Lego Mindstorms

Robot based on the NXT platform
Subject	Robotics
Licensed from	The Lego Group
Availability	1 September 1998 (1998-09-01)–31 December 2022 (2022-12-31)
Total sets	91[1]
Official website

Lego Mindstorms (sometimes stylized as LEGO MINDSTORMS) is a discontinued line of educational kits for building programmable robots based on Lego bricks. It was introduced on 1 September 1998 and discontinued on 31 December 2022.

Mindstorms kits allow users to build creations that interact with the physical world. All Mindstorms kits consist of a selection of Lego Elements, a "Smart Brick" (internally known as a programmable brick or "pbrick"), which serves as the "brain" for a Mindstorms machine. Each set also includes a few attachments for the smart brick (such as motors and sensors) and programming software. Unlike conventional Lego sets, Mindstorms kits do not have a main model to build. Sample builds are included with each version of Mindstorms, but the kit is open-ended with the intent of the user creating and programming their own designs.

In addition to at-home use, Mindstorms products are popularly used in schools and in robotics competitions such as the FIRST Lego League. Versions of Mindstorms kits specifically intended for use in educational settings are sold by Lego Education.

Children are the intended audience of Lego Mindstorms, but a significant number of Mindstorms hobbyists are adults. The latter have developed many alternative programming languages and operating systems for the smart brick, allowing for more complex functions.

While originally conceptualized and launched as a tool to support educational constructivism, Mindstorms has become the first home robotics kit available to a wide audience. It has developed a community of adult hobbyists and hackers as well as students and general Lego enthusiasts following the product's launch in 1998. In October 2022, the Lego Group announced that it would discontinue the Lego Mindstorms line while continuing to support the Scratch-based SPIKE controller.^[2]

The Robotics Invention System (RIS) was the flagship product of the first generation of the Lego Mindstorms line. It is a commercialization of technology produced by the MIT Media Lab in collaboration with the LEGO group. The RIS featured the programmable Robotic Command eXplorer (RCX) microcontroller, as well as 9V Lego-compatible motors and sensors and a selection of Lego parts. The original RIS was launched fall of 1998. It was replaced by a second version, RIS 1.5, in the summer of 1999; and a third version, RIS 2.0, in 2001.

The Lego Mindstorms product line was the first project of "Home Education", a division of Lego Education established by employee Tormod Askildsen in 1995. Askildsen, who had previously spent ten years working for Lego Education, had grown frustrated working with teaching professionals and wanted to create an improved educational experience that was delivered directly towards children. Home Education decided to incorporate technology into their products based on market research that concluded that children found learning that involved technology interesting.^[3] Lego Mindstorms started development in April 1996.^[4]: 1061 The concept for the set was based on technology created in partnership with the MIT Media Lab. MIT Media Lab had been experimenting with combining Lego and programming since the early 1980s, and Lego had previously commercialized some of this technology as classroom products in the Lego Dacta line. The programmable brick (or pbrick^[5]) was a refinement of these early concepts, which had limited range because they had to be tethered to a computer to run.^[6]: 24

Lego had been interested in mass-producing the pbrick since its creation in the 1980s, but at the time it was considered unfeasible due to the lack of computers in schools and households and the relative expense of electrical components.^[6]: 25 in the early 1990s Technology began to become more of a child's life, and the toy market accordingly began shifting more towards computerized toys.^[7]: 37 Many of Lego's attempts at producing electronic toys had languished at the point that Lego began developing MIT's programmable brick into a consumer product.^[4]: 1061 MIT continued developing the pbrick concept, creating a "Red Brick" version between 1994 and 1996 that improved the previous version. By the mid-1990s personal computers were relatively common in households and the components required to produce the pbrick went down in price, making mass production feasible.^[6]: 25 Development on what would later be known as the Robotics Invention System started in 1996 as the flagship product of the newly created home-learning division of Lego Education (Lego Dacta). The product line's name "Mindstorms" was intended to express the user experience of the product, it is named after Papert's book Mindstorms, as the user experience was similar to the educational constructivism concepts described in his book.^[8]

