Welcome to my blog


02/02/2014 - 17:01
Cassapa is a system to help aiming at pool games. It uses augmented reality to help the player to adjust the cue direction. Check this video:
Read more here

Rabiscoscopio rocks on ad

12/08/2013 - 14:55

I've just dropped a tear of joy: The American marketing firm Y&R Austin has an institutional movie made with Rabiscoscopio. How cool is that?

The movie was produced by the video production company Impossible Engine, and depicts a series of equipments, button presses, knob being turned and other tech stuff, all preparing for the gran finale, with the firm logo being drawn on an oscilloscope. According to the video producers, a CGI logo would be easier, but couldn't produce the same effect.

Check the video vimeo:


Maker Faire 2013

10/03/2013 - 11:54

These are my pics from Maker Faire 2013. I also made a video. See it at the end of this post

Maker Faire is an hacker/maker event created by Make Magazine. It's announced as "The Greatest Show (And Tell) on Earth". And it's exactly this: A big science faire, where makers and hackers all around the world (But mostly from USA) can attend and bring their projects. Of course, it also brings a lot of vendors and sponsors to pay the costs.

Visiting NYC Resistor hackerspace

10/03/2013 - 11:04

Last week I was in New York and had a few minutes to visit one of the worlds most famous hackerspaces: NYC Resistor.

NYC Resistor is, among other things, the birthplace of MakerBot 3D printers. Among the space founders are Bre Pettis and Zack Smith, founders of MakerBot Industries. They have a large and nice place in an old industrial building in downtown Brookly, NY.Visiting it was an amazing experience, even considering I just had 15 minutes (Left the wife in a nearby mall and had to get back to her as soon as possible).

Purpurina in New York

10/03/2013 - 10:33

On every tavel, I include some Purpurina boards on my baggage, to take unusual touristic photos.

Last week I was in New York. These pictures were made from a roof top on Brooklyn, using Manhattan skyline as background. I could even put a Kong on top of Empire State Building.

Biblioteca Sergio Mallandro para Arduino

06/01/2013 - 13:01

A bibliteca Mallandro permite reproduzir no Arduino algumas das clássicas falas deste que é um dos maiores artistas brasileiros vivos: Serginho Mallandro. Esta biblioteca foi desenvolvida para ser usada no projeto "Campainha Mallandrinha", que anuncia aos frequentadores do SJC Hacker Clube a chegada de visitantes.

Para utilizá-la, basta fazer o download do arquivo abaixo, que está em formato workspace do MariaMole, mas é fácilmente adaptável ao IDE do Arduino: Basta renomear o arquivo example.cpp para example.ino.

An Hollywood-style fake bomb to keep presentations on time

03/24/2013 - 17:30

On the night of March, 22, we had the first official activity of our hackerspace, and a big one: SJC Lightning Talks, which brought more than 150 people to check 9 quick presentations.

When speakers have to shrink their usual 45-minute presentations to fit in time limits as small as 5 ou 10 minutes,they usually start to mess up with other speakers slots. To keep all presentations, plus registration and meals, inside our 3h limit, we had to find a way to force speakers to keep the defined time limits.

Speaker helper

03/16/2013 - 08:27

This is a Processing project that helps speakers to keep track of their presentation time

Given the presentation time, this program will display an animation that emulates an old elevator indicator, going from "ground" to the last floor. As the pointer traverses from right to left, the speaker can watch it and adjust his/her presentation time according to the time left.

MariaMole with support for Leonardo

01/30/2013 - 07:58

And then comes my Leonardo board. After 3 months since I press the "buy" button on eBay, it finally arrived here from China. And then I could, also finally, figure out what was going wrong with the Leonardo programming and fix it. So, if you have a Leonardo, go to SourceForge get MariaMole version 0.5. There are other minor bug fixes, too.

If you want to understand what was keeping MariaMole to support Leonard, you can read it here:

Writing better Arduino programs - Part 1

12/08/2012 - 08:38

If you have learnt to program using Arduino, congratulations! You're probably very excited with this new world of controlling and monitoring objects.

But, chances are that you are writing bad code. Don't be sad or mad with me by saying that. The Arduino environment brought several non-programmers to this coding world, and it droped of some software quality aspects in order to make things easier for begginers.

For example, you may haven't noticed that, but you never defined any of your functions before using that. Check this example:

void setup() {                
  pinMode(led, OUTPUT);    

void loop() {

void blink_led()
  digitalWrite(led, HIGH);
  digitalWrite(led, LOW); 

You may recognized that this is a slightly changed version of the example Blink. The only difference is that the "blinking" code was put on a separate function. If you paste this code to Arduino IDE, you'll be able to compile it and upload to your board without any problems. But you'll wont be able to use this code in virtually any other development tool.

Well, at least not without a single change: