Video Hacks

620 Articles

Raspberry Pi Learns The Lost Art Of Teletext

July 7, 2013 by 35 Comments

rpi-teletext

Exploring dead protocols is often the calling card of hobby electronics enthusiasts. And why not? The mistakes have already been made and fixed — you can learn from them. This Raspberry Pi TeleText hack is the perfect example. It let [Moonlit] explore the realm of generating composite video, as well as establishing communications between the Raspberry Pi  and a microcontroller.

Teletext was a method of accessing information on a television before computer networks were available to the general public. It was pretty impressive at the time, as you can tell from this Retrotechtacular feature. [Moonlit] started looking into recreating a Teletext device by simply generating a PAL signal with an AVR chip. He was met with an equipment failure (remember, it’s always a hardware problem) in to form of a fake composite to USB dongle. After changing the receiving device he was up and running and ready to explore the particulars of the protocol. As you can see, his success even led him to spin a breakout board which plugs in to the RPi GPIO header. A Y-splitter (joiner?) combines the composite output of the RPi with the the overlay data from his own board.

MacBook Pro Retina Display With A Normal Computer

July 5, 2013 by 30 Comments

If you’ve seen one of the fancy, expensive MacBook Pro laptops with a Retina display, you’ll know how awesome having that much resolution actually is. This incredible resolution comes with a price, though: the MBP with a Retina display is about $500 more expensive than the normal resolution MPB model, and it’s very difficult to find a laptop of comparable resolution without cries of fanboyism being heard.

[Daniel] over at Rozsnyo came up with a neat solution that connects one of these fancy 15-inch Retina displays to just about any computer. The build is the beginning of a product that works just like the previous DisplayPort adapter for the iPad retina display, but with the possibility of a few added features such as HDMI input and use of the internal webcam and WiFi antennas.

This build isn’t really a finished product anyone can buy and plug into a replacement Retina display just yet. Even if it were, it’s extraordinarily difficult to find a replacement display for the high-end MacBook for under the price of a really good monitor, anyway. In a few years, though, when the old, busted Retina laptops are traded up for a new, shiny model, though, we’ll be the first to try out this mod and get some serious desktop space.

Modifying A CRT Television For Use As An Arcade Monitor

June 17, 2013 by 29 Comments

Finding himself in need of an arcade monitor [Eric Wright] turned to this ancient CRT television. The problem is that arcade monitors and televisions didn’t operate in the same way, differing in both resolution and refresh rate. [Eric] modified the television to work like an arcade monitor, but only with limited success. He’s hoping a few more alterations will lead him to a complete solution.

The image above shows him testing a Pac-Man machine on the altered Sharp television. Those familiar with the game will immediately notice that there is something wrong. We see most of the tracks upon which Pac-Man and the ghosts travel, but he maze itself is completely missing. To get to this point [Eric] consulted the television and arcade schematics to figure out how to connect the composite sync and three color channels directly to the arcade machine. This way the CRT timing is forced to conform to the game standard. The problem is that there is no way to adjust the drive and cutoff of the individual color channels. This is something [Eric] hopes to fix in the next iteration of his experiments.

If you already have a working arcade monitor but no gaming cabinet why not use a Raspberry Pi?

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Update: Live Video Played On LED Strip Display

May 26, 2013 by 11 Comments

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[Paul] took this LED display along with him to Maker Faire. To give it some interactivity he figured out a way to make it play live video. It is also activated using some stomp actuators built from piezo speaker elements and rubber floor mats.

This moves his original project in new directions. Back in February he was showing off the RGB LED strip display. He had it playing video but that was all dependent on using previously processed files. This upgrade uses a BeagleBone Black (the newest rendition of the ARM-based development board). [Paul] had tried using a Raspberry Pi board but had trouble with the webcam (mounted above the LED display) dropping frames. With the new board he is able to use the Video4Linux API to capture 30 frames per second and push them out to the display.

So far he’s had five out of the 1920 LEDs die on him. This shows off a couple of good things about using strips like this. A dead pixel doesn’t affect its neighbors. And replacement is as easy as cutting the ribbon on either side of the bad component, then soldering a new segment in place.

 

Anti-Tetris Project Is A Study In Hand Tracking

May 22, 2013 by 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 22 Comments

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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 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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