Matrix backpack was a fun design project

[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.

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Numerous quiz buttons built on the cheap

[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.

Rainbow board of many ping-pong balls

[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.

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This giant hand made LED matrix must be ours!

giant-led-matrix

[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.

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Video display from RGB strips makes it seem so easy

[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.

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G-35 Christmas lights do make a great LED matrix

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.

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Huge flexible LED matrix can be worn almost anywhere

lightbright_led_mesh

[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.

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