Give Your Solar Garden Lights A Color Changing LED Upgrade

April 24, 2019 by 14 Comments

White LEDs were the technological breakthrough that changed the world of lighting, now they are everywhere. There’s no better sign of their cost-effective ubiquity than the dollar store solar garden light: a complete unit integrating a white LED with its solar cell and battery storage. Not content with boring white lights on the ground, [Emily] decided to switch up their colors with a mix of single-color LEDs and dynamic color-changing LEDs, then hung them up high as colorful solar ornaments.

The heart of these solar devices is a YX8018 chip (or one of its competitors.) While the sun is shining, solar power is directed to charge up the battery. Once the solar cell stops producing power, presumably because the sun has gone down, the chip starts acting as a boost converter (“Joule thief”) pushing a single cell battery voltage up high enough to drive its white LED. Changing that LED over to a single color LED is pretty straightforward, but a color changing LED adds a bit of challenge. The boost converter deliver power in pulses that are too fast for human eyes to pick up but the time between power pulses is long enough to cause a color-changing circuit to reset itself and never get beyond its boot-up color.

The hack to keep a color-changing LED’s cycle going is to add a capacitor to retain some charge between pulses, and a diode to prevent that charge from draining back into the rest of the circuit. A ping-pong ball serves as light diffuser, and the whole thing is hung up using a 3D-printed sheath which adds its own splash of color.

Solar garden lights are great basis for a cheap and easy introduction to electronics hacking. We’ve seen them turn into LED throwies, into a usable flashlight, or even to power an ATTiny microcontroller.

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GPS Self-Adjusting Clock With An E-Ink Display

April 24, 2019 by 18 Comments

If you mention a clock that receives its time via radio, most people will think of one taking a long wave signal from a station such as WWVB, MSF, or DCF77. A more recent trend however has been for clocks that set themselves from orbiting navigation satellites, and an example comes to us from [KK99].  It’s a relatively simple hardware build in that it is simply an Arduino Nano, GPS module, and e-ink display module wired together, but it provides an interesting exercise in running through the code required for a GPS clock.

It does however give us a chance to remember the story from last year surrounding WWVB, as a budget proposal last year mooted the prospect of the closure of the Fort-Collins-based time signal transmitter. Were that to happen an estimated 50 million American clocks would lose their reference, and while their owners could always update them manually, there will always be time-based systems to which that won’t be applied for whatever reason.  Europeans meanwhile are safe in their time transmissions for now , but in case they think they have their mains grid to fall back on it’s worth remembering the time they lost six seconds.

GPS satellite image: USAF [Public domain].

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Radio Piracy On The High Seas: Commercial Demand For Taboo Music

April 24, 2019 by 32 Comments

The true story of pirate radio is a complicated fight over the airwaves. Maybe you have a picture in your mind of some kid in his mom’s basement playing records, but the pirate stations we are thinking about — Radio Caroline and Radio Northsea International — were major business operations. They were perfectly ordinary radio stations except they operated from ships at sea to avoid falling under the jurisdiction of a particular government.

Back then many governments were not particularly fond of rock music. People wanted it though, and because people did, advertisers wanted to capitalize on it. When people want to spend money but can’t, entrepreneurs will find a way to deliver what is desired. That’s exactly what happened.

Of course, if that’s all there was to it, this wouldn’t be interesting. But the story is one of intrigue with armed boardings, distress calls interrupting music programs, and fire bombings. Most radio stations don’t have to deal with those events. Surprisingly, at least one of these iconic stations is still around — in a manner of speaking, anyway.

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Power Measurement Oscilloscope Style

April 24, 2019 by 7 Comments

If you want to measure voltage you reach for a voltmeter. Current? An ammeter. Resistance? An ohmmeter. But what about measuring AC power? A watt meter? Usually. But if you know what to do, you could also reach for your oscilloscope. If you don’t know what to do, [Jim Pytel] has the video answers for you. Truth is, an oscilloscope can measure almost anything if you know how. [Jim] shows how to measure the voltage and current in a circuit and then it is simply a matter of doing a little math, something modern scopes can do very easily.

We like that [Jim] shows a circuit and how the math works before he verifies the math with the scope. Of course, theory doesn’t always match practice. The method uses a small current-sensing resistor that throws readings off a bit. The scope and signal generator are not perfect, either. However, the results match up pretty nicely with the computed results.

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3D Printering: The Quest For Printable Food

April 24, 2019 by 44 Comments

A video has been making the rounds on social media recently that shows a 3D printed “steak” developed by a company called NovaMeat. In the short clip, a machine can be seen extruding a paste made of ingredients such as peas and seaweed into a shape not entirely unlike that of a boot sole, which gets briefly fried in a pan. Slices of this futuristic foodstuff are then fed to passerby in an effort to prove it’s actually edible. Nobody spits it out while the cameras are rolling, but the look on their faces could perhaps best be interpreted as resigned politeness. Yes, you can eat it. But you could eat a real boot sole too if you cooked it long enough.

