Then it hit me. What if Alfred be able to do it? I’m a developer, and Alfred is extensible, so I got onto a new project to develop an Alfred extension to do this, just like Google does. Today I think my project is stable enough so I decided to go public with it. You can download the extension here.

How to use it

I’m assuming you’re already an Alfred user with the Powerpack installed. You’ll also be needing Growl to be able to see the results of your queries. After downloading and installing this extension, you can trigger unit conversions with the keyword cv (as in convert). You can change that to something else of your preference, of course.

Performing a unit conversion query with Alfred

Using it is simple. You open the Alfred command window, type the extension keyword and the query and press ENTER. You’ll see the results shown in a Growl notification, and you’ll also get the results copied to the clipboard.

As for the queries and how to phrase them, I won’t make an exhaustive explanation here. I rather prefer to list here some examples of valid unit conversion queries that you can perform. This will give you an idea of how to phrase queries and a sample of the variety of units supported out-of-the-box. The following are examples of valid queries. Be sure to type them in Alfred preceded with the keyword for the extension.

• 10 km in miles
• 100 kph in miles per hour
• 50 pounds in kg
• 134.5 seconds in minutes
• 200 milliliters in cubic centimeters
• 2 acre foot per year in liters per day
• 3 newtons in lb ft / square second
• -40 fahrenheit in celcius
• 1 megaparsec in astronomical units
• 6.5e17 decays per minute in megabecquerels
• 10 gallons in liters

Note how you can refer to units by their long or short name, and also how unit prefixes (like kilo-, milli-, etc.) are supported too. Long unit names can be given in plural or singular form.

You can also convert sums of quantities…

• 1.5 weeks + 2 days in hours
• 2 miles, 3 furlongs and 25 yards in km
• 100 km/h, 10 m/s and 2 feet per minute in miles per hour
• 3 hours 15 minutes in seconds

…or omit certain parts of the query. The following are valid queries too. Try them to see the results.

• 3 leagues
• ounces in grams
• parsec
• 3 minutes 23 seconds

The math is performed internally without loss of precision, so you get very accurate results. Also, you can work with really large or small numbers. Try the following queries:

• 1 cubic parsec in cubic picometers
• 1e-50 meV in petajoules

Supported units and measurements

From the examples above you can get an idea of the range of units and physical properties it supports. I won’t list all the units here, but just to give an idea, this extension supports units over a wide variety of physical properties, most of which are listed below.

Most common properties

Length (distance), time, temperature, mass (weight), area, volume, density, speed, acceleration, angular velocity, momentum, force, pressure, work (energy), power, plane angle, solid angle, amount of substance.

Electricity and magnetism

Electric current, electric charge, voltage, resistance/conductance, capacitance, magnetic flux, inductance.

Light and radiation

Luminous intensity, luminous flux, illuminance, luminous energy (quantity of light), radiation dose, ionizing radiation, radioactivity.

Other properties

Catalytic activity, reciprocal length, acoustic impedance and resistance, thermal resistance, dynamic viscosity, molar concentration, mass flow, volumetric flow.

In addition to physical phenomena, this extension also supports conversion of currency and units of digital information, such as data size and data rate (e.g. bits, bytes, kilobytes, kbits per second). In this last case, in addition to the SI prefixes, it also supports binary prefixes like kibi-, mebi-, etc.

A note about currency exchange rates

In the case of currency conversion, the extension will attempt to update currency exchange rates from the Internet at most once every hour, but it keeps a local cached version. The extension can only update the cached version when it’s used, even if it is not used for currency conversion. But if you spend many hours or days without triggering the extension while being online, you’ll end up with outdated currency conversions.

Also note that currency exchange rates given by this application are for information purposes only. It will always be approximate to what you’ll actually get when exchanging money. For your information, currency exchange rates are obtained by the extension from a wonderful public API hosted at openexchangerates.org, which is based on the currency bot project.

What’s next

First of all, enjoy it. You can also contact me to send feedback, bug reports and suggestions of improvements and new features.

If you’re a developer, you can also contribute to the unit conversion engine that powers this extension. It’s an open source Java library that I authored and published on github. You can check it out here.

Download the Alfred Unit Conversion Extension

Performing unit conversion queries using Google's search box.

Imagine if you could that offline, or even be able to have this functionality available to incorporate it in scripts or other programs as well. Imagine you could have this functionality as an extension in Mac’s AlfredApp.

