Hacking a Telecoms Frequency Standard for Your Lab

[Shane Burrell] came across a Nortel GPSTM and re-purposed it as a 10MHz reference for his lab. The GPSTM is designed to slot into a backplane, most likely for telecoms applications. So [Shane] needed to hack the board to run from a 48v PSU. Once powered up, it was relatively easy to interface as the card appears to contain the well known Trimble Thunderbolt module and is compatible with its software.

We’ve covered frequency references before and they can be a valuable addition to a lab. On the back of most scopes, spectrum analyzers and function generators you’ll find a 10MHz reference input allowing the user to supply a reference more accurate than that generated internally. Not only is an external reference often more accurate, it also allows you to keep all your equipment in sync with a common reference, which can be particularly important in some measurements. While some hackers opt for Rubidium sources, the GPS disciplined temperature-controlled oscillator in the Nortel unit should provide a nice stable reference.

A word of warning to [Shane] though, get sucked into hacking frequency references and you may become a time nut finding yourself climbing mountains to test the theory of relativity.

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Fast ADC Uses Old School Scope Hack for 48 MSPS

[Carlos] needed an ADC with a 50 nanosecond sample period for his laser lab, that’s 20Msps! (20 million samples a second). While in recent years, commodity ADCs reaching into the low GSPS have become available, integrated acquisition systems are still somewhat expensive. So [Carlos] decided to do what every good hacker does, and built his own solution. His project post pretty much just links to a whitepaper he wrote (PDF) so we’ll try and boil it down for you:

In order to simplify development [Carlos] borrowed a technique commonly used in the first era of digital oscilloscopes, Equivalent Sampling Time.

est

The figure to the right is from the TDS460 manual. While it may seem counter intuitive to those only familiar with modern scopes, the TDS460 achieved a 400MHz bandwidth using a 100MSPS ADC. In order to achieve this the scope acquires a single trace in multiple cycles, each time offsetting the acquisitions as shown and combining the result.

In this way, early digital scope developers could sidestep the limitations of the available ADCs to achieve a higher effective bandwidth. However there is of course one catch: the technique only works for periodic signals.

This was fine for [Carlos] who implemented a technique on a Cypress PSoC 4, which provides analog FPGA-like functionality. By offsetting the ADC trigger he has able to achieve an EST of 48MHz using a ADC sampling at 1MHz. If you want a little help getting into PSOC 4 yourself, check out the guide that [Bil Herd] made.

Neat hack [Carlos] and we hope to hear more about your laser lab in the future.

Why Is There Liquid Nitrogen On the Street Corner?

Any NYC hackers may have noticed something a bit odd this summer while taking a walk… Giant tanks of the Liquid Nitrogen have been popping up around the city.

There are hoses that go from the tanks to manholes. They’re releasing the liquid nitrogen somewhere… Are they freezing sewer alligators? Fighting the Teenage Mutant Ninja Turtles? Or perhaps, cooling our phone lines??

Luckily, we now have an answer. Popular Science writer [Rebecca Harrington] got to investigate it as part of her job. As it turns out, the liquid nitrogen is being used to pressurize the cables carrying our precious phone and internet service in NYC. The cables have a protective sheath covering them, but during construction and repairs, the steam build up in some of the sewers can be too much for them — so they use liquid nitrogen expanding into gas to supplement the pressurized cables in order to keep the them dry. As the liquid nitrogen boils away, it expands 175 times which helps keep moisture out of the cables.

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Trick Google Used Hides Secret Messages on LCD Screens

[Travis] didn’t get picked to go to Google I/O this year, but he did have some I/O inspired fun after the fact. His friends who did go told him about specially modified LCD screens Google had scattered around the event. The screens showed normal show information when viewed with the naked eye. When viewed through a special transparent badge included with the I/O swag though, a URL for Google’s scavenger hunt would magically appear. [Travis] was intrigued by the effect, and became hell-bent on reproducing it himself.