To be fair, the goals of NovaMeat are certainly noble. Founder and CEO Giuseppe Scionti says that we need to develop new sustainable food sources to combat the environmental cost of our current livestock system, and he believes meat alternatives like his 3D printed steak could be the answer. Indeed, finding ways to reduce the consumption of meat would be a net positive for the environment, but it seems his team has a long way to go before the average meat-eater would be tempted by the objects extruded from his machine.

But the NovaMeat team aren’t the first to attempt coaxing food out of a modified 3D printer, not by a long shot. They’re simply the most recent addition to a surprisingly long list of individuals and entities, not least of which the United States military, that have looked into the concept. Ultimately, they’ve been after the same thing that convinced many hackers and makers to buy their own desktop 3D printer: the ability to produce something to the maker’s exacting specifications. A machine that could produce food with the precise flavors and textures specified would in essence be the ultimate chef, but of course, it’s far easier said than done.

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Stealing DNA By Phone

April 24, 2019 by 8 Comments

Data exfiltration via side channel attacks can be a fascinating topic. It is easy to forget that there are so many different ways that electronic devices affect the physical world other than their intended purpose. And creative security researchers like to play around with these side-effects for ‘fun and profit’.

Engineers at the University of California have devised a way to analyse exactly what a DNA synthesizer is doing by recording the sound that the machine makes with a relatively low-budget microphone, such as the one on a smart phone. The recorded sound is then processed using algorithms trained to discern the different noises that a particular machine makes and translates the audio into the combination of DNA building blocks the synthesizer is generating.

Although they focused on a particular brand of DNA Synthesizers, in which the acoustics allowed them to spy on the building process, others might be vulnerable also.

In the case of the DNA synthesizer, acoustics revealed everything. Noises made by the machine differed depending on which DNA building block—the nucleotides Adenine (A), Guanine (G), Cytosine (C), or Thymine (T)—it was synthesizing. That made it easy for algorithms trained on that machine’s sound signatures to identify which nucleotides were being printed and in what order.

Acoustic snooping is not something new, several interesting techniques have been shown in the past that raise, arguably, more serious security concerns. Back in 2004, a neural network was used to analyse the sound produced by computer keyboards and keypads used on telephones and automated teller machines (ATMs) to recognize the keys being pressed.

You don’t have to rush and sound proof your DIY DNA Synthesizer room just yet as there are probably more practical ways to steal the genome of your alien-cat hybrid, but for multi-million dollar biotech companies with a equally well funded adversaries and a healthy paranoia about industrial espionage, this is an ear-opener.

We written about other data exfiltration methods and side channels and this one, realistic scenario or not, it’s another cool audio snooping proof of concept.

Self-aware Robotic Arm

April 24, 2019 by 16 Comments

If you ever tried to program a robotic arm or almost any robotic mechanism that has more than 3 degrees of freedom, you know that a big part of the programming goes to the programming of the movements themselves. What if you built a robot, regardless of how you connect the motors and joints and, with no knowledge of itself, the robot becomes aware of the way it is physically built?

That is what Columbia Engineering researchers have made by creating a robot arm that learns how it is connected, with zero prior knowledge of physics, geometry, or motor dynamics. At first, the robot has no idea what its shape is, how its motors work and how they affect its movement. After one day of trying out its own outputs in a pretty much random fashion and getting feedback of its actions, the robot creates an accurate internal self-simulation of itself using deep-learning techniques.

The robotic arm used in this study by Lipson and his PhD student Robert Kwiatkowski is a four-degree-of-freedom articulated robotic arm. The first self-models were inaccurate as the robot did not know how its joints were connected. After about 35 hours of training, the self-model became consistent with the physical robot to within four centimeters. The self-model then performed a pick-and-place task that enabled the robot to recalibrate its original position between each step along the trajectory based entirely on the internal self-model.

To test whether the self-model could detect damage to itself, the researchers 3D-printed a deformed part to simulate damage and the robot was able to detect the change and re-train its self-model. The new self-model enabled the robot to resume its pick-and-place tasks with little loss of performance.

Since the internal representation is not static, not only this helps the robot to improve its performance over time but also allows it to adapt to damage and changes in its own structure. This could help robots to continue to function more reliably when there its part start to wear off or, for example, when replacement parts are not exactly the same format or shape.

Of course, it will be long before this arm can get a precision anywhere near Dexter, the 2018 Hackaday Prize winner, but it is still pretty cool to see the video of this research: