Retro TO-3 Switching Voltage Regulator

July 25, 2015 by Al Williams 33 Comments

Restoring old gear often means replacing unavailable parts with modern equivalents. [Alex Eisenhut] needed to replace some old TO-3 voltage regulators and decided to make an authentic-looking switching power supply replacement. These three pin metal cans were very common, especially the LM340 5V regulator which was, of course, a linear regulator. Today, you are more likely to see a 7805 in a TO-220 case or something surface mount for a comparable linear regulator.

As you might expect, the board uses surface mount components. [Alex] used Mill Max machine pins to match the original regulator footprint and calls the regulator Ton3y. He plans to cover it up with a 3D printed lid, but it seems a shame to hide the fine PCB work.

In the pictures, you can see that the machine pins are a tight fit. [Alex] used a hammer to lightly tap them into place. Of course, the original TO-3 regulators were linear and would generate a lot of heat. The Ton3y, as you’d expect from a switching power supply, runs cool (according to the scientific measurement made with [Alex]’s pinky finger) and surely has a wider input voltage range and more output current capacity.

We’ve seen replacement switching regulators before, but this one is really a work of art.

Self Built Interferometer Measures Nanometer Displacement

July 24, 2015 by Nava Whiteford 56 Comments

[jrcgarry] hacked together this awesome interferometer which is able to measure displacements in the nanometer range. Commercial interferometers are used in research labs to measure tiny displacements on the nanometer scale, and can cost tens of thousands of dollars. [jrcgarry] used beam splitters from BluRay drives, mirrors from ebay and a 5mw laser diode.

We’ve covered the use of interferometers before. But never an instrument built from scratch like this. Interferometers exploit the wave-like nature of a beam of light. The beam is split and sent down two separate paths, where the beams bounce off mirrors to return to the beam splitter to be recombined. Because of its wave light nature the beams will interfere with each other. And as the beams have traveled different distances they may be in or out of phase. Resulting in either constructive (brighter) or destructive (darker) interference.

Because the wavelength of light is on the order of 100s of nanometers, by observing the interference patterns you can monitor the displacement of the mirrors with respect to each other at nanometer resolution. [jrcgarry] doesn’t use the interferometer for any particular application in this tutorial but it’s a great demonstration of the technique!

Puzzle Box Is Rigged To Blow

July 23, 2015 by Rick Osgood 23 Comments

[Sande24] needed a gift for his father’s birthday. He decided that rather than simply give his father the gifts, he would present his father with a unique challenge. The gifts are locked inside of a multi-stage puzzle box. This isn’t your average puzzle box though. This one is rigged to blow.

The puzzle box was designed to test his father’s reflexes, mind, and luck. The finished product looks sort of like a wooden crate made from particle board. The box contains three levels, each with its own gift and its own task to be completed.

With the lid opened, the first compartment and puzzle is revealed. Inside of the compartment were a new pair of gloves, meant to protect the father’s hands when working on the puzzles. The first puzzle is built into a sheet of wood with several custom-made levers. The levers must be moved into position in order to remove the wooden sheet and reveal the next level.

The first lever triggers a home-made detonator that eventually lights a series of fireworks placed around the box. You need to solve the puzzle box fast enough to prevent the fireworks from destroying the gifts that lay inside. [Sande24] was unable to legally purchase fuses where he lived, so he had to make his own.

The second level held a gas mask, also meant to protect the father from the booby traps of this mysterious box. This level, also made from a sheet of wood, has nine squares drawn on it. Each square is labeled with a different number which goes into solving a mathematical function (x^5-25x^4+233x^3-995x^2+1866x-1080 = 0). The solution to the function would reveal the safe path to be used to cut the wooden platform in half. Unfortunately [Sande24’s] father cut the wrong squares and released a huge amount of vinegar into the box. Oops.

The bottom level contained the final puzzle and the locked treasure compartment locked with an ordinary padlock. To find the key, another puzzle had to be solved based on a series of wooden levers labeled with different shapes. The shapes provided clues to the order in which the levers should be pulled. Once the levers were moved into position, two compartments were unlocked. One of them contained the key to the treasure box. The other contained another booby trap which would set off more fireworks, destroying the final gift of four cans of Kuld beer. That’s a lot of work to get a a few cans of frothy beverage!

[Thanks Ellery]

This Little Amiga Still Runs School District’s HVAC

July 23, 2015 by Dan Maloney 43 Comments

It’s the rare tech worker that manages a decade in any one job these days – employee loyalty is just so 1980s. But when you started your career in that fabled age, some of the cultural values might have rubbed off on you. Apparently that’s the case for an Amiga 2000 that’s been on the job since the late ’80s, keeping the heat and AC running at Grand Rapids Public Schools (YouTube video link.)

The local news story is predictably short on details and pushes the editorial edge into breathless indignation that taxpayer dollars have somehow been misspent. We just don’t see it that way. “If it ain’t broke, don’t fix it,” is somewhat anathema to the hacker ethos. After all, there’s no better time to “fix” something than when it’s working properly and you can tell if you’ve done something wrong. But keeping an important system running with duct tape and wire ties is also part of the hacker way, so we applaud [Tim Hopkins] and his colleagues at the GRPS Facilities and Operations Department for their efforts to protect the public purse. And a round of applause is also due not only to the Amiga design team, who produced a machine that can run for nearly three decades, but also to Johnson Controls, whose equipment – apparently a wide area radio modem linking the HVAC systems in the district’s buildings – is being run by The Little Amiga That Could. Sounds like they built stuff to last way back when.

So when this machine is finally retired, here’s hoping they give it a good sendoff. Perhaps we’ll see it with some other Amigas at some future Vintage Computer Festival. Or maybe it’ll be one of those active retirees and start a career in the music industry.

[Thanks Thinkerer!]

Hacking A Telecoms Frequency Standard For Your Lab

July 23, 2015 by Nava Whiteford 18 Comments

[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

July 21, 2015 by Nava Whiteford 41 Comments

[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.

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?

July 21, 2015 by James Hobson 107 Comments

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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