The BiT Bang Theory: 2013

Video of Episode 2 of Portuguese Makers Hangouts

Hi everyone :)

As I said in my last post, I have been invited to participate in Episode 2 of the Portuguese Makers Hangouts. It was on the 21st of May at 22:00 (Lisbon time). In case you weren't able to watch it live, here's the full hangout. It's in portuguese but you'll still be able to see the projects that were shown. I hope you like it! :) .

Take care! :)

Did you find this post helpful? Do you wish to contribute to other projects regarding computer science, electronics, robotics or mechatronics that will be posted in this blog? If you wish to do so, you can donate via paypal using the button below. Thanks! :)

Portuguese Makers Hangout - Episode 2

Hi! :)

Recently I've been invited to participate in Episode 2 of the Portuguese Makers Hangouts. Quoting from the webpage, "the purpose of these Hangouts is to gather the Portuguese Makers and get the world to know about their talents and their projects". They are used to share experiences and create contents around the best of the DIY/Make scene in our country.

(Click the photo for better resolution in Picasa Photostream)

From 3 to 5 participants are invited for each hangout and their goal is to show the audience their creations, talk about the problems and challenges they had while building them and their lessons learned. Live demos are usually provided :).
Anything that mixes creativity and art with technology counts. A robot, a quadcopter, a cool gadget, a 3D printer, a new technique or material, anything that comes out of the inventor's obsession to create things will do.
All the hangouts are recorded, saved, and made available on as many channels as possible. Currently, the Portuguese Makers Community is aiming to do an Hangout every month, but this might change (for the best).
In this hangout I'll be showing and talking about my homemade CNCs, specially TheMaker2, and some robotics stuff.
In this hangout there will also be participating the Portuguese Makers Nuno Correia showing his printrbot and João Frazão showing Ziphius (that recently won the Engadget's Insert Coin contest) and some other projects.

The live feed will begin on the 21st of May, at 22:00 Lisbon Time. You can confirm your attendance to the event here on G+. Share this event with everyone that may be interested :).
If you wish, you can see the 1st Episode of the Portuguese Makers Hangout here.
You can also join the Portuguese Makers community here.

Take care! :)

How to Download all photos from your Picasa account in Ubuntu

Hi! :)

This short post follows my recent post on How to Download Complete Albums from Picasa in Ubuntu. A blog reader asked on the blog's facebook page on how could he download all the photos and after a short research I found the solution.

(Click the photo for better resolution in Picasa Photostream)

To download the entire photo set from a specific user you'll need to have two programs installed: Mozilla Firefox and the Firefox extension DownthemAll. In a short way, here's what you have to do:

Install Mozilla Firefox;
Install the Firefox extension DownthemAll;
Open the following link in Firefox:
```
http://picasaweb.google.com/data/feed/base/user/USERNAME?alt=rss&kind=photo&access=public&start-index=1&max-results=1000&imgmax=d
```
You'll have to replace the "USERNAME" part with the correct username. The last parameter of the RSS link, "1000", means that the feed will have up to 1000 photos. If you have more pictures than that, just change it to a value that suits your needs.
Right click anywhere in the page, select DownThemAll and then the Links tab. The Pictures and Media stuff are just thumbnails.
Make sure the JPEG images filter is selected, choose the destination folder and click Start

After this process you should have the selected user's complete photo set being downloaded into your hard drive. Easy, isn't it? :)

Take care! :)

High torque encoded DC motors for robots from car window motors

Hi! As I mentioned in my latest post on how to make Tiny Encoders for DC Motors, some time ago I went to a junkyard to salvage two powerful high torque DC motors from car window lifting systems to use in a robot. I had to take my own tools and dismantle the doors from an old Renault Laguna myself to get the motors and then managed to negotiate with the seller to buy both motors for 25€, which I think was quite cheap.

(Click the photo for better resolution in Picasa Photostream)

Hi again! Today I'll show you a small part of a project that I did a long time ago and, due to some changes of plans I didn't end up using. Anyway, maybe this small project might come up handy for you.
Some time ago I went to a junkyard to salvage two powerful high torque DC motors from car window lifting systems to use in a robot and had to make some encoders to put in them. The space where I could put them was really small so I had to find really small sensors and design a PCB for them in Kicad.
The sensors that I used were Vishay's TCUT1300 IR Transmissive Sensor with photo-transistor output. Following the sensor's datasheet I designed a small board (10x8mm) that would fit in the space that I had available.

