Bag of Beans

Ladyada has a new howto on building a USB device charger based on two AA batteries, instead of previous, similar devices based on 9V batteries.

Another problem with the 9V+7805 scheme is that a 7805 is a linear regulator. That means if you want 100mA at 5V (basically, USB power) then you’re taking 100mA at 9V and then losing the 4V*100mA = 400mW (.4W) difference as heat. As the battery wears down to 7V the heat loss goes down to (7-5V)*100mA=.2W but you’re still getting bad efficiency. At best the efficiency is 72% (5V/7V) and at worst its 55% (5V/9V) That means you’re losing about a third of the battery power to heat!

• Link to announcement
• MintyBoost page
• A copy of the tutorial has also been posted on Instructables.

eConsultant has many useful lists in different categories. In particular, their freeware and open source software lists are very comprehensive.

• I want a Freeware Utility to … 450+ common problems solved
• Open Source Freeware : 400+ free applications and utilities

This is a good article by Ken Rockwell on taking better photos.

First and foremost your camera has NOTHING to do with making great photos. You have to master technique of course, but that’s just a burden to get out of the way to free yourself to tackle the really hard part of the art. The hard part is actually saying something with your images. This is art and it’s abstract and therefore difficult for many people to grasp. It’s easy and lazy to think a camera makes the photos and to blame bad photos on a camera. When you get better you’ll realize you would have been better off to pay more attention to your images and less to your camera.

• Link (via Digg)

This is quite an interesting article on building a pair of cheap infrared goggles and how they work.

At one point I started wondering just how much IR light a human eye could see. After all, if the infrared light was EXTREMELY BRIGHT (such as the IR of a sunny day,) human eyes might still detect it. And remember, if 30KHz ultrasonic sound is loud enough, you will hear it. Same basic idea. I got some of our black IR filter plastic and cut it into 2in. oblong disks to fit the eye-depressions in my own skull. I taped them onto my face with black electrical tape. Yes, I looked odd, but it worked! After I became accustomed to the darkness inside the filters, I could see through them. Going outside on a sunny day was stunning. The sky was almost black, while the trees and shrubs where all frosty pink. The grass looked like fluorescent red cherry Koolaid powder. Different colors of human skin were always the same light grey. People’s eyes looked very black, and certain dark clothing looked white. I was afraid that I might damage my eyes, since the IR sunlight was very bright, and my pupils were wide open. (After years of playing with these, I still haven’t hurt my eyes, so they’re PROBABLY somewhat safe to use.)

• Link (via Digg)

PC World has posted their list of the worst tech products they have seen since they began publishing.

Of course, most truly awful ideas never make it out of somebody’s garage. Our bottom 25 designees are all relatively well-known items, and many had multimillion-dollar marketing campaigns behind them. In other words, they were made by people who should have known better. In fact, three of the ten worst were made by Microsoft. Coincidence? We think not.

• Link

This short tutorial on the Windows Recovery Console has some useful info that may help you fix your Windows XP box if it no longer boots due to corrupted system files.

In an effort to expedite our repair time and retain the sanity of myself and other technicians, I received permission to undertake a case study on a variety of PCs currently in service that exhibited any of the aforementioned symptoms, and I took it upon myself to find a better solution. After crawling through the MSKB, Experts Exchange, MSDN and sundry websites all extolling the virtues of a solution to these problems, I only found one that worked, and it has been reliably serving me for the better part of two weeks on seventeen PCs to date.

• Link (via Digg)

Check out these wild glasses. You need to pierce the bridge of your nose to insert the supports, and then the glasses themselves are attached to the supports with magnets. Just don’t snag the piercing on anything.

• Link (via reddit)

Lighthouse in a Tree has a nifty pinhole camara that you download as a PDF and put together yourself. They also have a flash tutorial on how to assemble the camera.

• Link (via Lifehacker)
• This site has another version of the camera, as well as a little bit of the history behind these paper cameras.

Roedy Green has written a hilarious essay on the worst programming transgressions imaginable.

