用4*4键盘组成0-9数字键及确认键。

用8位数码管显示电路提示信息，当输入密码

时，只显示“8.”，当密码位数输入完毕按确

认键时，对应的密码与设定的密码进行比较，

若密码正确，则门开，此处继电器发出“叮咚”声；若

密码不正确，禁止按键输入3秒，同时发出“滴答”

报警声；若在3秒内仍有按键按下，则禁止按键

输入3秒被重新禁止-4* 4 keyboard with the composition of the number keys 0-9 and confirm key. With 8-bit digital tube display circuit message, when the input password, only shows " 8."　When the password confirmed by the median enter key when finished, the corresponding password and set password for comparison, if the password is correct, then the door open relay here a " ding dong"　sound　if the password is not correct to prohibit the importation of key three seconds, at the same time issued a " ticking"　sound alarm　if there are still three seconds press the button, the button to prohibit the importation of three seconds was to prohibit the