(Click the photo for better resolution in Picasa Photostream)

Hi there! :)

As you might have already noticed, all the photos used in this blog are stored in Picasa Web albums which was the photo service that, in my opinion, is the winner in a Flickr vs Picasa battle (see the Picasa/Flickr comparison post here). However, I don't have Picasa installed and sometimes I just have the need to download an entire album. An option would be to download the photos, one by one, but, gladly, there is an easy workaround to get a complete album. :)

(Click the photo for better resolution in Picasa Photostream)

To do the workaround that I'm going to describe you'll need to have two programs installed: Mozilla Firefox and the Firefox extension DownthemAll. In a short way, here's what you have to do:

Install Mozilla Firefox;
Install the Firefox extension DownthemAll;
Go to the page of the Picasa album that you wish to download and click the RSS link on the right;
When the RSS page opens, add "&imgmax=d", without quotes, to the end of the URL and then reload the page. Doing this will allow you to download the images in their original sizes.
Right click anywhere in the page, select DownThemAll and then the Links tab. The Pictures and Media stuff are just thumbnails.
Make sure the JPEG images filter is selected, choose the destination folder and click Start

After this process you should have the entire album being downloaded into your hard drive. Easy, isn't it? :)

Take care! :)

Zeitgeist-daemon using all the CPU

Hi there! :)

Some time ago I had a problem in my Ubuntu installation. All of a sudden, I had some weird process using all the CPU, causing the computer to become really slow and hot and making the laptop fans go crazy. Since I use conky, I quickly verified that the weird process causing all of it was zeitgeist-daemon. Zeitgeist-daemon is a process that keeps track of activities on your system (file usage, browser history, calendar events, etc.) and logs them into a central database. It does not only create a chronologic register, but also supports tagging and can establish relationships between activities.

Maybe due to some buggy update it went nuts and was keeping the whole CPU busy.

I tried to kill the process but it would just show up again and keep doing the same.

To temporarily disable it I had to perform a few steps (source):

Add the Zeitgeist PPA to the system:

sudo add-apt-repository ppa:zeitgeist/ppa

Install the latest version of Zeitgeist:

sudo apt-get update
sudo apt-get upgrade

Restart zeitgeist-daemon
```
zeitgeist-daemon --replace
```

Install activity-log-manager

sudo apt-get install activity-log-manager

Open activity-log-manager and click the "Logging active button" in the bottom right corner of the window to disable logging.

(Click the photo for better resolution in Picasa Photostream)

After disabling it in the activity-log-manager, all the problems were gone and everything was working as desired again :) .

If desired, it can be turned on again by clicking the same button.

It happened some time ago and I have reinstalled Ubuntu in the meantime and I have zeitgeist-daemon turned on ever since and never got the same problem again. I guess it was just due to a buggy update. Anyway, if it happens to you, now you know how to fix it :) .

Take care! :)

Steve Jobs Biography: must read!

Hi! :)

This post is going to be a little different from the usual posts. This time I'll make a short post about an excellent book that I've just finished reading: the Steve Jobs biography by Walter Isaacson.

And before you think it, no, I'm not an Apple fanboy nor I am against it. I've been using linux for some years now and I will keep myself as being a proud linux user :P. I enjoy my freedom to do whatever I want with my computer and the feeling of being learning something new (almost) every time I use my computer. :) I will not enter the "Apple vs Window$ vs Linux" domain since this post is about a great book, not about the typical flame wars that flood the internet every day.

Sticking to the title of this post, if you like technology, computing, innovation, and leadership, then you should definitely read this book. Although the name of the book is the biography of Steve Jobs, it is much more than that. You even forget it is a man's biography because it features lots of cool things such as the history of modern personal computers, music players and cell phones. By reading it you'll get to know how it all started, who were the creators and the geniuses behind the great innovations that led to existence of the device that you're using to read this blog today.

Hi! Recently I've been developing a GSM access control system for eLab Hackerspace using an old Siemens C55 cell phone and, as such, I needed a data cable to connect it to a PIC microcontroller. I searched on ebay for one but it turned out that they were a little expensive and I began thinking about a way to make myself a data cable.

(Click the photo for better resolution in Picasa Photostream)

Luckily, after searching for a while in my "old power supplies box" (a box where I store all the old phone chargers and power supplies), I found two chargers for old Siemens phones, having the connector that I needed. However, I quickly realized that they only had the VCC and GND pins and I needed a connector with Tx and Rx pins too.

Since I had two chargers I decided to try to modify the connector of one of them to add two more pins and it worked perfectly! :)

Hi there! Today I'll show you a simple but very useful tip for your hacking sessions in your home lab or local maker/hackerspace.

Probably sometimes you want to power some device from your laptop's USB or phone charger, but the device has a DC barrel power connector and there you go and make a USB A to DC barrel connector. Then, in some other day you actually need the same thing but with a micro USB, or a mini USB, or a USB B, or a thinner barrel connector, or a larger connector, or alligator clips, or a longer cable, or a shorter one, and so on... The problem is that after some time you'll end up with lots of connector converter cables and you'll still find yourself needing a different connector converter cable. Well, I'm going to share with you a simple solution to avoid making lots and lots of cables.

