Furthermore, too many wires affect the building’s outward appearance, the costs of installation and maintenance are generally high, and the poor mobility of the system makes upgrade and maintenance inconvenient and time consuming. Therefore, a combination with wireless communications, mobile computing and selforganization network technology, micro-electromechanical systems (MEMS) gives birth to a new intelligent network for information collection, transmission and processing—wireless sensor network [1], which has advantages in monitoring the target in the sensor monitoring area [2-8].
* Corresponding author. Tel.: +86-13503458600. E-mail address: cxy@ hhstu.edu.cn.
1876-6102 © 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of University of Electronic Science and Technology of China (UESTC). doi:10.1016/j.egypro.2011.10.097
2
Xiaoyan Cai Cai et et al. al. // Energy Energy Procedia 00 12 (2011) 000–000 718 – 725 Xiaoyan
The intelligent inductive security system based on wireless sensor network described in this article is an alarm system combining data collection, alarm, and remote control in one set with excellent performance of real-time, safety and reliability. It not only saves the labor cost but also is featured with wiring free and thus results in easy installation. Therefore it is suitable for military restricted zones, substation and so on. 2. System Structure This system includes inductive terminal, data communication network, console, and monitoring center. The system structure is shown in Fig. 1.
Fig.1. System structure
The inductive terminal is mainly responsible for processing the information collected by microwave perception module. After calculation and process, the inductive terminal will inform the alarm module to implement alarm, and at the same time it will upload alarm condition information to the data communications network. The data communication network is a wireless self-organization network composed of multiple WSN nodes, in charge of data receipt and delivery, console commands for transmission, etc. Specifically, the WSN nodes mainly receive information from sensing terminal, for example, receiving the sensation if there were a person approaching the area, and receiving the commands from the console. The console receives the data transmitted from the front terminal and displays the onthe-scene situation on the console screen, and then sends the information to the monitoring center through the wired or wireless manner. 3. Hardware Design The hardware structure is shown in Fig. 2. It includes four modules, which are sensor, processor, communication and alarm and power supply. The system adopts microwave detectors as sensors to collect invasion information in the monitoring area. The high-performance ATmega1281 processor is responsible
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Xiaoyan Cai et al. / Energy Procedia (2011) 718 – 725 000–000 Xiaoyan Cai et al. / Energy12Procedia 00 (2011)
for storing and processing of the data collected and sent together with information from other nodes. The communication module employs AT86RF231 chips for wireless communication with other sensor nodes, exchanging control messages, sending and receiving collected data. The acousto-optic alarm is applied to inform the personnel on a timely basis to take actions as soon as possible in exceptional circumstances, in order to reduce risks and avoid disastrous consequences. The power supply module provides the required energy for the entire system by using the solar. Alarm Module
Sensor Module
Microprocessor Module
Communication Module
Power Supply Module
Fig.2. Hardware structure
3.1. Power supply Module The power supply is the heart of the system and its quality affects the reliability of the system directly, therefore the design of power system is a key part of the entire system. The system uses the solar power which avoids the complicated traditional wiring, marked by no pollution, easy maintenance, long life, abundant resource and high cost performance. The output terminal of solar panels is connected with the regulator LM1117-5 whose voltage remains 8.4V by adjusting RW so as to charge two 4.2V lithium batteries of series connection. A diode is added at the output terminal of LM1117 to prevent the current backflow. The circuit is shown in Fig. 3. Since microwave sensor’s operating voltage is 5V, so the voltage of both ends of the battery should keep 5V by regulators while the node working voltage is 3.3V requiring stabilizing the 5V voltage at 3.3V. LM1117
Solar panels 12 v
100UF
RW
500
+ 47UF
Battery
Fig.3. Power module
3.2. Sensor Module The sensor node is responsible for collecting the information from around monitoring area. The sensors adopted in this system are GH100 microwave mobile sensor consisting of dielectric oscillator (DRO) and a pair of micro strip antennas with microwave frequency of 10.525 GHz. The schematic and the product are shown in Fig.4.and Fig.5, respectively.
