Lego Mindstorms NXT

The kit's main component is the NXT Intelligent Brick computer, which can accept input from up to four sensors and control up to three motors with a modified version of RJ12 cables (similar to, but incompatible with, RJ11 phone lines). The plastic pin to hold the cable in the socket is moved slightly to the right. The brick has a 100×64 pixel monochrome LCD and four buttons that can navigate a user interface with hierarchical menus. It has a 32-bit ARM7TDMI-core Atmel AT91SAM7S256 microcontroller with 256 KB of FLASH memory and 64 KB of RAM, an 8-bit Atmel AVR ATmega48 microcontroller, and Bluetooth support. The kit has a speaker, and can play sound files at sampling rates up to 8 kHz. Power is supplied by 6 AA batteries (1.5 V each) in the consumer version of the kit, and a rechargeable Li-Ion battery in the educational version. The brick is compatible with sensors and motors of its successor Lego Mindstorms EV3. Development kits Lego has released open source firmware for the NXT Intelligent Brick and schematics for all hardware components. Several developer kits are available with documentation for the NXT: • Software Developer Kit (SDK), with information on host USB drivers, executable file format, and bytecode reference • Hardware Developer Kit (HDK), with documentation and schematics for the NXT brick and sensors • Bluetooth Developer Kit (BDK), documenting protocols used for Bluetooth communications == Programming ==

Simple programs can be created using the menu on the NXT Intelligent Brick. More complicated programs and sound files can be downloaded with a USB port or Bluetooth. Files can be copied wirelessly between two NXT bricks, and some mobile phones can be used as a remote control. Up to three NXT bricks can communicate simultaneously via Bluetooth when user-created programs are run. The kit's retail version includes software for writing programs that run on Windows and Mac OS personal computers. The software, based on National Instruments LabVIEW, provides a visual programming language for writing simple programs and downloading them to the NXT Brick; instead of requiring users to write lines of code, they can use flowchart-like blocks to design their program. Ch is a C/C++ interpreter running C/C++ code to control Lego NXT or EV3. No firmware upload/download or compilation is needed. A C/C++ code running in Ch can control a Lego NXT, EV3, or multiple of NXT/EV3. == Sensors and actuators ==

The Lego Mindstorms NXT base kit includes: • Three servo motors with built-in reduction gear assemblies and internal optical rotary encoders which sense their rotations within one degree of accuracy. • A touch sensor detects whether it is pressed, has been bumped, or is released. The orange enter button and the gray right and left NXT buttons can be programmed as touch sensors. In the NXT-G programming software, a value of 0 is given when it is not pressed and a value of 1 is given if it is pressed. • A light sensor detects the light level in one direction, and includes an LED for illuminating an object. It can sense reflected light values with the built-in red LED, or ambient light. In the NXT-G programming software, it senses light on a scale of 0 to 100; 100 is very bright, and 0 is dark. If calibrated, the sensor can be used as a distance sensor. • A sound sensor measures volume on a scale of 0 to 100; 100 is very loud, and 0 is silent. • An ultrasonic sensor can measure the distance from the sensor to something it is facing and detect movement. It can show distance in centimeters and inches. The maximum distance it can measure is , with a precision of . The sensor sends ultrasonic sound waves that bounce off an object ahead of it and then back, and senses the time it took. Other parts may be bought separately. Third-party companies manufacture sensors such as a compass, gyroscope, infrared tracker, RFID reader and accelerometer sensors sold by Lego. The temperature sensor can measure in Celsius or Fahrenheit. Connector Sensors are connected to the NXT brick with a six-position modular connector with analog and digital interfaces. The analog interface is backward-compatible (using an adapter) with the older Robotics Invention System. The digital interface is capable of I2C and RS-485 communication. == NXT 2.0 ==

Lego Mindstorms NXT 2.0 is the second set in the Lego Mindstorms series, introduced on August 5, 2009, at the Lego Shop in the U.S. The set contains 619 pieces, including a sensor that can detect colors. It was followed by the Lego Mindstorms EV3. Features • A sound editor for recording a sound and programming the NXT brick to play it. • An image editor for downloading an image to the NXT brick to appear on the screen. NXT intelligent brick • 32-bit Atmel AT91SAM7S256 main microcontroller (256 KB flash memory, 64 KB RAM) • 8-bit Atmel ATmega48 microcontroller @ 4 MHz (4 KB flash memory, 512 Bytes RAM) • 100×64 pixel LCD screen • Four RJ12 input ports (ports 1–4) • Three RJ12 output ports (ports A-C) • USB port • Bluetooth Class II V2.0 • Loudspeaker – 8 kHz sound quality, 8-bit resolution, 2–16 kHz sample rate • Four push buttons to navigate menus and use in programs • Powered by six AA batteries or the NXT rechargeable battery == See also ==