Raspberry Pi是什么？
引用维基百科的一句话：
The Raspberry Pi is a credit card sized single-board computer developed in the UK by the Raspberry Pi Foundation with the intention of stimulating the teaching of basic computer science in schools.
简单地说，它就是一个基于ARM CPU的、信用卡那么大的迷你计算机。
In short, Pi is an ARM-based mini computer which has a credit card size.
前段时间公司举行hackathon比赛，我做了一套如题所示的系统，整个过程太累了，连续30个小时没睡，简直要了我半条命，现在我打算把它的主要实现记下来。