This book is all about wearables, which are defined as computational devices that are worn on the body. A computational device is something that can make calculations of any sort. Some consider mechanical clocks to be the first computers, since they make calculations on time. According to this definition, wearables have been around for centuries, if you think about it. Pocket watches were invented in the 16th century, and a watch is basically as small device that calculates time. Glasses are also an example of wearable technology that can be worn on your head, which have also been around for a long time. Even if glasses do not fit our more specified definition of wearables, they serve as a good example of how humans have modified materials and adapted their bodies to gain new functionality. If we are cold, we dress in clothing to keep us warm, if we break a leg, we use crutches to get around, or even if an organ fails, we can implant a device that replicates their functionality. Humans have a long tradition of developing technology to extend the functionality of the human body.

With the development of technology for the army, health care, and professional sport, wearables have a long tradition. But in recent years, more and more devices have been developed for the consumer market. Today, we have smart watches, smart glasses, and different types of smart clothing.

In this book, we will carry on this ancient tradition and develop some wearable projects for you to learn about electronics and programming. Some of these projects are just for fun and some have a specific application. The knowledge presented in all the chapters of this book progresses from the chapter before it. We will start off slow, and the chapters will gradually become more complex both in terms of hardware and software. If you are already familiar with Arduino, you can pick any project and get started. If you find it too hard, you can always go back and take a look at the chapter that precedes it. If you're completely new to Arduino, continue reading this chapter as we will go through the installation process of the Arduino IDE and how to get started with programming.