我们知道，一个动圈式的电磁扬声器，既可以播放声音，也可以作为麦克风来检测声音。同样，一个直流电机可以将电能转换成动能，也可以将动能转换成电能。那么一个LED是否也可以将光转化成电信号，进而可以当做光电传感器呢？ 为什么提出这个问题？

Recently, we published an entry-level Arduino project with a single seven-segment LED display. Although it’s an amazing DIY project, we noted that most of the readers are looking for more advanced ...