The LEGO? MINDSTORMS? Robotics Invention System (RIS) is a wildly popular kit for building mobile robots. This book contains all the information you need to get the most out of your kit. Based on hands-on robot projects, the book includes descriptions of advanced mechanical techniques, programming with third-party software, building your own sensors, working with more than one kit, and sources of extra parts. This book goes far beyond what you'll find in the official documentation to enable you to build and program whatever you can imagine. The center of the RIS kit is a small programmable robot brain called the RCX. This book explains the software architecture of the RCX as well as the various options that are available for programming it. The book includes: Hands-on robot projects, with complete building instructions and programs. Different aspects of these projects are used to explore fundmental issues of mobile robot design. A chapter on NQC, a popular programming environment for RIS. You'll learn how NQC fits into the RIS software architecture, as well as how to write programs using NQC's C-like syntax. Includes copious examples. A chapter on legOS, an alternate operating system for the RCX. legOS provides very low-level access to the resources of the RCX, enabling complex robot programming. This chapter describes legOS's structure and includes useful sample programs. A chapter on pbForth, another powerful option for RCX robot programming. The chapter includes sample programs in Forth. A chapter about building your own sensors. Making your own sensors is economical and educational. This chapter describes how to build several different sensors that will work with the RIS kit. The book includes numerous illustrations and code examples. Many URLs are listed to serve as an introduction to the thriving online MINDSTORMS? community.