In the interests of creating employment opportunities in the Java programming field, I am passing on these tips from the masters on how to write code that is so difficult to maintain, that the people who come after you will take years to make even the simplest changes. Further, if you follow all these rules religiously, you will even guarantee yourself a lifetime of employment, since no one but you has a hope in hell of maintaining the code. Then again, if you followed all these rules religiously, even you wouldn’t be able to maintain the code!

*shudder*

• Link

A new research initiative seeks to discover what type of society might evolve with millions of software agents.

Future disaster victims rescued by robots may perhaps owe their survival to the software agents currently being prepared for life in the NEW TIES engine – which, within a few months, will be running across a Grid of 60 computers. “No one has ever created an engine of this complexity,” says Eiben, adding that it will support about 1,000 agents at first, building up to millions – each one a unique entity with its own characteristics, including gender, life expectancy, fertility, size, and metabolism. The agents will not be labelled, but will have their own distinguishing characteristics to make them recognisable. Their traits will be inherited from their parents, and passed on to their offspring, but they will be able to learn from their own experiences and from each other.

• Link (via Digg)

Stanford Magazine has a fascinating article on Donald Knuth, author of the highly respected reference The Art of Computer Programming.

Knuth was one of the first people to pronounce computer programming an art, believing that even the programs that crunch your taxes and produce your bank statements should be elegant. Like artists, he says, programmers have individual style and are propelled by intuitive leaps—Knuth knows he’s not really ready to solve a problem until he can think of it without using pencil and paper; his best ideas rise up from his subconscious while he swims. And like artists, he says, computer scientists are driven to produce. “Like a poet has to write poetry, I wake up in the morning and I have to write a computer program,” he says.

• Link (via reddit)

Gizmo at Tech Support Alert has just made some major updates to his recommendations for the best freeware utilities available. Lots of useful stuff here.

• Link

This incredible display projects an image onto a “transformed” plane of air. Check out the video of this thing in action.

Now this is sweetness. IO₂ Technology has the coolest sounding display I have ever seen called the M2i. The device projects a 30″ diagonal 4:3 aspect ratio display into the air. That’s right, into the air like a hologram. The entire projection unit is designed to be hidden out of site so that only the display image shows.

• Link (via Digg)
• Direct link to video on YouTube

Skype has announced that SkypeOut calls to landline and mobile phones within the US and Canada are now free, at least until the end of 2006.

Is it really free? What are the strings attached?

Yes. It is really very, very free. There’s no prepayment, no minimum use, no subscription, no monthly fee, no nothing. You just download and install Skype and then you start calling. Both the caller and the number called must be in either the US or Canada. There are no strings attached.

The only condition is that we have said free SkypeOut within the US and Canada is guaranteed to last until the end of this year — that is, until December 31, 2006. We’re not quite sure yet what we will do after that. Maybe we extend the free period, maybe not. You’ll hear more about this towards the end of the year.

Until then, happy calling.

• Link (via Digg)

This article examines the often-repeated myth that NASA spent a billion dollars to develop a pen that would work in space, while the Russians just used a pencil.

Space has its urban legends of course, and the Million Dollar Space Pen is one of the more enduring ones. It is neither as outlandish nor as unbelievable as the story about faking the Moon landings, and even though it seems more credible than a massive government conspiracy, it is probable that fewer people have heard it.

• Link (via Digg)

This is pretty funny. A group of around 80 people dressed in blue shirts and khaki pants infiltrated a Best Buy store and assisted customers…until the store employees noticed one of their hidden cameras, freaked out and called the cops.

The idea for this mission was submitted by a stranger via email. Agent Slavinsky wrote in to suggest I get either a large group of people in blue polo shirts and khakis to enter a Best Buy or a group in red polo shirts and khakis to enter a Target. Wearing clothing almost identical to the store’s uniform, the agents would not claim to work at the store but would be friendly and helpful if anyone had a question. There aren’t any Targets in Manhattan, so I decided to go with the two-story Best Buy on 23rd Street.

• Link (via Reddit)