Full-color Video On A Spinning POV Display

September 11, 2012 by Mike Szczys 30 Comments

Watching Big Buck Bunny on a spinning POV display is pretty impressive. Sure, the circular display area cuts off some of the picture, but otherwise it looks fantastic. This POV display is based on a Gumstix board. It runs embedded Linux which makes video playback rather easy. But translating each frame to the round display is another story.

The device is the result of a course project at Telecom ParisTech. [Félix], [Sylvain], and [Jérémy] used an FPGA to do the pixel mapping. This uses an encoder wheel (rather than a traditional hall effect sensor) to ascertain the blade’s position. The sensor that monitors the disc sends quadrature encoded pulses which result in 10-bit position data. The FPGA uses that data to calculate where each LED falls in its arc, then looks up the pixel color for that position. It’s not the largest POV display we’ve seen, but it certainly has the very best RGB resolution by far.

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Disco Planet, A Massive RGBW LED Array In A 6′ Globe

September 11, 2012 by Jesse Congdon 24 Comments

About half a year ago [John] over at Frank’s Kitchens came to me with an idea for a giant lighting project. He had this 6ft diameter aluminum frame globe rescued from the Philadelphia Theater Company and wanted it to be an interactive display of sorts. After a few discussions we got together and somehow managed to order 800 3 watt LEDs in red, green, blue, and white. We had a system that worked great on paper, and managed to get it built by Valentines day for a big show. It failed miserably and hardly even illuminated the LEDs. I, naturally, took this far too personally and set out for a complete redesign, looking in the direction of digitally addressable LED strips.

In addition to building a crazy turbo charged LED array I also spent a lot (a whole lot) of time coding a nice clean fully functioning RGB LED strip controller using an Arduino Pro Mini (5V 16 MHz), the MSGEQ7 audio frequency multiplexer (PDF) , and an IR remote. I plan on using this for other projects so the code can be easily reconfigured to use many different LED strips and a whole slew of IR remotes.

The schematic of the globe is here. The top half of that schematic be catered to other projects using a variety of pre-built LED strips. The pastebin with code is here, fastSPI_LED and IRRemote here and here. Some code jockeying was required to get IRRemote.h and FastSPI_LED to play nicely together, so check the code comments.

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It Was Only A Matter Of Time Before We Saw Nixie Modules For The Arduino

September 9, 2012 by Brian Benchoff 33 Comments

The Nixie tube, a neon-filled tube with a series of 10 cathodes shaped like numerals, is a classic display for any build wanting a unique, vintage, or steampunk aesthetic. We shouldn’t be surprised a factory in China is now turning out Arduino-compatable Nixie modules (English translation, but don’t get your hopes up), but there it is.

The modules are based on the QS30-1 Nixie tube capable of displaying the digits 0 through 9, and include an RGB LED behind the tube for some nice additional illumination. According to the manual, the modules themselves are based on a pair of 74HC595 shift registers, and are ‘stackable.’ By applying 12 volts to a pair of pins and connecting another 5 wires to an Arduino, it’s possible to drive as many of these Nixie modules as you’d like.

[Paul Craven] got his hands on a quartet of these modules and is planning on building a steampunk style alarm clock as a personal project. [Paul] was able to get the modules up and running fairly quickly, as seen after the break.

While they’re most certainly not the cheapest option, if you’re planning a build with Nixies, this probably is the easiest way to get a vintagey, steampunkey numerical display.

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Putting 300 Watts Of LEDs On An RC Plane

September 7, 2012 by Brian Benchoff 35 Comments

Being a member of the FPVlab forums, [HugeOne] is really in to strapping a video camera to RC airplanes and flying around by the seat of his pants. He’s also in to flying his plane at night. Combine these two interests, and you’ve got 300 watts of LEDs flying around at night, most likely causing a spike in UFO reports in [HugeOne]’s native Quebec.

