From the Toysit archive
LEGO Mindstorms Robotics Invention System
An RCX-era building and programming kit, with official instruction links and a distinction between the original system and later Mindstorms features.
The play at a glance
Build a mechanism, then give it a program
The original Toysit description concerns an RCX-based Robotics Invention System: LEGO parts, motors and sensors paired with a programmable brick. It describes a PC, CD-ROM software and an infrared transmitter as part of the setup.
Start with the set number when looking for instructions. The wider Mindstorms name covers different systems, and the general discussion preserved below should not be read as a specification for this kit.
Find instructions by set number
If your box is 3804, Robotics Invention System 2.0, LEGO provides an official set page and construction instructions (PDF). For another number, use LEGO’s instruction search.
The old Toysit description names the RCX system but does not give a confirmed set number. Its 717-piece claim also differs from the 720 pieces on LEGO’s 3804 listing. The official link is a route for owners of that identified set, not proof that every detail of this older description belongs to it.
The RCX setup in the original description
- Controller
- An RCX programmable microcomputer.
- Computer connection
- A PC and an infrared transmitter, with CD-ROM software.
- Parts named
- Two motors, two touch sensors and one light sensor.
- Activities described
- A light-sensitive alarm, line following and responses to obstacles.
These details summarize the retained Toysit description. They are not a new parts inventory or a compatibility test.
Keep the generation clear
Identify the brick, transmitter, software and set number together. Instructions for a build are useful, but they do not answer whether the original programming software or interface works with the computer you have now.
The wider discussion below mentions Bluetooth, Wi-Fi and several sensor types. Those are general claims about versions of Mindstorms. They should not be carried into an RCX specification or used to select a replacement cable, sensor or controller.
The historical record
Original Toysit coverage
The first paragraph describes the RCX kit. The broader Mindstorms discussion that follows is also retained from the old page. Its references to Bluetooth, Wi-Fi and different sensors are family-level commentary, not verified features of the RCX kit described here.
Build and program your own Lego Robots.
Build and program your own Lego Robots! Contains everything you need to create thousands of robotic inventions. The key to this awesome new invention system is the revolutionary Lego RCX, a programmable microcomputer that acts as the brain of your robotic inventions. Using your PC and the RCX, you can control the behavior of an infinite number of robotic inventions--from a light-sensitive intruder alarm to an undercover robot that can follow a trail, move around obstacles, even duck into dark corners. The set includes an RCX microcomputer; CD-ROM software; 717 Lego pieces, including two motors, two touch sensors, and one light sensor; a Constuctopedia; 12 guided challenges, and an infrared transmitter.
The LEGO robotics system, particularly known through the LEGO Mindstorms series, has revolutionized the way children and hobbyists approach robotics and programming. The system's programmable microcomputer, often referred to as the "Intelligent Brick," serves as the heart of the system. Here are some of the key features:
- Programmable Intelligent Brick: This microcomputer allows users to program and control LEGO robots. It can be programmed using various programming languages, including LEGO's graphical programming language, making it accessible to users of different skill levels.
- Sensors and Motors: The system includes various sensors (such as touch, light, sound, and distance sensors) and motors that can be connected to the Intelligent Brick. These components enable the robot to interact with its environment and perform complex tasks.
- Graphical Programming Interface: LEGO provides a user-friendly graphical programming interface that allows even young children to create programs by dragging and dropping code blocks. This fosters creativity and introduces coding concepts in an engaging way.
- Expandable and Customizable: The LEGO robotics system is designed to be modular and expandable. Users can add additional sensors, motors, and LEGO pieces to create custom robots that suit their interests and challenges.
- Wireless Connectivity: Many versions of the Intelligent Brick offer Bluetooth or Wi-Fi connectivity, allowing for remote control and programming via computers, tablets, or smartphones.
- Community Support: The LEGO robotics community is active and supportive, offering online forums, tutorials, and resources to help users learn, share, and grow in their robotics endeavors.
- Educational Focus: The system is widely used in educational settings to teach STEM (Science, Technology, Engineering, Mathematics) concepts. It encourages problem-solving, logical thinking, and collaboration through hands-on projects.
- Compatibility with LEGO Building System: The LEGO robotics system is compatible with standard LEGO bricks and Technic pieces, allowing for endless creativity and integration with existing LEGO collections.
The LEGO robotics system with its programmable microcomputer offers a versatile and engaging platform for learning robotics and programming. Its user-friendly design, expandability, and strong community support make it a popular choice for hobbyists, educators, and learners of all ages.
Sources and editorial notes
The original Toysit page records an August 12, 2023 update and no original publication date. LEGO’s set page and the title page of its linked construction PDF were checked on October 15, 2026. Building instructions do not establish that old software, drivers or an infrared interface will work with a current computer; that compatibility has not been tested here.
- LEGO: Robotics Invention System 2.0, set 3804 — Official listing identifies this set as a 2001 release and provides its construction instructions.
- LEGO: set 3804 construction instructions (PDF) — Official document titled Robotics Invention System 2.0, Construction A, 3804.
- LEGO building-instructions search — Use the number from your own set if it differs from 3804.
Images and descriptions are retained as historical material. How Toysit covers toys.
Created for Toysit by Tabbloza — the artwork in our header.