The project's at-first low profile allowed the Mindstorms team the freedom to develop the product using operating procedures then-unorthodox to the Lego Group.^[4]: 1062 Unlike traditional Lego sets, the Mindstorms Robotics Invention System did not come with step-by-step instructions.^[3] The kit also did not have a main model, nor was the play driven by storytelling.^{[citation needed]} To bridge the gap between this new play experience and pre-existing Lego ones, the Mindstorms team created a lot of opportunities for users to engage with each other, such as the creation of Mindstorms.com, Mindstorms Discovery Centers, and the FIRST Lego League.^[8] The creation of these experiences was done through partnerships with external groups that the Mindstorms team interacted with as equal partners, something that was uncommon for the Lego group at the time.^[4]: 1063 To ease tensions between Mindstorms and more conventional products, the project team was given autonomy from Lego's product development process and instead reported directly to the company's senior management.^[4]: 1064

The Lego Mindstorms team used the insights that MIT researchers discovered from testing the 3rd Generation Logo Brick ("Red Brick") in schools as the basis for the development of the mass-produced programmable brick.^[9]: 5 The physical programmable brick was re-engineered from the ground up, as the experimental programmable bricks were not designed for robustness or cost-effective manufacturing.^{[6]: 19, 26} The programming language of the product was developed with help from members of the MIT Media lab. Lego decided to use a visual programming language for Mindstorms, inspired by the LOGOBlocks language previously used with programmable brick experiments, in order to make the product accessible to children who might be unfamiliar with programming.^[6]: 29 While the technology that Mindstorms was based on was aimed towards "all children", the chosen target demographic of Lego Mindstorms was intentionally narrow, in order to garner positive press by outselling expectations. The decision was made to aim the product towards 10 to 14-year-old boys, partly because it was Lego's main target demographic, and partly based on market research (not substantiated by the findings of the MIT Media Lab) which concluded that this demographic would be most attracted to computerized toys. This choice of target demographic directly informed the color of the RCX brick (which was made yellow and black to resemble construction equipment) and the sample uses for the Mindstorms kit (such as making autonomous robots).^[6]: 28

Promotion of the Lego Mindstorms Robotics Invention System began 6 months before the product was planned to launch.^[8] The product was first soft launched with the opening of the Mindstorms Discovery Center at the Museum of Science and Industry, where children could interact with the Mindstorms Robotics Invention System to complete set tasks, getting them familiar with the product.^[10] The Mindstorms product was launched concurrently with the Cybermaster, another Lego product spun off from the MIT programmable brick technology that was more in line with the traditional product philosophies of the Lego group.^[4]: 1067

The Lego Mindstorms Robotics Invention System (RIS) was released September 1998^[11] at a retail price of $199. Instead of being sold at toy stores, the product was sold at electronics stores like BestBuy and CompUSA, due to the relatively high cost of the set.^[8] The entire production run (of between 60,000 and 100,000 units^[12]) sold out within 3 months.^{[7]: 181 [6]: 30}

The second edition of the RIS, Robotics Invention System 1.5, was released in the summer of 1999,^{[7]: 187 [5]} with a third edition, RIS 2.0, launched in 2001.^[13]

Despite being aimed towards children, the Robotics Invention System quickly found an audience with adults and hackers of all ages; Lego company surveys conducted a few months after launch determined that seventy percent of Lego Mindstorms Hobbyists were adults. Shortly following the product's launch, adult hobbyists began sharing reverse-engineered versions of the RCX brick's Microcode and Firmware on the internet, leading to the development of alternative programming languages for the RCX such as "Not Quite C" (NQC) and alternative operating systems for the brick like lejOS. The Lego Group briefly considered sending cease-and-desist letters to websites sharing the RCX's proprietary code.^[7]: 183 However, The Mindstorms team successfully argued that the embrace of the product by the hacking community proved that the product was worth developing. In order to foster this burgeoning community, an official forum was established on the Lego website and a "right to hack" clause was added to end user license agreement of the Lego Mindstorms software. An official software developers kit for the RCX would later be released on the Mindstorms website. A number of products focusing on the RIS were released by adult hobbyists, including how-to books, and unofficial sensors and hardware. A convention for Lego Mindstorms hobbyists, named Mindfest, started in 1999.^{[7]: 181–184}

