Lego Mindstorms


Lego Mindstorms is a hardware and software structure which is produced by Lego for the development of programmable robots based on Lego building blocks. Each version of the system includes an intelligent brick computer that controls the system, a set of modular sensors and motors, and Lego parts from the Technic line to create the mechanical systems.
Since creation, there have been four generations of the Mindstorms platform: the original Robotics Invention System, NXT, NXT 2.0, and EV3. With each platform release, the motor and sensor capabilities expanded. The latest system, Lego Mindstorms EV3, was released on 1 September 2013. Some robot competitions use this set, such as the FIRST Lego League and the World Robot Olympiad.

History

The original Lego Mindstorms Robotics Invention System was born out of a collaboration between The Massachusetts Institute of Technology and the Lego group. In 1985, Kjeld Kirk Kristiansen, then Chief Executive Officer of The Lego Group, heard of the work of MIT's Seymour Papert and was struck by how similar his goals of learning through building were to those of The Lego Group's newly formed educational division. The Lego Group began a partnership with Papert's Media Lab, funding their research and sharing ideas. Born out of this collaboration was the idea to have children use the LOGO programming language to command Lego brick robots of their own design connected to a computer. In 1988 the Media Lab created a Lego Brick compatible computer that could be used to control a robot without connection to a desktop computer. There was interest within The Lego Group to commercialize this Brick compatible computer as soon as personal computers became widespread, and in 1996 The Lego Group began developing this computer into what would eventually be known as the Robotics Invention System.
In 1996, the newly formed Home Learning division of Lego Education began developing Media Lab's "Grey Brick" into an official product. At the same time, Media Lab was working with the Epistemology and learning group to develop a version of the "Grey Brick" specifically for classroom instructions and the collaboration between these three organizations led to two separate versions of the brick computer: The Lego Group's Robotics Command eXplorer and Media Lab's "Red Brick". The Liquid Crystal Diode display that the two bricks share was specifically requested by teachers interviewed by the Epistemology and Research group, in order to give readouts of the status of the motors or sensors in real time. Both bricks also ran programs created through the use of visual programming, the RCX using a coding software based on MIT's LOGO Blocks. The Mindstorms' project development team had to redevelop the language after finding out it was too complicated for the target audience which caused them to miss the original 1997 launch date. Lego Mindstorms' Robotic Invention System 1.0 was released in September 1998.

Pre-Mindstorm

Before Mindstorms, Lego had previously done some experimentation with robotic sets. One of the main foundations of these sets was the Lego Technic system and its 4.5 V and later 9 V system for electrical peripherals that had been evolving through the 1980s.

Computer Interfaces

One of the first examples of programmable Lego was the LEGO Interface-A adapter, used for the educational-only Lego Dacta TC-Logo system. These sets from the mid-late 1980s provided a dedicated hardware interface to control the Lego Technic 4.5 V system using a computer, and for the first time it introduced electric Lego sensors. This interface was controlled from an IBM-PC or Apple-IIe by the use of a special version of Logo, a simple programming language designed for use in children's education. In the mid-1990s, the Lego Dacta Control Lab released as a follow-up for Lego 9 V system, using a standard serial port rather than a custom hardware interface card. This move also introduced new 9 V sensors, which would later become a key component for the first-generation Mindstorms sets. It is worth noting that the Control Lab had dedicated ports for active and passive sensors, while later products like first generation Mindstorms provided support for both kinds on the same ports.

Technic Control Center

The control center was the first programmable standalone Lego product, in the sense of being able to store sequence-based programs and run them. It featured three output ports and manual control, and it was only capable of storing linear sequences of manual input plus timing information. It could store up to two programs at once.
The manual controls could be used to independently control the three motors. To record a program; the controller had to be put in programming mode, and then any manual control would be recorded to the program. Pauses could also be included in a program. When the recording was done, the controller could successfully recall and execute any manual action done during the recording. The executing program could be set to loop infinitely.

Cybermaster

Cybermaster was mainly sold in Europe and Australia/New Zealand and was available for a short time in the United States via the Lego Club magazines.
It was aimed at an older audience as an early attempt of merging with robotics and Lego.
The brick shares many, especially software, features with the RCX but differs in appearance and technical specifications: one output and four sensors.
Despite its obvious limitations it has a number of advantages over its 'big brother', the RCX.
This makes it very useful for various mobile platforms and performing advanced motion/positioning tasks.
It talks the same protocol as the RCX but cannot communicate directly to it but with a repeater they can communicate indirectly.

Codepilot

Sold as part of the Barcode Truck kit.
This unit was the first programmable brick.
It features a single motor, a single touch sensor and a light sensor.
It is programmed by setting it to 'learn' and using the light sensor to feed barcoded commands. The command set is very limited.
Since barcode is just a series of variances in light, this form of command entry was dubbed VLL and has been used in several later Lego models.

Robotics Discovery Set and Droid/Darkside Developer Kit

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 as well.

