It’s finally here. One of the “three recognizable rings in the world” is sitting on my finger. I didn’t take my camera to Ring Delivery, which was held last night at the Boston Public Library, but I did get a few shots of the ring this morning. The lighting conditions weren’t great, though; I’ll try to get some better shots some other time.
Edit: here are a few full-resolution (4000×3000) photos using longer exposure times.
Today was the first warm day in quite a while here in Cambridge, so I decided to go out (*gasp!*) and walk along Memorial Drive and shoot a few pictures with my camera.
For some pictures, I used my Tiffen Sky filter (blocks UV). On others, I used my polarizing filter (also from Tiffen) to get bluer skies. On some, I used both, but the vignetting was particularly bad… I have to zoom in quite a bit (~3x) to prevent it, or I can just crop the picture later.
MIT’s yearbook club, Technique, sponsors a fun little event every year called ADITL — “A Day in the Life” (MIT does everything in acronyms and numbers, remember?). Basically, the group invites students to bring their cameras around from 12am Thursday, September 24 to following midnight. The goal: take pictures of the things you typically do during the day. I snapped a few photos; some were a little better than others. I wasn’t nearly as diligent as I planned to be and I missed the entire night, so the end result wasn’t great. Next year, I’ll try much harder to do a good job.
Take a look here:
http://jwcxz.com/pictures/aditl09
Well, yesterday, I finished moving back into my dorm.
Look familiar? It’s the same room as last year, plus my new computer. My dad and I built the cabinet it’s sitting on from scratch last week. The painting on the wall was done by a friend of mine.
Classes start on Wednesday, so I have a few days to relax and get ready. It should be an interesting year.
Well, it’s May, so I have about two weeks of classes left followed by a week of finals. The weather around here is finally decent and all of the trees are in bloom, so I suppose that Spring has officially arrived. To celebrate the change of seasons, I decided to take some pictures of my room:
The view outside my window is no longer snowy. 
Oh, and here’s a picture of my desktop.
As for the wallpaper, I’ve been messing around with The GIMP‘s rendering capabilities. Right now, it looks a little too cluttered… I plan to work on it this summer.
I noticed that the newest version of Firefox seems to be significantly faster than the old version in that the random hangs that used to occur have stopped. This made me happy, but I wasn’t planning on switching back from Opera, whose use of Qt has made my system seem very unified. Then, I tried Vimperator.
Vim, for those who aren’t familiar with it, is a powerful console text editor designed to provide developers with an elegant interface with a ton of context-sensitive shortcuts. I’ve never been a particularly big user of Vim because I have always preferred graphical editors. But in a pinch, it’s definitely a great tool to use.
Vimperator is an extension for Firefox that tries to harness the elegant Vim interface. First, it gets rid of all the toolbars and replaces them with a single status bar with a command line below it. It works just like Vim in that you can type : and then a command to do something, or you can use a single keystroke as a shortcut (e.g. t invokes :tabopen, which allows you to open a new tab with a URL). Autocompletion is nicely implemented. Theoretically, using Vimperator, you can browse the web without ever having to touch a mouse (no, you don’t have to hold tab down to go from field to field, there is a more elegant solution involving pressing ‘f’ and then typing a corresponding number).
I still like to use a mouse on occasion, so I’ve create somewhat of a hybrid environment. For example, I added :set guioptions+=B to my .vimperatorrc.local config file in order to leave the bookmarks toolbar up at the top of my screen (I haven’t restored any of the other toolbars, though).
Oh, also a view at night:
The CPW search engine I wrote is now up and running on the MIT Admissions CPW website. You can take a look here:
I’ll fix the character encoding issue soon, hopefully… I’m also planning a mobile version.
I randomly decided to burn through a CD case yesterday, and I discovered that upon doing so, this awesome effect is produced:
Video:
In other news, I’m starting to use Opera more and more lately. I’m tired of Firefox hanging constantly when I type an address in the bar. Opera is about as fast in terms of rendering, but is much more responsive. Plus, it actually integrates with QT4, so it looks like the rest of my desktop (GTK’s QT emulation themes do not like dark color schemes). I still have to iron out a few bugs with the color theme; I have the problem of white text on white backgrounds a lot because the skin assumes that your default system text color is black.
I’m using a development snapshot of Opera 10 right now. It works beautifully, but definitely has a bunch of bugs that need to be ironed out. If I decide to switch to Opera permanently, I will probably go back to a QT4 version of Opera 9. The integrated developer tools are nice, but I think I prefer Firebug, so I’m still using Firefox for web development.
On that note, Admissions is letting me add my CPW schedule filter app to their webpage so that all the 2013 prospectives can use it. I rewrote the entire script (using JQuery now!). It’s all set to go and should be up on the admissions site by early April.
One:
Seeing Randall Munroe’s comic for the MIT Class of 2013, I was inspired to create this meme.