Despite strong sales, the Mindstorms development team was neglected by upper management. As a cost-cutting measure, the Mindstorms office was shut down in 2001, and team members were laid-off or assigned to other projects.^[5] The Lego Group continued to produce the Robotics Invention System 2.0, selling around 40,000 units per year without advertising ^[7]: 189 until the set was discontinued in 2006.^[14]

The RCX is based on the 8-bit Renesas H8/300 microcontroller, including 32 KB of ROM for low-level IO functions, along with 32 KB of RAM to store high-level firmware and user programs. The RCX is programmed by uploading a program using a dedicated infrared interface. After the user uploads a program, the RCX can run it on its own without the need for computer access. Programs may make use of three sensor input ports and three 9 V output ports, in addition to the IR interface, enabling RCX bricks to communicate with one another. A built-in LCD can display information including the battery level, the status of the input/output ports, and the program currently running.^[15]

Version 1.0 RCX bricks feature a power adapter jack in addition to batteries. In version 2.0 (as well as later 1.0s included in the RIS 1.5), the power adapter jack was removed. Power adapter-equipped RCX bricks were popular for stationary robotics projects (such as robot arms) or for controlling Lego model trains. In the latter context, the RCX might be programmed with Digital Command Control (DCC) software to operate multiple wired trains.

The IR interface on the RCX is able to communicate with Spybots, Scout Bricks, Lego Trains, and the NXT (using a third-party infrared link sensor). The RCX 1.0 IR receiver carrier frequency is 38.5 kHz, while the RCX 2.0 IR carrier frequency is 76 kHz. Both versions can transmit on either frequency. The RCX communicates with a computer using a Serial or USB IR tower. As the RCX is discontinued, support for the interface is limited on more recent operating systems than Windows XP.

All RCX versions have a unique number printed on them, which could be registered on the now-defunct Lego Mindstorms RCX website. This was necessary to obtain technical support. The first RCX produced is marked "000001," and was on display at the Mindstorms 10th Anniversary event.^[16]

The Lego RCX was available in new sets from 1998 (Lego Set 9719: Robotics Invention System 1.0) through 2003 (Lego Set 9786: Robo Technology Set, with USB cable). The original RCX 1.0 worked with existing Lego power supply products from the Lego Train theme, Lego Product 70931: Electric Train Speed Regulator 9V Power Adaptor for 120v 60 Hz - US version (Years: 1991 thru 2004), Lego Product 70938: Electric Train Speed Regulator 9V Power Adaptor for 230v 50 Hz - European version (Years: 1991-1996). Both of these products converted wall power to 12VAC ^{[dubious – discuss]}, through a coaxial power connector (also called a "barrel connector"), 5.5 mm outside, 2.1 mm inside. These were sometimes sold alone and sometimes available as part of other sets such as Lego Set 4563: Load N' Haul Railroad (Year: 1991) and Lego Set 10132: Motorized Hogwarts Express (Year: 2004).^{[17][18][19][20][21][22]}

The Robotics Discovery Set was a more affordable and simpler package than the Robotics Invention Set. Instead of being based on the RCX, it had its own programmable brick called the Scout. An even simpler version of the Scout would be featured in two Star-Wars-themed Mindstorms sets.

Lego also released a blue computer called the Scout, which has 2 sensor ports, 2 motor ports (plus one extra if linked with a Micro Scout using a fiber-optic cable), and a built-in light sensor, but no PC interface. It comes with the Robotics Discovery Set. The Scout can be programmed from a collection of built-in program combinations. In order to program the Scout, a user must enable "power mode" on it. The Scout can store one program.

The Scout is based on a Toshiba microcontroller with 32 KB of ROM and 1 KB of RAM, where about 400 bytes are available for user programs. Due to the extremely limited amount of RAM, many predefined subroutines were provided in ROM. The Scout only supports passive external sensors, which means that only touch, temperature and other unpowered sensors can be used. The analog-to-digital converters used in the Scout only have a resolution of 8 bits, in contrast to the 10-bit converters of the RCX.^[23]

There was a plan for Lego to create a booster set that allows programming the Scout from a computer with software such as RCX code. However, due to the complexity of this project, it was abandoned.

