Dissecting A Mechanical Voltage Regulator

April 20, 2020 by 55 Comments

When the fuel gauge of his 1975 Triumph Spitfire started going off the scale, the collected knowledge of the Internet indicated that [smellsofbikes] needed to replace a faulty voltage regulator behind the dash. For most people, that would be the end of the story. But he, like everyone who’s reading this right now, really wanted to see what the inside of a 45 year old voltage regulator looked like.

After prying open the metal case, he discovered that not only is the regulator mechanical in nature, but there’s even a tiny screw that allows you to adjust the output voltage. Luckily for us, not only is [smellsofbikes] curious enough to open it up, but he’s also got the tools and knowledge to explain how it works in the video after the break.

Put simply, the heart of the regulator is a bimetallic strip with a coil of wire wrapped around it. When power from the battery is passed through the coil it acts as a heater, which makes the strip move up and break the connection to the adjustable contact. With the connection broken and the heating coil off the strip rapidly cools, and in doing so returns to its original position and reconnects the heater; thus starting the process over again.

These rapid voltage pulses average out to around 10 VDC, though [smellsofbikes] notes that you can’t actually measure the output voltage of the regulator with a meter because it moves around too much to get any sort of accurate reading. He also mentions a unique quirk of this technology: due to the force of gravity acting on the bimetallic strip, the output of the regulator will actually change depending on its mounting orientation.

On the oscilloscope, [smellsofbikes] is able to show us what the output actually looks like. As you might expect, it looks like a mess to 21st century eyes. But these were simpler times, and it should go without saying there aren’t any sensitive electronics in a sports car from 1975. Interestingly, he says he’s now replaced the mechanical assembly with a modern regulator chip. Here’s hoping we’re around long enough to see if he gets another 50 years out of it.

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A Basketball Hoop That Never Lets You Brick

April 20, 2020 by 25 Comments

With none of the major leagues in any team sport currently meeting, sports fans have a huge void that has to be filled with something. For [Shane Wighton], the machine shop is the place to go when sports let you down, and the result is this basketball backboard that lets you sink every shot every time.

When we first saw this, we thought for sure it would be some overly complicated motorized affair that would move the hoop to catch the basketball, sort of like the dart-catching dartboard we featured some time ago. And while that would be awesome and somebody should totally build that so we can write it up, [Shane]’s hoop dream is a lot simpler mechanically, even if the math needed to determine the proper shape for the backboard was complex. He wrote software to simulate throws from hundreds of positions to determine the shape for the board, which ends up looking like a shallow elliptic paraboloid. The software created a mesh that was translated into CNC tool paths in Fusion 360, and the backboard was carved from blocks of softwood.

The first tests were disappointing; instead of landing every shot, the board seemed to be actively denying them. [Shane] had to puzzle over that for a while before realizing that he didn’t account for the radius of the ball, which means the centroid never actually contacts the backboard. Rather than recalculate and create a new backboard, he just shifted the hoop out from the backboard by a ball radius. With that expedient in place, the setup performed exactly as calculated.

[Shane] may have taken the long road to hoops glory, but we appreciate the effort and the math lesson. And the fact that this ends up being the same shape as some antennas is a plus.

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COBOL Isn’t The Issue: A Misinterpreted Crisis

April 20, 2020 by 144 Comments

Is history doomed to repeat itself? Or rather, is there really any doubt that it isn’t, considering recent events that made the news? I am of course talking about New Jersey’s call for COBOL programmers to fix their ancient unemployment system, collapsing under the application spikes caused by the COVID-19 lockdown. Soon after, other states joined in, and it becomes painfully apparent that we have learned absolutely nothing from Y2K: we still rely on the same old antiques running our infrastructure, and we still think people want to voluntarily write COBOL.

Or maybe they do? Following the calls for aid, things went strangely intense. IBM announced to offer free COBOL trainings and launched a forum where programmers can plug their skills and availability. The Open Mainframe Project’s COBOL programming course suddenly tops the list of trending GitHub projects, and Google Trends shows a massive peak for COBOL as well. COBOL is seemingly on its way to be one of the hottest languages of 2020, and it feels like it’s only a matter of time until we see some MicroCOBOL running on a Teensy.

However, the unemployment systems in question are unfortunately only a tiny selection of systems relying on decades old software, written in a language that went out of fashion a long time ago, which makes it difficult to find programmers in today’s times. Why is that?

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Hacking Apollo Hack Chat

April 20, 2020 by 2 Comments

Join us on Wednesday, April 22 at noon Pacific for the Hacking Apollo Hack Chat with “CuriousMarc” Verdiell, Ken Shirriff, Mike Stewart, and Carl Claunch!

When President Kennedy laid down the gauntlet to a generation of scientists and engineers to land a man on the Moon before the close of the 1960s, he likely had little idea what he was putting in motion. The mission was dauntingly complex, the science was untested, and the engineering was largely untried. Almost everything had to be built from scratch, and entire industries were born just from the technologies that had to be invented to make the dream come true.

