244 9 Volt Batteries In Series – Arcing Ensues!

December 18, 2012 by Jeremy Cook 49 Comments

Here’s another hack that we would definitely discourage you from trying at home, 244 9 volt batteries wired in series. There’s really not much more to it than that, but [jersagfast] takes this setup through its paces arcing through air first, a LED light second, and then a CD. The air arc is probably the most impressive, but a CD doesn’t look happy after this kind of abuse either. Around 4:38, a capacitor is abused for yet more arcing.

In theory, 244 9 volt batteries in series should be nearly 2200 volts, but as measured (in sections), it “only” came out to a “measly” 2000 volts. Still plenty of voltage to be harmful or even deadly depending on the current emitted. Passing on this hack at home is strongly encouraged. On the other hand, you should watch the video after the break to see what happens. Much safer. Arcing starts around 1:44!

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Beautiful Tube Amp Uses A TV Tube

December 16, 2012 by Brian Benchoff 23 Comments

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Most audio tube amps we see use common tubes – usually a 12AX7 for the preamp and one of the more common power tubes such as an EL34.[Daniel], on the other hand, decided to build his own audio tube amp with a 13EM7, a tube originally used for a television’s vertical oscillator. The resulting project is a wonderful stereo amp that sounds really good, to boot.

[Daniel] picked up the idea of using a 13EM7 tube from [Fred Nachbaur]’s MiniBlok SET amplifier. This very tiny 1-watt tube amplifier uses a single tube originally designed for use in old, old televisions. The secret behind this build is the fact this tube is actually two triodes in one package; one side of the 13ME7 has tons of gain but not much power, making it perfect for a preamp. The other side has a lot of power, useful for delivering two watts of power into a speaker.

After [Daniel] etched a few boards for his amp, he milled out a piece of wood for the chassis. When everything was mounted he had an awesome looking stereo amplifier that also sounds great.

Web Scraping Tutorial

December 10, 2012 by Mike Szczys 36 Comments

Web scraping is the act of programmatically harvesting data from a webpage. It consists of finding a way to format the URLs to pages containing useful information, and then parsing the DOM tree to get at the data. It’s a bit finicky, but our experience is that this is easier than it sounds. That’s especially true if you take some of the tips from this web scraping tutorial.

It is more of an intermediate tutorial as it doesn’t feature any code. But if you can bring yourself up to speed on using BeautifulSoup and Python the rest is not hard to implement by trial and error. [Hartley Brody] discusses investigating how the GET requests are formed on your webpage of choice. Once that URL syntax has been figured out just look through the source code for tags (css or otherwise) that can be used as hooks to get at your target data.

So what can this be used for? A lot of things. We’d suggest reading the Reddit comments as there are several real world uses discussed there. But one that immediately pops to mind is the picture harvesting [Mark Zuckerburg] used when he created Facemash.

Retrotechtacular: Similarities Of Wave Behavior

December 2, 2012 by Mike Szczys 23 Comments

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This installment of Retrotechtacular looks at a video lecture that is much more substantive than the usual fare. [Dr. J.N. Shive] was a researcher at Bell Labs at a time when just about every technological breakthrough was coming from that singular collection of minds.

This video, called Similarities of Wave Behavior, was made to help bring students up to speed on the principles of waves. To aid in the experience he invented the apparatus seen in front of him. It’s called a Shive Wave Machine (in the prelude to the video they call it the Shive Wave Generator). Having not taken any physics classes at University we hadn’t seen one of these devices before. It uses a series of horizontal rods connected to each other with torsion wire. When you upset the balance of one of the rods the wire conducts that energy to its neighbors as an energy wave. This turns out to be a perfect representation of wave action whether it be mechanical, electrical, or acoustic. The 28-minute video after the break makes extensive use of the device, and explains concepts in a way that is easy to understand for just about anyone.

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St. Optimus Of Prime

November 30, 2012 by Mike Szczys 17 Comments

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We’re pretty sure they’re not canonizing alien robots, but this Optimus Prime stained glass sure looks good enough for a place at the local cathedral. It is [Kobachi’s] very first glass project, but we’d say he’s got a bright future ahead of him. Especially since it’s about ten times more complex than the assignment called for.

The design is based on artwork by [NinjaInkArt] called Optimus Noveau. It is included in the album linked above and shows Optimus with the matrix of leadership behind his head. This of course doubles as the halo you would find around the head of a saint in religious artwork. [Kobachi] started by simplifying the design into rough outlines and colors. He then split those outlines to make for easier cuts and then got down to business assembling the pane. It uses 121 different pieces and took him 80-100 hours to complete the work. We can’t wait to see the landscape follow-up showing Optimus as a semi truck.

If you’re not handy with colored glass you could try making this with colored circuit boards instead.

[via Reddit]

Bilbio-mat Is An Awesome Yet Simple Used Book Vending Machine

November 22, 2012 by Mike Szczys 9 Comments

You’ll find this used book vending machine at The Monkey’s Paw in Toronto, Canada. For two Loonies you can buy a random book from the machine’s hopper. Silly? Absolutely. But as you can see from the video after the break, the act of buying a book this way is a lot of fun, and we always like to see the insides of a machine like this.

[Craig Small’s] creation looks vintage, and the chugga-chugga and mechanical bell that accompany each sale go along well with that appearance. Of course the machine is new. A trio of hoppers behind the façade hold stacks of books at a forty-five degree angle. Each stack is raised one at a time by a winch and pulley. Once the top book on the stack is high enough to slide into the dispenser chute the winch stops and the bell rings. A simple solution to dispensing something that is not a standard size.

Because the Biblio-Mat is meant to clear out the discount books, slight damage caused by falling down the chute won’t even be noticed. And if you end up really loving the book you can digitize it by running it through one of these.

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Button Automatically Tells People To Bugger Off In Gmail

November 22, 2012 by Brian Benchoff 14 Comments

[Kevin]’s friend is a remarkably helpful engineer, and when his friend gets requests to help out on a few projects he always has a hard time saying no. Really, [Kevin]’s friends’ time is much too valuable to take up many more projects, but saying no to someone will drag you down. To alieve his friend of the torment of saying no, [Kevin] built an automated Gmail assistant that will automatically replay to an annoying email with the words, “Go F*** Yourself!”.

The automated Gmail assistant is built around a Teensy 2.0 microcontroller equipped with a key that serves as a safety, lest an accidental “F*** you” be sent to friends, family, or employers.

If [Kevin]’s friend feels bad for telling so many people off there’s also a handy feature to make sure the engineer friend doesn’t seem too unhelpful: there’s a one percent chance of the Gmail assistant of replying with, “That’s a Great idea, I’ll get right on it!”.