Robotics Invention System 2.0

Lego kicked off their MINDSTORMS product line in 1998 with the Robotics Invention System (RIS) 1.0. The following year, the set was updated and released as RIS 1.5. This year Lego has once again updated the set and Robotics Invention System 2.0 can now be found on store shelves (set #3804). The changes between RIS 1.5 and RIS 2.0 are described below.


The RCX is a computerized Lego brick that is the brains behind any RIS creation. The RCX in RIS 2.0 is nearly identical to those found in earlier sets. The only difference is that it now has the text "RCX 2.0" stamped on its side.


The RCX's firmware (its operating system) has been considerably enhanced for RIS 2.0. These enhancements allow more powerful programs to be written for the RCX, while at the same time providing complete backwards compatibility for previous programs.

The 2.0 firmware can be installed on older RCX's, enabling previous MINDSTORMS owners to also utilize the new features.

One minor twist is that the firmware no longer appears as a separate file on the CD-ROM supplied with the set, so it is necessary to install the Lego software on your computer in order to get the firmware. For users of Mac OS and Linux, this makes the firmware a bit more difficult to obtain.


RIS 2.0 consists of the same lego pieces as RIS 1.5 plus one new item: a fiber optic strand that can be used to route the light used to communicate between the USB IR Tower and a device that uses Visible Light Link (VLL) such as the Scout or MicroScout.

USB Infrared Tower

The Infrared (IR) Tower is what allows the host computer to communicate with the RCX and download programs to it. RIS 1.5 and earlier used a tower that connected to a 9-pin RS-232 port. RIS 2.0 includes a new tower that attaches to a computer's Universal Serial Bus (USB). The Lego software supplied with the RIS 2.0 set includes a Windows driver for using the USB tower.

The biggest impact of the USB IR Tower is that many of the third party programming environments were built around an RS-232 connection to the IR Tower. Some of them are now starting to support the USB Tower, but since driver support is heavily dependent on which operating system you are using, there are still some gaps. If you plan on using a third party programming environment, you should first verify that it supports the USB tower on your operating system.

NQC users: USB support for Windows and Mac OS X has been added to NQC version 2.4. Support for Linux and Classic MacOS may be added shortly. See the NQC site for details.

RCX Code

The biggest changes for RIS 2.0 are in the RCX Code software (Lego's visual programming environment for the RCX). Numerous improvements have been made to the user interface. For example, loading and saving files now uses a standard Windows file dialog, making it easier to share programs since they can be saved and loaded from anywhere on your computer.

The program blocks themselves have been given a facelift. In many cases, the change is trivial - just a slightly difference shape or color for the blocks. However, in some cases, the blocks have been reorganized. For example, previously a "set direction" block could operate on multiple motors. With 2.0, each "set direction" block can only affect a single motor. When loading older program, the system is smart enough to convert any old blocks to new ones that perform the same task. In the case of "set direction", if an old program reversed motors A and C, then when imported to 2.0, the program will now contain two "set direction" blocks- one for motor A and one for motor C.

Several new program blocks are also available for building programs with the 2.0 software. These new blocks include the ability to use multiple variable, increased control over the display and sound, and the ability to "globally" control the motors (overriding the normal motor commands from other stacks).