The RCX can control the Scout brick using the "Send IR Message" program block. The RCX does all of the controlling, and therefore can be programmed with the PC, while the Scout accepts commands. The Scout brick must have all of its options set to "off" during this process.

The Micro Scout was added as an entry-level to Lego robotics. It is a very limited Pbrick with a single built-in light sensor and a single built-in motor. It has seven built-in programs and can be controlled by a Scout, Spybotics or RCX unit using VLL. Like the Scout, the Micro Scout is also based on a microcontroller from Toshiba.

The unit was sold as part of the Droid Developer Kit (featuring R2-D2) and later the Dark Side Developer Kit (featuring an AT-AT Imperial Walker).

Lego Mindstorms NXT was a programmable robotics kit released by Lego in August 2006, replacing the first-generation Lego Mindstorms kit.^[24] The kit consists of 577 pieces, including: 3 servo motors, 4 sensors (ultrasonic, sound, touch, and light), 7 connection cables, a USB interface cable, and the NXT Intelligent Brick. It lets the robot autonomously perform different operations. The kit also includes NXT-G, a graphical programming environment that enables the creation and downloading of programs to the NXT. The software also has instructions for 4 robots: Alpha-Rex (a humanoid), Tri-Bot (a car), Robo-Arm T-56 (a robotic arm), and Spike (a scorpion)

The Development of Lego Mindstorms NXT began in 2004. At the time, The Lego group was in the middle of a financial crisis. As part of the turn-around effort, the product line developed for release in 2006 would feature relatively few products that were guaranteed to be profitable. A revival of The Mindstorms Robotics Invention System was chosen as of these products, as Lego Mindstorms had a strong fan following and kits continued to sell well without advertising.^{[7]: 187–188}

Fans were extensively involved in the development and promotion of Mindstorms NXT. The development team collaborated with four hobbyists considered experts in Lego Mindstorms fan community. These fans were collectively known as the Mindstorms Users Panel (MUP). They were shipped early prototypes of the Mindstorms kit and communicated to Mindstorms team members on a private internet forum. MUP gave extensive feedback on the hardware and design of the NXT kit. Features of NXT directly based on requests of the MUP include the use 32-bit processor, more powerful motors, and Bluetooth compatibility.^[7]: 194

Promotion of Lego Mindstorms NXT was largely word-of-mouth based, because the company was in the middle of a financial crisis and did not have enough money for a large marketing campaign.^[7]: 189 Mindstorms NXT was unveiled in January 2006 at the 2006 Consumer Electronics Show. At the show, Lego requested applications for a beta-testing phase, where 100 users, known as Mindstoms Community Partners (MCP)s would receive NXT kits at a discounted price months before launch. The intention of the MCP program was to build support for the product prior to launch, and receive feedback on the near-final kit.^{[7]: 196–198 [5]} Fans involved in the MCP program provided a significant amount of PR for the set upon launch, such as alternate models, finished book drafts, and web content like blog posts.^[5] News outlets like Wired and CNN also provided free publicity for Mindstorms NXT by reporting on the inclusion of fans in its development process.^[7]: 199 The launch of Mindstorms NXT, measured in airtime hours, web content and magazine pages; generated more public interest than the entire company had previously accumulated in its entire lifetime.^[5]

Lego Mindstorms NXT (Product no. 8527) was released August 1 of 2006.^[5] $30 million worth of kits were sold in the first year.^[7]: 199

The Lego Mindstorms NXT 2.0 was launched on 5 August 2009. It contains 619 pieces and five sensors; two touch sensors, and one sound, light, and ultrasonic distance sensor. The NXT 2.0 uses Floating Point operations whereas earlier versions use Integer operation.^[25] The kit costs around US$280.

EV3, the third generation Mindstorms product, is a further development of the NXT.^[26][27] The system was released on 1 September 2013. There are three versions of the Lego Mindstorms EV3:

• LEGO MINDSTORMS EV3 31313

This set contains 601 pieces and includes 3 servo motors (2 large and 1 medium), 3 sensors (touch sensor, infrared sensor and colour sensor), the EV3 programmable brick and a remote control (the Infrared Beacon, which is only on Home/Retail mode).

