This project requires Arduino UNO, Arudino Ethernet Shield, and a 1602 LCD display. My plan is to build a simple OpenWeatherMap client using Arduino UNO + Ethernet Shield and output weather information to LCD. OpenWeatherMap Signup We have to get an APPID from OpenWeatherMap to use their Weather API. The free account is sufficient for this project. Arduino Ethernet Library Arduino website has a complete reference to the Ethernet library. This library allows an Arduino board to connect to the Internet.