Snowden Immortalized As Bond Villain In Edge-Lit Acrylic Poster

December 17, 2013 by Kristina Panos 12 Comments

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[Wilywyrm] needed to come up with a final project for art class that commented on a social issue. Healthcare, schmealthcare, he said, and busted out this movie poster about the NSA spying scandal instead.

The circuit uses three extended-duty astable 555 timers to control the brightness of the 5050 RGB common-anode LED strips that run up the sides of the 24″ x 12″ x 1/4″ acrylic panels. Each of the three panels was laser-engraved at 600 DPI on an Epilog laser engraver and features a different aspect of the poster. There’s one for Snowden, one for Daniel Craig, and one for the text.

[Wilywyrm] tied the color channels together in the first panel to output white light. He used red for the second panel and blue for the third. A complete list of parts with build notes is available on his Google Drive. [Wilywyrm]’s notes include improvement ideas, like making all the RGB strips color-adjustable with more 555s or a microcontroller and timers.

Perhaps [Wilywyrm] could get into the clear whiteboard business after college.

Particle System Busy Box Keeps Baby Occupied

December 17, 2013 by Brian Benchoff 20 Comments

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Any child born today has a bright future ahead of them—mostly consisting of watching glowing rectangles for 80 or 90 years. To give his progeny a jump-start on a lifetime of watching LEDs flicker, [Dan] created a busy box. It’s really just an Arduino, RGB LED matrix, and a programmed particle system, but if we’re fascinated by it, it will probably blow an infant’s mind.

The idea for this busy box originated with an earlier Hackaday post that used an 8×8 matrix of RGB LEDs to create a moving color cloud. [Dan] took this project as a jumping off point and created an infant’s busy box with four modes that are sure to be entertaining.

Inside the is a Rainboduino: an Arduino compatible board capable of driving an 8×8 RGB LED matrix. Also stuffed inside the busy box is a 9V battery, rocker switch for the power, and four arcade buttons that cycle through each mode. The first mode is some sort of ‘plasma cloud’ simulation, the next is a ‘painter’ light display. The final two modes spell out [Dan]’s spawn’s name, and all the numbers and letters of the alphabet.

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Reverse Engineering A Candle Flicker LED

December 16, 2013 by Eric Evenchick 55 Comments

Candle flicker LEDs are a one part replacement for a real candle. They contain both a yellow LED and a control chip that modulates the light to create a candle effect. [Cpldcpu] took a deep look into reverse engineering one of these LEDs.

To analyze the circuit, which is potted into the LED itself, a shunt sense resistor was connected to the LED. By connecting this resistor to a logic analyzer, the control signal could be observed.

This control signal looked like pulse width modulation, with some randomness to the duty cycle. [Cpldcpu] determined that a linear feedback shift register was most likely used to generate a pseudeorandom bitstream, and some shaping was applied to make the LED look more like a real candle.

It turns out a blinking LED can be quite complex, and this takes a deep look into it by analyzing the signal. [Cpldcpu] took the lessons learned and wrote an implementation of the algorithm for AVR.

Controlling High Voltage 7-Segment Displays

December 15, 2013 by Kevin Darrah 8 Comments

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The MAX7219 is one of those parts in your bin that has a “done and done” attitude. In case you’re unfamiliar, this chip can be used to control 7-Segment displays, 8×8 Matrix displays, or even a pile of random LEDs. You talk to it via a simple serial interface and it handles the tasks you don’t want to fuss with, such as multiplexing and modulation. Not all displays are alike, however, so [Raj] wrote in to show how he used the MAX7219 to control high voltage 7-segment displays.

The spec on the MAX7219 only allows an input voltage of 5V, which limits the driver output to around 4V and can cause problems when using large displays that series-connect LEDs internally. [Raj’s] solution allows the MAX7219 to control displays with combined forward voltages of up to 24V, and as an added bonus, the circuit maintains compatibility with existing microcontroller libraries. We imagine this could be a nifty trick to keep on hand the next time you need to control large scoreboard displays.