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Xiaoyan Cai et et al. al. / Energy Energy Procedia 00 12 (2011) 000–000 718 – 725 Xiaoyan
Fig.4. Schematic diagram
Fig.5. Products diagram
This mobile detector is low cost, non-contact, low powered, high sensitivity, compact and free from the influence of heat, noise, humidity, aerial currents, dust and other ambient factors. Thus it is suitable for harsh environment particularly. Since the output intensity of the sensor signal output is related to the reflection intensity of emission energy, usually on microvolt level, an amplifier with high gain and low frequency is needed to process the signal so that it can be handled by the processor. Amplifier circuit is shown in Fig. 6. Amplified signal is shown in Fig. 7. 3.3. Processor Module and Communication Module The processor is responsible for receiving the alarm signal and controlling, coordinating each functional module to work normally. It also responds to alarm information including information record, on-site alarm, remote communications alarm etc. ATmega1281 produced by Atmel Corporation is a kind of 8-bit microcontroller with low energy consumption and abundant resources greatly. This chip provides internal 256KB Flash memory, 8KB SRAM data memory (which can be expanded to 64KB by external connections) and 4KB EPROM memory. The chip also has 8/16 channels of 10-bit ADC, two 8-bit and four 16-bit hardware timing/counter, four 8-bit PWM channels, programmable watchdog timer and onchip oscillator, on-chip analog comparator, 2/4 programmable serial USART, 51/86 programmable I/O port lines, SPI, I2C bus interface. Both of JTAG programming and ISP programming are applicable for this chip. Besides the normal work pattern, ATmega1281 also has 6 kinds of sleep patterns: idle mode, ADC noise-suppressing mode, electricity-saving mode, power-down mode, standby mode and extended standby mode. Therefore ATmegal281 [9] is very suitable for low energy consumption situation.
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Xiaoyan al. / Energy Procedia 12 (2011) 718 – 725 Xiaoyan Cai et Cai al. /etEnergy Procedia 00 (2011) 000–000 +5
R2 100k
+5 C1 105
C3 100u
GND
GND
_
C2
IF R1 12k
R4 330k
_
4.7u
C6
+
GH100
R3 100k
GND
LM324
C4 2.2nF GND
C5 4.7u
R6
R5
10K
1M
4.7u
R7
+
LM324
OUT
8.2k C7 2.2nF R8 100K
Fig.6.Amplifier circuit
1.5m waveform
3m waveform
Fig.7. IF waveform amplified
The wireless communication module adopts AT86RF231 as wireless transceiver chip with low power consumption, low voltage and SPI interface. This chip is also in compliance with 2.4GHZ IEEE802.15.4.standard [10]. AT86RF231 is connected with the ATmega1281 processor through the SPI interface and executes data reading and writing through the serial output (MOSI) and serial input (MISO). The reading and writing function is controlled by the serial clock (SCK). The connection between processors and peripheral devices are shown in Fig. 8.
Fig.8. Processors and peripheral devices connection graph
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Xiaoyan Cai Cai et et al. al. // Energy Energy Procedia 00 12 (2011) 000–000 718 – 725 Xiaoyan
3.4. Alarm Module The alarm modules include on-site alarm and remote alarm, both using the acousto-optic alarm. The on-site alarm uses a buzzer and LED lights to achieve the function. The buzzer and LED are connected with the processor’s I/O port while buzzer needs a transistor as a driver. When someone invades, the buzzer and LED lights will be controlled by raising the I/O port level. At the same time, remote alarm will be realized when alarm information is transmitted to the backstage and displayed on the screen. 4. Software Design After establishing the network, terminals (microwave intrusion detector nodes) request to join it and then collect data periodically. As shown in Fig. 7, the amplitude and frequency of the amplified intermediate frequency signal are related to the object’s moving speed and distance. Furthermore, the change of amplitude is more obvious than that of frequency when the object is moving and it’s easier to detect amplitude than frequency. For the reasons given above, this system only detects its amplitude and runs analog-to-digital conversion for the amplitude of IF signal by using the A/D channel of microcontroller. Alarm event will be recognized when the magnitude detected is higher than the threshold. The processor will send out alarm and transfer the intrusion information to the monitoring center. Software design flow chart is shown in Fig. 9. Initialization network Initialization success？ Y build a network
Node to join
？
N
Y collect data Threshold comparison
Have invaders or not？
N
Y alarm Send to monitoring center to display
Fig.9. Software flow charts
5. Experimental Analysis and Test Results Fig.10. shows the experimental setup conducted. Sensing terminal is set on column at the height of 2.6 m from the ground level, as shown in Fig. 10 (a). Let the angel of the triangular bracket be α. The sensing distance is 3m with α = 30º; when α = 45º, the sensing distance is 6.6 m. Experimental test image is shown in Fig.10 (b) and (c). Experimental results as shown in Fig. 11.
