CS 102B Robot Design Tuesday, 12704

1
CS 102B Robot DesignTuesday, 12/7/04

• Todays Class
• Return Exam 2
• Discuss Final Project
• Correction to DFS and HC navigation programs
• Intro to Java for Legos and leJOS

2
Mindstorms Software Architecture

• System ROM Layer
• Low Level Control Software
• Allows a second piece of software - the firmware
• Can be bypassed for direct control of the
  hardware
• Lego Firmware v. 2.0 permits
• 5 separate programs
• 10 threads (concurrent tasks)
• 32 global variables
• 16 local variables per thread
• Broadcast IR protocol

Typical Software Architecture Levels
3
Alternative Firmware/Languages

• Firmware replacements further push the limits of
  the RCX
• Examples
• BrickOS
• Environment for C programming, plus includes
  NQC (C language), and can be adapted to
  accommodate other languages, such as
• see http//brickos.sourceforge.net
• LejOS (Java)
• see http//lejos.sourceforge.net/
• RCXLisp (Lisp)
• Part of the LMICSE project
• See http//robotics.csc.villanova.edu/

4
What is leJOS (and how do you pronounce it?!)

• leJOS Lego Java Operating System
• Pronounce either leh-joase or leh-hoase
  (original designer named Jose)
• Permits Lego programming in the Java programming
  language
• Like NQC, it is free, open-source code
• Unlike NQC, it uses its own firmware, which
  replaces the RCX firmware

5
Differences between leJOS and NQC

• More RCX memory available for programs
• leJOS firmware is smaller than RCX firmware
• Can directly program RCX buttons
• Programs can print on the RCX screen
• Has floating-point numbers (numbers with
  fractional parts)
• Permits RCX to do accurate algebraic and
  trigonometric calculations
• Has arrays indexed lists of numbers
• Permits up to 255 threads (versus 10 for Lego
  firmware!)
• But NQC probably has better ease of use than
  any other full-featured lego robotics language
  available today

6
Programming Language Paradigms

• A programming language paradigm is a philosophy
  underlying the design of a programming language,
  that affects the way you approach problem-solving
  using that language.
• Modular design Essentially all modern languages
  are modular complex programs are built up out
  of smaller program modules
• Special purpose libraries of program modules are
  made available to make it easier to program
  things like graphics, database processing, etc.

7
Programming Paradigms of RCX code, NQC, leJOS

• RCX code is iconic
• Programs are built using visual, graphical
  pieces, rather than instructions written in
  narrative language
• NQC is procedural
• A program module is a viewed as a sequence of
  commands to be executed
• Java, C (hence leJOS) are OOP languages
• OOP Object-oriented programming
• Program modules are viewed as entities or
  objects that have properties and abilities, and
  the objects are programmed to work together to
  solve a problem.

8
IDEs for leJOS programming

• IDE Integrated Development Environment
• All-in-one software package providing editor,
  compiler, program execution (or download to
  robot), debugging
• Examples Lego Mindstorms software, BricxCC
• leJOS IDEs
• Any Java IDE can be adapted to permit leJOS
  programs
• BricxCC can be adapted to permit both NQC and
  leJOS programs but no color-coding for leJOS!
• JCreator Lite free online IDE provides nice
  environment for leJOS programming (color-coding,
  automatic completion of brackets, auto-indent,
  etc.)