# Arduino Tutorial 5: Understanding and Working With Binary Numbers

In this series of Tutorials, I really want you to understand the magic that is happening under the hood of your digital devices. Whether you are talking about in Iphone, a laptop or a digital camera, they all work on the same, very simple principle. That principle is as follows. Any thing around you in the physical world can be represented as a number. You can create a different number for each letter, so letters can be represented by numbers. By stringing those numbers together we can create words, paragraphs and even entire books. Similarly, music and colors can be represented by numbers. At their core, digital devices only understand numbers, so everything around you must be converted to a number for the computer to understand it. The thing is, though, that computers only understand special numbers, known as binary numbers. Binary numbers contain only two characters . . . “0” and “1”. Hence all numbers must be converted to sequences of zeros and ones strung together. With this, any number you can come up with can be represented equally well by a long sequence of zeros and ones. This video shows how Binary numbers work.

Digital devices are simply made up of very large numbers of tiny switches. A modern digital computer might have over 10 billion switches cleverly connected together. Each switch can be thought of as a zero or a one. Hence, even though a switch is a very simple device, when you have lots of them, very complicated things can be done.