防误班报警系统分析

Analysis on the prevention of overdue alarm system

防误班报警方法很多,小到简单的闹钟,大到各种大型的集成电路。本设计本着准确和低成本的考虑,采用价格低廉的微电脑时控开关进行时间控制,利用继电器实现对报警电路工作状态的控制,设计过程简单易行,比以前用的电容充放电以改变电压值从而改变报警部分开关的方法有效准确,且没有加大成本。此系统共分为3部分,第一部分为电源部分,采用变压器将220 V市电降为15 V交流电,再对其进行整流,成为可直接使用的低压直流电;第二部为时控部分,微电脑开关可以利用蓄电池供电,两个微电脑门开关实现了对报警电路是否工作和报警时间的控制;第三部分为报警部分,其利用前路供电对蜂鸣器供电,实现报警功能。

There are many methods of preventing overdue alarm, small to simple alarm clock, large to a variety of large integrated circuits. This design is based on accurate and low cost consideration, adopts microcomputer time controlled switch with low cost for time control, the relay is used to control alarm circuit status, the design process is simple. The method is more effective and accurate than the way using the capacitor charging and discharging to change voltage so as to change alarm part switch, and there is no extra cost.This system is divided into 3 parts, the first part is the power, taking advantage of the transformer to reduce the 220 V city power to 15 V AC, and then rectify it to make it low-voltage direct current that can be used directly, the second part is time control, microcomputer switch can use battery to supply power, two microcomputer door switches achieved the control for alarm circuit work and alarm time, the third part is alarm, which uses anterior power supply to supply power for the buzzer, then realize the alarm function.