LED Hacks

1824 Articles

Home Made BlinkM Units

May 15, 2011 by 33 Comments

[Stephen] wrote in to show us this fun LED wall he constructed in his house. He says he was inspired by this project, but found the cost of the BlinkM units from sparkfun to be out of his price range. He really liked how they worked though, so he downloaded the schematic and firmware and built his own. He was able to fabricate 130 of his own for roughly 250 euros as opposed to the 1,452 euro price tag his sparkfun shopping cart had. That’s not a bad deal at all if you’re willing to invest the time in making your own PCBs and assembling the units. You can follow along on his site to see the entire construction process, as well as some pictures of his glass wall in action. The videos, however, aren’t loading for us. Great job [Stephen]!

Bringing The Game Of Tag Into The Digital Age

May 12, 2011 by 8 Comments

tagurit

How long has it been since you’ve played a game of tag?

[Sylvia Cheng, Kibum Kim, and Roel Vertegaal] from Queen’s University’s human media lab have concocted a fun twist on the classic game that just might compel you to start playing again.

Their game, called TagURIt, arms two players with Lumalive LED t-shirts which sport embedded touch sensors. A third player, known as the “chaser” attempts to touch either of the other players in order to capture the token displayed on the player’s chest-based LED matrix. The game is score-based, awarding points to the chaser for capturing tokens, while giving the other players points for avoiding capture.

If both players wearing the LED shirts are near to one another, the token will jump to the other player in an attempt to thwart the chaser. In this game, each player is a location-tagged URI, and proximity is determined by either tracking the users with cameras indoors, or via RF sensors if the game is played outside.

It is definitely an interesting way of playing tag, and we imagine it could be quite fun in large groups.

Continue reading to see a video demonstration of the TagURIt game being played.

[via Adafruit blog]

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Improve Charlieplexing Performance With Interrupts

May 6, 2011 by 20 Comments

single_chip_led_matrix

[Dmitry] was shopping for LEDs and accidentally pulled the trigger on the wrong type. Since he didn’t want to be wasteful, he figured he should at least take the time to build something with them.

A LED matrix display was the obvious project choice, but he only had a PIC16F688 at his disposal. Since the micro controller only has 11 output pins, charlieplexing was the only way he would be able to light the entire matrix.

While testing his LED array, he found charlieplexing to be a bit disappointing. The fact that the LEDs can get relatively dim, depending on the number of units lit at any particular time struck him as annoying.

In order to improve the performance of his charlieplexed array, he first decided to scan through all of the LEDs rather than just those that needed to be lit. This ensured that all of his LEDs had the same 1/110 duty cycle and were always as bright as possible. He also chose to use interrupts when lighting the LEDs. This meant that his code does not need to take into consideration any specific timing requirements to maintain persistence of vision. He also double-buffers the display to help reduce flicker.

He says that he ran into certain constraints with the PIC chip he chose, so he used a handful of lookup tables to ensure smooth operation of his display. He was quite satisfied with the results, and we think that the interrupt-driven display looks like it works just fine from where we’re standing as well.

Be sure to stick around for a quick video explaining and demonstrating his single-chip LED matrix.

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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

my_shades_are_so_bright_i_gotta_wear_um_something

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

game_of_life

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]