Thursday, June 05, 2008

Lego Mindstorm: NXT brick-shaped computer

The main component in the kit is a brick-shaped computer called the NXT brick. It can take input from up to four sensors and control up to three motors, via RJ12 cables, very similar to but incompatible with RJ11 phone cords. The brick has a 100x64 pixel greyscale LCD display and four buttons that can be used to navigate a user interface using hierarchical menus. 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.

Technical specifications

* 32-bit AT91SAM7S256 main microprocessor (256 KB flash memory, 64 KB RAM)
* 8-bit ATmega48 microcontroller @ 4 MHz (4 KB flash memory, 512 Bytes RAM)
* 100×64 pixel LCD matrix display
* Can be programmed using Windows or Mac OS (NBC/NXC supports Linux as well)
* Users create a program with new software, powered by LabVIEW from National Instruments
* A single USB 2.0 port
* Bluetooth (Class II) wireless connectivity, to transfer programs to the NXT wirelessly or offer ways to control robots remotely (through mobile phones and possibly by PDA's)
* 4 input ports, 6-wire cable digital platform (One port includes a IEC 61158 Fieldbus Type 4/EN 50 170 (P-NET) compliant expansion port for future use)
* 3 output ports, 6-wire cable digital platform
* Digital Wire Interface, allowing for third-party development of external devices

Other software can also be used.

Firmware and developer kits

Lego has released the firmware for the NXT Intelligent Brick as Open Source.

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