Reclaiming your second monitor in OS X Lion

Upgraded to Lion?  Use dual monitors?  Notice the full screen problem?  My lab mate Rob and I found an interesting hack.

  1. Open an application in full screen mode (e.g. Terminal)
  2. Use three fingers on the trackpad and move slightly to the right or left so you are transitioning into the respective space (the ‘transition position’). Hold this position.
  3. While maintaining the transition position, launch another application.  For example, use spotlight to launch TextEdit by pressing the apple key + space and search for TextEdit. Choose it, and press enter.
  4. Still holding the transition position, wait until your application loads.
  5. Let go of the transition position by lifting your three fingers.

I stumbled across this by accident while trying to open system preferences when in full screen mode as you can see in the attached picture.

Now your second screen is not a paperweight 🙂

Wikipedia on your coffee table!

So I recently thought I had this awesome idea that you could take the “featured articles” in Wikipedia and turn them into a book or volume of books that people could buy and just keep one on their coffee table.  You may agree with me that there’s a certain serendipity associated with traditional binded books or journals that is hard to replicate when browsing the web on a desktop, laptop or iPad-like device.

I was not too surprised, a little disappointed, and pretty excited to find out that this has been done.  The most comical creation of a Wikipedia book has to go to Rob Matthews for actually attempting to bind all the featured articles.  On a more serious front, I was happy to see that PediaPress, wiki-to-print publishing service, is partnered with the Wikimedia foundation to do exactly this.  It’s integrated quite well with Wikipedia so you can click on the articles you want to include in your own book or you can select books that have already been compiled by PediaPress.

As an alternative to purchasing a book, you can also generate a PDF that you can print at your own leisure.  My only gripe when immediately trying this is that scalable content Latex equations are embedded in the PDFs as if they are images.  It still looks decent, though, and is pretty cool!

A fun electromagnetic induction demo

A couple of days ago, I had a lunchtime-preoccupation with antennas and electromagnetic induction. We observe a neat phenomenon if you put two wires near each other, and Maxwell stated the phenomenon quite eloquently in his treatise on electromagnetism.  Basically, the instant you change the voltage across one of the wires, the wire next to it (but not touching it) responds with a current that quickly goes away.

By wiggling around the voltage in certain patterns, we can find interesting ways to transmit information back and forth between one another, and through induction we can do this without direct physical contact.  These days it’s easy to take for granted the all the internets sent to us via WiFi and forget about how highly developed an area radio is.

But to get taste of the physical communication, not much is required: basically some power sources and wires. A wire can in fact be practically used as an antenna for certain radio frequencies.

A simple way to check out induction with a laptop is to see if you can transmit a song that usually plays from your speaker through the air and back to yourself.  Since the sound card does both audio input and output as well as the analog-to-digital conversion, a lot of the hairy parts are taken care of for us.

To do this, we need to have the sound output (i.e. from your headphone audio jack) go to a wire.  Next to that wire is another wire that goes into the microphone or “line in” audio jack.  Keep in mind, these are just wires–that’s all.  I just forced myself to part with the headphone that came with my music player and another that I got on an airline flight.

Wires out of headphone and microphone jacks

As you can see, the ends of the two headphones lay prostrate next to the two wires connected into the microphone and headphone jacks:

Close up of decapitated headphones microphone and headphone jacks

So, now all you have to do is start up some music and record the input with some audio recording program (I used GarageBand since I’m on a Mac):

Capturing inducted audio

The green bars towards the middle-right wiggle around while recording indicating that the wire is receiving something.  Doing the same thing without the wires in the line in and out yields no green bars wiggling around.

Because there’s so much power loss, the signal is faint, so I digitally amplified it some in the software.  But horray! I rather shittily transmitted sound back tomyself over air via just two wires.  This, I think, is a neat way to illustrate induction.  Listen for yourself. You’ll need to turn up your volume a bit.