Solving Mazes with Graphics Cards

What if we told you that you are likely to have more computers than you think? And we are not talking about things that are computers while not looking like one, like most modern cars or certain lightbulbs. We are talking about the powerful machines hiding in your desktop computer called ‘graphics card’. In the ordinary gaming rig graphics cards that are much more powerful than the machine they’re built into are a common occurrence. In his tutorial [Viktor Chlumský] demonstrates how to harness your GPU’s power to solve a maze.

Software that runs on a GPU is called a shader. In this example a shader is shown that finds the way through a maze. We also get to catch a glimpse at the limitations that make this field of software special: [Viktor]’s solution has to work with only four variables, because all information is stored in the red, green, blue and alpha channels of an image. The alpha channel represents the boundaries of the maze. Red and green channels are used to broadcast waves from the beginning and end points of the maze. Where these two waves meet is the shortest solution, a value which is captured through the blue channel.

Despite having tons of cores and large memory, programming shaders feels a lot like working on microcontrollers. See for yourself in the maze solving walk through below.

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The Grafofon: An Optomechanical Sequencer

There are quick hacks, there are weekend projects and then there are years long journeys towards completion.  [Boris Vitazek]’s grafofon falls into the latter category. His creation can best be described as electromechanical sequencer synthesizer with a multiplayer mode.
The storage medium and interface for this sequencer is a thirteen-meter loop of paper that is mounted like a conveyor belt. Music is composed by drawing on the paper or placing objects on it. This is usually done by the audience and the fact that the marker isn’t erased make the result collaborative and incremental.
 These ‘scores’ are read by a camera and interpreted by software.This is a very vague description of this device, for a reason: the build went on over six years and both hard- and software went through several revisions in that time. It started as a trigger for MIDI notes and evolved from there.
In his write up [Boris] explains the technical aspects of each iteration. He also tells the stories of the people he met while working on the grafofon and how they influenced the build. If this look into the art world reminds you of your local hackerspace, it is because these worlds aren’t that far apart.

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Exploiting Weak Crypto on Car Key Fobs

[tomwimmenhove] has found a vulnerability in the cryptographic algorithm that is used by certain Subaru key fobs and he has open-sourced the software that drives this exploit. All you need to open your Subaru is a RasPi and a DVB-T dongle, so you could complain that sharing this software equates to giving out master keys to potential car thieves. On the other hand, this only works for a limited number of older models from a single manufacturer — it’s lacking in compatibility and affordability when compared to the proverbial brick.

This hack is much more useful as a case study than a brick is, however, and [tomwimmenhove]’s work points out some bad design on the manufacturer’s side and as such can help you to avoid these kind of mistakes. The problem of predictable keys got great treatment in the comments of our post about an encryption scheme for devices low in power and memory, for instance.

Those of you interested in digital signal processing may also want to take a look at his code, where he implements filtering, demodulation and decoding of the key fob’s signal. The transmission side is handled by rpitx and attacks against unencrypted communications with this kind of setup have been shown here before. There’s a lot going on here that’s much more interesting than stealing cars.

[Via Bleeping Computer]

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Space Technology and Audio Tape to Store Art

[Blaine Murphy] has set out to store an archive of visual art on cassette tape. To do so he encodes images via Slow-Scan Television (SSTV), an analogue technology from the late 50s which encodes images in for radio transmission. If you are thinking ‘space race’ you are spot on, the first images of the far side of the moon reached us via SSTV and were transmitted by the soviet Luna 3 spacecraft.

Yes, this happened

Encoding images with 5os technology is only one part of this ongoing project. Storage and playback are handled by a 90s tape deck and the display unit is a contemporary Android phone. Combining several generations in one build comes with its own set of challenges, such as getting a working audio connection between the phone and the tape deck or repairing old consumer electronics. His project logs on this topic are solid contenders for ‘Fail Of The Week’ posts. For instance, making his own belts for the cassette deck was fascinating but a dead end.

The technological breadth of the project makes it more interesting with every turn. Set some time aside this weekend for an entertaining read.

Just a couple of years back ham radio operators had the opportunity to decode SSTV beamed down from the ISS when they commemorated [Yuri Gagarin’s] birthday. Now if the mechanical part of this project is what caught your interest, you’ll also want to look back on this MIDI sampler which used multiple cassette players.

Fix Everything and Get Your Own Flailing Arms Tube Man

The staple of used car dealerships that prompted Houston to ban all ‘attention getting devices’ is called an ‘air dancer’ and was invented in 1996. And now you can build your own, even if until now the space requirements kept you from doing so.

[dina Amin] shows how to make one from a bunch of discarded hair dryers and stuff everybody is likely to find in his or her workshop. While the build as such is rather basic — these things are really simple devices after all — [dina Amin]’s project video takes us through the interesting detours that turn a build into a project. It touches on the topics of painting plastics, hardware repairs, diagnosing and fixing DC motors, and how hair dryers actually work. As an added bonus we get a good-looking solution for fixing that enclosure with the worn out threads. All that in five minutes flat.

And while you might not know if you need one, [dina Amin]’s wacky waving inflatable arm flailing arm tube man is pretty much guaranteed to work. Unlike this one.

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