Christmas Tree Analyzes Your Tweets

It’s Christmas time. You have a string of 50 individually addressable RGB LEDs, what would you do? Well, [Barney] decided to try something different. He’s made a Christmas tree that reflects Twitter’s current sentiments about the holiday.

Wait, what? We admit, it’s a kind of weird concept, but the software behind it is pretty cool. As it turns out Stanford University’s Natural Language Processing Group released the source code for their sentiment analyzer. Unlike a normal sentiment analyzer which assigns points to positive words and negative points for negative words, this one actually uses a deep learning model which builds up a representation of entire sentences based on their structure — only problem? It was designed and trained to analyze movie reviews, not Christmas tweets.

Regardless, it still does the trick (kind of), but, it’s pretty slow. [Barney] has his fastest computer running four instances of the analyzer, which pulls Christmas tweets that have been sorted by the Twitter API — it then analyzes them, assigns the sentiment, and places them in a second queue. He’s using beanstalkd for the queuing and a Raspberry Pi to control the lights. The result is a pretty light display whose colors represent the sentiments of incoming tweets — it’s hard to say if it’s actually successful in reflecting the opinion of the tweets, but it’s a pretty cool concept.

Stick around after the break to see the Christmas Tweet Analyzing Tree in action — say that 5 times fast!

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Hacking a Christmas Tree for Less Blinkyness

What good is a fiber optic self-lighting Christmas tree if it flashes so fast it will put you into an epileptic attack? The answer is “Not very good”, if you ask [Mads Nielsen] a.k.a [EcProjects]. So [EcProjects ] started a little project to slow the Christmas tree’s blinkyness down to a more reasonable rate. The task didn’t seem too difficult at first but turned into a quality tutorial building a variable frequency H-bridge motor control.

After opening the base of the tree [EcProjects] found a 12 volt AC geared synchronous motor turning a multi colored translucent plastic disk. A bright spotlight was shining upwards through the turning disk into the ends of hundreds of small fiber optics. This mechanism dumps loads of multi colored light out the ends of the fibers at the tips of the Christmas tree branches as the disk turns.

His goal was to slow down the motor; however, the rotation was based on the 50 Hz mains signal. In order to continue using this motor a lower frequency AC power source was needed. What follows in the video is an excellent lesson on how an AC synchronous motor works plus how to build a variable frequency control and H-bridge using some transistors, resistors and CMOS 4069 inverter chip.

In the end the frequency drive could only be lowered to about 30 Hz before the synchronous motor would stall and reverse using his design. [EcProjects] was bold enough to include several fails which always provides more opportunity for learning and is greatly appreciated.

If you believe you have a better solution please share your idea in the comments. I’m sure the first proposal will include an Arduino and servo modified for continuous rotation, but any solutions would be fascinating including modifications to his design. You can join us after the break to watch the video.

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Mega Tree Game Display

Christmas may be over, but the holiday hacks keep rolling in, like this awesome interactive Mega Tree Game Display! [Lior] loves setting up light shows every year (just check out last year’s awesome White Christmas display with music!), but taking them down just… well… sucks! So this year he decided to make a fully controllable non-holiday specific light display that he can reuse it all year long.

It features 12 x 5 meter long waterproof RGB LED strips secured firmly to the front of his house, making a trapezoidal 12 x 150 pixel display. It was originally controlled with an Arduino but he found the USB connection was far too slow for the high frame rates he was aiming for — so he’s using a combination of a Raspberry Pi and a Teensy 2.0 instead.

Now, just making a programmable light show suitable for all holidays is pretty cool we must admit, but as [Lior] puts it, a plain light show is “so last decade”. So he’s gone and made the whole thing smartphone interactive. Yep, you can actually log in with your phone and play a silly game that involves dropping gifts on houses and snowmen. He’s also got a pretty cool Hanukkah display that features a spinning dreidel! Check out the full demonstration video after the break.

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Serializing Dickens to LEDs

[ch00f] managed to capture some holiday spirit this year by translating all of A Christmas Carol to scrolling text. Dickens’s work has long since entered public domain, which led [ch00f] to wire up a GeekCatch programmable display from Amazon. It has a low refresh rate, which means videos look a bit goofy, but it’s perfectly acceptable for text. [ch00f] ditched the remote control and instead used the display’s serial connection to program in the novella. Unfortunately, he could not find any documentation for the serial protocol, but he was able to reverse engineer it with some freeware applications found online.

It takes over six hours for the sign to spit out the entirety of A Christmas Carol, which easily surpassed the display’s limited text buffer. [ch00f] instead had to send text to the display one paragraph at a time via a custom Python script. This solution takes advantage of the sign’s fixed-width font to estimate the time it takes for each character to scroll by, then immediately feeds the sign a new line.

Check out the blog post for a quick teardown of the display itself and for a detailed description of the protocol in case you decide to use this display for a project. Stick around for a video below!

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An Animated Elf

Halloween receives the bulk of the attention for installation-type hacks, but [Stephen's] animated elf hack-in-progress provides the perfect example of bringing the Christmas spirit to life. [Stephen] constructed both the background and the elf’s body from a scrap piece of plywood, drawing and painting everything by hand, and then secured the plywood with a simple 2×4 that serves as a stand.

The bulk of the hack is rather simple, and reflects the longstanding technique of traditional cel animation: the non-moving portions are kept stationary and only the moving parts need to change. In this case, [Stephen's] shortcut is to insert a tablet as the elf’s face.

The tablet is a BlackBerry PlayBook, which moves the eyes around and spouts off a few Santa-related quips while animating the mouth. [Stephen] encountered a problem with the PlayBook’s 5-minute screen timeout function, and had to design a custom application to prevent the tablet from entering sleep mode while it played through the animations.

His future plans are to drill a hole through the plywood and expose the tablet’s light sensor to detect when someone walks by, then have the elf spring to life in response. You can see his progress so far in the video below.

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Spherebot: Decorating Xmas Baubles

The Spherebot is an open source machine capable of printing designs onto spherical objects, such as Xmas baubles! The design is based on the ever-popular Egg-Bot, which we have seen derived into many other useful printers such as the Mug Plotter, and the Ping Pong Printer.

The Spherebot features two stepper motors, one servo motor for marker actuation, some cheap mounting hardware, and a whole bunch of 3D printed parts—all of which are available on Thingiverse. In this design they used a 3D printer controller board called the 3Drag by Open-Electronics, which is based on the ATmega2560 (the same microcontroller as the Arduino MEGA). The Spherebot doesn’t require all three axes or an extruder, so they only installed 2 out of the 4 stepper drivers on the board to save cost.

Once you have it all built, it’s a simple matter of uploading your design into the free Spherebot-Host-GUI provided on GitHub. Stick around after the break to see just what it is capable of!

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CartoLucci: A Candle-Powered Christmas Card

If you’re looking for a last-minute Christmas present, you probably won’t have enough time to reproduce [Helmar's] candle-powered Christmas card. He’s been working on it for a few years now, since his first prototype in 2010. Though he pieced together the original card with parts lying around his workshop, the most recent iteration looks like it belongs on the shelf in a store.

We last saw [Helmar's] work two years ago, when he shared his Full Color Laser TV. This project is a bit more compact: the circuitry was printed with conductive ink on the cardstock, and all the required components are held together by conductive adhesive. To power the electronics, he decided against a battery and instead chose to embed a solar cell on the inside of the card. Placing a lit candle inside the open card provides enough juice for the exterior of the card to shine.

You can see a video of both the current and prototype versions of [Helmar's] cards after the break.

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