Lejos (en)

Lejos is an open-source alternative operating based on Linux including a Java virtual machine which provides a full development environnement for Java programmers, including an Eclipse plugin.

  • Reference web sites: lejos.org / SourceForge / Wiki
  • The system is compact (<2 Go) and isloaded on an SD card (between 2 and 32 Go) [ref]
  • Before running on the EV3 brick,  a version was developed for the NXT brick and beafore again on the RXC brick from a derivation of the TinyVM project launched by Jose H. Solorzano in year 2000 [getting started].
  • The system set is convenient [it appears to be more operational on previous windows version (windows 7) than MacOS or Linux according to student’s experimentations] but it also getting old [no commits since 2017] and now people look toward EV3dev which is more up-to-date.
What is leJOS? source http://www.lejos.org/rcx.php
leJOS (pronounced like the Spanish word “lejos” for “far”) is a tiny Java Virtual Machine for the Lego Mindstorms RCX.leJOS was originally forked out of the TinyVM project.  It contains a VM for Java bytecodes and additional software to load and run Java programs.
These are some of the features offered:

  • Object oriented language (Java)
  • Preemptive threads (tasks)
  • Arrays, including multi-dimensional ones
  • Recursion
  • Synchronization
  • Exceptions
  • Java types including float, long, String, but with some restrictions
  • Math class
  • Well-documented Robotics API

Documentation and Tutorials

for sake of simplicity, we do not translate here our french page [Lejos]

Getting started with leJOS EV3 (mainly complied from lejos wiki)

This section provides information on how to get started with leJOS on the Lego EV3.

At the moment to develop programs for the EV3 you will need to create a bootable micro SD card.

The following sections provide more details on how to set things up and get started:

[Installing leJOS]
[Windows Installation]
[Installing the Eclipse plugin]
[Configuring Wifi]
[Using the Menu System]
[Developing with leJOS]

Tutorials (fr/en)