设计以电磁继电器模拟密码锁，由单片机8051来控制锁的打开与闭合，由HD7279来管理器键盘及显示，密码从键盘输入，用8051来控制7279显示当前锁的状态信息及报警。本次设计用单片机开发系统来模拟密码锁的多种功能，密码由4-6位数字组成，当输入密码相符时开锁，输入三次不符报警，同时密码输入正确时可以修改密码，此时指示灯亮。开锁单片机开发出开关量，通过光电耦合器控制，打开密码锁。报警则由单片机发出报警信号，控制音频放大电路发出报警声音。-Designed to simulate electromagnetic relay locks, by the microcontroller 8051 to control the lock open and closed, by the HD7279 to manage the keyboard and display device, the password from the keyboard input to control the 7279 with 8051 shows the current lock status information and alarms. The microcontroller development system designed for use to simulate the lock of a variety of functions, the password from 4-6 digits, when the lock when the password match, enter the three inconsistent with the police, at the same time when you enter the correct password can modify the password, this time indicator light . SCM developed unlocking switch volume control through the optocoupler, open the lock. Alarm alarm signal sent by the MCU to control the audio amplifier circuit alarm sounds.