Graphene? Soybean!

February 3, 2017 by Elliot Williams 37 Comments

True graphene is a one-atom thick layer of carbon. It’s incredibly conductive, transparent, and of course thin. It’s one of those materials that, if it were only cheaper, would be used in everything from batteries to water filtration. Researchers from CSIRO in Australia have found a novel, dirt-cheap, and simple way to make graphene, and it’s hacker-friendly, for certain values of hacker.

The method is to take a sheet of polycrystalline nickel foil, spread a thin layer of soybean oil on it, and heat it up to 800° C for three minutes. It’s cooled off, slid off the foil, and it’s done. While 800° is a lot hotter than a standard toaster oven, their setup isn’t really all that much different. Notably lacking are things like esoteric gasses, partial vacuums, and the like. The nickel foil has some kind of catalytic role in the process — you should read the original if you’re more of a chemist than we are. Continue reading “Graphene? Soybean!” →

Yes/No Neural Interface Partly Works

February 2, 2017 by Elliot Williams 19 Comments

It sounds like something out of a sci-fi or horror movie: people suffering from complete locked-in state (CLIS) have lost all motor control, but their brains are otherwise functioning normally. This can result from spinal cord injuries or anyotrophic lateral sclerosis (ALS). Patients who are only partially locked in can often blink to signal yes or no. CLIS patients don’t even have this option. So researchers are trying to literally read their minds.

Neuroelectrical technologies, like the EEG, haven’t been successful so far, so the scientists took another tack: using near-infrared light to detect the oxygenation of blood in the forehead. The results are promising, but we’re not there yet. The system detected answers correctly during training sessions about 70% of the time, where the upper bound for random chance is around 65% — varying from trial to trial. This may not seem overwhelmingly significant, but repeating the question many times can help improve confidence in the answer, and these are people with no means of communicating with the outside world. Anything is better than nothing?

It’s noteworthy that the blood oxygen curves over time vary significantly from patient to patient, but seem roughly consistent within a single patient. Some people simply have patterns that are easier to read. You can see all the data in the paper.

They go into the methodology as well, which is not straightforward either. How would you design a test for a person who you can’t even tell if they are awake, for instance? They ask complementary questions (“Paris is the capital of France”, “Berlin is the capital of Germany”, “Paris is the capital of Germany”, and “Berlin is the capital of France”) to be absolutely sure they’re getting the classifications right.

It’s interesting science, and for a good cause: improving the quality of life for people who have lost all contact with their bodies. (Most of whom answered “yes” to the statement “I am happy.” Food for thought.)

Via Science-Based Medicine, and thanks to [gippgig] for the unintentional tip! Photo from the Wyss Center, one of the research institutes involved in the study.

No-Etch: The Proof In The Bluetooth Pudding

February 2, 2017 by Elliot Williams 40 Comments

In a previous episode of Hackaday, [Rich Olson] came up with a new no-etch circuit board fabrication method. And now, he’s put it to the test: building an nRF52 Bluetooth reference design, complete with video, embedded below.

The quick overview of [Rich]’s method: print out the circuit with a laser printer, bake a silver-containing glue onto the surface, repeat a few times to get thick traces, glue the paper to a substrate, and use low-temperature solder to put parts together. A potential drawback is the non-negligible resistance for the traces, but a lot of the time that doesn’t matter and the nRF52 reference design proves it.

The one problem here may be the trace antenna. [Rich] reports that it sends out a weaker-than-expected signal. Any RF design folks want to speculate wildly about the cause?

Continue reading “No-Etch: The Proof In The Bluetooth Pudding” →

33C3: Hunz Deconstructs The Amazon Dash Button

February 2, 2017 by Elliot Williams 22 Comments

The Amazon Dash button is now in its second hardware revision, and in a talk at the 33rd Chaos Communications Congress, [Hunz] not only tears it apart and illuminates the differences with the first version, but he also manages to reverse engineer it enough to get his own code running. This opens up a whole raft of possibilities that go beyond the simple “intercept the IP traffic” style hacks that we’ve seen.

