STM32 Driving A PCIe Video Card

October 8, 2012 by Mike Szczys 33 Comments

[Gpuhackr] chose his username to explain exactly how he spends his time. For instance, here he’s using an STM32 Discovery board to drive an AMD Radeon HD 2400 graphics card. The ARM microcontroller isn’t actually using the PCIe interface on the card. Instead, [Gpuhackr] has patched into the debugging interface built into the card itself. This isn’t quite as straight forward as it sounds, but if you do the wiring carefully it’s a pretty intersting way to connect an ARM to an LCD monitor.

This project would be almost impossible if it weren’t for the open source code which AMD has released. This lets him implement the card’s 3D rendering features. The demo directly programs the UVD Xtensa CPU which is on the video card. It draws a cube with color gradients on each side. The cube spins while the debug information is overlaid on the screen. In this case the ARM chip/board is really being used as a programmer to upload some custom firmware. But we think a real code-ninja could implement a communications protocol to open up a simple way to drive the card in real-time.

[Thanks uMinded]

Laser-etched LED Zeotrope Looks Like A Circular Monochrome Screen

October 3, 2012 by Mike Szczys 12 Comments

The still image of this animated display really doesn’t do it justice. But you can get an idea of how this really does look like an old monochrome display. It’s actually a zeotrope made from LEDs and etched acrylic. The LEDs blink at a rate that synchronizes with the spinning acrylic to produce an animated image.

You probably already know that a zeotrope uses moving physical models to trick the eye into seeing an animation. In this case the models are etched into a piece of acrylic so that their outline glows when the material is edge-lit. Twelve pie piece shaped panes were designed in Inkscape to look like a scene from the Linux game World War IV. A stepper motor spins the ring which allows for the perfect synchronization seen in the clip after the break.

Continue reading “Laser-etched LED Zeotrope Looks Like A Circular Monochrome Screen” →

Volumetric Display Projects 200 Million Voxels Per Second

September 23, 2012 by Brian Benchoff 42 Comments

Over the last four years, [Will] and [Gav] have spent their time creating a huge, high-resolution 3D display. The’re just about done with their build, so they decided to offer it up to the Internet in the hopes of people creating new 3D content for their display. They call their project the HoloDome, and it’s the highest resolution volumetric display we’ve ever seen.

The HoloDome operates by spinning a translucent helix around its vertical axis at 20 rotations per second. A pico projector above the helix capable of projecting 1440 frames per second (an amazing device by itself) displays 72 ‘z-axis’ frames for each of the 60 ‘x and y frames’ per second. The result is a 3D display with a 480 * 320 * 72 voxel resolution capable of displaying 20 frames per second.

This isn’t the first time we’ve seen a swept helix used as a volumetric display, but it is by far the highest resolution display of its type in recent memory. [Gav] and [Will] have put their HoloDome up on the Australian crowd-funded site Pozible if you’d like to buy your own, but thankfully the guys have included enough detail on the main site to reconstruct this project.

Check out the video after the break to see the HoloDome in action.

Continue reading “Volumetric Display Projects 200 Million Voxels Per Second” →

VISUALIST – A Hardware Visual Effects Synthesizer

September 12, 2012 by Mike Szczys 12 Comments

[Berto] wrote in to tell us about the visual effects synthesizer he built. It works as a pass-through for a video signal, rendering crisp clean images into a more psychedelic flavor like the one seen above. On the one hand this does a dishonor to the high-quality video devices we carry around in our pockets these days. On the other hand it will make some really interesting background video at a party or at your local dance club.

This is not a filter for a PC, or an FPGA-based processing system. A set of analog parts alter the incoming composite video (NTSC or PAL formats) and pipes the result to a television or projector. [Berto] included controls to alter the effects. They’re mounted on a panel and everything is given a home inside of a handy carrying case. Check out the video clip after the break to get a better idea of the video manipulations this things can pull off.

Continue reading “VISUALIST – A Hardware Visual Effects Synthesizer” →

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.

Continue reading “Full-color Video On A Spinning POV Display” →

Mixing Video For Old School Effects

September 7, 2012 by Brian Benchoff 19 Comments

For all the high production values Final Cut Pro and Adobe Premier have released upon the world, there’s still a cinematographic aesthetic only possible with analog video, linear editing, and video feedback. [gijs] just sent in a video mixer he’s been working on to allow crossfading between two video signals and introducing some very cool analog video distortion effects.

[gijs]’ mixer uses the LM1881 video sync separator also found in the Arduino video experimenter shield. Because two different video feeds are unlikely to send their sync signal at exactly the same time, the selected video will stay still on the screen while the second video feed will slowly scroll horizontally across the screen.

This isn’t the first analog video hack [gijs] has come up with; last year he released an Arduino video sampler capable of recording about a second of video and playing it back forward, reverse, looped, or inverted.

We’re sure combing both the video mixer and sampler would produce an aesthetic similar to the experimentation seen on 80s-era public access or our time in AV club. Either way, a very cool build that just can’t be done digitally.

Video of the mixer after the break.

Continue reading “Mixing Video For Old School Effects” →

Visualizing Water Droplets And Building A CT Scanner

August 26, 2012 by Brian Benchoff 9 Comments

Since his nerves were wracked by presenting his project to an absurdly large crowd at this year’s SIGGRAPH, [James] is finally ready to share his method of mixing fluids via optical tomography with a much larger audience: the readership of Hackaday.

[James]’ project focuses on the problem of modeling mixing liquids from a multi-camera setup. The hardware is fairly basic, just 16 consumer-level video cameras arranged in a semicircle around a glass beaker full of water.

When [James] injects a little dye into the water, the diffusing cloud is captured by a handful of Sony camcorders. The images from these camcorders are sent through an algorithm that selects one point in the cloud and performs a random walk to find every other point in the cloud of liquid dye.

The result of all this computation is a literal volumetric cloud, allowing [James] to render, slice, and cut the cloud of dye any way he chooses. You can see the videos produced from this very cool build after the break.

Continue reading “Visualizing Water Droplets And Building A CT Scanner” →