Design Of Infrared Alarm System Of High Sensitivity Based On Telephone Net

With great improvement of the standard of people's living, as well as the rapid development and abroad application of microelectronics, automation and computer ability, the security of storage,emporium,home etc. is been more and more important. The security keeping away system is emerged as the times required.In this text, the development survey of security keeping away technology in the world is debated. According to the developmental direction of the technology overseas and the situations of our countries, we have researched and designed a kind of intelligent alarm system. The system can have muli-detected points aims at large area, performing automatic detection and automatic dial. This thesis uses the pyroelectric infrared sensor that designed personally, it based on the combined of characteristics of sensitive element and optics system. It is more sensitive and has a longer distance than classical pyroelectric infrared sensor, and it can identify resting flesh. The mufti-sensors make the least fail to alarm and false alarm and enhance the reliability of the system. When detectors have detected any abnormality signals, an interrupt request will be sent to the MCU. Next the MCU control the interface circuit of telephone to accomplish simulated off-hook, then auto-dial by dial-up circuit of DTMF, and play the phonetic information which has been recorded beforehand by phonetic circuit, to tell the user and the surveillant center of the section which circs has occurred. In addition, the code validation has been intercalated in the system. In order to buildup the systemic security and stability, the system has standby power supply and can inspect whether the wire and the power break or not.The system is based on a great deal of correlative experiments. It has been validated in hardware and software' s emulation, so it has some definite practicability. As far as research and exploitation later, this has some definite referenced meaning.