[dual-lcd-3Travis] figured out the transparent badge was actually a polarizing filter. Every standard LCD has two of them, usually bonded to the glass of the LCD itself. If you remove the filters from a LCD, you’ll get a prime view of the backlight – unless you’re wearing polarizing glasses of course. Google’s monitors didn’t have that effect though. They showed a full color display, with a second full color hidden display only visible through the polarizer. [Travis] is intelligent and experienced, so it only took a bit of three-dimensional thinking for him to figure out Google’s trick. There are actually two LCDs used in the display. The first is a standard LCD with backlight. The trick is to strip the polarizing film off a second LCD and place it in front of the first. The second LCD will be invisible to anyone – without the polarizer.

[Travis] quickly set about replicating the display using several obsolete VGA LCDs. He quickly found that the hard part was peeling the polarizing plastic from the thin glass LCD sandwich. Several LCDs gave up their lives in the effort, but in the end [Travis] was successful. He made everything fit in one case by using a thin LED backlight in a case designed for a monitor with a Cold Cathode Fluorescent Lamp (CCFL).  The result looks exactly like a standard LCD – that is, until viewed through a polarizing filter. Click past the break to see the hidden message LCD in action!

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Vintage Electronics Magazines Predicted Our Current Future

Do you remember the magazine Popular Electronics? What about Radio Electronics? These magazines were often the first exposure we had to the world of hacking. In December we learned that Americanradiohistory.com has gone to the trouble of scanning nearly every copy of both, and continues to add many many others — posting them online for us to enjoy once more. Since then we’ve been pouring through the archive pulling out some of the best in terms of nostalgia, entertainment, and fascinating engineering.

Yes much of this material is very dated; CB Radios, all-mighty computers, phasors, stun guns, levitating machines, overly complex circuits for simple tasks, and aviator eyeglasses. But found among all of this, many innovative mixed-signal circuits and other interesting ideas that have been developed into our tech-centric world. Many of those modern inventions you’ve welcomed into your life actually started long-long ago in the forward-thinking hacks shown off in these publications. The Google Glass precursor seen above is but one example. Keep reading to see the early roots of the tech we tend to think of as “new”.

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CD Execution Chamber Sends old Discs off with a Bang

Welded steel safety cage? Check! Polycarbonate blast shield? Check! Vacuum cleaner motor wired to an inviting red button? Double check! Stack of CDs to dispose of as destructively as possible? [Firas Sirriyeh] has got you covered with his CD Terminator 1.0.

While [Firas’s] build log is a little short on descriptive text, there’s really no need for it. His pictures tell the tale. The combination media shredder and interactive performance art piece is a stoutly constructed affair, which you’d want anything capable of flinging razor-sharp plastic and Mylar shrapnel to be. [Firas] has displayed his CD execution chamber at the Jerusalem Mini Maker Fair 2015 (in Hebrew; English link) and the Musara Mix Festival where the must-see video after the break was shot (mildly NSFW language). Some CDs give up the ghost very quickly, but one held out for a remarkable long time before finally exploding; you can see it flexing and warping in a way that almost appears to be slow-motion.

For those who’d rather not fuss with all that bothersome safety, there’s always this automatic CD launcher to play with.

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Shapeshifting Material For Weather Adaptive Structures

Where [Isaac Newton] had his apple (maybe), [Chao Chen] found inspiration in a pine cone for a design project that lead to a water-sensitive building material. He noticed the way some pine cones are sensitive to water, closing up tight when it rains, but opening up with dry conditions. Some dissection of a pine cone revealed [Mother Nature’s] solution – different layers that swell preferentially when exposed to moisture, similar to how a bimetallic strip flexes when heated. [Chao Chen’s] solution appears to use balsa wood and a polystyrene sheet laminated to a fabric backing to achieve the same movement – the wood swells when wet and pulls the laminate flat, but curls up when dry.

As [Chao] points out, the material is only a prototype, but it looks like a winner down the road. The possibilities for an adaptive material like this are endless. [Chao] imagines a picnic pavilion with a roof that snaps shut when it rains, and has built a working model. What about window shutters that let air and light in but close up automatically in that sudden summer storm? Self-deploying armor for your next epic Super Soaker battle? Maybe there are more serious applications that would help solve some of the big problems with water management that the world faces.

Make sure you check out the video after the break, with a more decorative application that starts out looking like an [M.C. Escher] print but ends up completely different.

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