(Click the photo for better resolution in Picasa Photostream)

Hi! In this post I'm going to explain you one of those things that the music industry doesn't want you to know: how to record audio playing in your computer. :)

Some years ago, back in the days when I was still using Micro$oft Windows XP, I remember that in the sound properties there was an option named "stereo mix" that would allow you to do record the audio being sent to the output of your sound card. However, from what I've read some time ago, that useful option has vanished from the sound controls in more recent versions of Micro$oft Windows.

When I heard about it I started wondering why would they remove a useful feature from the audio options. I googled about it and the history is that the music industry made some pressure next to sound card manufacturers, Micro$oft and Apple so that they would drop that feature in hardware and software, so that people wouldn't be able to copy music. If the history is true or false, I do not now, but, honestly, it wouldn't surprise me and certainly is a kind of measure that fits within the spirit of SOPA, PIPA, ACTA, etc. : limiting the freedom of people to get money at all cost.

However, using linux gives you back that freedom. Moreover, using the audio-recorder application you can do it in an even better way! :)

(Click the photo for better resolution in Picasa Photostream)

The audio-recorder application allows you to record audio being played by any program of your choice, instead of the final sound card output mix. To install it you can download the appropriate package for your Ubuntu version and computer architecture (32- or 64-bit) here.

Hello everyone! :) In the title of this blog I mention that it is also about robotics. However, and to be honest, I've realized that I haven't posted much stuff about it. I hope to fix that in the following posts since recently I've finally finished some robot projects that I have been doing in the past months. Unfortunately I can't publish them yet. Maybe in a month or two :) Anyway, I'll start with a simple post regarding a simple but very useful part for small robots: ball casters!

You can buy ball casters from several robotics shops online and they're not the most expensive thing on earth. However, there are other options that can be cheaper and will save you from the waiting until you receive the ball casters that you may order from shops online. Some of the options fit in the spirit of Green Robotics, which is the idea of reusing and recycling everyday things to make robots. I'm going to show you three options that may suit your needs :) .

(Click the photo for better resolution in Picasa Photostream)

I'll start with the option that I think to be the best of the three that I'm going to talk about. See the shiny metal balls stuck in a white plastic piece? They look really good, don't they? :)

Hi there! I don't know if you've heard about it but this week we had some great news for the open source community and Linux: LibreOffice 4.0 has just been released. :) I'm not going to describe all the new features and improvements since you'll get a better glance at them by visiting the release notes. I'll just point out four of them which I think to be the most significant:

(Click the photo for better resolution in Picasa Photostream)

Better interoperability - Interoperability with other file formats is a very important feature for any user and a critical one for enterprise users;
Remote control Android app for presentations - a month ago I was just discussing with my brother how this would be cool to do and gladly the LibreOffice development team made it a reality. Now you can control and view the presentations simultaneously in your Android phone or tablet;
Preetier User Interface - it now supports Firefox Themes. Now you can customize the looks of your Libreoffice instalation;
Better Performance - faster, faster and... did I already say faster?

Hi! I have some good news about this blog! :) Probably you've noticed the little Portuguese flags at the beginning and at the end of each post. Well, they're direct links for The Bit Bang Theory blog's Portuguese twin brother: Teoria do Bit Bang :) .

When I started this blog I decided to write in english for several reasons:

We no longer live in our street, village, city, country, etc. We live in a global world. With the evolution of Internet we now have access to things made on the other side of the world in a matter fo seconds;
English is the universal language;
Portugal is a really small country and I thought that the number of readers would be rather small;
Most of the Portuguese people that are interested in the things written in this blog understand English pretty well.

However, after one year and a few months of blogging, after creating a Hackerspace with some friends, after knowing some more people with the same interests and after seeing that Portuguese people are the #2 readers of this blog (being people from the United States of America the #1) I decided to create a twin brother for this blog and embrace some new objectives:

Provide technical information regarding robotics, electronics, computer science, etc. to Portuguese readers;
Show some people that technical stuff doesn't happen only in universities and big companies, it can happen at home too, and it can happen here, in Portugal;
Motivate others with the same interests to get into electronics, robotics, mechatronics, computer science, etc..

So, if you're Portuguese, from now on you can read this blog in your mother language :) If you're not, you can still read it in English. I hope this to be a good decision and a big step forward for this blog :) .

Take care!

The BiT Bang Theory

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Video of Episode 2 of Portuguese Makers Hangouts

Portuguese Makers Hangout - Episode 2

How to Download all photos from your Picasa account in Ubuntu

High torque encoded DC motors for robots from car window motors

Tiny Encoders for DC motors

How to Download Complete Albums from Picasa in Ubuntu

Zeitgeist-daemon using all the CPU

Steve Jobs Biography: must read!

Making a Siemens C55 Data Cable

Lab tip for power connectors

Record Audio playing in your computer

Cheap Ball Casters for Small Robots

How to Install LibreOffice 4.0 in Ubuntu 12.04

The Bit Bang Theory's Portuguese twin brother: Teoria do Bit Bang