Karol Krizka

PSP Go Looks Nice

Karol Krizka — Tue, 02 Jun 2009 19:24:08 +0000

I haven’t touched the PSP scene in some while, but I’ve just got more interested. Apparently Sony is coming out with a new model (pictured above), with a lot of cool hardware changes. They actually almost complete my old wishlist!

Ditch the UMD drive. UMDs are hard to carry around and take a lot of space. Sony could replace the UMD drive with other additions that I will mention below.
Built-in camera. With a built-in camera one could use the PSP to take pictures. The PSP screen is quite large can could provide great previews.
Built-in microphone. With Skype integration, PSP could become a great cellphone. The only problem would be that it is a bit large. (Ok, there is one in PSP-3000)
Bluetooth. I just love Bluetooth enabled devices. They are easy to connect with the computer and you do not have to carry around any cables.
E-Mail and RSS Newsfeed client. Both are already available as homebrew applications.

Of course, my wishlist grew after I got my iPod Touch. Right now, I think it would be nice if PSP got a touch screen. It would make typing words much easier and is a very natural way to control some games. Another wish is to be able to play homebrew games out of the box. The new PSP has already an internal drive, so this seems like a good idea. Sony does not have to allow low level languages (C/C++) with access to low level features of the hardware, which can be used to play pirated games. Something like a Python interpreter or even LUA Script would be very nice!

As for the games coming out for it, there are some great titles:

Gran Turismo PSP
LittleBigPlanet PSP
Jak & Daxter
Metal Gear Solid

I’ve played older version of 3/4 of the games, and they were all pretty good. I might actually buy PSP Go, as long as someone figures out a way to put custom firmware on it or have some way to play homebrew games.

FYI, EuroGamer has a nice collection of pictures of the PSP Go.

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The World of Chemistry

Karol Krizka — Mon, 01 Jun 2009 18:16:13 +0000

The European Research Commission created the above clip to promote their Marie Curie Actions initiative and science in general. It’s quite cleverly done, since it demonstrates many of the common themes in basic chemistry (ionic vs conveland bonding, what happens when you mix and alkaly metal with water). Now my question is; where is the physics version?!?

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Loving Wolfram|Alpha

Karol Krizka — Sun, 31 May 2009 13:40:56 +0000

I have to say that I’m loving Wolfram’s new “search engine”, Wolfram|Alpha! As I’m going through some practice problems in David Griffiths’s Introduction to Elementary Particles, I come across this: “…determine the corresponding energy and compare it with that of an electron emitted in, say, the beta decay of tritium.” The problem is I don’t have a textbook with me where I could find that value… That’s where Wolfram|Alpha came to rescue me, as a simple search for “tritium” lead to this result:

BINGO! That’s the number (Q-value) I was looking for. Heck, I might as well throw away my PDG data booklet, because it also has entries for many of the elementary particles.

For those wondering, I was trying to calculate the minimum energy an electron emitted through beta decay would have, if it did not come from a decaying neutron but existed all along. A simple manipulation of the uncertainty principle leads a result of 49MeV, which is inconsistent (as expected) with the value returned from Wolfram|Alpha.

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John Oliver, The Daily Show and LHC

Karol Krizka — Sat, 02 May 2009 17:47:01 +0000

The Daily Show had a funny bit on the Large Hadron Collider. The main point to take from the clip, is that if the LHC does indeed destroy the world and you and your friend are the only ones left, then there is a 50/50 chance that you can recreate the human population!

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Check Out The Conficker Eye Chart

Karol Krizka — Tue, 14 Apr 2009 06:26:30 +0000

There is now a simple way to check if your computer has been infected by the infamous Conficker worm. Just point your browser to the Conficker Eye Chart, and if you see all of the images then there is a pretty good chance that you are not infected.

The test actually works on a very simple principle. The worm blocks your computer from accessing several security sites, so no images from those sites will load if you are infected. However, they also might not load because of problems with internet connection, so the test site also tries to load other random images (Random being FreeBSD, OpenBSD and Linux logos. What is the author trying to hint at?)

I wanted to share this, because it seems like quite a clever idea for detecting the worm. It is quite immune to any future variants of the worm and works without anti-virus software. Also it is platform independent, so I could check that my Linux box was not infected.