Introducing Metric: A Unit Conversion Library for Java

I needed this functionality to develop an extension for Alfred, the most wonderful Mac launcher, and I wanted it to work offline, without having to retrieve the results from Google or another online source. So I created a Java library that’s capable of performing unit conversion queries expressed in natural English. I called it simply Metric, made it open source, and published it on Github. You can clone it, fork it, play with it or contribute back if you will. The code is fairly well documented and organized. The library includes some supporting sub-libraries that may be used independently in other projects, including a plural/singular inflector for the English language.

Metric meets Alfred

The original goal of developing a library like Metric was to use it as an Alfred extension. Alfred (http://www.alfredapp.com/) is a wonderful productivity application for Mac, much like Quicksilver or Google’s Quick Search Box, but  a little bit better in my opinion. You can grab a copy of Metric as an Alfred extension here. After you install this extension, you can type unit conversion queries on Alfred using cv as keyword.

Performing a unit conversion query with Alfred

This Alfred extension shows the results of the conversion using Growl, but I guess if you already have a Mac chances are that you Growl installed. If not, you can get it here.

Links and resources

• Metric source code repository on Github
• Unit Conversion extension for AlfredApp
• Alfred App and Growl

I was most recently getting along with PlainText, a note-taking iPhone app that stores your notes in a folder in your Dropbox account. It’s a very simple yet powerful concept, specially for those of us who already use Dropbox. Instead of having yet another syncing environment for notes, they already take advantage of the Dropbox user base out there.

The interface is simple and visually appealing, yet out of the ordinary. The notes are always in sync between the iPhone and the computers thanks to Dropbox, and I can get to organize my notes into folders. No more nasty notes from the default iPhone notes app getting into my mail (whoever thought that notes were related to mail is insane).

But then the simple got even simpler…

Today I stumbled on a simpler and better alternative: SimpleNote. It’s an online web service with an iPhone app, an API, and a set of third-party supporting apps and tools that complete the picture.

Great features

The killer features over PlainText are tagging, versioning and sharing. Yes, you read it right.

With SimpleNote you organize your notes with tags, instead of placing them on folders. You can associate any number of tags to a single note, and you can also list all notes regardless of tagging. It’s of course a bit unfair to make this comparison against PlainText, since its Dropbox storage paradigm would not allow for anything else than folders.

You can also share notes with other people. I did not found a way to do this on the web app, although there should be. In the iPhone app you can activate sharing, and it’ll give you a URL, plus the possibility to send an email with an invitation to the share note. I haven’t tested this though because I still have no one on SimpleNote to share with.

Also worth mentioning are its versioning capabilities. You can check past versions of your notes, up to a limit of 10 versions in the past. There’s a premium non-free plan for a mere $12 a year (that’s $1 per month) which extends this limit to 30, plus extra features such as no ads, better support, creating notes by email and more.

On the desktop side of the equation

On the desktop side there’s no “official” app for SimpleNote, but on the downloads page I found a couple of third-party client applications for Windows and Mac that I am really liking. On the Mac side we have JustNotes, which syncs with the online service and supports tagging and searching. On the Windows side I was not expecting much, but it turns out that ResophNotes is a pretty good client with email, printing and Markdown support. The downside is that it does not support tagging. It did not support tagging until recently, so be sure to have the latest version.

There are some other options for both platforms, specially for the Mac, and there are options for Android as well. There’s even an Emacs package and extensions for Firefox and Chrome!

What other alternative services do you use for note-taking on the iPhone with desktop-sync support?

Since I don’t have $14 to spare on this app, and I also do not really think it’s worth it, I went on to find some alternative softwares for this. This wonderful website alternativeto.net allows you to look for software applications on certain platforms and find out about some other softwares that could serve as alternatives or equivalents, either in the same platform but free, or perhaps because you are looking for an alternative to switch or use in another platform.

In this case I wanted to find an alternative to Divvy also for the Mac, but free as in beer. I didn’t really care that much if it was open source, although it would be a plus. Thankfully I found ShiftIt, wich is not only free and open source, but also even better than Divvy in my opinion.

ShiftIt, just as Divvy, sits unobtrusively in the menu bar. It would be nicer if it had an icon instead of text, but that’s a minor complain. What makes it great is that it already comes with sensible default shortcuts for positioning windows in logical default locations, such as covering the left or right halves of the screen, or top, or bottom. Plus covering the four screen areas formed by dividing it in four parts: top left, top right, bottom left and bottom right. And of course, two more options for full screen and center a window respectively.

