A New Household Security Robot System Based on Wireless Sensor Network Reporter :Wei-Qin Du

Outline INTRODUCTION STRUCTURE OF THE MONITORING SYSTEM HARDWARE OF THE MONITORING SYSTEM SOFTWARE OF THE MONITORING SYSTEM EXPERIMENTAL RESULTS CONCLUSION

Introduction An new environment monitoring system of household security robot is proposed based on wireless sensor networks, which is composed of the robot node and the sensor nodes for monitoring temperature and humidity, gas leaking,fire and housebreaking in family. Zigbee is a communication standard intended to develop a wireless communication standard at low-cost,very-low power consumption. ZigBee wireless network, with the characteristic of the self- organizing and robust, solves many problems such as single function of previous monitoring system, complex installation, poor mobility, and the no-robust system

STRUCTURE OF THE MONITORING SYSTEM

Sensor nodes: In this figure, the wireless sensor nodes are installed in different indoor rooms for the acquisition of indoor temperature, humidity, infrared, smoke, and gas information. Smoke node is mainly used to monitor indoor smoke density, realize the family fire alarm by the information of temperature and humidity.

STRUCTURE OF THE MONITORING SYSTEM Robot node: The robot node is the central link of monitoring system. The robot node sends the collection and the query command to the sensor nodes, analyses data from the sensors, judges alarm threshold, and sends messages to remote users.

HARDWARE OF THE MONITORING SYSTEM Hardware implementation of the monitoring system can be divided into two parts: One is the hardware design of sensor nodes which mainly complete environmental information collection, storage, simple processing and wireless communication. The other is the hardware design of the robot node which finishes computing and processing information from the sensors, sends alarm messages and connects with external units.

HARDWARE OF THE MONITORING SYSTEM A.Design of Sensor Network Nodes: The sensors collect the signal from the environment and the original signal will be processed by the signal processing module. Then the processed signal will be uploaded to the ZigBee module. The ZigBee module sends the information to the robot node. The node should have three kinds of capability: sensing capability, computing capability and wireless communication capability.

HARDWARE OF THE MONITORING SYSTEM Choose CC2430 as the ZigBee protocol chips. The chip CC2430 as the core of the hardware, CC2430 integrated RF transceiver,CPU, and 128K flash memory, and very few external components required in the CC2430 typical application. It also includes A/D converter, some Timers, Watchdog Timer, 32K crystal Sleep mode Timer, Power On Reset, Brown Out Detection.

HARDWARE OF THE MONITORING SYSTEM B. Design of Robot Node: The robot node is composed of control unit, ARM920T,Linux2.6 operating system software platform, various peripheral sensors (including distance, temperature, images,sound, and etc.), executor, wireless communication module,memory and man- machine interfaces. Communication between the robot node and all wireless sensor nodes is achieved by the use of wireless communication module

SOFTWARE OF THE MONITORING SYSTEM A.Routing Protocol: In respect to route, we have adopted a hybrid wireless routing protocol HWMP (Hybrid wireless MESH protocol) program, which combines flexibly dynamic AODV routing protocol (Ad hoc On- Demand Distance Vector Routing) with quasi-static tree routing protocol (Tree Based Routing), to make the network well adapt to variable communication status in the wireless environment.

SOFTWARE OF THE MONITORING SYSTEM B. Software Establishment of the Monitoring System: (1) System initialization: The system is to complete the initialization of all nodes and address settings of robot node and sensor nodes and to set up the routing table and agent table.

SOFTWARE OF THE MONITORING SYSTEM (2) Routing table and agent table : The agent table records terminal MAC addresses of the nodes followed. The routing table of a node records MAC addresses of its father node and parent nodes. If the address in the agent table already exists, it updates its living time. Each address in routing table must identify its node type, that is, a father node or a parent node.

SOFTWARE OF THE MONITORING SYSTEM (3) Mechanism of route forwarding : By the combination of routing table and the agent table,data can be transmitted and addressed.

SOFTWARE OF THE MONITORING SYSTEM (4) Tree routing protocol design:

EXPERIMENTAL RESULTS 1.The packet delivery ratio

EXPERIMENTAL RESULTS 2. the average end-to-end delay

CONCLUSION Based on ZigBee sensor wireless network, an environmental monitoring system of the family security robot is achieved. how to design lowpower,highly reliable, intelligent ZigBee sensor node and how to achieve network security.

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