[Greg] is really working on a small scale with his LED Matrix backpack PCB. It’s a toy that he designed as an activity. He constrained himself to a board which would exactly match the outline of an 8×8 bicolor LED matrix package.

What you see here is the side of the PCB which will be facing the underside of the LED dot matrix module. Let’s call this the top of the board. The underside has a CR2032 battery holder which provides enough juice to run the display. Since the matrix is bi-color there’s a slew of pins to drive. [Greg] uses three shift registers for the high side, and sixteen N-channel MOSFETS for the low side. He’s chosen an MSP430G2201 microcontroller which has a nice sleep mode for power conservation. It has no problem driving tri-color animations as seen the clip after the break, but also has an unpopulated clock crystal footprint if you wanted to use it as a timepiece.

Despite the small footprints and cramped board [Greg] still hand soldered all of the components. He even posted a time-lapse of the process in the page linked at the top.

[Sprite_TM] was tapped to build a rather large quiz buzzer system. Judging from his past work we’re not surprised that he seemed to have no trouble fulfilling the request. As the system is not likely to be used again (or rarely if it is) he found a way to finish the project that was both quick and inexpensive.

Each buzzer consists of a base, a button (both mechanical and electrical), and a couple of LEDs to indicate who buzzed in first. The mechanical part of the button uses a plastic bowl from Ikea and a wooden dowel surrounded by some pipe insulation. A momentary push switch is glued on the top of that dowel, and the insulation projects above that just a bit. This way it acts as a spring. The Dowel has been sized so that the bowl lip will hit the wooden base just as it clicks the switch.

As you can see, all of the buzzers are interlinked using Ethernet cable. The real trick here is how to read 14 buttons using just one CAT5 cable. This is done with the clever use of a 4×4 button matrix for a total of 16 buttons. The matrix also includes the LEDs for each buzzer. Since CAT5 has four twisted pairs this works out perfectly.

Looking for a more robust system thank this? Here’s a pretty nice one.

[George] just finished his first project: an 8×8 matrix “Board of Many Ping-Pong Balls” with 64 RGB LEDs. He started this project when he was 14 years old and finished the build over this last Christmas break. We won’t make any presumptions about [George]‘s age, but we couldn’t think of a better project to start out on.

For the build, [George] used a Colorduino LED driver shield for his Arduino. This made the wiring simple, but the finished product is where this project really shines. For the base, [George] got a board laser cut at his school and used ping-pong balls to diffuse the LEDs. We’ve seen this many times but with this build there’s a neat way to drill a hole in a ping-pong ball; simply put the drill into reverse. The friction is enough to open the ball up, and the chips of plastic come outside instead of remaining in.

We’re really impressed with [George] and his winter break project. He’s lucky enough to have access to a laser cutter at school, and from a look at his monitor, he’s reading the right websites. You can check out his demo rainbow pattern after the break.

[Martin] wrote in to share a project his company has been working on for some time, a gigantic 1470 pixel LED wall. The group provides lighting for clubs, parties, etc, and their hand-built LED matrix is always certain to be the hit of the show.

The amazing matrix was designed from the ground up and built by hand in [Martin’s] living room. They designed small 32x32mm “pixel” boards, each of which features 6 PLCC6 RGB LEDs driven by a single WS2801 LED controller. The PCBs were populated by hand and each one was reflowed in a small pizza oven that [Martin] owns. After the pixels were completed, they were attached to aluminum bar and combined to build thirty 70x70cm frames which are connected together to form a giant matrix.

As you can see in the collection of videos below, the display is very impressive. We just hope that they will be compelled to release the schematics for their boards so that we can build one of these in the office.

[Fabien] wrote in to share a link to this RGB video display which he made. He’s got some pretty cool routines that make it more functional than you would think, but first we want to comment on the construction. He used an RGB strip, which makes this look like an incredibly simple build. The strip has a data and power bus running the length of it. You can it into smaller segments, then just solder jumper wires to reconnect the buses. That’s exactly what he did here, making it what must be the fastest method of putting together a display of this size (16×10 pixels).

It’s driven by a Netduino which easily addresses the LPD8806 drivers responsible for the LEDs. It gets input from a computer via Xbee, making it easy to include data from the net, or to push visualizations. The video after the break shows a [Van Gogh] self-portrait. Since 160 pixel resolution wouldn’t do it justice, the visualization software shows a zoomed in portion of the painting which is constantly panning to let you see the entire work. It’s a fabulous effect.

This fully-addressable RGB LED matrix was built by [John Graham-Cummings]. He didn’t start from scratch, but wisely repurposed a strand of GE Color Effect lights and built a pleasant looking case in which to mount the G-35 hardware.

We’ve seen this hardware used in a similar way before. Because each ‘bulb’ has its own microcontroller, color data is shifted in via a serial bus. Orient the modules in any pattern you choose and account for that layout in software.

Since the strings have 50 bulbs, [John] simply cut off the one on the end to form his 7×7 matrix with the remaining 49 units. A square of plywood with a grid of holes holds each in place. Cord mess is not a problem as the extra was cut out and the remainders were soldered together again. [John] uses an Arduino Pro to feed in the data, which you can see for yourself in the clip after the break.

[Thanks Evalpix]

[Erik] has been keeping extremely busy with his latest project, a flexible RGB LED matrix that he calls “Project Light Bright”. The folks at BuildLounge tell us that this is the first entry they have received so far in their “Light Contest”, in which they are giving away a free laser cutter to the best entry.

