Study Of Home Security System Based On WSN

The home safety is facing a new challenge, along with the continuous improvement of people’s living and wealth accumulation. Wireless sensor network (WSN) perceives changes of monitoring objects and transfers to the user, by means of many inexpensive sensor nodes in the monitoring area, could provide data support for user decision-making. To realize the automatic monitoring and processing of home environment, an intelligent home security system is designed based on WSN and computer technology. The following four aspects are mainly researched in this paper:(1) Design of WSN system based on 6LoWPAN. First, the hardware platform of sensor network is constituted by microcontroller of Tiva C series from TI, and a variety of input and output devices. And then, based on Contiki operating system, networking, management and task scheduling of 6LoWPAN sensor network are designed. Finally, combined with the sensors of temperature, humidity, gas and pyroelectric infrared, the data collection, processing and transmission of home environment are achieved(2) Implementation of the application layer protocol to the 6LoWPAN network based on MQTT. Low power consumption and low data rate are characteristics of WSN, the data transmission of MQTT utilized by publish/subscribe model, could ease the coupling between sensor network and user, reducing network traffic and power consumption of WSN. By setting event triggers of Contiki, the sensor data is sent to server forwardly via MQTT by sensor nodes, and the network traffic caused by the request message is avoid, which could improve the stability of the sensor network and reduce the power consumption of the network.(3) Design of mobile video surveillance system based on robot and IP camera. In order to improve the flexibility of video surveillance, the mobile video surveillance is realized by using IP camera and robot technology. The hardware structure of system is composed based on IP camera and six legged robot, and the control of video surveillance is realized by STM32F401, combined with ESP8266, the core of WiFi module. Applying the mobile video surveillance, the entire environment of home could be surveillance just utilizing a single camera, the privacy of user protected and cost saved.(4) Design of user terminal based on Linux, Android and.NET framework. To realize the flexible access and control to the security system, the applications based on Linux and Android are designed. The Raspberry Pi is selected as the control terminal of WSN, and MQTT proxy server based on mosquitto is designed in it, used to receive and process the data from WSN, reduced the cost of system. At the same time, the data is sent to user by control terminal, utilizing cloud server of Espressif. The subscribe client of MQTT, running in Windows, used for real-time monitoring and testing to the sensor network, is designed utilizing C# and WPF, based on.NET framework. The user application designed by Android, could realize remote video surveillance, environment monitoring and other functions to the security system, under the support of cloud server.The components of system are tested, on the basis of the hardware and software design. Functions of data acquisition, transmission, processing and other parts of the sensor network are verified, and the overall operation of the security system is simulated. Test results show the system works orderly and achieves anticipative aim, and could provide an effective support for personal and property security. The design of wireless sensor network based on 6LoWPAN ensures the feasibility of system, reducing the complexity and improves the stability.