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Lego Mindstorms NXT robotics kit has been out for a while. It is a successor to the original Mindstorms Robotic Invention System (RIS) also from Lego. If you are interested in robotics the Mindstorms NXT is for you. You can start building and programming a robot straight out of the box.

Note: The Mindstorms NXT 2.0 is available now. The core pieces this new kit includes are identical to the Mindstorms NXT, so this article also applies to it.

Lego Mindstorms NXTLego has put a lot of thought into making the NXT. It comes complete with servo motors, sensors and a USB programmable brick. The software and assembly guides make it all look simple and as always is the case with Lego the pieces simply fit.

The Mindstorms NXT kit pieces are mostly from the Lego Technic series and include gears, shafts, wheels and washers. Few pieces from Lego Bionicles are used as well to make pincers and grippers. Finally there are pieces that are Mindstorms exclusives and these include servo motors and sensors and the programmable brick.

The Programmable Brick

This is the brain of the NXT system. You can connect the brick to your computer using the supplied USB cable and download your programs onto it. The brick has three ports for connection to supplied servo motors and four ports for connection to supplied sensors.

Internally this uses an ARM7 microprocessor running at 48MHz with 256KB flash and 64KB RAM. It also has a 8-bit single chip Atmel AVR micro controller. Legos firmware on the brick has been released as open source allowing for third-party modifications if needed. Lego has also released various SDK kits allowing writing of custom compilers and software for the NXT Brick. In short, all effort has been made to keep the architecture and internal workings open for everyone allowing for hacks and mods and this is a great step.

The NXT Brick supports Bluetooth and can be connected wirelessly to three other NXT bricks or Bluetooth devices. It can also be connected to the computer over Bluetooth for uploading programs into it, though not all Bluetooth adapters are supported.

The Sensors

NXT Sound SensorThe NXT Kit comes with four sensors out of the box. These include the touch sensor, the light sensor, the ultrasonic sensor and the sound sensor. The servo motors supplied with the kit can also act like rotation sensors and the NXT brick buttons can act like additional touch sensors. The NXT brick also has three timers which can measure elapsed time. All sensors give analogue feedback. So the sound sensor not only detects the presence of sound but also measures its level. Similarly the light sensor can measure light intensity, not just the presence or absence of light. All this combined makes for a very powerful and necessary set of tools that help build robots that can intelligently interact with the environment. Besides the sensors supplied, you can buy additional sensors like the gyroscopic ad temperature from the Lego shop. Note that the NXT brick only supports connection to 4 different sensors at a time.

The Motors

The kit includes three servo motors which allow for precise control of the robot. The motors have in-built rotation sensors that can measure rotations upto 1 degree of accuracy. You can buy additional motors from the Lego website, but the NXT Brick allows connection of a maximum of three motors at any time.

The Software

The kit comes bundled with software from LabView which allows graphical programming of the NXT Brick. A number of updates have also been released for the original which are either freely downloadable or can be purchased from the Lego support website. The software programming environment is easy to use and you can drag various Blocks that control sensors or motors or perform math operations and then wire them together. You do not have to be a skilled programmer. Besides due to the openness Lego has shown to share the software aspects of its NXT Brick, you can use more traditional programming languages like C and even Java for the NXT Brick.

The Models


Supplied with the kit are specifications for building a simple moving bot (Mouse), a vehicle (TriBot), a scorpion (Spike), a RoboArm (T-56) and a humanoid (AlphaRex). Besides you can download instructions for making a cuckoo clock, soundbot and a musicbot from the Lego website.

Besides there are inspiring ideas everywhere of what other people have come up with, including a Rubik cube solver.