Chief among these new fields was computer science, which was barely in its infancy when the 1960s started. By the end of the decade and the close of the Space Race, computers had gone from room-filling, power-guzzling machines to something compact and capable enough to fly men to the Moon and back. The computers that followed all built on the innovations that came about as a result of Apollo, and investigating the computers of the era and finding out what made them tick is an important part of our technological culture.

That’s where this retrocomputing dream team came into play. Together, they’ve poked and prodded at every bit of hardware from the Space Race era they could find, including a genuine Apollo Guidance Computer (AGC) that was rescued from the trash. What’s more, they actually managed to restore it to working condition with a series of epic hacks and sheer force of will.

Marc, Ken, Mike, and Carl will stop by the Hack Chat to talk about everything that went into getting the AGC working again, along with anything else that pops up. Come ready to have your Apollo-era hardware itches scratched by the people who’ve been inside a lot of it, and who have seen first-hand what it took to make it to the Moon and back.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, April 22 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Measuring Sharpie Thickness… The Ink Itself, Not The Pen!

April 20, 2020 by 29 Comments

How we missed this one from a few years ago is unknown, but we’re glad to catch up with it now. Have you ever needed to measure how thick the ink in a Sharpie line is? Of course you haven’t. But if you needed to, how would you do it? Using a wicked-sensitive indicator gauge and levering an interesting test setup.

[Tom] from [oxtoolco] got his hands on a tool that measures in 1/10,000,000th (that’s one ten-millionth) increments and was wondering what kind of shenanigans you can do with this Lamborghini of dial indicators. It’s one thing to say you’re going to measure ink, but coming up with the method is the leap. In this case it’s a gauge block — a piece of precision ground metal with precise dimensions and perfectly perpendicular faces. By zeroing the indicator on the block, then adding lines from the Sharpie and measuring again, you can deduce the thickness of the ink markings.

After arraying diagonal lines on the gauge block it is placed lines-down under the dial indicator. This distributes the ink layer across a larger area, as probing the ink line directly would likely result in inaccurate readings. On that topic the gauge block is moved using pliers, as introducing heat from your fingers could result in expansion of the metal upsetting the readings.

The results? Black, blue, and red Sharpie were all tested, alongside blue and black Dykem layout fluid. Ten samples of each were run and the readings were all very close, save a couple of obvious outliers. Clocking in the thinnest is black Sharpie at about 118 millionths of an inch (~30 microns) and blue Dykem was the thickest at 314 millionths (86 microns). [Tom] quips that since we now know the thickness, you could even use ink as a shim.

If you can’t get enough Sharpie in your life, try it as an extremely satisfying add-on for your plasma cutter.

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Inputs Of Interest: The Differently Dexterous DataHand Directionalizes Digits

April 20, 2020 by 24 Comments

If you had debilitating pain from repetitive stress injury in the 1990s, there were a lot of alternative keyboard options out there. One of the more eye-catching offerings was the DataHand keyboard made by DataHand Systems out of Phoenix, AZ. The DataHand debuted in 1993 with a price tag around $2,000. While this is admittedly pretty steep for the average consumer, it was well within the IT budgets of companies that wanted to avoid workman’s comp claims and keep their employees typing away.

In theory, this is holy grail territory for anti-RSI keyboards. The DataHand was designed to eliminate wrist motion altogether by essentially assigning a d-pad plus a regular push-down button to each finger. The layout resembles QWERTY as closely as possible and uses layers to access numbers, symbols, and other functions, like a rudimentary mouse.

Although if you put them this close together, you’re kind of missing the point. Image via Bill Buxton

Ergonomic to the Max

Typing on the DataHand is supposed to be next to effortless. The directional switches are all optical, which probably has a lot to do with the eye-popping price point. But instead of being spring-loaded, these switches use magnets to return to the neutral position.

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Test Unknown Fuses Without Destroying Them

April 20, 2020 by 31 Comments

There’s a problem with fuses. On the face of it, testing would seem to be a one-shot deal — exceed the rated current and see if it blows. But once you know the answer, the device is useless. If only there were a way to test fuses without damaging them.

As it turns out there is, and [Kerry Wong] weaves quite a tale about his attempts to non-destructively test fuses. The fuses in question are nothing fancy — just the standard glass tube type, from a cheap assortment kit off Amazon. Therein lies the problem: can such cheap devices be trusted? Finding out requires diving much deeper into the technology of fuses than many people will have done, including understanding how the thermal and electrical characteristics of the fuse element behave.

[Kerry]’s test setup is simple, consisting of a constant current power supply and a voltmeter across the fuse to measure the voltage drop caused by the resistance of the fuse element. As he ramps up the current, the voltage drop increases linearly due to the increase in resistance of the alloy with increasing temperature. That only lasts up to a point, where the fuse resistance starts increasing exponentially. Pushing much past the point where the resistance has doubled would blow the fuse, so that’s the endpoint of his tests. Perhaps unsurprisingly, his no-name fuses all went significantly beyond their rated current, proving that you get what you pay for. See the video below for the tests and an analysis of the results.

It’s handy to know there’s a way to check fuses without popping them, and we’ll file this one away for future reference. Don’t forget that you should always check the fuse when troubleshooting, because you never know what the last person did to it.

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