Arduino Cookbook, 3rd Edition

WiFi and Ethernet

15.0 Introduction

Want to share your sensor data? Let other people take control of your Arduino’s actions? Your Arduino can communicate with a broader world over Ethernet and WiFi networks. This chapter describes the many ways you can use Arduino with the internet. It has examples that demonstrate how to build and use web clients and servers, and it shows how to use the most common internet communication protocols with Arduino.

The internet allows a client (e.g., a web browser) to request information from a server (a web server or other internet service provider). This chapter contains recipes showing how to make an internet client that retrieves information from a web service. Other recipes in this chapter show how Arduino can be an internet server that provides information to clients using internet protocols and can even act as a web server that creates pages for viewing in web browsers.

The Arduino Ethernet and WiFi libraries support a range of methods (protocols) that enable your sketches to be an internet client or a server. The libraries use a suite of standard internet protocols, and most of the low-level plumbing is hidden. Getting your clients or servers up and running and doing useful tasks will require understanding of the basics of network addressing and protocols, and you may want to consult an online reference or one of these introductory books:

• Head First Networking by Al Anderson and Ryan Benedetti (O’Reilly)

• Network Know-How: An Essential ...