An excerpt from Lord Rayleigh’s published manuscript.

Estimating The Size Of A Single Molecule Of Oil Using Water

September 26, 2024 by Maya Posch 21 Comments

What is the size of a single molecule of oil? What may initially seem like a trick question – answerable only through the use of complicated, high-tech scientific equipment – is actually as easy to calculate as the circumference of planet Earth. Much like how [Eratosthenes] used a couple of sticks to achieve the latter feat back in about 240 BCE, the size of a molecule of olive oil was calculated in 1890 by [Lord Rayleigh], which is the formal title of [John William Strutt]. Using nothing but water and said olive oil, he managed to calculate the size of a single olive oil molecule as being 1.63 nanometers in length.

To achieve this feat, he took 0.81 mg of olive oil and put it on a known area of water. Following the assumption that the distributed oil across the water surface would form a monolayer, i.e. a layer of oil one molecule thick, he divided the volume of the oil by the covered area, which gave him the thickness of the oil layer. Consequently, this result would also be the dimension (diameter) of a single olive oil molecule.

Many years later we know now that olive oil is composed of triacylglycerols, with a diameter of 1.67 nm, or only about 2% off from the 1890 estimate. All of which reinforces once more just how much science one can do with only the most basic of tools, simply through logical deduction.

An Ode To The SAO

September 26, 2024 by Tom Nardi 23 Comments

There are a lot of fantastic things about Hackaday Supercon, but for me personally, the highlight is always seeing the dizzying array of electronic bits and bobs that folks bring with them. If you’ve never had the chance to join us in Pasadena, it’s a bit like a hardware show-and-tell, where half the people you meet are eager to pull some homemade gadget out of their bag for an impromptu demonstration. But what’s really cool is that they’ve often made enough of said device that they can hand them out to anyone who’s interested. Put simply, it’s very easy to leave Supercon with a whole lot more stuff than when you came in with.

Most people would look at this as a benefit of attending, which of course it is. But in a way, the experience bummed me out for the first couple of years. Sure, I got to take home a literal sack of incredible hardware created by members of our community, and I’ve cherished each piece. But I never had anything to give them in return, and that didn’t quite sit right with me.

So last year I decided to be a bit more proactive and make my own Simple Add-On (SAO) in time for Supercon 2023. With a stack of these in my bag, I’d have a personalized piece of hardware to hand out that attendees could plug right into their badge and enjoy. From previous years I also knew there was something of an underground SAO market at Supercon, and that I’d find plenty of people who would be happy to swap one for their own add-ons for mine.

To say that designing, building, and distributing my first SAO was a rewarding experience would be something of an understatement. It made such an impression on me that it ended up helping to guide our brainstorming sessions for what would become the 2024 Supercon badge and the ongoing SAO Contest. Put simply, making an SAO and swapping it with other attendees adds an exciting new element to a hacker con, and you should absolutely do it.

So while you’ve still got time to get PCBs ordered, let’s take a look at some of the unique aspects of creating your own Simple Add-On.

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Remembering CompuServe: The Online Experience Before The World Wide Web

September 25, 2024 by Maya Posch 29 Comments

July 1981 cover of CompuServe's magazine. — July 1981 cover of CompuServe’s magazine.

Long before the advent of the Internet and the World Wide Web, there were other ways to go online, with Ohio-based CompuServe being the first to offer a consumer-oriented service on September 24, 1979. In an article by [Michael De Bonis] a listener-submitted question to WOSU’s Curious Cbus is answered, interspersed with recollections of former users of the service. So what was CompuServe’s contribution to society that was so important that the state of Ohio gave historical status to the building that once housed this company?

The history of CompuServe and the consumer-facing services which it would develop started in 1969, when it was a timesharing and remote access service for businesses who wanted to buy some time on the PDP-10s that Golden United Life Insurance as the company’s subsidiary used. CompuServe divested in 1975 to become its own, NASDAQ-listed company. As noted in the article, while selling timeshares to businesses went well, after business hours they would have these big computer systems sitting mostly idly. This was developed by 1979 into a plan to give consumers with their newfangled microcomputers like the TRS-80 access.

Originally called MicroNet and marketed by Radio Shack, the service offered the CompuServe menu to users when they logged in, giving access to features like email, weather, stock quotes, online shipping and booking of airline tickets, as well as online forums and interactive text games.

