Recent content on Janitha Karunaratne
Lately I’ve been working with large sets and analyzing them for work… and as a side effect, I’m now hooked on the art of data visualization. A few weeks ago when I was getting started, I wanted a dataset that was somehow directly related to me that would also be able to produce a cool looking graph, so I decided to map out the publicly directed chatter on the #startups irc…
Wired networks are everywhere whether you like it not. Almost every building is wired inside out, from businesses to schools to hotels. Unfortunately in most cases, little or no thought given to the physical security of the wiring. Don’t take my word for it, just lift a ceiling tile in any hallway and take a peek for your self. 
 This indirectly affect wireless networks as well, as the…
If you are ssh’ing constantly to a lot of boxes using long ssh
commands with many switches, you are doing it wrong. Make your life
easier with the ssh config file ~/.ssh/config . 
 Host home home.example.com
 HostName home.example.com
 User j
 Port 12345
 LocalForward 45901 localhost:5901
 LocalForward 40080 localhost:80
 
 Now all you need to do is…
Lately, all my primary technology news sources have been polluted with
articles about Twitter and other related
 url shortening 
 services . A part of my dies inside every time I hear
about one of these. I can understand the hype about Twitter, but the
only reason there is a hype about URL shortening is because of
Twitter. 
 I have an open suggestion to Twitter that…
Last night I was wondering how interesting it would be to have your
friends Facebook status updates, twitter tweets, and other types of
live feeds be read back as speech in real time as they are updated. 
 A coffee cup later, jFeedSpeak was written. It’s a Feed-to-Speech
script I wrote in python and it accepts any number of RSS feeds
(facebook status updates, twitter,…
Want to map out a whole bunch of telephone numbers by their location? 
 That was my Sunday afternoon project. Inspired by @joshuabaer’s tweet
looking for such service, decided to implement one just for fun
today. Sorting through the data was fun, loads of wget, bash scripts
to cut, awk, grep and process, python to mix and match, some php to
whip out a interface, and sweet…
So lately I’ve been hanging out a lot at Coffee Station and on campus
using my Laptop. Doing this, one of the biggest annoyances I had was
whenever I had to leave the area to get a coffee or something, I risk
leaving the Laptop unattended. Using a cable lock every time was
annoying, so instead I wrote a anti theft alarm script that utilizes
the Laptop’s built in…
A few days ago I was messing around with some face detection libraries
when an idea hit me, what better place to look for faces than
Facebook! After a few hours and a copious amounts of coffee, I started
piling one idea after other until I ended with a rather interesting
combination of technologies and data sources. 
 Before I explain any further, please step back for a second…
When I finally have a need and I am looking for a tool/system to
accomplish that task, I tend to be extremely picky and very demanding
of certain features. This happened when I finally made up my mind to
consolidate all my photo’s in to one central system and organize
them. Pictures started coming out the woodwork, now I have a jumble of
hundreds of folders with thousands…
The other day I was trying to figure out how much I can do with
accessing only one port without tripping IDS before that
machine. Hiding a service or two services in one port. Lets take an
example, it would make more sense. 
 You have a server with only port 80 open. How can I rig the server so
it would continue to serve web data as normal on port 80 to regular
clients, but…
I got my hands on a bricked WRT350N router was trying different magic
trying to flash a new firmware and get it working. I was trying to
connect it to a serial console when I realized that on the WAN port in
the back, on the opposite side of the RJ-45 jack there were 4
pins… named UR1 UR2 UR3 UR3… that got me thinking, could those be
for a serial connection…
Sometimes it’s necessary to sort sets of data based on metrics that
are not usually recognized by a computer such as artistic quality of a
picture. For example you can sort a set of numbers in increasing or
decreasing order easily because each element in the set is comparable
with another in a manner the computer can understand. For
example 
 Given set:
5 6 4 7 3…
Almost all cellphones and carriers support SMS’s now, and sms bundles
of hundreds or unlimited plans are really cheap. One spiffy feature
that most major carriers provide is email to SMS relaying. Below are
some of the major carriers relaying addresses. 
 Alltel
1234567890@message.alltel.com

AT&T Wireless / Cingular
1234567890@mmode.com

Boost…
I wondered a few days ago why I need to press a few buttons to set the
time and start the microwave oven every time I put something in it. If
I put something in the microwave, majority of the time it’s to either
cook it or to defrost it. Instead I would much prefer if the only
thing I had to do was to put something in the microwave and press only
a single button to start…
Rest In Peace A7M266-D (March 2003 - March 2007). No… it’s not a
person, but it’s my motherboard that served me well for 4 straight
years in my main server along with two Athlon 2000 MPs. When I say
straight years, I mean it was chugging numbers, rendering random stuff
or juggling files non stop except when I was moving it around or
during hardware upgrades.…
Carl Sagan is the man. Below is one of his most popular and insightful
quotations I have ever come across, and it manages to break my mind
every time I read it. 
 
 This was a response by Sagan regarding the above photograph Voyager
1 sent back, which includes our home, Earth. 
 
 We succeeded in taking that picture [from deep space], and if you look
at it, you see…
Getting Spam these days is normal, even with several spam filters, but
what’s interesting is when the spammer’s automated scripts are
malfunctioning. Take this for example, I had a couple of these sitting
in my inbox today. 
 
 Dear member, 
 {SPUR_1} 
 {SPUR_3} 
 {SPUR_4} 
 You may find what you need here: {SPUR_DOMAIN}
Just check yourself!…
I noticed how boring my ceiling fan was just a few minutes ago. So I
decided to do a small modification to it to make it a little more
interesting. 
 
