LED Hacks

1842 Articles

Light Painting – Still Shots And Animations

May 5, 2011 by 12 Comments

[Kim Pimmel’s] been doing some really interesting light painting with an Arduino. In the past we’ve seen several light painting projects which use long exposures to capture moving LEDs, or moving LCD displays. But [Kim’s] stepping it up a notch, using cold cathode flourescent lamps, electroluminescent (EL) wire, and lasers. The vibrant colors put out by these sources make for some great photos, but that’s not all she’s got up her sleeve. After accumulating a ton of still photographs from various shoots she decided to edit them together into stopped motion videos.

After the break you can see that one method she used to make these images was to spin the light sources on a standard audio turntable. An Arduino is controlled through processing via Bluetooth in order to move the stepper motor-mounted lights while the record player spins. Add some futuristic music thanks to Daft Punk (which is exactly what she did) and you’re in business.

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LED Matrix Helmits Inspiried By You-Know-Who

May 4, 2011 by 17 Comments

Here is a post from [John’s Projects]. For the insane, satirical, and incredible 2011 Omaha Groundhog Prom [John] and his buddy fabricated  helmets reminiscent of our favorite robot rockers.  [John] needed something harder, better, faster, stronger than the competition and wound up creating LED matrices that mount behind aerodynamic motorcycle helmet visors.

The helmets were constructed in about a weeks time and in a similar fashion to the real helmets. [John] sourced some cheap motorcycle headgear and mounted the LEDs, their driving transistors, and ballast resistors to a 1/32″ (flexible) plexiglass sheet that sits face to face with the wearer. [John] walks through the whole process starting with a half inch grid drawn onto a paper template. The template is cut from the plexi using tin snips, then LED holes are carefully drilled in the thin plastic using various bits up to 13/64″. The 90 some odd LEDs are, one more time, fitted then hot glued in place and soldered in vertical columns to simplify things and prevent any short circuit. An Arduino Pro (via common emitter 2n2222 on/off circuits) provides some digital love to the 18 LED columns and is connected to a Velleman Sound-to-light kit which modulates the brightness of the whole visor based on da funk. Two pots are also wired to provide sensitivity and pattern selection to the human after all.

We can’t imagine the technologic setup is fresh after being subjected to the steam machine, high life, and whatever else for too long. Oh yeah, Some brighter LEDs could give the helmets night vision and make the whole thing come alive with emotion. Something about us is burnin to know what powers the helmets. Nice work [John]!

If you are looking to do some homework on these high fidelity rock’n roll outfits in the prime time of your life check out this very detailed example, a helmet construction video,  or finish the costume off with some EL wire.

Check out some videos of these superheros rollin’ & scratchin’ after the jump!

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LED Matrix Glasses Keep All Eyes On You

May 3, 2011 by 17 Comments

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Instructables user [llopez-garcia] was looking for something that would make him stand out at music events or clubs, and decided that an LED matrix built into a set of sunglasses would do the trick.

He grabbed some LEDs and the biggest pair of sunglasses he could find at WalMart, then he got down to business. He had no experience in programming micro controllers, so he chose a PICAXE 20X2 to run his glasses, figuring that it would be easier to program in BASIC for his first project than C.

He drilled holes in the lenses and wired up two 5×5 LED grids, connecting them to the PICAXE as a single 10×5 array. That setup was chosen because the 20X2 limited him to 15 usable pins and he wanted to avoid using a shift register or LED driver to keep the part count down. The rest of the build is relatively straightforward with resistors in all the right places, and a pair of AAA batteries to power it – one strapped to either temple.

We think these are pretty cool, though we’re not sure if he can see anything while wearing them. Then again, who cares? You don’t need to be able to see with glasses this awesome.

If he had to do it all over again, [llopez-garcia] says he would beef up the LED structure a bit, as well as choose a different micro controller that can be programmed in C since he felt the PICAXE was a bit limited by BASIC.

Stick around to see a quick demo video of the glasses in action.