The circuit works with the help of intermediate drivers to essentially level-shift the voltage to the display, which both provides the high voltage and protects the MAX7219’s inputs. One of the drawbacks of this circuit is losing the MAX7219’s constant current feature, requiring that each segment connection includes a current-limiting resistor. We appreciate this design’s attention to default states, because you wouldn’t want all of your LEDs turning ON during boot-up!

Flying Spaghetti Monster Display

December 13, 2013 by James Hobson 91 Comments

[Anthony Liekens], one of our favorite hackers from Belgium, recently completed this large (and awesome!) Flying Spaghetti Monster LED display!

With so many different holidays in December, [Anthony] decided he wanted his family to celebrate a slightly less traditional deity. The body is a massive 4′ by 8′ wooden board that we think [Anthony] cut out by hand, with a total of 300 RGB LEDs driven by an Arduino. Chicken wire mesh provides support for the LEDs in the FSM’s mouth and eyes. [Anthony] built everything in his very own backyard hackerspace called the Open Garage, which is a fantastic neighborhood hackerspace (and we should know—we stayed at his place during our European Hackerspace Tour!)

[Anthony] has a bunch of videos showing off the display on his personal YouTube channel, but stick around after the break for a quick sample that features the Flying Spaghetti Monster in the front window of his home.

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Status Light Tells You The Code Is Borked Again

December 12, 2013 by Adam Fabio 5 Comments

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[Arthur] is teaching himself product development. Rather than create a few mock-up products, he’s taking the path of designing real devices he can use. His current device is a status light for automated software tests. We’ve seen test and GitHub status lights before, however this is the first one to integrate with an outside web service. The status light’s state is based upon output from CodeShip, an online continuous deployment test engine.

The electronic design is simple. An Electric Imp retrieves test status data from CodeShip. The Imp then sends the status data over two GPIO lines to an AdaFruit Trinket. The Trinket controls a NeoPixel ring. A green ring indicates all tests are passing. Purple means tests are in progress. A spinning red ring (of death) means one or more tests have failed. Power is supplied via a mini USB connector.

[Arthur] spent quite a bit of time on the mechanical design of the status light as well. All the parts are 3D printed. This allowed him to quickly go through several revisions of each part. We like the use of white PLA for a frosted effect on the top section of the light, as it diffuses the eye piercing glow from all those RGB LEDs. As a finishing touch, [Arthur] created a fake product page for his light. He doesn’t have any plans to sell it, but we hope he drops the source and STL files so we can create one of our own.

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Finally, An Animated GIF Light Painter

December 12, 2013 by Brian Benchoff 6 Comments

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Light painting, or taking a picture of a moving RGB LED strip with a very long exposure, is the application du jour of Arduinos, photography, and bright, glowey, colorful things. Hackaday alumnus [Phil Burgess] has come up with the best tutorial for light painting we’ve seen. It’s such a good setup, it can be used to create animated .gifs using multiple camera exposures.

The build uses an Arduino Uno, SD card shield, and Adafruit’s new NeoPixel strip with 144 RGB LEDs per meter. Despite a potentially huge mess of wires for this project, [Phil] kept everything very, very neat. He’s using an Altoids case for the ‘duino, an 8 AA-cell battery holder and 3A UBEC for the power, and a wooden frame made out of pine trim.

Part of the art of light painting involves a lot of luck, exponentially so if you’re trying to make a light painted animated .gif. To solve this problem, [Phil] came up with a very clever solution: using a rotary encoder attached to a bicycle. With the rotary encoder pressed up against the wheel of a bike, [Phil] can get a very precise measurement of where the light strip is along one dimension, to ensure the right pixels are lit up at the right time and in the right place.

It’s a wonderful build, and if Santa brings you some gift certificates to your favorite electronics retailer, we couldn’t think of a better way to bring animated .gifs into the real world.