One of the most popular is Not eXactly C (NXC), a C-like language that uses the standard firmware on the NXT. John Hansen, the developer of NXC, has also developed Next Byte Codes (NBC), which uses an assembly language syntax. Hansen's recently published book, LEGO MINDSTORMS NXT Power Programming: Robotics in C (Variant Press, 2007), teaches both languages. I've written a review of Hansen's book, which you can find at the book's page on Amazon.com. You can download NXC and NBC and other resources for free from Hansen's Web site: http://bricxcc.sourceforge.net/nbc.

Are you interested in a "real" C language for the NXT? If so, then you'll like RobotC, a C-based language available from http://www.robotc.net. RobotC is not free, however, and you must purchase it from the RobotC Web site where you can download a copy for immediate use or buy a CD-ROM version.

How about Java? The leJOS community at http://lejos.sourceforge.net developed leJOS NXJ: Java for the NXT. You can download the software for free from the leJOS Web site, and a great resource for learning more about leJOS NXJ is Brian Bagnall's book, Maximum LEGO NXT: Building Robots with Java Brains (Variant Press, 2007).

These are only some of the languages available for the NXT, and you can discover many more programming resources on the "Internet Resources" section of my Web site at http://www.nxtguide.davidjperdue.com/internetresources.html.

Computer-Aided Design
As you may have noticed, I rendered most of the images in this article with CAD (computer-aided design) software. There's another large segment of the LEGO community that develops CAD software specifically for LEGO, and most of these resources are available online for free.

First, the "official" CAD software is LDD (LEGO Digital Designer), which recently added support for the NXT set, as shown in Figure G.

FIGURE G

LDD (LEGO Digital Designer) is official CAD software. Click picture for a larger image.

Using LDD, you can assemble virtual robots and then automatically generate building instructions. You can download LDD for free from http://ldd.lego.com. Unfortunately, LDD still needs some development to make the NXT features more user-friendly, but the software is still worth checking out.

Second, the unofficial LDraw system of tools is currently the most powerful LEGO CAD software available. The central Web site for LDraw is http://www.ldraw.org where you can download the software for free. One of the most popular LDraw programs is MLCad, shown in Figure H, but there are a host of other programs available that serve different purposes (MLCad, like LDD, is for creating virtual LEGO models and building instructions).

FIGURE H

MLCad is unofficial but powerful LEGO CAD software. Click picture for a larger image.

Numerous authors of LEGO books, including me, use LDraw to create print-quality building instructions. If you're interested in learning more about LDraw and the various software tools available, visiting the LDraw Web site will get you started.

Online communities
Since the NXT set's release, numerous Web sites have sprung up that focus specifically on the NXT set. The ultimate online community for NXT fans is the official MINDSTORMS Web site at http://mindstorms.lego.com.