Want To Learn Artificial Intelligence? Good.

September 5, 2011 by Brian Benchoff 39 Comments

In a little more than a month, tens of thousands of people around the world will attend a class on Artificial Intelligence at Stanford. Registration for this class is still open for both class ‘tracks’. The “basic” track is simply watching lectures and answering quizzes, or a slightly more advanced version of MIT OpenCourseware or Khan Academy. The “advanced” track is the full class, requires homework and exams, and aspires to Stanford difficulty.

With thousands of people taking this class, there’s bound to be a few study groups popping up around the web. The largest ones we’ve seen are /r/aiclass on Reddit and the stack overflow style aiqus. The most common reply to ‘what language should I learn from this class?’ is Python, although there’s an online code repo that has the text’s working code in Lisp, Java, C++ and C#.

If AI doesn’t float your boat, there are two more classes being taught from Stanford this fall: machine learning and introduction to databases. Any way you look at it, you’re getting to take a class from one of the preeminent instructors in the field for free. Do yourself a favor and sign up.

Thanks to everyone who sent this in. You can stop now.

Czech-ing Out The View From 31 Kilometers

September 5, 2011 by Brian Benchoff 19 Comments

The team at czANZO, the Czech Amateur Near-Space Object group, sent up one of the best high-altitude balloons we’ve ever seen last weekend and the resulting video is remarkable.

The team’s build blog (Google Translate link for everyone without Chrome) goes through the design and construction of their payload. Like every other balloon build we’ve seen, a styrofoam cooler is used for the enclosure, but there’s a lot of really neat additions that make this build special.

The team included a cut down device in the event the balloon gets caught in the jet stream. Without this cut-down device the balloon could end up hundreds of miles away from the launch point. That’s the reason for the cut-down device they’ve given, although we suspect it’s an excuse to play around with pyrotechnic rope cutting. The optical and audible alarm is something we haven’t seen on many high-altitude balloon launches, which is odd because it made ground recovery much easier.

The team has a lot of video from the flight that [Pavel Richter] dumped onto Vimeo. We really like the footage showing all of Prague, you can check that out after the break.

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The Partyscroller LED Display

September 5, 2011 by Jeremy Cook 16 Comments

As [Plasma2002] put it, “Those jumbo screens at concerts that display your text messages can be a lot of fun. Wouldn’t it be great if you could have the same thing for your own parties or social gatherings?” The answer to this question came in the form of this hack, a scrolling marquee sign that guests simply had to text to get it to display messages. Apparently guests at the party loved the device, and who wouldn’t?

More importantly for [HAD] though, is that [Plasma2002] decided to show everyone how it’s done. He gives us an overview of the process via a nicely illustrated block diagram, then breaks everything down into the actual code used. A Google voice account is used as the dial-in number and everything is kept anonymous. A “bad-word” filter is used to keep everything semi-appropriate.

Really a cool device, and one that we hope will show up at hacker’s parties everywhere. Who knows, maybe something like this could enjoy mainstream success as well. Check out the video after the break to see this device in action! Continue reading “The Partyscroller LED Display” →

Upgrading RAM In An Arduino Mega

September 5, 2011 by Brian Benchoff 24 Comments

[Andy] stuffed some more RAM onto an Arduino Mega and his three-part walk through on the design, construction, and software is a great read and one of the more ‘hard core’ Arduino builds we’ve seen.

The build is centered around a 512K × 8 SRAM module [PDF warning]. Because the RAM is divided up into about 512,000 chunks of 8 bits, the Arduino has to access the RAM through 16 ‘address lines’, then send the data through 8 ‘data lines’. [Andy] didn’t want to use up 24 pins on his Arduino, so he used a latch to multiplex the lowest 8 address lines and the data lines together. With the 512KB RAM expansion installed, the Mega is able to address a whopping 520 Kilobytes.

We’ve seen a few builds that have been limited by the amount of RAM available in the Arduino, like capturing video and some robot hacks, and adding some more RAM to those builds would be great. Multiplexing data and address lines using a latch can be expanded even further, but 520KB ought to be enough for anybody.

Engine Hacks: A Pulse Jet UAV By Any Other Name Would Still Be A Cruise Missile

September 5, 2011 by Brian Benchoff 33 Comments

Imagine our surprise when we learned [Bruce Simpson], who made headlines in 2003 with his $5000 DIY cruise missile, is still alive, not illegally interned in a black ops prison, and still doing what he does best: building really awesome remote-control airplanes.

The first ~~successful~~ mass-produced pulse jet aircraft was the German V-1 flying bomb. The V-1 had a very primitive guidance system, but the unmanned pulse jet aircraft quickly evolved into a few target drones used by the US Air Force. There was never any significant advancement towards improving the fuel consumption, noise level, or heat signature of pulse jets, so they were superseded by the superior turbojet. Despite their failings, pulse jets are remarkably easy to build and amazingly fast.

Instead of being antagonized by the New Zealand and United States governments, [Bruce] spends most of his time now working on pulse jet projects. He’s flown quite a few modified R/C planes and has an electronic Engine Control Unit for his jets. One of his most impressive projects is the 100 pound thrust pulse jet that was later attached to a go-kart. His no weld version of a pulse jet can be built in even the most minimalist work shop and is the epitome of an easy-to-build jet engine.

To get an idea of how fast [Bruce]’s planes can be, check out his Long-EZ R/C pulse jet in action after the break.

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Material Of Choice: Felt Pen On Glass

September 4, 2011 by Mike Szczys 20 Comments

If you’re paying big bucks for those floor-to-ceiling windows why not make them into a canvas for your art as well. Der Kritzler is a motorized plotter that can make this into a reality. It’s a laser-cut pen holder suspended from a pair belt pulleys. Those belts have counterweights, which make it easier for the stepper motors to move the pen jig smoothly. The firmware running on the Arduino that controls Der Kritzler has some very precise setup requirements. Since there is no feedback for the Arduino to sense the position of the pen, the two stepper motors must be exactly 1500 mm apart with 1060mm of toothed belt between the carriage and each stepper motor when the power is turned on.

Input images are converted to code for the device using a processing sketch. So far [Alex] has tried out a couple of different effects, starting with a vector graphic, or using some open source tools to convert bitmaps to vector graphics. Don’t miss his video demonstration embedded after the break.

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Freakin’ Huge CNC Router

September 4, 2011 by Brian Benchoff 22 Comments

[Tom] sent in a gigantic 3-axis router that he pieced together during a 2 week-long work experience placement. Looking at this picture showing a 12-inch ruler on the work area, we realized that this may be the largest CNC router we’ve seen on Hack A Day.

[Tom]’s employer gave him some obsolete axes, so piecing the mechanical components together was very easy. The only real problem was interfacing the CNC controller to a computer. This meant [Tom] had to convert G Code to the code used by the antiquated NSK axes. Where G Code defines arcs with a start point, end point, and radius, the NSK code defines arcs with a start point, end point, and another point along the arc. It’s a tricky bit of math, but [Tom] built some software that did this in Visual Basic.

Right now, [Tom] only has a pen tool attached to the router; you can check that in action after the break. We’re trying to imagine what we would do with a 4 m² work area; this could easily be used to make a giant reprap or other 3D printer.

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