Several times, on a computer projecting system, we don't have the projector and the projection screen correctly aligned. Some times we don't even have a flat (plane) screen. Other times we wan't to join the images of many projectors in order to comprise a single, larger image.

UPDATE: I made a new version of this software. Check the link at the bottom of this page

Have you ever seen someone making a drawing on an oscilloscope screen? Did you ever wanted to? Well, now you can. And, by "now", I'm not saying that you need to buy some hardware or mount some hacking device to create your drawing. "Now" is right now.

Let me introduce you to Rabiscoscopio: A simple and free software that convert your drawings into oscilloscope images.

Purpurina ("Glitter" in Portuguese) is an open-source device for light-painting photography. It can be used to create beautiful and surreal images, using the light as a paintbrush over the photographed scenario.

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.

This is my home-made arcade machine:

I used to have this full-size retro arcade that I've also done, but that thing was a huge monster at my tiny apartment. This new guy is small, and has been a huge success when people come to my place. I usually just leave it connected to the TV, when I'm expecting to receive some guests.

The project is really simple:

Tired of attending your cat's requests to open the faucet? I was. And also my region is going through one of the biggest droughts in its history

However, those comercial cat fountains are very expensive here, and they keep the water flowing the whole day, even when no cat is around.

So I solved all my problems by building this Automatic Cat Fountain. It's really simple, the parts are cheap and easy to find, and it takes only a few hours to build. And it's open-source! :)

Neste sábado (14/fevereiro - Carnaval) tivemos mais um tradicional encontro "Automação no Parque", com a turminha remanescente do Sabugosa hackerspace. Como em todos os encontros, sempre tem várias coisas acontecendo ao mesmo tempo.

After months of good work, the quality of my 3D prints started decaying until there was no extrusion at all.

This is usually caused by a clogged nozzle: low quality impure ABS filaments leave traces of other material sticked to the nozzle channel. You can solve this easily by leaving the nozzle soaked on acetone overnight.

But after I removed the nozzle to clean it, I realized that I sill couldn't extrude. So, I disassembled the whole extruder and saw that the fault was on the teflon (PTFE) tube, as you can see on the following image:

ESP-8266 is an easy and low-cost alternative to the expensive Arduino WiFi shields. While those shields can cost over USD 50, you can find an ESP module for less that USD 3 at ebay

There are several ESP module models around there. All of them are based on the same IC. This article is based on the ESP-01, which is, probably, the most common model.

All ESP-8266 modules are programable. You can use the default factory firmware or you can write your own firmware and upload it to your module. My module came with the firmware version 0018000902-AI03.

Bem vindo à minha horta wifi:

A caixinha amarela acima monitora a umidade do solo e a quantidade de luz recebida pelas plantas. Estes dados são capturados continuamente, e enviados a um servidor, que gera relatórios e alarmes: