Finally Your Air Drumming Has An Outlet

Two engineering students are hard at work on this air drum which they hope will help disabled people and people in nursing homes. Though, we think it just looks fun!

Each board is its own module consisting of the electronics and 3D printed cases. The modules each contain an arduino mini, IR sensor, and LEDs. They share power, audio, and communicate with an i2c bus. Two modules are special, one holds the power system and the other a Raspberry Pi. The units can be put together in different configurations. Finally, they are capped with speaker units.

The demo shown in the video, which you can see after the break, looks fun. The response time is pretty fast and it looks like you can measure all sorts of parameters. This can then be translated into different velocities, pitches, and instruments. It’s somewhere between a theremin and a drum kit, very cool.

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DSP Spreadsheet: IQ Diagrams

In previous installments of DSP Spreadsheet, we’ve looked at generating signals, mixing them, and filtering them. If you start trying to work with DSP, though, you’ll find a topic that always rears its head: IQ signals. It turns out, these aren’t as hard as they appear at first and, as usual, we’ll tackle them in a spreadsheet.

What does IQ stand for? The I stands for “in phase” and the Q stands for quadrature. By convention, the I signal is a cosine wave and the Q signal is a sine wave. Another way to say that is that the I and Q signals are 90 degrees out of phase. By manipulating the amplitude of I and Q, you can create complex modulation or, conversely, demodulate signals. We’ll see a spreadsheet that shows that completely next time.

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Needling Your Projects: 3D Printed PCB Probing Jig Uses Accupuncture Needles

Trying to probe a modern electronic circuit with tiny SMD components, without letting the magic smoke escape in the process, can be quite a challenge. Especially since we hackers have not yet developed the number of appendages required to hold 3 different probes in place while operating both an oscilloscope and a computer. [Giuseppe Finizia] solved this problem with a 3D printed PCB probing jig that uses acupuncture needles.

As part of [Giuseppe] day job as an engineer at an electronic forensics laboratory, he does technical investigations on seized devices, which involves quite a bit of probing. The jig consists of a base plate with slots in which PCB holders of various configurations slide to hold all shapes and sizes of PCBs. Around the circumference of the plate there are multiple positions for adjustable probing “cranes”, each of which hold an acupuncture needle that is crimped or soldered to a wire. Each needle holder has a bit of flex which allows it to maintain downward pressure for a positive connection.

Making one-off tools and jigs is arguably one of the best applications for 3D printing, of which this is a perfect example. You can of course point solder wires or use test hooks if you have something to grab onto, but for easily probing multiple point on any PCB, this looks like a damn good solution. If you’re trying to trace a single signal, a precision pantograph might be your friend, or you can add a foot switch to your oscilloscope for quickly checking a circuit by hand.

[Jonathon Oxer] from the YouTube channel SuperHouse did a very nice video on the jig and made some small modifications. Check out the video after the break.

This Week In Security: Fuzzing Fixes, Foul Fonts, TPM Timing Attacks, And More!

An issue was discovered in libarchive through Google’s ClusterFuzz project. Libarchive is a compression and decompression library, widely used in utilities. The issue here is how the library recovers from a malformed archive. Hitting an invalid header causes the memory in use to be freed. The problem is that it’s possible for file processing to continue even after that working memory has been freed, leading to all kinds of problems. So far an actual exploit hasn’t been revealed, but it’s likely that one is possible. The problem was fixed back in May, but the issue was just announced to give time for that update to percolate down to users.

Of note is the fact that this issue was found through Google’s fuzzing efforts. Google runs the oss-fuzz project, which automatically ingests nightly builds from around 200 open source projects and runs ClusterFuzz against them. This process of throwing random data at programs and functions has revealed over 14,000 bugs.
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Credit Card Skimmers Evolve – Shimmers Are Here

Credit cards are loaded with security features, but the game of cat and mouse goes on. Nefarious syndicates continue to develop technology to steal data in new and innovate ways. After SparkFun did a teardown on some illicit hardware, they were visited by local law enforcement, who requested their help once more.

[Nick] from SparkFun refers to the device in question as a “shimmer”. It’s intended to be installed inside the chip reader of a credit card terminal, in between the terminal and the user’s credit card. Fabricated on a flexible film PCB, it’s thin enough to glue inside without being obvious even during maintenance.

The investigation begins with identification of the major components on board, followed by attempts to communicate with the device. Unfortunately, the hardware was largely unresponsive, even when connected to a card reader. In an effort to learn more, a schematic was produced. [Nick]’s analysis raised more questions than answers, and the suspicion is that the hardware may have been damaged at some point. However, the basic capabilities of the device are obvious, given the ability of the hardware to interact with a card via its contacts and offload the data through the onboard nRF24L01 radio module.

Thanks to people like [Nick], and earlier work from SparkFun, we all now have a better understanding of the risks when using payment terminals out in the wild. Unfortunately, unless your local gas station is willing to let you spend 20 minutes disassembling their card reader before paying, there’s not a whole lot the individual can do about it. Stay vigilant, and if you’ve got the skinny on a skimmer, drop us a line.

Penny Diode

A Radio For The Apocalypse

There’s been a spate of apocalypse related articles over the last few weeks, but when I saw an AM radio made from a hand-wound coil and an oxidized British penny, I couldn’t help but be impressed. We’ve covered foxhole radios, stereotypical radios that are cobbled together from found parts during wartime.

This example uses a variable capacitor for tuning, but that’s technically optional. All that’s really needed is a coil and something to work as a diode. Surprisingly, copper oxide is a semiconductor, and the surface oxidation on a penny is enough to form a rudimentary diode. Though, note, not all pennies have that necessary coating of copper. If a penny has green oxide, it’s likely a candidate.

Need a quickly cobbled together AM radio? Have some wire and a penny? Yeah, watch the video below the break, and you’ll know how to make it happen. When the apocalypse comes, you’ll thank us.

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Quick And Dirty Digital Conversion For Analog SLR

The unarguable benefits of digital photography has rendered the analog SLR obsolete for most purposes. This means that a wide selection of cameras and lenses are available on the second hand market for pennies on the dollar, making them ripe targets for hacking. [drtonis] decided to experiment with a quick and easy digital conversion to an old Canon A-1, and it’s got us excited about the possibilities.

Who needs Instagram filters? Just distort in-camera!

It’s a simple hack, but a fun one. The SLR is opened up, and the spring plate for holding the film is removed. A Raspberry Pi camera then has its original lens removed, and is placed inside the film compartment. It’s held in with electrical tape, upon a 3mm shim to space it correctly to work with the original optics.

[drtonis] notes that the build isn’t perfect, with some aberration likely caused by the reflective electrical tape in the film cavity. However, we think it’s a nice proof of concept that could go so much further. A Raspberry Pi Zero could be easily squeezed inside along with the camera, and everything glued in place to make things more robust. A specialist paint such as Stuart Semple’s Black 2.0 could also help cut down on light leaks inside. Plus, there’s plenty of small screens that can be used with the Raspberry Pi that would provide a useful preview function.

We’d love to see more conversions like this one. While it’s unlikely they’ll compete with commercial DSLRs on outright performance, everyone loves a little bit of charming distortion here and there, and all manner of fancy lenses can be had for cheap for analog platforms. We’ll be keeping a close eye on the tipline for further This fundevelopments – you know what to do!

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