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Counting Steps With the iPod Accelerometer

Karol Krizka — Sat, 11 Apr 2009 00:02:03 +0000

During my daily run, I’ve decided that I’ll have some fun with the accelerometer in my iPod Touch. Using the RC Physics App (free from the App Store), I recorded the force felt by the iPod, hoping that I will be able to see a pattern as I run and be able to extract the number of steps taken during my run. And to no surprise, there is a pattern, as seen in the accelerometer data from a quick test run (~20 steps), shown below.

The physics, I think, behind the above graph is quite simple. As the iPod is stationary, then it only feels the force of gravity, thus the graph is centered at 1G. But as soon as I make a step, my body rises slightly. Since the body goes from stationary to moving, it must accelerate and thus the attached iPod must accelerate. If the acceleration is upward (start of the step), then the accelerometer feels a pseudo-force that is opposite to that and thus detects an increase in gravity. But what comes up, must come down, and so my body falls back to the ground at the end of my step. Since I am now acccelerating downwards, the force felt by the iPod is upwards and a decrease in gravity (remember, gravity acts down) is detected. This is then repeated for the next step.

So to extract the number of steps, all I have to do is count how many times the gravity went from greater than 1G to less than 1G. Or similary, I can count how many times gravity turned from increasing (reaching the top) to decreasing (falling back down). The latter is much simpler and allows me to filter our random shaking of the iPod during preparation. In my case, I only count a step if the detected gravity was greater than 2G. This filters out noise and, as I found experimentally, walking. The following is the cummulative number of steps as time progressed, for the data shown above:

My run consisted of around 20 steps, which is what the method detected. Also it is sensitive to me turning around, as seen in the jump at 5 seconds.

And finally, here is the step count for my actual run:

As you can see, I kept a pretty constant pace during the whole time. The only exception is the two points at which I reached a hill. I walked up those…

The next step is to see if I can get the iPod to this processing automatically via an application. I’m sure something like that already exists, but what is the fun in that?

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The First Solar Eclipse Viewed From The Moon

Karol Krizka — Sun, 01 Mar 2009 07:05:12 +0000

The above picture is a sequence of images from the first video of a solar eclipse, as seen from the moon. It was made on February 10th, 2008 by the Japanese Kaguya lunar orbiter and JAXA (Japan’s NASA) made it available online. Pretty, isn’t it?

JAXA also published a very short English press release commemorating the event.

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Sync Your iPhone/iPod With Google Calendar and Contacts

Karol Krizka — Thu, 26 Feb 2009 03:38:51 +0000

I am a big fan of the different Google services (and no, I don’t care that they know that I spend my mornings in a math lecture), so I was quite excited when I found out that it is possible to automatically synchronize your schedule kept in Google Calendar and contacts in Google Address Book with the built-in calendar and address book in an iPhone/iPod Touch. I’ve been using my iPod Touch for organization for a while now and I find it very useful. I even plan to “upgrade” to an iPhone after my current cell contract expires (or when Telus starts to offer it).

Google offers this synchronization service via an Microsoft Exchange server, which could mean that one can synchronize Google with any Exchange-enabled application. I’m currently looking if it is possible to use KDE4’s KOrganizer for this and I might post another guide later. But for now, the steps for synchronizing the iPhone are quite simple:

Back up your data! All current entries in your iPhone will be erased!
On the iPhone, go to Settings -> Mail, Contacts, Calendar -> Add Account -> Microsoft Exchange
Fill in the following fields:
- Email: Anything you want
- Domain: Leave empty
- Username: Your full Google email account (ie: user@gmail.com)
- Password: Your Google password
Click next and fill in the following fields that appear:
- Server: m.google.com
Click next and turn Mail off (not supported) and turn Contacts and Calendar on.
Click Done.
You will be warned again that any current data in your iPhone Contacts and Calendar apps will be deleted. If you agree, press Sync.
???
Profit

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Don’t Panic!

Karol Krizka — Wed, 25 Feb 2009 06:15:58 +0000

The popular webcomic XKCD published today what I think is one of their funniest comics.

Source: XKCD

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Find Files Not Under Subversion Control

Karol Krizka — Sun, 04 Jan 2009 21:02:13 +0000

Here is a quick line of code that will show you which files are not under version control. It helps me to remember which files I need to add to the repository after a long programming session.

svn status | grep -e ^?

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