Summary.

I have decided to write this article because I would like to explain how to develop software for NXT brick using Java. In the market exists several robotics platforms, but personally, I like so much NXT platform because it allows to develop with Java. I could say that NXT brick is the Sun Spot's "small brother"

In the article I will try to show clear idea about leJOS project and I invite to test this platform.

Introduction.

leJOS NXJ is a Java programming environment for the LEGO MINDSTORMS NXT ®. It allows you to program LEGO ® robots in Java.

It consists of:

• Replacement firmware for the NXT that includes a Java Virtual Machine.
• A library of Java classes (classes.jar) that implement the leJOS NXJ Application Programming Interface (API).
• A linker for linking user Java classes with classes.jar to form a .binary file that can be uploaded and run on the NXT.
• PC tools for flashing the firmware, uploading programs, debugging, and many other functions.
• A PC API for writing PC programs that communicate with leJOS NXJ programs using Java streams over Bluetooth or USB, or using the LEGO Communications Protocol.
• Many sample programs

As leJOS is a firmware replacement, the new firmware leJOS NXJ firmware must be flashed onto the NXT, and will replace the standard LEGO MINDSTORMS firmware. This wipes out any files currently held on the LEGO firmware. The LEGO firmware can be restored using the LEGO supplied software.

leJOS is an open source project hosted in the sourceforge repository.  It was originally created from the TinyVM project that implemented a Java VM for the LEGO Mindstorms RCX system.  The RCX version of leJOS proved very popular with the LEGO Mindstorms Robotic Inventions Systems owners, and close to 200,000 downloads of all versions of leJOS have been done.  The original author of TinyVM and the RCX version of leJOS was Jose Solorzano.

Along  the time, leJOS project has developed others projects as:

• leJOS iCommand, a project to develop software in PC to control the NXT brick using PC
  
• leJOS PC API, a project to develop software to collaborate with leJOS software installed in NXT brick.
  
• leJOS Mobile API, a project to develop sofware to collaborate with leJOS software installed in NXT brick.
  

This article will explain how to use Lego Mindstorms NXT Platform to develop robust robots with Java leJOS.

The article will cover the following areas:

Why NXT Brick?

Why Java leJOS?

leJOS features and future developments?

I2C, Multithreading, Neural Networks, Kalman filter, etc...

Juan Antonio Breña Moral

www.juanantonio.info