[Erik] hand soldered ten 16×16 RGB LED panels together in order to build this display, and the results are awesome. The entire thing is controlled by a WiFi-enabled Beagleboard, which drives all of the panels and then some. The Beagleboard features embedded web and DNS servers, which allows it to act as a wireless AP, enabling him to control the display using any WiFi capable device. The Light Bright displays all sorts of predefined artwork, but [Erik] can also alter the display on the fly via his phone as well. The entire thing is powered by a reasonably sized LiPo battery pack that he keeps tucked away in his pocket, which allows the display to run continuously for about 20 hours.

Check out the video below to see a quick walkthrough of [Erik’s] Light Bright suit, then be sure to stop by his site for more videos, details and updates on the project.

[Retro Brad] has come a long way with his 8×8 gaming device which he calls Super Pixel Bros. The newest rendition has a fab house PCB and freshly rewritten code. The game is still played on an 8×8 LED matrix, but it looks like he’s sourced a version with square pixels, which is a nice touch since he was inspired by the block-based Super Mario games. Also new in this version is the character LCD screen which displays score, level, and life information. But it’s not just the shiny new hardware that’s different, he’s rewritten the software in Swordfish Basic to run on the PIC 18F4550. The new code allowed him to tweak how levels are loaded and stored. He’s even written a level editor and has finished 20 levels thus far.

The demo after the break does a great job of showing off the hardware and the game play. He’s added a lot, including enemies, the ability to shoot fire, and of course the common moves of jumping and breaking blocks is all there. He mentioned that the fab house he used is selling boards for around $5 and he’s looking into the possibility of getting a kit service up and running.

His progress since we last checked in on the project is quite impressive.

It’s time for everyone’s favorite comment thread game: Real or Fake? This week’s edition comes in from a tip that [Fabian] sent us about the music video Bright Siren by the band Androp. The video starts by showing bundles of cables being sorted and connected to breadboards. We get a brief shot of a large LED matrix (presumably being used for testing purposes) then footage of a lot of DSLR cameras with external flashes. These are mounted on racks to produce the marquee seen in the image above. The band performs in front of it for the rest of the video.

We’ve embedded the original video, as well as a ‘making of’ video after the break. There’s also a website you can checkout that lets you write your own message on the marquee. That bit could be easily done in flash so there’s no que, you’ll notice there’s no live feed. While we think the theory is real, we’re a bit skeptical about whether this performance is real or video editing magic. In the behind the scenes clip you can see breadboards attached to each camera flash with rubber bands so we’d guess that at least some of the hardware was setup. But we’re wondering if the animated effects were done in editing like that tea light animation. Let us know what you think by leaving a comment.

Music Video:

Making of:

Instructables user [Rohit] had an out-of-warranty microwave with a broken membrane keypad. Much like our friend [Alexandre] from Brazil, he found the cost of replacement parts beyond reasonable, so he had to find a way to repair it instead.

He disassembled the front cover of his microwave to get at the main controller board. Once it was detached, he removed the keypad’s cover to get a closer look at the matrix underneath. While taking notes on how the matrix was wired, he found that some keypad traces connected to other traces rather than buttons. He says that they are likely used by the microwave to detect that the keypad is present, so he made sure to short those traces out on the controller board when he wired everything back together.

He replaced the aging keypad with microswitches, but rather than mount them on the front panel of the microwave, he drilled holes for each switch so that he could mount them inside the face plate. Once everything was wired and glued in place, he re-mounted the keypad’s cover. Now the microwave looks stock but has firm, reliable, user-serviceable buttons that are sure to last quite a while.

[Alexandre Souza] needed a microwave pretty badly, but he didn’t have a lot of cash on hand. He located one for a great price, but once he got home he found that things weren’t working quite like they should be (Google translation).

After some investigation, he narrowed the problem down to a bad keypad membrane. Unfortunately for him, this model of microwave was never sold in Brazil (who knows how it got there) and the only membrane he could track down had to be shipped in from the US at a cost of $80.

Rather than pay such a high price for a simple membrane, he opted to fix the microwave himself. He dismantled the control panel and thoroughly traced the keypad matrix to get an understanding of which pins toggled which functions. With a piece of protoboard and almost two dozen push buttons in hand, he built his own keypad and wired it directly into the microwave’s control board.

With labels written in marker it might not be the nicest looking thing you have ever seen, but it works a treat and is a great money-saving hack.

[Mathieu] was on holiday in China and picked up some fun toys while perusing the numerous electronics markets there. The most interesting things he discovered were a pair of RGB LED matrices. They came in two different flavors, one made for indoor and one for outdoor displays, sporting a 64×32 and 32×16 resolution, respectively.

If you’ve read his blog before you know he is a big fan of LED matrices, so it’s only natural that bought a whole bunch of them and started experimenting once he got home. Using the same Amtel FPSLIC LED matrix control board he showed off in this previous hack, he was able to get the LED matrices up and running in no time. He adapted his webcam project to utilize the new panels, and he added a whole new feature as well. Via MatLab, he can now display any sort of animated gif on the panels, as you can see in the video below. The panels look great, and if we had a few of these around, there’s no doubt we would probably play this video on infinite repeat.

He says that the despite their somewhat questionable origins, the panels are of top notch quality, and he is willing to organize some sort of group buy if others are interested.

[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]!

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.

[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.