• LEGO MINDSTORMS Education EV3 Core Set 45544

This version contains 541 pieces and always includes 3 servo motors (2 large and 1 medium), 4 sensors (2 touch sensors, ultrasonic sensor, colour sensor and gyro sensor) and the EV3 programmable brick.

• LEGO MINDSTORMS Education EV3 Expansion Set 45560

This set instead contains 853 Lego Technic elements

The EV3 can be controlled by smart-devices. It can boot an alternative operating system from a microSD card, which makes it possible to run ev3dev, a Debian-based operating system.

Spike Prime was announced in April 2019.^[28] While not being part of the Mindstorms product line, the basic set includes three motors (1 large 2 medium) and sensors for distance, force and color^[29] a controller brick based on an STM32F413 microcontroller^[30] and 520+ Lego Technic elements.^[31] Majority of these motors and sensors, including the hub, would serve as the electric components for the then-upcoming Robot Inventor set.

Lego Mindstorms Robot Inventor was announced in June 2020^[32] and released later in autumn. It is the last commercially available Mindstorms set before the discontinuation of the theme announced in October 2022. It has four medium motors from Spike Prime, two sensors (distance sensor and color/light sensor) also from Spike Prime, a Spike Prime hub with a six-axis gyroscope, an accelerometer, and support for controllers and phone control. It also has 902+ Lego Technic elements. This set was discontinued in 2022 with Lego promising app support through 2024.^[33]

Mindstorms kits are also sold and used as an educational tool, originally through a partnership between Lego and the MIT Media Laboratory.^[35][36] The educational version of the products is called Mindstorms for Schools or Mindstorms Education, and later versions come with the ROBOLAB GUI-based programming software, developed at Tufts University^[37] using the National Instruments LabVIEW as an engine.

Due to its user friendliness towards children, Lego Mindstorms has been used as a platform for several child-oriented robotics competitions, most prominently the FIRST Lego League (FLL), but also World Robot Olympiad or Robocup Junior^[38]

FIRST Lego League Challenge (founded as FIRST Lego League) is a robotics competition that uses Lego Mindstorms products.^[a] It was founded in 1998 concurrent with the launch of LEGO Mindstorms and continues to exist to this day. It is a collaboration between FIRST and The Lego Group to involve a lower age bracket than the FIRST Robotics Competition.^[3] FLL teams consist of children between the ages of 9 and 14, and an adult coach.

• FIRST Lego League
• World Robot Olympiad (WRO)
• Robofest
• FIRST Tech Challenge
• RoboCup Junior
• Lego Education (WeDo 2.0)
• Big Trak
• iRobot Create
• Robotis Bioloid
• The Robotic Workshop
• Robotics suite
• C-STEM Studio
• Botball
• CubeStormer II
• Cubestormer 3

• Bagnall, Brian. Maximum Lego NXT: Building Robots with Java Brains. Variant Press. 2007. ISBN 0-9738649-1-5.
• Bagnall, Brian. Core Lego Mindstorms. Prentice-Hall PTR. 2002. ISBN 0-13-009364-5.
• Baum, Dave. Definitive Guide to Lego Mindstorms, 2nd ed. Apress. 2002. ISBN 1-59059-063-5.
• Erwin, Benjamin. Creative Projects with Lego Mindstorms (book and CD-ROM). Addison-Wesley. 2001. ISBN 0-201-70895-7.
• Ferrari et al. Building Robots with Lego Mindstorms: The Ultimate Tool for Mindstorms Maniacs. Syngress. 2001. ISBN 1-928994-67-9.
• Gindling, J., A. Ioannidou, J. Loh, O. Lokkebo, and A. Repenning., "Legosheets: A Rule-Based Programming, Simulation and Manipulation Environment for the Lego Programmable Brick", Proceeding of Visual Languages, Darmstadt, Germany, IEEE Computer Society Press, 1995, pp. 172–179.
• Breña Moral, Juan Antonio. Develop LeJOS programs Step by Step.

• Official website