Just getting into the Dash is a bit of work, so buy two: one to cut apart and locate the parts that you have to avoid next time. Once you get in, everything is tiny! There are a lot of 0201 SMD parts. Hidden underneath a plastic blob (acetone!) is an Atmel ATSAMG55, a 120 MHz ARM Cortex-M4 with FPU, and a beefy CPU all around. There is also a 2.4 GHz radio with a built-in IP stack that handles all the WiFi, with built-in TLS support. Other parts include a boost voltage converter, a BTLE chipset, an LED, a microphone, and some SPI flash.

The strangest part of the device is the sleep mode. The voltage regulator is turned on by user button press and held on using a GPIO pin on the CPU. Once the microcontroller lets go of the power supply, all power is off until the button is pressed again. It’s hard to use any less power when sleeping. Even so, the microcontroller monitors the battery voltage and presumably phones home when it gets low.
Continue reading “33C3: Hunz Deconstructs The Amazon Dash Button” →

33C3: How Can You Trust Your Random Numbers?

February 1, 2017 by Elliot Williams 49 Comments

One of the standout talks at the 33rd Chaos Communications Congress concerned pseudo-random-number generators (PRNGs). [Vladimir Klebanov] (right) and [Felix Dörre] (left) provided a framework for making sure that PRNGs are doing what they should. Along the way, they discovered a flaw in Libgcrypt/GNUPG, which they got fixed. Woot.

Cryptographically secure random numbers actually matter, a lot. If you’re old enough to remember the Debian OpenSSL debacle of 2008, essentially every Internet service was backdoorable due to bad random numbers. So they matter. [Vladimir] makes the case that writing good random number generators is very, very hard. Consequently, it’s very important that their output be tested very, very well.

So how can we test them? [Vladimir] warns against our first instinct, running a statistical test suite like DIEHARD. He points out (correctly) that running any algorithm through a good enough hash function will pass statistical tests, but that doesn’t mean it’s good for cryptography.
Continue reading “33C3: How Can You Trust Your Random Numbers?” →

Horten Fyr Is Norwegian For Blinkie

January 31, 2017 by Elliot Williams 5 Comments

Our Norwegian is pretty weak, so we struggled a little bit with the documentation for a big public LED art project in the lighthouse (translated) in Horten, Norway. But we do speak the universal language of blinkies, and this project has got them: 3,008 WS2812b LEDs ring the windows at the top of the lighthouse and create reactive patterns depending on the wave height and proximity of the ferry that docks there.

This seems to be an evolving project, with more features being added slowly over time. We love the idea of searching for the WiFi access point on the ferry to tell when it’s coming in to port, and the wave height sensor should also prove interesting data, with trends at the low-frequency tidal rate as well as higher frequency single waves that come in every few seconds. What other inputs are available? How many are too many?

It’s so cool that a group of tech-minded art hackers could get access to a big building like this. Great job, [Jan] and [Rasmus] and [everyone else]!

Continue reading “Horten Fyr Is Norwegian For Blinkie” →

Awesome Prank Or Circuit-Breaker Tester?

January 31, 2017 by Elliot Williams 54 Comments

Many tools can be used either for good or for evil — it just depends on the person flipping the switch. (And their current level of mischievousness.) We’re giving [Callan] the benefit of the doubt here and assuming that he built his remote-controlled Residual Current Device (RDC) tripper for the purpose of testing the safety of the wiring in his own home. On the other hand, he does mention using it to shut off all the power in his house during an “unrelated countdown at a party”. See? Good and evil.

An RCD (or GFCI in the States) is a kind of circuit breaker that trips when the amount of current in the hot and neutral mains power lines aren’t equal and opposite, which would suggest that the juice was leaking out somewhere, hopefully not through someone. They only take a few milliamps of imbalance to blow so that nobody gets hurt. Making a device to test an RCD is easy; a resistor between hot and the protective ground circuit would do.

[Callan] over-engineers. He used a 50 W resistor where 30 W would do under the worst circumstances. A stealthy solid-state relay switches the resistor in, driven by an Uno and a Bluetooth module, so he can trip his circuit breakers from his smartphone, naturally.
Continue reading “Awesome Prank Or Circuit-Breaker Tester?” →