Two:
I got my Blu-Ray diode and now my laser is finally working! Pics coming soon.
Three:
I went to test the power output of my lasers on Thursday, but the results were… well odd, to say the least.
I brought my 6 lasers with me: 1 50mW green pointer, a “5mW” green that was measured in October to be 55mW, an actual ~5mW green, a Blu-Ray driven at around 120-125mA, a $2 red pointer, and finally, my 300mW SKYlasers portable.
I started by testing the 55mW greenie. With a Scientech 362, the laser reported only around 20mW. This worried me, so I tried using a Scientech Astral calorimeter, also in the lab. Similar results.
That was perplexing, to say the least. I tried my 50mW pointer from LEDshoppe and got the same result. I then tried the 300mW SKYlasers laser and got only about 75-110mW.
Even my Blu-Ray, which, in theory should be lasing at around 80-90mW based on the current it is driven at, reported around 40-50mW.
The conclusion? Both meters were horribly inaccurate. Alone, the fact that a pointer that was rated in October to be 55mW was now reporting 20mW could suggest two things: the meter was in accurate or the diode was dying. However, there has been no appreciable drop in brightness or burning capability (yes, it can burn!). Furthermore, the fact that the Blu-Ray diode (without a lens, even) was reporting far less than it should be outputting given the current it is being driven at really is a strong indicator that these meters have been calibrated incorrectly.
I am currently talking with the original owner of these calorimeters to see what to do. I will also try to get access to other meters that are used more often. In the meantime, I apoligize for the delay.
(finally getting back to blogging)
IAP is yet another MIT acronym. It officially stands for Independent Activities Period, but in reality means different things to different people. For some, it really stands for “extra-long vacation” (which I suppose is great if you live far away and would like to spend the cold Cambridge winters elsewhere). Others come back to campus to take classes, work on projects, or participate in insane competitions. At any rate, IAP lasts through the month of January and you are not required to take any “official” academic classes (although you can).
Since winter in Lexington is pretty much the same as winter in Cambridge, I decided that I would head back to campus after two weeks of eating delicious home-cooked food (and yes, that’s pretty much all I did during my vacation). I signed up in a lottery for a class called 6.091 (MIT does everything in numbers, remember?), which is a hands-on introductory course in EE. I was lucky enough to get in, so I’ll be starting that next week.
I have a few more things lined up for IAP, too, including:
So, yes, even though I don’t have any official classes, I’m staying very busy.
Anyways, I’m drawing up plans for the Blu-Ray lasers. Hopefully I’ll have them completely finished soon.
Last thing: I updated my homepage a bit to reduce some menu clutter. You can get to my software from “Projects”.
I’ve disappeared for the past few weeks because of the insane amount of work I’ve had. However, in addition to all of the schoolwork, I have also been able to feed my newfound passion for lasers.
It all started with the “5mW” greenie I bought. Soon after, I purchased another 5mW green laser and a red laser as well. I immediately noticed the difference between the two green lasers; one had a far brighter dot than the other.
Soon after, I discovered LaserPointerForums.com and eventually decided that I would build a Blu-Ray laser. Using diodes extracted from Blu-Ray and HD DVD players, laser enthusiasts design laser pointers based on small LED flashlights and other similar housings. The coolest thing about these pointers is that since they operate at wavelengths very close to ultraviolet light (typically about 405nm), they fluouresce objects. So, if you’re pointing the laser at a white screen, you may not see the dot clearly, but the screen itself will fluouresce. The uranium vaseline glass marbles that I bought will glow brightly. Furthermore, the laser will also burn pretty much anything when pumped up to about 100mW.
These pointers basically consist of 4 components: the laser diode mounted in a focusing module, the driver (a device used to regulate current and voltage output to protect the diode), and the battery. Blu-Ray diodes typically require about 5V to lase. The PHR-803T diode (currently the most common one available) requires fairly low currents. Most people report that the diode is stable at 100mW, which requires about 125mA of current (see this sketch).
Anyways, while researching different build methods, I came across the website of Colin Joye, who had been working on a Blu-Ray laser based on the KES-400A diode for the PlayStation 3. It was about 3 minutes before I realized that the site was hosted on the MIT servers; as it turns out, Colin was a recent grad student who was finishing up his dissertation. Colin showed me a laser calorimeter he had in his lab and I tested my 3 existing lasers. The first green reported 55mW of combined Green and IR power. The second reported about 20 and the red reported about 20 as well. The 55mW was quite a shocker; no wonder the beam is visible and it can cut through electrical tape easily.
After playing around with the calorimeter, we the began to discuss building a Blu-Ray laser from scratch. I’m designing some models in Autodesk Inventor (which is free for anyone with a .edu email account!) that will provide us with a housing that will carry the diode, the driver, and a CR123A battery.
I’ll post pictures once we are able to get some working products. Hopefully, we’ll have something soon!