Scout

Lego also released a blue computer called the Scout, which has 2 sensor ports, 2 motor ports, 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.
There was a plan for Lego to create a booster set that allows you to program the Scout from a computer with a 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".

Micro Scout

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 and later the Darkside Developer Kit.

Robotics Invention System

The main core of the first generation of Mindstorms sets were the Robotics Invention System sets. These were based around the RCX brick, and the 9 V LEGO Technic peripherals available at the time. It also includes three touch-sensors and an optical sensor, using the technology from the earlier 9 V sensors from the pre-Mindstorms sets.

RCX

The RCX is based on the Single-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 needing access to a computer. Programs may take use of three sensor input ports and three 9 V output ports, in addition to the IR interface, enabling several RCX bricks to communicate. A built-in LCD can display the battery level, the status of the input/output ports, which program is selected or running, and other information.
Version 1.0 RCX bricks feature a power adapter jack rather than solely batteries. In version 2.0, the power adapter jack was removed. Power-adapter equipped RCX bricks were popular for stationary robotics projects or for controlling Lego model trains. In the latter context, the RCX might be programmed with Digital Command Control 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. 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 versions of the RCX have a unique number printed on it, 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.

Expansion Packs

Six expansion-packs were made for the Robotics Invention System. Most expansion sets contains more parts and instructions, while other expansion sets were more ambitious. These sets include:
Notable sets include the Ultimate Accessory Set, containing more sensors and an IR remote-control for sending commands to the RCX. Another notable set, Vision Command, came with a Lego Camera and dedicated software. This software was capable of detecting different lightings, motion, and colors.

Lego Mindstorms NXT

Lego Mindstorms NXT was a programmable robotics kit released by Lego in July 2006, replacing the first-generation LEGO Mindstorms kit.
The kit consists of 577 pieces, including: 3 servo motors, 4 sensors, 7 connection cables, a USB interface cable, and the NXT Intelligent Brick. The Intelligent Brick is the "brain" of a Mindstorms machine. 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, Tri-Bot, Robo-Arm T-56, and Spike

Lego Mindstorms NXT Educational Version

This is the educational version of the NXT set from Lego Education, which is made for school use. Software was sold separately, and the Education Resource Set for the best use. It includes a light sensor, an ultrasonic sensor, a sound sensor, three lamps and a pair of touch sensors. The first set consists of about 400 pieces, and the extra set consists of about 600 pieces. The Education Version is most suited for those who have older versions of Mindstorms sets around, mostly thanks to its three converter cables.

Lego Mindstorms NXT 2.0

The Lego Mindstorms NXT 2.0 was launched on 5 August 2009. It contains 619 pieces, two Touch Sensors, an Ultrasonic Sensor, and introduced a new Color Sensor. The NXT 2.0 uses Floating Point operations whereas earlier versions use Integer operation. The kit costs around US$280.

Lego Mindstorms EV3

The Lego Mindstorms EV3 is the third generation Lego Mindstorms product. EV3 is a further development of the NXT. The system was released on 1 September 2013. The LEGO MINDSTORMS EV3 set includes motors, sensors, the EV3 programmable brick, 550+ LEGO Technic elements and a remote control. 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 , a Debian-based operating system.

Programming languages

Use in education

Mindstorms kits are also sold and used as an educational tool, originally through a partnership between Lego and the MIT Media Laboratory. The educational version of the products is called Mindstorms for schools or Mindstorms Education, and later versions comes with the ROBOLAB GUI-based programming software, developed at Tufts University using the National Instruments LabVIEW as an engine. In addition, the shipped software can be replaced with third party firmware and/or programming languages, including some of the most popular ones used by professionals in the embedded systems industry, like Java and C. One of the differences between the educational series, known as the "Challenge Set", and the consumer series, known as the "Inventor Set", is that it includes another touch sensor and several more gearing options. However, there are several other standouts between the two versions that one may not recognize unless doing a side by side analysis of what each offers. The version sold through LEGO Education is designed for a deeper level of learning or teaching that often happens in a classroom or school setting. The LEGO Education version comes with support called the Robot Educator. This includes 48 tutorials to walk the learner through the basics of coding to more sophisticated and complex concepts such as data logging. This resource to support the learner and/or educator are not included in the retail version of Mindstorms. It's always a good idea to reach out to a LEGO Education consultant to inquire of other differences as there are several more. The retail version was designed for more of a home/toy use vs the educator model was designed to support deeper learning with extra resources and pieces to do so. This is why the LEGO Education Mindstorms contains more sensors and parts than the retail version.

Community

There is a strong community of professionals and hobbyists of all ages involved in the sharing of designs, programming techniques, creating third-party software and hardware, and contributing of other ideas associated with Lego Mindstorms. The Lego Mindstorms system/website is organized much like a wiki, harnessing the creative potential and collaborative efforts of participants. Lego also encourages sharing and peering by making software code available for downloading and by holding various contests and events.

Citations

Additional references