Security Alarm System

The security system can promote the city's image, strengthen the management of organization, and guarantee to provide good service, is an important part in an advanced city. At present, security alarm system, such as the use of photoelectric alarms technology, the smart alarm technology, network technology, did not solve the problem which must be a certain power, auxiliary power (AC power) supply, which increases system cost, installation space.once the power was cut off, the whole security system will be completely lost function. Since all designs are not a low-power design, it which makes use of auxiliary backup power supply has become very difficult. Thus that becomes a key constraint of security system performance.Alarm information through the telephone lines achieves the basic means of information links. The use of electrical energy from the telephone line obtains the power and auxiliary power supply coupled with the method is to improve the security system, which is one effective way of power supply reliability. However, the telephone lines can only support a load of about 500 uA, which uses telephone lines to become a fundamental obstacle to power. This paper attempts by a basic security alarm system to all aspects of the low-power design, in order to minimize the security alarm system, the average energy consumption, so as to realize the use of telephone line-powered solutions.This paper analysis and compares current the security system in common, and set up the structure of security system that based on the DTMF and completed the system hard, software development and design the work. The system takes the Low -Power chip microcomputer MSP430F2001 as a core, and it achieves the function such as the alarm deletion and identification through the Low -Power electric circuit such as the Low -Power infrared signal processing chip, sensor, the HT9200A,Because the system ascertain the telephone number,the paper studied the DTMF basic principle and hardware decoding, DTMF decoder algorithm and realizes the technique thoroughly, at last,the paper analysis the DTMF decoder algorithm based on comparator saved hardware source and time and the power consumption. thus,the entire circuit of the standby power consumption of using telephone lines has an acceptable power supply area.As same time, the entire security system of the software and hardware design has been completed.As the basic functional verification, there is no auxiliary power design, the wireless alarm, the user settings of personalized phone numbers, and others interface functions. Whether decoding algorithm off-line simulation, or the operation of the simulation system have confirmed the software decoding and the actual feasibility of the system with a certain degree of promotion prospects.