Lego Mindstorms NXT is a programmable robotics kit released by Lego on August 2, 2006. It replaced the first-generation Lego Mindstorms kit, which was called the Robotics Invention System. The base kit ships in two versions: the Retail Version (set #8527) and the Education Base Set (set #9797). It comes with the NXT-G programming software, or optionally LabVIEW for Lego Mindstorms. A variety of unofficial languages exist, such as NXC, NBC, leJOS NXJ, and RobotC. The second generation of the set, the Lego Mindstorms NXT 2.0, was released on August 1, 2009, featuring a color sensor and other upgraded capabilities. The third generation, the EV3, was released in September 2013. NXT Intelligent Brick The main component in the kit is a brick shaped computer called the NXT Intelligent Brick. It can take input from up to four sensors and control up to three motors, via a modified version of RJ12 cables, very much similar to but incompatible with RJ11 phone cords. 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 be used to navigate a user interface using hierarchical menus. It has a 32-bit ARM7TDMI-core Atmel AT91SAM7S256 microcontroller with 256 KB of FLASH memory and 64 KB of RAM, plus an 8-bit Atmel AVR ATmega48 microcontroller, and bluetooth support. It also has a speaker and can play sound files at sampling rates up to 8 kHz. Power is supplied by 6 AA (1.5 V each) batteries in the consumer version of the kit and by a Li-Ion rechargeable battery and charger in the educational version. The Intelligent Brick remains unchanged with NXT 2.0. A black version of the brick was made to celebrate the 10th anniversary of the Mindstorms System with no change to the internals. Development kits Lego has released the firmware for the NXT Intelligent Brick as open source, along with schematics for all hardware components. Several developer kits are available that contain documentation for the NXT: Software Developer Kit (SDK), includes information on host USB drivers, executable file format, and bytecode reference Hardware Developer Kit (HDK), includes documentation and schematics for the NXT brick and sensors Bluetooth Developer Kit (BDK), documents the protocols used for Bluetooth communications Programming Very simple programs can be created using the menu on the NXT Intelligent Brick. More complicated programs and sound