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Large Remote-controlled Game Of Life Display

May 3, 2011 by 5 Comments

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Sometimes it’s just plain fun to over-engineer. [Stephanie] gets a warm fuzzy feeling when she successfully adds way more electronics components to a project than she really needs – just because she can. We can’t really argue with her if that is the intended goal, nor can we find fault with the sweet Game of Life display she put together.

She started off with six Game of Life kits from Adafruit, but she quickly caught the LED bug and her collection grew until she had 20 kits (that’s 320 LEDs for those of you keeping count). After piecing them all together, they were mounted in a wooden frame and placed behind a dark piece of acrylic. It looked great and worked just fine, but it wasn’t overdone enough for her tastes.

In the end, she added a small Arduino and Xbee module to the Game of Life display, which enables it to be controlled by her network-enabled thermostat we featured a few weeks back. The thermostat was fitted with an Xbee unit as well, which allows it to turn the Game of Life on and off at whatever times [Stephanie] specifies.

We’ll take two please.

[via Adafruit Blog]

A Beginner’s Guide To LED Matrices

April 29, 2011 by 4 Comments

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[Rajendra Bhatt] wrote in to share a tutorial he put together demonstrating the basics of using LED dot matrix displays. While this subject might be old hat to many out there, his helpful walkthroughs are geared more towards beginners who are exploring various electronics concepts for the first time.

He explains the theory behind LED displays using a PIC-driven 5×7 matrix as an example. He discusses persistence of vision and how tricking the human eye can save you quite a bit of time and a whole lot of pins. Multiplexing is broken down into its most basic steps, which [Rajendra] illustrates by showing how a letter would be drawn on the LED display one column at a time. The use of a ULN2803A Darlington Array is also discussed, and he details why it is used when pulling the five columns of LEDs to ground.

The only portion of the tutorial we thought could be expanded upon was the programming section. While he does show how each letter of the alphabet can be displayed via a series of five hex values, he does not cover the “why” part of the process. Obviously while anyone familiar with binary and hex can figure it out in pretty short order, we think that it would be a great place to pause and expand the readers’ knowledge even more.

Overall it’s a useful tutorial, and most beginners would likely find it quite helpful.

The Start To Finish Of An Interactive Exhibit

April 29, 2011 by 7 Comments

[Andrew & Deborah O’Malley] were tapped to created an interactive exhibit. The mission was to show that social problems take continual support from a lot of people before they can be solved. The piece needed to be architectural in nature, and they ended up building this touch-sensitive model building with individually lighted windows.

The project log that the [O’Malleys] posted shows a well executed battle plan. They used tools we’re all familiar with to achieve a highly polished and pleasing result. The planning stages involved a virtual mock-up using Google SketchUp. The details needed to order the shell from a fabricator were pulled from this early work, while the team set their sights on the electronics that shed light and that make the piece interactive. The former is provided by a Shiftbrite module for each window, the latter comes from the Capacitive Sensing Library for Arduino. Despite some difficulty in tuning the capacitive grid, and getting all of those Shiftbrites to talk to each other, the exhibit went swimmingly. It’s not hard to imagine how easy it is to start a conversation once attendees are attracted by the seductive powers of touch sensitive blinky lights.

Small POV Device Shows Off Some Big Features

April 26, 2011 by 21 Comments

We’ve already added the components needed to build [Rucalgary’s] tiny POV device to our next parts order. The little device sets a new standard for tiny persistence of vision boards. Instead of relying on the user to find the best speed and timing for swinging the board around, [Rucalgary] used an accelerometer. This is the point at which we’d usually groan because of the cost of accelerometers. We’re still groaning but this time it’s for a different reason.

The accelerometer used here is a Freescale MMA7660. It’s an i2c device at a super low cost of less than $1.50. The reason we’re still groaning is that it comes in a DFN-10 package that is a bit harder to solder than SOIC, but if you’ve got patience and a good iron it can be done. An ATmega48 drives the device, with 8 LEDs and one button for input. On the back of the board there’s a holder for a CR2032 coin cell battery and a female SIL pin header for programming the device.

Check out the video demonstration embedded after the break. We love it that the message spells and aligns correct no matter which way the little board is waved.

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