You'll need to add some HW, specifically, a wheeled or tracked platform, to make your project mobile. There are a lot of choices. Some are completely assembled, others have some assembly required, and you may even choose to buy the components and construct your own custom mobile platform. Throughout this book, we're going to assume that you don't want to do any soldering or mechanical machining yourself, so let's look at a couple of the more popular variants that are available completely assembled or can be assembled using simple tools (screwdriver and/or pliers).
The easiest mobile platform is one that has two DC motors, each that controls a single wheel, with a small ball in the front or back. Here is a picture of one such ...