 
 I had 60 extra LEDs sitting around (excess from my LED Projector
project), so I took 4 of those, a cell phone battery, 4 resistors,
some wire and ductape (most important of them all). I had run out of
solder, so…
There have been lots of activity going on in the DIY Projector scene,
specially using a design involving a 15" LCD panel, two
 fresnel lenses , a projection lens and the
metal halide light sources. This design can be built for less than
$500 easily using all new components to project a bright and very high
quality image. 
 Last year I had helped a few people in constructing…
The more I use emacs, the more fascinating it becomes. When one starts
exploring the deep end stuff of emacs, they start to realize that
emacs isn’t a text editor after all; it’s more like a virtual
operating system, or a regular text editor on every drug known to
date. A while back I read in the O’Reilly book on how to bypass init
and start a process such as…
When you get on a trans pacific flight, you would expect everything to
go smooth. But that didn’t work out so well for me. Just a few moments
after the take off from Detroit, I look out my window to see
something weird. 
 
 I didn’t know wings were suppose to do that, and I fly somewhat
regularly. Then to take off my headphones and hear the announcement
that…
Someone mentioned to me that they don’t have a irc client today. This
is no excuse, so of course I thought I will write a article on how to
connect to a IRC channel through raw connection. For this example I am
using netcat (nc) but you can also use telnet or similar. 
 First thing to do is to Connect. For example sake, I am using
irc.freenode.org using port 6667.
It turns out Xscreensaver can do
much more than just act as a screen saver. All the different screen
savers are actually separate applications. All of these can act as
your desktop as well. First navigate into your folder where you can
find all the screen savers. If you don’t know where do
this. 
 # whereis xscreensaver
xscreensaver: /usr/bin/xscreensaver…
It seems slashdot 
along with multiple
 other 
 sources 
are reporting the working of google’s Instant Messenger service dubbed
“Google IM” based off talk.google.com, which is suppose to use the
open source IM protocol Jabber . 
 I really hope this will boost the Jabber’s popularity, and personally
I am forced to use aim now because everyone…
After starting on the Automatic Scheduler application, I have realized
there there are no simple program (there are big & bloated ones…) to
enable me to develop C++ applications to run specifically as CGI
applications which does small annoying tasks such as extracting usable
data from the POST form data. So I am developing a CGI C++ helper
library, a very simple but…
When you mix these three things, aa xine and ssh, you get the most
pointless result ever, the ability to watch movies stored in your
computer over a ssh connection in ascii art remotely. Better yet in a
secure fashion. 
 You need a few things, xine first of all along
with aa (ascii art library), and of course a ssh daemon
(optional). Now compile these up, install them, do…
Ever wonder what all the data in your hard drive sounds like? Or
simply want to kill the silence in your server room? Simple, just
direct devices into the audio device and listen to the sweet beautiful
sound of your data (or other device). Reminds me of the good old days
of 56k dialup. The more cluttered the data in your drive is, the more
interesting the sound is. As root…
It seems that I have under estimated the amount of time required by
these 5 week summer sources I am taking, which are squeezing in 15
weeks worth of information, a 3:1 compression ratio. This has crippled
most of my projects I had in mind for the summer, including this site
which is quite poorly being updated recently. The custom case design
mod I had in mind for almost 2…
Low temperatures and things that cause items to drop their temperature
dramatically fascinates me, or simply process of taking away lots of
heat energy from random items around is quite fun. And one of the
easiest ways to do this is by letting something evaporate fast taking
away heat from around it, and normal gases in the liquid state do this
really well. Liquid Nitrogen is…
Washing cloths to be me is quite possibly the most boring and time
consuming thing, and making this process faster is and optimal is on
the top of my list. I hate shopping for cloths, so I expect the few
cloths I do have (in which most are free from Lan Parties and other
events) not to fade away and go to shit, so I take the daunting task
of really reading what the stupid label…
Much improvements were done to the dry ice cannon in the past few
days. Old version 1.0 is below. 
 
 As you can the only mechanism implemented on this was a simple one way
valve to put in compressed air, and on one side a screw in cap which
which was put in place to drop the dry ice from. But then we realized
that the screw in cap was very leaky. After insane amounts of…
Below is how I made a Asynchronous linear induction motor which is
also known as a gauss rifle or simply a coil gun at 2am in 15
minutes. 
 After beating the crap out of an old polaroid camera I picked up a few
weeks back from a garage sale for $1, I noticed a few really
interesting components. A somewhat large capacitor (409uF 350v), and a
solenoid (1cm long one, very…
It seems that I have finally come to a decision about the perfect
Window Manager (at least for me), and that is just simply vanilla
enlightenment. I am not sure what else to ask for, I have tried
fluxbox, blackbox, windowmanager, along with several more. Some had
nice features, like the fluxbox/black box with the extremly
minimalistic, but it was too minimalistic. enlightenment…
This was done about a year ago, when I was too lazy to carry my whole
computer to some event due to its size and unease of carrying. When
such situation comes up, one starts to think of ways to reduce the
weight. The problem with it was the steel computer case, which
accounted for about 80% of the total mass, which was no fun. Then it
hit me, what I needed was to somehow rip…
As you can see, I have finally set up and organized a website. A
proper one. I had one before, but the only thing it said was “under
construction”. Expect to find ideas and projects I am currently
working on, and other interesting things. This will not be a site
where I come to whine about my daily events and ‘vent’ into the world,
as most people would…
Hi, I’m Janitha. I solve problems and make stuff.
You can reach me at janitha@janitha.com 
 https://keybase.io/janitha 
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