Overlaying Video On Encrypted HDMI Connections

January 21, 2012 by Brian Benchoff 25 Comments

[bunnie] is up to his old tricks again. He successfully implemented a man-in-the-middle attack on HDCP-secured connections to overlay video in any HDMI video stream. There’s a bonus, too: ~~his hack doesn’t use the HDCP master-key~~. It doesn’t violate the DMCA at all.

HDCP is the awful encryption scheme that goes into HDMI-compatable devices. Before HDCP, injecting video overlays or even chroma keying was a valid interpretation of fair use. [bunnie] thinks that HDMI devices should have the same restrictions analog devices have, so he decided to funnel his own video into his TV.

The build uses the NeTV, a handy and cheap FPGA board with an HDMI input and output. [bunnie] got the FPGA to snoop the HDMI bus and decide if a pixel needs to be changed or not. This isn’t much different from what researchers in Germany did a few months ago, but unlike the academic security researchers, [bunnie] gives you a shopping list of what to buy.

As an example of his work, [bunnie] implemented something like a ‘tweet ticker’ on HDCP-encrypted video. There’s very little the NeTV setup can’t do from chroma keying, filters, or simply dumping the HDMI stream to a hard disk. Check out the slides from [bunnie]’s talk to get better idea of what he did.

[PAPPP] found a video of the talk in question. Check that out after the break.

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An E-paper Information Panel

January 13, 2012 by Brian Benchoff 19 Comments

With all the Kindles and Nooks we’re bound to find at yard sales and thrift shops in the coming years, this might be useful. [Chris] made a door-mounted e-paper display to keep himself up to date on recent events.

The hardware comes from an e-paper development kit [Chris] and his friend [Deian] were given a few years back. The dev kit sat in a dusty drawer until [Chris] decided to do something with it. With his door looking like a suitable palette, [Chris] decided to make an information panel that displays the date, his calendar, the weather, and a few RSS feeds.

There was already a Gumstix single board computer attached to the e-paper display, so [Chris] wrote a few scripts on his server and upload information to the paper display. The server renders the display as a PNG image at 800×600 resolution, converts it to PGM and compresses it for the Gumstix. There is a script running on the Gumstix to download the image from the server every five minutes and put it up on the display.

With the awesome readability and low power consumption of e-paper, we’re surprised we haven’t seen a project like this before. Guess we’ll have to wait until Kindles start showing up at flea markets.

3D Printed Zoetrope

January 11, 2012 by Brian Benchoff 25 Comments

Normally, 29 men walking around in an endless circle would be the stuff of an [M.C. Escher] engraving. [Tobias] turned this into a reality with a little help from some LEDs and a 3D printer.

Like his earlier project, [Tobias] built himself a nice little strobing zoetrope that maintains the illusion of movement by flashing LEDs at precise intervals. Instead of a flat 2D image, [Tobias] went for a walking 3D figure that marches to the beat of a timer circuit. The figures themselves were printed via Shapeways.

The electronics were improved for this iteration. Formerly, [Tobias] used a 555 and a whole bunch of auxiliary components. The circuit was improved for this version to uses Schmitt triggers and an optical encoder. The easy-to-build-on-perfboard schematics and layouts are available, so feel free to build one for yourself.

[Tobias]’ zoetrope isn’t much different from the gigantic Charon sculpture seen at last year’s Burning Man. Sure, it’s not 40 feet tall but it’s still a nice piece of work.

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Projector Project Bears No Fruit But It Was A Fun Ride

January 9, 2012 by Mike Szczys 18 Comments

No matter how good the intentions or how strong your hack-fu may be, sometimes you just can’t cross the finish line with every project. Here’s one that we hate to see go unfinished, but it’s obvious that a ton of work already went into reclaiming these smart white-board projectors and it’s time to cut the losses.

The hardware is a Smartboard Unifi 35″ computer with a projector mounted on a telescoping rod. It was manufactured for use with a touch-sensitive white board which the guys at the Milwaukee Makerspace don’t have. The projector works, but all it will display is a message instructing the user to connect the computer to the white board. Since they’ve got a couple of these projectors, it would be nice to salvage the functionality.

The first attempt was to replace the video signal to the projector. A few test boards were etched to experiment with DVI input. This included several logic sniffing runs to see what the computer is pushing to get the warning message to display. Alas, the group was not able to get the device to respond. But this opens up a great opportunity for you to play Monday morning hacker. Take a look at the data they’ve posted in the link above and let us know how you would’ve done it in the comments.

Censoring All The ‘F’ Words On TV

December 15, 2011 by Brian Benchoff 25 Comments

[Milton] sent in a build that censors every ‘F’ word on TV, and not just the one that rhymes with ‘duck,’ either. His setup sounds the alarm every time someone inside the moving picture box says a word that contains the letter F.

The build is based around Nootropic Design’s Video Experimenter Shield. This neat little shield has been used as a video sampler and has analyzed what the talking heads are actually saying. The Video Experimenter Shield has support for closed captions, meaning a transcript from a TV show can be read in real-time. All [Milton] had to do so the ‘F word’ alarm could be sounded was strchr().

The F-Chip, as [Milton] calls his build, includes three outputs – a solenoid sounds a bicycle horn, sends some air through a whistle, and lights up an ‘F-word’ alarm. From the video of the F-Chip in action (available after the break), we can tell that this build is awesome, thoughtful, and annoying. The only way it could be made more annoying is by making an ‘E-word’ alarm, but there are ways around that.

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Simulating PenTile RGBG Displays

December 9, 2011 by Mike Szczys 22 Comments

Here’s an interesting experiment that lets you simulate PenTile displays on a normal LCD monitor. [Barrett Blackwood] wanted to test out how some graphics look on PenTile RGBG displays with different pixel densities. These PenTile RGBG matrices are sometimes used in OLED displays. For instance, the Nexus One smart phone features a display of this type. Because red, green, and blue OLEDs emit different intensities of light, the pixels are laid out differently from LCD panels in order to balance the color mixing. Our eyes see the green light very well, and so green sub-pixels are made much smaller than their red and blue counterparts.

Because the hardware layout is different, some graphics appear to have crosshatching artifacts in them when viewed on the PenTile displays. [Barrett] made the example above to simulate how graphics look on a traditional LCD screen (image on the left), and how they appear on the PenTile scren (image on the right). The magenta hue seen above is a result of resizing the image. Since the simulation method turns off 1/3 of the green pixels in the image, resizing it ruins the careful calculation. It must be view at a 1:1 ratio to see the image correctly, at which point the magenta magically disappears.

Combine 2 Non-Working Sony TVs Into One That Works

December 7, 2011 by Jeremy Cook 16 Comments

Have you ever wondered if you could fix your two broken LCD TVs by combining them? Neither had we, but [Redion] did, and the answer is yes, it can be done. Although it may sound like a serious kludge, the finished product actually looks quite nice from the view provided. On the other hand, we don’t know how the internals will hold up, but it apparently works well now.

For this hack, the working internals from a 32 inch Sony LCD TV with a broken display were combined with a 40 inch Sony LCD TV that had an undamaged display but fried internals. Although this would most likely not work for every TV out there, it’s still a pretty neat experiment. Many people would simply assume something like this would not work, and trash both TVs. We would suggest the new TV be named “Nomad”, just avoid wearing a red shirt around it.

Keep in mind with any TV hack, taking one apart can expose you to large capacitors that may or may not be charged and can be quite dangerous (they can stay charged for a long time). We don’t necessarily recommend duplicating anything here, but use extreme caution if attempting anything like this.