带ad转换的单片机实现，第一次采集电压，等1分钟左右 再次采集，与第一次的采集的电压进行比较，如果相差太大 则蜂鸣器响-Microcontroller with ad conversion implementation, the first collection voltage, and other gathering again about 1 minute, and the first acquisition of the voltage, and if the difference is