| Along with the value of nation to education, increase teaching equipments and the student of the school, population in the school is complication, It is inseparable with contacting of social, the existent recessiveness danger inside the campus also aroused extensive concern.of social. In order to raise campus safe coefficient, prevent from burglar illegal entry, this topic particularly makes use of infrared ray to spread a feeling technique and surrounds a passive alarm design that works in the campus safety. The infrared ray is unseen, in special weather, for example, in cloud, mist and the material to be full of suspending the ion it not easy to disperse and have the stronger penetrating power and anti-interference, it is easy to a creation and a few influences to the environment, can’t interference nearby the wireless equipments. The passive infrared detector can’t transmit infrared ray,Make use of inrared sensor, it attain for probing into supervision from the little infrared ray that the object that will have a life characteristic sends out converts and carry on a homologous processing, it is mainly heat-released infrared sensor, fresnel lens, signal processing circuit and alarm circuit to constitute, make use of stabilized voltage supply, infrared ray detector, mu-circuit, voltage comparison, monostable trigger and alarm circuit. Each circuit according to in brief practical principle at design aspect in the circuit, All circuits is analogous circuit.The circuit is simple and easy to understand, and is very convenient and simple in producing, the cost is low, power dissipation is small.All part of circuit be simulated and debuged, If there is illegal member unlawful entry, the electronics detector installed indoor send alarm sign to duty worker. Report to the sign host then automatically show to alarm location, the worker will arrive accident place with the quickest speed to control according to the sign that the sensor sends out, it can better assurance campus safety. |
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