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Month: February 2008

Walker Sphere

For a while I’m thinking about this hardware project idea and now I’m opening here to get some opinions. After that maybe I’ll submit it for the Sun SPOT Open Grant Program.

What is Walker Sphere? Walker Sphere is a project to made an robot capable with a diferent aproach, without heels, mats, propellers or wings. The main idea is to move only changing its center of gravity.

How change its center of gravity?

It’s a sphere

Sphere Walker Anatomy

with some compartments

Sphere Walker Anatomy

and a Sun Spot.

Sphere Walker Anatomy

One compartment is filled with a liquid. The liquid is pumped to another compartment and so the compartment got heavier and the sphere moves towards its direction.

How the sphere walks

Why a sphere? We can distribute the mass uniformly in a sphere and it’s shapes make it easier to roll. A sphere can encapsulates all components and protect them from the outside world and at the same time all sensors can work, especially using some transparent material for the bark.

Why Sun Spot? The Sun Spot have some advantages that fits perfectly in this project:

  • A broad set of sensors including accelerometers that made possible to know the current state of the sphere.
  • Radio communication that can make possible two or more spheres collaborate to achieve a common task.

Spheres robots talking

  • Programmable using Java.
  • Open and Free Source JVM, Squawk.

It will be free? Yes. I’d like to know more about open and free licenses for hardware projects.

How to pump the liquid into the compartments? I don’t know. Have you some good idea?

Some random ideas:

  • A pressure device.
  • Something like an injection.
  • An Archimedes’ screw.
  • Not using a liquid, use something else.

I’m open for ideas, critics and suggestions. ;)

Sun SPOT Open Grant Program

Dado o sucesso e a procura, o projeto Sun SPOT reabriu as portas para submissões de propostas de trabalhos com o Sun Spot para professores, alunos e hobistas. Você submete uma proposta de trabalho livre usando o Sun Spot e o projeto entra lhe doando os kits de Sun SPOT necessários. A idéia é criar projetos livres que possam ser reutilizados em futuros projetos livres.

Sun Spot Kit por dentro

As vantagens:

  • Acesso a um equipamento de tecnologia de ponta equipado com vários sensores e comunicação por wifi.
  • Trabalhar com um ramo novo da cultura livre: o hardware livre e aberto.
  • Criar um projeto inovador e quem sabe até inédito.
  • Ter apoio da comunidade do Sun Spot através dos vários fóruns e listas.

Gif animado do Sun SPOT

Você pode obter mais informações sobre o Sun SPOT Open Grant Program aqui ou aqui.

Eu estou pensando em algo para submeter, e você?

Tech Demo February

Today I did one more Tech Demo about Netbeans and also Sun Academmic Initiative and Community Innovation Awards Program.

Below are the slides (in Portuguese). They are an continuation from those from the last demo. You can also download them in ODP or PDF.

I have really little time to prepare this presentation (one day) but everything goes right. I prepared the slides during the night, took some food, soft drinks and gifts, called the students using our mail list. We had few people but was a good audience for the first weak of the university calendar.

Some guys at the beginning of the demo.

We talked two hours about stuff like:

  • Netbeans: Netbeans history, architecture and available modules. We did a demo showing some functionalities and I showed how use Issuezilla to report an bug.
  • Sun Academmic Initiative: how can we benefit from the program using Sun Learning Connection and 60% discount for Sun Certifications.
  • Community Innovation Awards Program: Sun Microsystems is giving one million dollars for innovations in Open and Free Software. I showed to the students details of the program and how to participate.

Hora do almoço
Lunch: Sfiha and soda.

Sorteio de Brindes
We used the JavaFX Wheel of Fortune for give prizes.

The next tech demo will be about one of those themes: JavaFX, Opensolaris or How to develop a module for Netbeans. I’m open for suggestions.

More photos at Flickr.

JavaFX: Side-scrolling

An side-scrolling game attempt.

an plane

I used two images, this mountain background made with Gimp (xcf sources here) and that ship above made with Inkscape (svg sources here).

import javafx.ui.*;
import javafx.ui.canvas.*;
var scroll;
scroll = [1..800] dur 60000 linear continue if true;
var mountains = Clip{
    transform: bind translate(-scroll,0)
    shape: Rect {x:bind scroll, y:0, width:400, height:200}
    content: [ImageView {
            transform: translate(0,0)
            image: Image { url: ""}
        ImageView {
            transform: translate(800,0)
            image: Image { url: ""}
var h = 50;
var ship = ImageView {
    cursor: HAND
    transform: bind translate(0,h)
    image: Image { url: ""}
    onMouseDragged: operation(e) {
        h += e.localDragTranslation.y;
Canvas {
    content: [mountains, ship]

JavaFX: Color picker

An simple color picker that can be also used as a gadget.

import javafx.ui.*;
import javafx.ui.canvas.*;

var colors = [red:Color, orange:Color, yellow:Color, green:Color,
     cyan:Color,blue:Color, magenta:Color, gray:Color];

var chosenColor: Paint;
chosenColor = black:Color;

var x = 120;
var y = 70;

    content: Group{
        transform: bind translate(x,y)
        content: [Star{
            points: sizeof colors
            rin: 30
            rout: 50
            fill: bind chosenColor
            onMouseDragged: operation(e) {
                x += e.localDragTranslation.x;
                y += e.localDragTranslation.y;
        foreach (i in [1..sizeof colors]) Circle {
            var: self
            transform: [rotate(i*360/sizeof colors,0,0), translate(50,0)]
            radius: 10
            fill: colors[i%sizeof colors]
            onMouseClicked: operation (e){
                chosenColor = self.fill;