Anti-Tetris Project Is A Study In Hand Tracking

May 22, 2013 by Mike Szczys 6 Comments

anti-tetris

The game of Anti-Tetris is played by standing in front of a monitor and watch falling Tetris pieces overlaid on a video image of your body. Each hand is used to make pieces disappear so that they don’t stack up to the top of the screen. We don’t see this as the next big indie game. What we do see are some very interesting techniques for hand tracking.

An FPGA drives the game, using a camera as input. To track your hands the Cornell students figured out that YUV images show a specific range of skin tones which can be coded as a filter to direct cursor placement. But they needed a bit of a hack to get at those values. They patched into the camera circuit before the YUV is converted to RGB for the NTSC output.

Registering hand movement perpendicular to the screen is also a challenge that they faced. Because the hand location has already been established they were able to measure distance between the upper and lower boundaries. If that distance changes fast enough it is treated as an input, making the current block disappear.

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Vine App Hack On IPhone Makes Time-lapse Movies

May 22, 2013 by Mike Szczys 22 Comments

time-lapse-with-smashed-iphone

The Vine app is all the rage these days. It lets you shoot six-second videos on your iPhone and easily post them on the Internet. The problem is that [Sean Hodgins] doesn’t find the time limit to be useful for traditional video. But you can cram a lot more info into a half-dozen seconds if you make it a time-lapse video. The rig above is his solution to making the Vine app act as a time-lapse recorder.

The trick is in how the app itself works. It only records video when you’re touching the screen. So you record one second of video, then remove your finger and it ‘pauses’ the recording until you’re ready for the next scene. [Sean] automated this by adding a servo motor and a stylus. An Arduino drives the servo, making quick taps on the screen to get as many different frames into the six seconds as possible. He had a bit of trouble registering quick taps at first. His solution was to inject 3.3V into the stylus he gutted for the project. Click through the link above to see some example videos, or watch this embedded video to see the hardware at work:

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GoPro Hack Delivers Live Video Feed For Piloting Your Quadcopter

May 13, 2013 by Mike Szczys 43 Comments

The GoPro line of HD cameras seem like they were specifically designed for use with quadcopters. We say that because the small, light-weight video devices present a payload which can be lifted without too much strain, but still have enough horse power to capture video of superb quality. Here’s a hack that uses the camera to provide a remote First Person View so that you may pilot the aircraft when it is out of your line of sight.

The camera in question is a GoPro Hero 3. It differs from its predecessors in that the composite video out port has been moved to a mini USB connector. But it’s still there and just a bit of cable splicing will yield a very clear signal. The image above shows the camera in the middle, connecting via the spliced cable to an FPV transmitter on the right. This will all be strapped to the quadcopter, with the signal picked up by the receiver on the left and piped to a goggle display worn by the pilot. You can see the cable being construction process in the clip after the break.

If you’re looking for other cool stuff to do with your GoPro camera check out the bullet-time work [Caleb] did with ours.

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Trashed LCD Monitor Turned Into A Light Box

May 8, 2013 by Mike Szczys 30 Comments

light-box-from-lcd-monitor [x2jiggy] was given a non-functioning LCD monitor. He made a small effort to trouble-shoot its inability to display anything on the screen but couldn’t get it working again. When that failed he decided to repurpose it as light box instead of just sending it off for recycling.

Monitor manufacturers put in a lot of effort to make sure the back lights distribute brightness as evenly as possible and that will make this a pretty good light box. [x2jiggy] starts off the conversion by removing the case. While it was off he gave it a new coat of paint. The LCD panel, the PCB that drives it, and the light diffuser sheets were all removed, leaving just the backlight and inverter PCB. A bit of probing with the multimeter and he even found a place to connect a toggle switch to actuate the inverter’s power. You can see the silver switch he added to the bezel in the image above. The full build video is embedded after the break.

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Video Player Built From Stellaris Launchpad

April 27, 2013 by Mike Szczys 11 Comments

stellaris-launchpad-playing-video

We think it’s pretty impressive to see a Stellaris Launchpad playing back Video and Audio at the same time with a respectable frame rate. It must be a popular time of year for these projects because we just saw another video playback hack yesterday. But for this project [Vinod] had a lot less horsepower to work with.

He’s using a 320×240 display which we ourselves have tried out with this board. It’s plenty fast enough to push image data in parallel, but if you’re looking for full motion video and audio we would have told you tough luck. [Vinod’s] math shows that it is possible with a bit of file hacking. First off, since the source file is widescreen he gets away with only writing to a 320×140 set of pixels at 25 fps. The audio is pushed at 22,400 bytes per second. This leaves him very few cycles to actually do anything between frames. So he encoded the clip as a raw file, interlacing the video and audio information so that the file can be read as a single stream. From the demo after the break it looks and sounds fantastic!

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Connect A Retina Display To A Regular Computer

April 22, 2013 by Mike Szczys 99 Comments

You don’t have to search very long before you find someone raving about the Retina display used in Apple iPads. We’re not going to disagree. These 9.7″ panels pack in a whopping 2048×1536 resolution and the color is fantastic. But we were surprised to hear you can get one of these for a meager $55. That’s how [Andrzej] sourced the part when he set out to connect a Retina display to a regular PC.

It turns out this isn’t all that hard. The display uses the eDisplayPort protocol. This is an extension of DisplayPort which is an alternative to LVDS that is gaining a foothold in the industry. An external DisplayPort adapter can already be found on higher-end laptops, which means this should be a snap to use as an external display if the signals can be routed correctly.

To do this, [Andrzej] figured out how to order the PCB connector for the panel’s ribbon cable. He then etched and populated his own board which serves as an adapter for a DisplayPort cable. It even powers the panel, but an external 20V supply is necessary for the backlight.

[Thanks Adam]

GUI Window Manager On An AVR Chip

April 20, 2013 by Mike Szczys 31 Comments

avr-window-manager-gui

This project is reminiscent of the old days when window managers were an amazing new idea. The difference is that this window-based GUI is running on an ATmega1284 microcontroller. But the behavior and speed of the interface is pretty much exactly what you’d expect if working on an early 90’s home computer. It even uses a mouse as input.

So how is this even possible? The key to the project is a serial to VGA module which handles the heavy lifting involved with generating a VGA signal. We featured one of [Andrew’s] past projects which used an AVR chip to generate the VGA signal. But that doesn’t leave nearly enough cycles to implement something like a window manager, not to mention the fact that it got nowhere near the resolution shown here.

He uses a serial mouse with an RS-232 converter chip to interact with the windows. This is best shown in his video after the break. He’s able to generate and interact with new windows. He even implemented a set of rudimentary controls which allow him to adjust the theme of the windows and drive the audio playback feature included on that VGA controller he’s using.

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