Monthly Archive for May, 2009

Finalizing Core i7 Computer

Published on May 14, 2009 in Computers. 1 Comment

Here’s the current snapshot of my wishlist on NewEgg.

Total cost (without shipping): $1673.88

I may also throw a card reader and/or other accessories in as well.

I’ve decided to go with an EVGA mobo because the reviews on NewEgg are pretty decent.  I was debating whether or not to go with the E758 or the E759 but eventually decided on the former because I don’t think I am ever going to use true 3-way SLI and 24GB of RAM; I simply couldn’t justify spending another $200.  Plus, 3-way SLI isn’t very good right now (bottlenecking issues still exist on most motherboards).  Unfortunately, the E758-A1 is out of stock right now, so hopefully by the time I order the parts (early June), it will be back.  If not, NewEgg sells another E758, but without all the cables and extra stuff that I may or may not need.

I found a good guide on overclocking the Core i7 920 CPU.  The disadvantage of buying the 920 (as well as the 940) over the 965 is that by default, the highest CPU frequency multiplier (20x) is selected (22x for the 940).  So, in order to overclock the processor, it is necessary to increase the base frequency and then decrease the multiplier for the memory (the multipliers for the cache and QPI bus are usually at their lowest values for most motherboards).  Keeping the Vcore value at the nominal 1.2V, the author of the article managed to clock the CPU up to 3.4GHz without an issue.  This is roughly the frequency that I’m looking to end up at when I overclock my system.  I definitely do not want to push it up to the maximum stable frequency that the author achieved with air cooling: 3.8GHz.

So here’s the setup plan:

  1. Unpack everything (taking pictures!!!) and make sure that nothing looks physically damaged.
  2. Read some manuals (yes, I’m going to actually try to read them and contain my excitement)
  3. Install the CPU onto the mobo.
  4. Install RAM
  5. Apply AS5 and install heatsink (apparently, since the heatsink is so huge, it’s pretty difficult to install the RAM afterwards).
  6. Install mobo into case.
  7. Install PSU, hard drives, DVD drive (I have some old ones that I can use).
  8. Turn it on and hope like heck it works.

I’ll probably start by installing a non RAID drive for Windows so that I can use Prime95 to make sure that my attempts at overclocking resulted in a stable system.

Afterwards, I’ll install the 3 WD drives in a RAID 5 setup and install Arch Linux on them.  I’ll probably use XFS for my filesystem, but I’m not quite sure yet.  I’ll also install another drive for Windows and/or other operating systems, but it won’t be part of the RAID array.

I’m worried about the performance of RAID 5.  Under certain conditions, a RAID 5 array can suffer huge performance losses.  However,  these losses are mainly limited to situations where there are multiple small simultaneous writes, something not really seen in normal desktop use.  Another option would be to buy a fourth drive and use RAID 0+1 or something.

I have a feeling that by the time I order the parts (early June), the list will change again.

TradeKing: A Spectacular Broker

Published on May 11, 2009 in General. 1 Comment

I usually try to keep my blog as commercially neutral as possible, but sometimes, if I find something really good, I can’t resist.  TradeKing is a perfect example.

Back in the fall, I began looking for a good cheap broker.  I have an existing brokerage account that was also tied to my college fund and my IRA, but that’s only for ultra long-term growth.  Instead, I wanted a broker with cheap commissions; in fact, that’s really all I wanted.

I came across several brokers, including some that offered free trades so long as you made a certain number of trades a month.  TradeKing seemed like the least gimmicky out of all the brokers I looked at.  Their pricing scheme is simple: if you trade 10 shares, you pay $4.95 commission.  If you trade 100 shares, you still pay $4.95.  If you trade 100 million shares, you pay (yep, you guessed it) $4.95.  The only exception to this rule is that stocks trading for less than a buck cost an extra dollar for every hundred shares.  Options contracts are $0.65.

The other thing that I really like about TradeKing was that in addition to providing rock solid trading services to independent traders, it also boasts a large community website where traders can share tips and examine strategies.  The community site has a very active forum, a leaderboard, statistics on recently traded companies, etc.  You can elect to display the investments you make (as well as to post notes for each trade) so that others can follow your line of thinking.  Every member gets their own trading blog where they can post more detailed analyses.

So, I signed up for an account and deposited a small amount of money so that I could start trading.  Right now, I’m just investing in stocks and ETFs; eventually I’d like to start trading options contracts too.  I have been following many of the community discussions in hopes of learning how to effectively work with options.

Above all, TradeKing boasts an absolutely spectacular staff.  The CEO, Don, routinely posts interesting news stories to his blog, which I read daily.  Every Friday, he posts his weekly shout-out, highlighting the week’s top performers and interesting discussions held on the forum.

