Fake Hollywood bomb

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.

Home-made arcade machine

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:

Cat Fountain

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! :)

Unclogging a 3D printer extruder

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:

Connecting your Arduino to WiFi via an ESP-8266 module

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.

Kitchen Gas Leakage Alarm

This is a very simple weekend project: A gas leakage alarm for your kitchen.

It's based on a MQ-2 sensor, which detects LGP (Liquefied Petroleum Gas), alcohol, smoke, propane and some other gases. It comes froma family of sensors, all of them with the same pinout, so any project using them can be easily "ported" to detect different gases. For example, MQ-7 detects Carbon Monoxide and ME2-O2 detects Oxigen.

Poor man's motion capture

This is the result of my home-made motion capture system. I've used it to animate videogame characters for another project

Of course, there's a lot of free game assets around the net, but, as usually, it's funnier to go with your own solution.

On the video, the character seems to lose a keyframe, but I've managed to fix this at the game


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