Lego Mindstorms

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A Lego Mindstorms kit

LEGO Mindstorms is a line of Lego sets combining programmable bricks with electric motors, sensors, Lego bricks, and Lego Technic pieces (such as gears, axles, and beams).

Mindstorms originated from the programmable sensor blocks used in the Lego Dacta line of educational toys. The first retail version of Lego Mindstorms was released in 1998 and marketed commercially as the Robotics Invention System (RIS). The current version was released in 2006 as lego mindstorms nxt.

The original Mindstorms Robotics Invention System kit contained two motors, two touch sensors, and one light sensor. The NXT version has three servo motors and four sensors for touch, light, sound, and distance. Lego Mindstorms may be used to build a model of an embedded system with computer-controlled electromechanical parts. Many kinds of real-life embedded systems, from elevator controllers to industrial robots, may be modelled using Mindstorms.

Mindstorms kits are also sold and used as an educational tool, originally through a partnership between Lego and the MIT Media Laboratory.^[1][2] The educational version of the products is called Lego Mindstorms for Schools, many schools used legos for a fun learning experience, and comes with the ROBOLAB GUI-based programming software, developed at Tufts University^[3] using the National Instruments LabVIEW as an engine. The only difference between the educational series, known as the "Challenge Set", and the consumer series, known as the "Inventor Set", is another included light sensor and several more gearing options.

Mindstorms is named after the book Mindstorms: Children, Computers, and Powerful Ideas by Seymour Papert.

Robotics Invention System

RCX brick

First-generation RCX programmable brick.

The first generation of Lego Mindstorms was built around a brick known as the RCX. It contains a 8-Bit Renesas H8/300 microcontroller as its internal CPU.It also contains 32K of RAM that stores the Firmware and User Programs. The brick is programmed by downloading a program (written in one of several available programming languages) from a PC or Mac to the brick's RAM via a special infrared (IR) interface. After the user starts a program, an RCX-enabled Mindstorms creation may function totally on its own, acting on internal and external stimuli according to the programmed instructions. Also, two or more RCX bricks can communicate with each other through the IR interface, enabling inter-brick cooperation or competition. In addition to the IR port, there are three sensor input ports and three motor output ports (also usable for lamps, etc). There is also an LCD that 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 to allow continuous operation instead of the limited operation time when using batteries. In version 2.0, the power adapter jack was removed. Power adapter-equipped RCX bricks are popular for stationary robotics projects (such as robot arms) or for controlling Lego model trains. In the latter context, the RCX needs to be programmed with Digital Command Control (DCC) software required for automated model train operation..

The IR Interface on the RCX is able to communicate with Spybots, Scout Bricks, Lego Train, and the NXT(Through the HiTechnic IR Link). The RCX IR Frequency is 38.5KHz which is generated by one of the RCX's internal Timers.

Each RCX, including 1.0 and 2.0, has a unique number printed on it. Little is known about the reasoning behind this number, except for the use of technical support and as a ID number of the RCX for your Lego Mindstorms account on the Lego RCX website(The Lego RCX website was discontinued in 2003)^{[citation needed]}.

Programming languages

Lego-supplied languages:

• RCX Code (included in the Mindstorms consumer version sold at toystores)
• ROBOLAB (based on LabVIEW and developed at Tufts University)

Popular third-party languages:

• C and C++ under BrickOS (formerly LegOS)
• Java under leJOS or TinyVM
• NQC ("Not Quite C")
• pbFORTH (extensions to the Forth programming language)
• pbLua (An NXT API for the Lua programming language)
• Visual Basic (Through the COM+ interface supplied on the CD)
• RobotC (New Language and NXT Compatible)
• Interactive C (Language similar to C used in robotics competitions.)
• XSLisp an implementation of Lisp for the RCX (1 + 2) and NXT

Lego camera

The Lego camera on its own is technically not a robotic toy; rather, it is a normal webcam (a Logitech Quickcam Web) packaged into a Lego shell. Being a normal webcam, the Lego Camera is, unlike most Mindstorms products, not programmable and is only usable connected to a PC or some other device that supports USB webcams.

The Lego camera is meant to be used with the included Vision Command software which can also interface with an RCX and thus enables creating robots with "vision". The software is capable of detecting different lightings, motion, and colors. It can also be used with any other software that uses a webcam. The webcam is capable of recording up to 30 frames per second. It also contains a microphone to record sound for videos.

Cybermaster

Lego Cybermaster

Cybermaster was mainly sold in Europe and Australia/New Zealand, but was available for a short time in America via the Lego Club magazines. It was aimed at a younger audience as an early attempt of merging computer gaming with robotics and Lego. The Pbrick shares many, especially software, features with the RCX but differs in appearance and technical specifications: 1 output (plus 2 built-in) and 3 sensors.

• It uses RF (27 MHz R/C band) instead of IR for communication.
• It has two built-in motors with integrated tachometers and speedometers.
• It is limited to passive sensors (a simple A/D with internal pull-up resistors).
• The sensors shipped with it are color coded and have internal resistors in their open state (allowing the Pbrick to sense which sensor is attached to which port).
• It has a fixed firmware (so it cannot be upgraded or replaced).
• It has limited RAM for programs and only one program slot.

Despite its obvious limitation it has a number of advantages over its 'big brother', the RCX.

• The RF link has greater range and is omnidirectional.
• The built-in tachometer and speedometer sensors on the internal motors provides the same function as the external rotation sensor to the RCX, but without using up sensor ports.

This makes it very useful for various mobile platforms and performing basic motion/positioning tasks.

It talks the same protocol as the RCX but cannot communicate directly to it (due to IR vs RF) but with a repeater (a computer with 2 serial ports and a simple program) they can be integrated.

Codepilot

Sold as part of the Barcode Truck kit. This unit was the first programmable brick (or Pbrick). 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 (Visual Light Link) and has been used in several later Lego models.

Scout

Lego also released a brick named the Scout, which has 2 sensor ports, 2 motor ports, a built in light sensor, and no PC interface. It came with the Robotics Discovery Set. The Scout can be programmed, but the user usually selects one of a collection of built-in programs. In order to program the Scout, a user must enable "power mode" on it. The Scout can store one program.

There was a plan for Lego to create a booster set that allows you to program the Scout from a computer with a Scout version of the 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 acts as a "slave". The Scout brick must have all of its options set to "off".

The Scout is also capable of using VLL to control a Micro Scout.

Micro Scout

The Micro Scout was added as an entry level to Lego robotics. It is a very limited Pbrick with a single 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.

The unit was sold as part of the Droid Developer Kit (featuring R2D2) and later the Darkside Developer Kit (featuring an AT-AT Imperial Walker).

Spybotics

Main article: Lego Spybotics

Spybotics was more of an attempt to expand on the Cybermaster line. The kits were sold together with a computer game where part was played on the computer and part was played by controlling the Spybot to solve a number of fixed missions. The Pbrick itself shares many features with the Cybermaster, but it has no tachometers or speedometers and a single integrated touch sensor.

It also features a light sensor which doubles as computer interface. This interface can also be used to connect to the Scout, Micro Scout and possibly the Codepilot using VLL. It has an expanded IR functionality allowing it to communicate with other Spybots or RCX units. The IR unit also has limited direction and range function, allowing it to track and locate other Spybots, IR Remote Controls/beacons or RCX units.

lego mindstorms nxt

Main article: lego mindstorms nxt

lego mindstorms nxt is a programmable robotics kit released by Lego in July 2006, replacing the first-generation LEGO Mindstorms kit.^[4] The kit consists of 519 Technic pieces, 3 servo motors, 4 sensors (ultrasonic, sound, touch, and light), 7 wires, a USB cable, and the NXT brick. It also includes NXT-G, a graphical programming environment that enables the creation and downloading of programs to the NXT.

The NXT is the "brain" of a Mindstorms robot. This computer-controlled Lego brick lets the robot autonomously perform different operations.

Programming languages

Further information: lego mindstorms nxt#Programming

Community

There is a strong community of professionals and hobbyists of all ages involved in the sharing of designs, programming techniques, and 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 codes available for downloading and by holding various contests and events.

See also

Robotics portal

• FIRST Lego League
• RoboCup Junior
• Legoscript
• Vex
• Big Trak
• iRobot Create
• LabVIEW
• Robofest
• Actor Lab
• The Robotic Workshop
• URBI
• Lego Logo, an earlier use of Lego bricks with computer control.
• Robotics suite

Notes

References

• 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.

External links

Wikimedia Commons has media related to:

Lego Mindstorms

• Official Lego Mindstorms (NXT)
• Official Robotics Invention System
• Lego Mindstorms at the Open Directory Project