translation.en: When I laid out my plan, I realized that I faced three main challenges: first, creating a sensor; second, designing a circuit; and third, coding a smartphone app.
translation.zh: 当我开始细化我的计划时，我意识到我面临三大挑战 第一，创造一个传感器 第二，设计电路 第三，写出一个手机App