A few months ago, TradeKing held a nice promo where they gave out nice “Elvis-style” sunglasses to people who filled in their community profile.  It ended before I joined TradeKing, but when I contacted Don, he was kind enough to reply back personally and have his staff ship out a few.

In summary, if you are looking for a dependable broker with excellent customer service, yet you wish to be an independent investor, TradeKing is absolutely perfect.  Over the past year, I haven’t had the chance to really use all of the tools they offer, but hopefully, I’ll have much more time this summer to do so.

Important note: this entry was not endorsed by TradeKing in any way.  I wrote this article solely as a happy customer and was not reimbursed by any means for this post.  If you have questions about TradeKing, please contact their customer service desk (contact info is on their site).

Improving Cheap Green Laser Pointers

Published on May 5, 2009 in Lasers and Tutorials. 2 Comments

I own several cheap green laser pointers and I’ve noticed that some of them behave very differently from others.

I bought my first green laser pointer back in September for a little over $20.  It was this one.  At that time, I had no clue of what a typical 5mW pointer looked like, but I expected that I received somewhat of an overpowered unit since it could burn through trash bags and had a clearly visible beam (as it turns out, the pointer is about 50-80mW based on a few readings I took).

I then purchased a few more pointers for my family for Christmas a few months later.  The units I received were nothing like what I had originally bought.  First of all, they had different stickers on them and the size of the apertures was much smaller.  Secondly, not only were they extremely weak, but on rechargeable (NiMH) batteries, they needed about 30-45 seconds of warm-up in order to produce a decent dot.  With alkaline batteries, they were a bit better.

A few months ago, I purchased a 50mW pointer from LEDshoppe.  It was also bright on alkalines but miserable on rechargeables.  It occurred to me that the driver seemed to be the problem.  Alkaline batteries probably allow the driver to just cross the threshold voltage required by the IR pump diode.  So, rechargeables, which have a nominal voltage of about 1.2-1.3V, cannot quite reach this barrier and as a result, the laser will barely lase.

The driver used in the first laser I purchased clearly had to be a boost driver; i.e. it boosts the voltage output to compensate for low voltage input.  The other drivers were just linear constant-current drivers.

So, since I don’t really want to pay for new alkalines constantly, I decided to look into another method that was already being used by a few members of LaserPointerForums.com.  10440 batteries are 3.6V lithium cells that are the same size as standard AAA batteries.  Therefore, if I use a single 10440 with a spacer in my laser pointer, the output should be at its intended maximum.

There are a few downsides to this:

  • Assuming that the driver is linear and outputs constant current, a significantly higher input voltage will result in excess heat dissipation.
  • These batteries are typically only around 300mAh, so lots of recharging will be needed, as a typical ~100mW pointer will draw up to 600mA.

While discussing these issues on LPF, member Warske recommended using a diode to lower the voltage going to the driver so that heat would be dissipated in the spacer instead of on the driver board.

I got my 10440s and charger today, so I quickly built a spacer with some cardboard, wire, and a diode.

The results were spectacular.  The laser is drawing its full 600mA or so and is definitely over 100mW (I’ll test it on my LPM when I get home).

Here’s a comparison between my improved laser (on the left) and one that’s doing roughly 50-60mW.

This picture was taken in broad daylight with a limited exposure time, so that's why the lasers aren't particularly bright.

So here’s what you can do if you want to make your green laser pointer more powerful:

  1. Buy a pack of 10440s.  I know it’s tempting, but don’t put both batteries into the pointer because you’ll fry the driver.
  2. Buy a charger.  I used this one, which seems to be the best.  Be careful though, if you’re using your own lithium charger, make sure it is designed to charge 10440s.  They need a significantly lower charging current than CR123As or 18650s.
  3. Buy a regular-ol’-diode from Radioshack or anywhere cheaper.
  4. Get some ~22 gauge wire and make two little coils like I did in the first picture.
  5. Solder the ends of the coils to each end of the diode.  Make sure that the total length is about the same as a standard AAA battery, but err on the side of making it a little longer.
  6. Get some cardboard or thick paper and wrap it around the wire/diode setup so that just the coils stick out on either end.
  7. Finally, make a little paper tube so that you can connect the positive end of the 10440 battery with the coil without the chance of that coil touching the side walls (otherwise, the diode is useless!).  Make sure that the diode is in the correct way; i.e. the white painted stripe should be connected to the coil that touches the end of the barrel.
  8. Put it all together, and enjoy!

Springtime Pictures

Published on May 2, 2009 in Computers and MIT. 1 Comment

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: