Best of Hackaday – 2011 edition

2011 was an interesting year here at Hackaday. We have about 24% more viewers now than we did last year. We started producing our own video content and we have shown some pretty interesting projects in our daily posts. In this post, we are gathering together the best of the best.

Our #1 post for the year with 175,000 views is about a 1 megawatt laser pulse pistol. Not only does this build work but it also looks cool. It’s definitely one to take a look at.

Coming in with 157,000 views is a post about how to insert your logo into a QR code. This one was done by our own [Brian Benchoff] and was a runaway success from the first week that we posted it.

In third place with 151,000 views is a post that could help you if you are trying to pick a development board to learn a new processor with. This post breaks down the various development boards available at the time of its writing into three different categories organized by price.

In fourth place with 114,000 views is one about an unique lock composed of color changing buttons. Your pass code is a series of colors instead of digits in an ordinary code lock. This build fits behind a standard wall plate so that it can be mounted cleanly using off-the-shelf hardware from the hardware store.

Wrapping things up at fifth place is a post describing how you can download books from Google using an utility called Google Book Downloader. We have no idea of the legality of this one. The original link is down but it seems that it is still available elsewhere on the internet.

Disco icosahedron rings in the new year

While city engineers were setting up the multicolored ball of lights in Times Square this year, [Phil] at adafruit was busy designing the X2 Time Ball, a disco icosahedron perfect for celebrating the new year.

The ball is made of 20 acrylic triangles zip-tied together into an icosahedron. On each face, six RGB pixels light up via commands from an Arduino. The entire project is able to be controlled remotely thanks to the help of a pair of XBees. [Phil] whipped up a Processing sketch to control the LED ball any way we could possibly imagine.

Although it may be a little late to build an LED disco ball for this year’s New Year’s Eve party, that doesn’t mean we couldn’t use it the other 364 days of the year. It’s perfect for parties, weddings, and our weekly lightswitch raves. Check out the action video of the Time Ball after the break.

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Using mains wiring as an antenna

Make sure to brush up on your safety protocol if you undertake this project. The penalty for messing up when using live wiring as a radio receiver antenna is rather severe. But after reading about it in some old books [Miroslav] decided to give this technique a try.

We love the old-school chalk board he used to map out his test circuit. With safety in mind, he uses two high voltage capacitors in series. If these should somehow fail, there is also a fuse which would blow, disconnecting the apparatus from mains. But just to be sure, he isolated the circuit using a two coils. These step down the voltage, but would also burn out if hit with a voltage spike.

You can see the results he gets using the setup as an AM radio receiver in the video after the break. He tested against a meter long antenna and found that his setup far outperforms it. Actually, he found that a six foot extension cord which is not plugged into the wall will also outperform the 1m antenna. Something to keep in mind the next time the ball game isn’t coming in as clear as you would like.

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Zombie [Jackson] bot dances to Thriller

[Marc Cryan] built this little bugger which he calls Wendell the Robot. But what good is an animatronic piece like this unless you do something fun with it? That’s why you can catch the movements matching [Michael Jackson's] choreography from the music video Thriller in the clip after the break.

This is a ground-up build for [Marc]. He started by designing templates for each of the wood parts using Inkscape. After printing them out, he glued each to a piece of 1/4″ plywood and cut along the lines using a band saw. We don’t have a lot of adhesive spray experience, but he mentions that the can should have directions for temporary adhesion so that the template can be removed after cutting.

During assembly he makes sure to add servo horns for easy connection when adding the motors. All together he’s using five; two for the wheels, two for the arms, and one for the neck. A protoboard shield makes it easy to connect them to the Arduino which is used as a controller.

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Full color laser TV

Back in 2001, [Helmar] made an awesome monochrome video display out of a red laser pointer and a spinning 18-sided mirror. Blue and green lasers are much less expensive than they were a decade ago, so [Helmar] decided to go full color with his laser projector. (In German, so fire up Chrome or get the Google translation)

The ancient website for [Helmar]‘s green-only projector goes over the principles of operation. A single laser shines onto a multi-faceted polygonal mirror. This is reflected onto another mirror that provides the reflection for each line in a frame of video. Earlier this year, [Helmar] hacked up a red and blue laser to complement the preexisting green laser. The end result is an RGB projector powered by friggin’ lasers.

As far as we can tell, the projector only has composite input; the attached DVD player provides all the signaling for that. Amazingly, [Helmar] didn’t use a microcontroller for the circuitry. All the electronics are simple logic gates. Really amazing if you ask us.

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Homebrew on the Rigol DS1052E ‘scope

We love our little Rigol 1052E oscilloscope. It’s seen us through some perplexing problems and loved being upgraded from 50 MHz to 100 MHz. We’ve always been pleased with its role dictating waveforms for us, but we never thought we’d see homebrew apps for our little ‘scope.

We’re not exactly sure who [Krater] is, but he’s been working on some homebrew development for the Rigol DS1052E oscilloscope. Right now the capabilities are somewhat limited; all programming is via PEEKs and POKEs. Still, this is a fairly impressive development.

This wonderful little ‘scope has already had some time in the limelight by being easy to upgrade to 100 MHz. Hopefully with the new capabilities (Tetris, somebody make Tetris), this scope will become a staple in workshops around the world.

A tip ‘o the hat goes to [Rainer Wetzel] for sending this one in. Check out the video after the break to see an almost-working game of Pong playing on the 1052E

EDIT: [krater] dropped into the comments to tell us about his blog entry. Keep up the good work.

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Printing with clear polycarbonate

Those of us with 3D printers have had two major choices when selecting a material to print with – ABS, a very hard plastic, and PLA, a more brittle plastic with a lower melting point. [Alex] and [Luke] have been experimenting with printing polycarbonate and creating clear crystalline objects on a standard 3D printer.

The first foray into printing polycarbonate didn’t go so well for [Luke]. Objects came out looking very milky and there was a bit of popping during filament extrusion. The guys solved this problem by putting the polycarbonate filament in a food dehydrator overnight to get rid of the moisture. Polycarbonate has a higher melting temperature than other plastics – around 260 degrees Celsius – which can cause some problems with Teflon insulators in the hot ends of extruders. The guys didn’t have any problems with fumes, though.

If you’ve ever wanted to print something clear, it looks like it’s now possible. Check out the video after the break to see a Makerbot Thing-O-Matic printing with clear polycarbonate.

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