Multifunctional Home Alarm System Based On Wireless Sensor Design

With the rapid development of social economy and the continuous improvement of living standards,people's demand for home security is also increasing.,The traditional home security system is costly,bulky,cumbersome to install and single function.And there is the risk of being hacked into the video surveillance system,resulting in the disclosure of personal privacy.To solve the shortcomings of the traditional home security system,this thesis designs a multifunctional home alarm system based on the wireless sensor technology.The system includes one host and three slaves,the first slave was loaded with MQ-2 smoke sensor and DS18B20 temperature sensor for gas monitoring and temperature monitoring,the second slave is loaded with MQ-2 smoke sensor for gas monitoring,and the third slave is loaded infrared pyroelectric sensor for anti-theft monitoring.The host and slave communicate through nRF24L01 wireless sensor chip,and adopt time division multiplexing communication mode.The host analyzes the data reported by each slave to determine whether to give an alarm and display the data,and waits for instructions of the host to processes while the slave reports the data.In case of any abnormal situation,the host sends an alarm command to the slave and sends an alarm message to the user's mobile phone through the GSM module.In order to facilitate human-computer interaction,the system also designs an upper computer to communicate with the host.The host can not only real-time display the temperature,gas value,human feeling state and the networking state of each slave,but also conveniently send instructions to the host to set the alarm threshold value of the temperature and the gas,the state of the human feeling and the alarm number.Therefore,it singificantly improves the convenience of the system.The security of the system is also improved by setting the alarm number and the state of human feeling by the upper computer.This paper completed the hardware design,software design,communication protocol design and upper computer design of the whole alarm system.Through the joint debugging of software and hardware,the system can work normally,each node has stable communication within the range of 30 m,the temperature value,gas value,as well as the human feeling status are displayed normally in real time,the alarm is normal,the communication of the upper computer is normal,and the mobile phone can receive the alarm information in time.Finally,a low cost,small size,convenient installation,good safety and multifunctional integrated home alarm system based on wireless sensor is achieved.