When I saw this I immediately uninstalled Divvy. I found in ShiftIt preconfigured what I was manually configuring in Divvy just a few minutes ago. Exactly those very options, perhaps with some similar shortcuts I invented. Somebody would say that ShiftIt should allow you to customize the shortcuts and/or allow you to add some other configurations, but I guess they just want to keep it simple, and as simple as it is, it is still useful and able to replace Divvy 90% of the time.

I also found out about other similar alternatives, like SizeUp, Cinch, etc. But I only really tried the free one, as this was my goal. But maybe you want to try them all and stick with what you think is the best. And don’t be shy about making any suggestions here, either free software or not.

Do you know about any alternatives to Divvy and ShiftIt, be it for the Mac or not? Maybe with better or different features?

Google Chrome running on Leopard

I received with great joy today the news that Google’s web browser, Google Chrome, has been officially released for Mac (and Linux), even if it is still tagged as beta.

Since its first appearance in the web browsers scene more than a year ago, Google Chrome has been a source of innovation the area, with isolated processes per tabs, a revolutionary javascript engine, and the great news that its source code would be freely available as open source.

Sure that many were worried by its controversial privacy-violation practices, but the openness of its source code will always allow anyone with the know-how to modify it to their own needs, and that of the worried ones (me included to some extent, I’ll give you that). Indeed there’s a project called Iron which offers precisely that: Google Chrome for the privacy fanatics.

But just as about anything that’s new, Chrome for the Mac and Linux has several shortcomings compared to its Windows version that most people are accustomed to. The Apple Blog notes a few of these issues, at least those that affect Mac users, which are probably the same features not present yet in the Linux version as well. The most striking absence, at least for me, is Gears, of which I have become extremely dependent since Gmail offline appeared. This one even comes as a great negative surprise, since Chrome is the only browser that comes with Gears bundled, and being both (Gears and Chrome) from the same provider, I kind of assumed that they were inseparable

Not everything is bad news though. Google Chrome for both platforms integrates itself very well, or so they say. At least for the Mac I can confirm it. Google Chrome feels more like a Mac app than Opera does, which is kind of surprising if you take into account that Opera has been around for the Mac since, well, forever, I guess. And according to the official announcement in Google Chrome’s blog post about this beta release, Chrome seems to blend just well with a variety of GTK themes.

I really hope that this browser and the open source project behind it continue to improve. This news today is indeed a big step, and I’m sure those differences in feature sets will become smaller with time. I also hope that projects similar to the Iron alternative appear for other platforms too. Its open source nature makes it possible for this to come true.

Having migrated to Mac not so long ago, I am aware that Apple’s default picture managing software already had this feature, although I cannot really say how it worked. I did try iPhoto for a few hours on my first days with my new MacBook, but I immediately hated it for trying to hide my pictures from me. Picasa at least respects my organizational scheme at the file-system level, instead of imposing me one, and I am still able to access my pictures through Finder.

As Picasa recognizes faces, you can add information about this people as you tag them. It can even use (and sync with) your Google Account contacts if you are signed in to Picasa Web Albums. It would be nice though, if it gave you the choice in Mac OS X to use the system’s address book instead, or alternatively. And as a side note, face recognition is not the only new feature of Picasa 3.5, also including in the package geo-tagging with a Google Maps panel withing Picasa’s interface, and more. For the time being, this new version has only been released for Windows and Mac in its English version. Non-English speaking users, or Linux fans, will have to wait a bit. Not to say that Mac people should be completely happy though, because I am still waiting for Picasa to port the very nice picture viewer that it installs on Windows.

In the mean time, I can enjoy watching a slideshow of pictures with me and my girlfriend in it, or detailing how my niece’s face has changed over time since she was born just a few years ago. Face recognition rocks. But beware, if you are a fanatic of organization, it can get become addictive!

PS: I wanted to include a screenshot, but I don’t feel right to publish an image with lots of pictures of faces and names of actual people, without their consent, and painting black areas over names and faces renders the screenshot useless for its original purpose. So I am going on without it. If you want to see it working, download the program and give it a try.

My new MacBook seen from behind

I finally ended this mac envy that has been consuming me for the last few months. Being a Ruby on Rails developer for some time now, all those screencasts and tutorials always based in MacOS X and Textmate have had an effect on me. Although it seems that I’ll be playing mostly with xcode instead of Textmate for some time, but it’s sexy to have Textmate just an inch away in case I need it.

PS: For the couple of friends of mine that already had a Mac, my envy was not malicious.