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Xiaoyan al. / Energy Procedia 12 (2011) 718 – 725 Xiaoyan Cai et Cai al. /etEnergy Procedia 00 (2011) 000–000
Columns Triangle Bracket
a
Inductive Terminal
2. 6 m
Invaders Ground Induction Distance
(a) Schematic diagram of experimental installation
(b) Laboratory experiments picture
(c) Outdoor experiments picture
Fig.10. experimental setup conducted
Fig.11. experimental result
6. Conclusion This article describes each module incorporated in the system in details with purpose to realize the real-time monitoring for remote target. The system is highly stable, compact, safe, reliable, and easy to install, and the sensors selected meet the technical requirements of power system. The entire system is assembled in hemispherical plastic shell as waterproof thus internal components can be protected to ensure high quality and excellent performance, which enable it operate normally even in outdoor harsh conditions.
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Xiaoyan Cai Cai et et al. al. // Energy Energy Procedia 00 12 (2011) 000–000 718 – 725 Xiaoyan
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References [1] Ren Fengyuan, Huang Haining, Lin Chuang. Wireless sensor networks [J]. Journal of Software .2003, 14 (7):1282 -1291. (in Chinese) [2] AKYILDIZ I, SU W, SA N K ARA S U B RA MA N IA M Y, et al. A survey on sensor networks, IEEE Communications Magazine,2002 (8) :102-114 [3] T.He,S.Krishnamurthy,J.A.Stankovic,T.F.Abdelzaher,L.Luo,R.Stoleru,T.Yan,L.Gu,J.Hui,and B. Krogh. An energy-ef cient surveillance system using wireless sensor networks. In Proc. of Intl. Conf. on Mobile Systems, Applications, and Services (MobiSys), June 2004. [4] Sun Limin. Wireless sensor networks [M]. Beijing: Tsinghua University Press .2005. (in Chinese) [5] Lin Ruizhong. Facing the target tracking wireless sensor network research [D]. Ph.D. thesis, Zhejiang University, 2005. (in Chinese) [6]
P.Dutta,M.Grimmer,A.Arora,S.Biby,andD.Culler. Design of a Wireless Sensor Network Platform for Detecting Rare,
Random, and Ephemeral Events. In IPSN’05, 2005. [7] V.A.Petrushin,GangWei,O.Shakil,D.Roqueiro,andV.Gershman,Multiple-Sensor Indoor Surveillance System Computer and Robot Vision, the 3rd Canadian Conference, June 2006. [8] M.Waelchli, P.Skoczylas, M.Meer, and T. Braun, Distributed Event Localization and Tracking with Wireless Sensors, 5th International Conference on Wired/ Wireless Internet Communications (WWIC’07), Coimbra, Portugal, May 23-25. [9] Atmel Corporation. ATmega640/1280/1281/2560/2561 Preliminary [DB / OL]. [2009-10]. Http://www.atmel.com [10] Atmel Corporation. AT86RF231 [DB/OL]. [2009-09]. http: // www. atmel.com
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