将激光阻断和恢复正常时产生的信号先后输入单片机，单片机通过内部定时器来计算被阻断的时间，并在LCD1602 上显示。-Will return to normal when the laser block and has the input signal generated by the microcontroller, the microcontroller through an internal timer to calculate time to be blocked, and the LCD1602 display.