lcd1602用红外实现，没有带遥控的情况下可以用4X4的矩阵键盘实现输入密码，如果输入的密码错误则发出警报，如果密码正确的话则蜂鸣器会发出滴答的声音-Lcd1602 by ir, did not take control of the situation can be realized by 4X4 keyboard input matrix input password, if the wrong password is warning, if the correct password is