This document provides an overview of connecting Arduino devices to Android via USB, NFC, and WiFi. It begins with an introduction to Arduino and its open source hardware platform. It then covers Google's Open Accessory Protocol for USB communication between Android and third party devices. Next, it discusses using NFC for two-way communication between devices via tag reading/writing, Android Beam, and card emulation. Finally, it presents using the Arduino Yun and its OpenWrt component to enable WiFi connectivity. Demos are provided for various connectivity methods.