用4×4组成0－9数字键及确认键。

用8位数码管组成显示电路提示信息，当输入密码时，只显示“8.”，当密码位数输入完毕按下确认键时，对输入的密码与设定的密码进行比较，若密码正确，则门开，此处用LED发光二极管亮一秒钟做为提示，同时发出“叮咚”声；若密码不正确，禁止按键输入3秒，同时发出“嘀、嘀”报警声；若在3秒之内仍有按键按下，则禁止按键输入3秒被重新禁

-4 × 4 form with the number keys 0-9 and confirmation button. With 8-bit digital tube display circuit composed of tips, when to enter a password, it only displays " 8." , When finished press Enter to confirm password-digit key, enter the password for the password to compare with the settings, if the password is correct, then the door opened here with a second light-emitting diode LED as a prompt at the same time issued a " ding-dong"　sound　if the password is not correct to prohibit the importation of key 3 seconds at the same time issued a " tick, tick"　sound alarm　if the there within 3 seconds of the button is pressed, then the ban was re-key input 3 seconds prohibited.