The main issue with putting 16 CREE XM-L LEDs in such a confined space is the issue of heat; even though these LEDs are amazingly efficient, they still produce a good amount of heat. [HugeOne] solved this problem by soldering these LEDs to a piece of copper pipe and connecting two radiators to his plane for liquid cooling.

The result is a small, lightweight LED array capable of producing more than 20,000 lumens flying around the wilds of Quebec. This greatly improves [HugeOne]’s night flying ability (video after the break), and has surely annoyed the local police department with an increase in UFO reports.

Does anyone know how bright the nav and landing lights on single-engine passenger airplanes are?

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Building Your Own LED-based Home Lighting

September 3, 2012 by Mike Szczys 10 Comments

We see LEDs used in all kinds of projects but rarely does someone build a home lighting system from scratch with them. [Paulo Oliveira] decided to give the idea a try, included a fading power supply for the LEDs which he built himself. Here you can see the installation at full brightness, but his controller also offers a single lower setting.

We saw [Sprite_TM] use an RGB LED strip to light up his living room. [Paulo] went with individual LED modules instead, all the same color. They are Cree XM-L power LEDs so some thought needs to be put into heat dissipation. All six are mounted along an aluminum strip which serves as the heat sink. They’re wired in series and powered by an old laptop power supply. A PIC 12F683 uses PWM to dim the string via a MOSFET.

The control system for the two brightness levels uses the wall switch. When turned on, the LEDs fade in to full brightness. If you turn the switch off and back on before they are all the way on, the dimmed setting takes over. This was complicated by the capacitance of the PSU but [Paulo] solved that by adding a power resistor.

Simulating LED Cubes In Blender

September 3, 2012 by Brian Benchoff 8 Comments

[youtube=http://www.youtube.com/watch?v=bl-kvfJxYwM&w=470]

The Jyväskylä, Finland hackerspace hacklab-jlk was lucky enough to work on a public arts project for their home town. They had the opportunity to design, build, and install a trio of LED cubes in Jyväskylä’s central Church Park. As such a high-profile project, the hacklab-jlk team decided to take their time and ended up implementing a lot of very cool features for their LED cubes, including simulating the light show in Blender.

The LED cube is similar to all the other LED cube builds we’ve seen before; it’s an 8x8x8 cube controlled by an ATMega328. The Elovalo project, as it is called, is a trio of LED cubes – one using red LEDs, one using green LED, and a blue LED cube each mounted on a pedestal in a Jyväskylä park.

Because the Elovalo is a permanent installation, the team needed a way to verify new firmware for the LED cubes. They came up with a LED cube simulator for Blender that allows them to write a new display function in C and render either single frames or a full animation of the lighting pattern.

A very cool build, and nearly too awesome for a public arts project. We look forward to a video of the complete installation, but until then we’ll make do with the short preview video available after the break.

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Building A Driver For Absurdly High Power LEDs

August 30, 2012 by Brian Benchoff 26 Comments

A few years ago, the highest power LEDs you could buy capped out around three watts. Now, LED manufacturers are taking things to ridiculous power ratings with 30, 40, and even 90 watt LEDs. Getting these high-power LEDs are no longer a problem, but powering them certainly is. [Thomas] built a LED driver capable of powering these gigantic LEDs and creating a light show that is probably bright enough to cause bit of eye damage.

[Thomas]’ LED driver is based on Linear Technology’s LT3518 LED driver. This driver is part of a project to build a huge WiFi controlled RGB LED, so the driver has outputs for three separate LEDs capable of sourcing 700 mA each.

Because [Thomas] is dealing with crazy amounts of heat and power required to light up these huge LEDs, the driver board features a temperature sensor next to each LED driver. When the board gets too hot, the driver automatically shuts down, preventing bad things from happening.

You can check out a few pictures of [Thomas]’ LED driver over on the build page for his WiFi LED project. A truly awesome amount of lighting power here, that also makes it impossible to get a good picture of the board in operation.