用单片机控制DAC0832芯片输出电流，让发光二级管D12由灭均匀变到最亮，再由最亮均匀熄灭。在最亮和最暗时使用蜂鸣器分别警报一声，完成整个周期时间控制在5S左右，循环变化。-DAC0832 chip microcontroller to control the output current, light emitting diode D12 from off the uniform change to the brightest, and then goes out from the bright uniformity. The brightest and darkest buzzer, respectively, the alarm sound, complete the entire cycle time is controlled at about 5S, cyclic changes.