Later renamed to CompuServe Information Service (CIS), it remained competitive with competitors like AOL and Prodigy until the mid-90s, even buying one competitor called The Source. Ultimately it was the rise of Internet and the WWW that would close the door on this chapter of computing history, even as for CompuServe users this new Internet age would have felt very familiar, indeed.

Tech In Plain Sight: Zipper Bags

September 25, 2024 by Al Williams 24 Comments

You probably think of them as “Ziploc” bags, but, technically, the generic term is zipper bag. Everything from electronic components to coffee beans arrive in them. But they weren’t always everywhere, and it took a while for them to find their niche.

A Dane named Borge Madsen was actually trying to create a new kind of zipper for clothes in the 1950s and had several patents on the technology. The Madsen zipper consisted of two interlocking pieces of plastic and a tab to press them together. Unfortunately, the didn’t work very well for clothing.

A Romanian immigrant named Max Ausnit bought the rights to the patent and formed Flexigrip Inc. He used the zippers on flat vinyl pencil cases and similar items. However, these still had the little plastic tab that operated like a zipper pull. While you occasionally see these in certain applications, they aren’t what you think of when you think of zipper bags.

Zipping

Ausnit’s son, Steven, figured out how to remove the tab. That made the bags more robust, a little handier to use, and it also rendered them less expensive to produce. Even so, cost was a barrier because the way they were made was to heat seal the zipper portion to the bags.

That changed in the 1960s when the Ausnits learned of a Japanese company, Seisan Nippon Sha, that had a process to integrate the bags and zippers in one step which slashed the production cost in half. Flexigrip acquired the rights in the United States and created a new company, Minigrip, to promote this type of bag.

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Fukushima Daiichi: Cleaning Up After A Nuclear Accident

September 23, 2024 by Maya Posch 47 Comments

On 11 March, 2011, a massive magnitude 9.1 earthquake shook the west coast of Japan, with the epicenter located at a shallow depth of 32 km, a mere 72 km off the coast of Oshika Peninsula, of the Touhoku region. Following this earthquake, an equally massive tsunami made its way towards Japan’s eastern shores, flooding many kilometers inland. Over 20,000 people were killed by the tsunami and earthquake, thousands of whom were dragged into the ocean when the tsunami retreated. This Touhoku earthquake was the most devastating in Japan’s history, both in human and economic cost, but also in the effect it had on one of Japan’s nuclear power plants: the six-unit Fukushima Daiichi plant.

In the subsequent Investigation Commission report by the Japanese Diet, a lack of safety culture at the plant’s owner (TEPCO) was noted, along with significant corruption and poor emergency preparation, all of which resulted in the preventable meltdown of three of the plant’s reactors and a botched evacuation. Although afterwards TEPCO was nationalized, and a new nuclear regulatory body established, this still left Japan with the daunting task of cleaning up the damaged Fukushima Daiichi nuclear plant.

Removal of the damaged fuel rods is the biggest priority, as this will take care of the main radiation hazard. This year TEPCO has begun work on removing the damaged fuel inside the cores, the outcome of which will set the pace for the rest of the clean-up.

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Switching Regulators: Mistake Fixing For Dummies

September 19, 2024 by Arya Voronova 31 Comments

Some time ago, while designing the PCB for the Sony Vaio replacement motherboard, I went on a quest to find a perfect 5 V boost regulator. Requirements are simple – output 5 V at about 2A , with input ranging from 3 V to 5 V, and when the input is 5 V, go into “100% duty” (“pass-through”/”bypass”) mode where the output is directly powered from the input, saving me from any conversion inefficiencies for USB port power when a charger is connected. Plus, a single EN pin, no digital configuration, small footprint, no BGA, no unsolicited services or offers – what more could one ask for.

As usual, I go to an online shop, set the parameters: single channel, all topologies that say “boost” in the name, output range, sort by price, download datasheets one by one and see what kind of nice chips I can find. Eventually, I found the holy grail chip for me, the MIC2876, originally from Micrel, now made by Microchip.

MIC2876 is a 5 V regulator with the exact features I describe above – to a T! It also comes with cool features, like a PG “Power good” output, bidirectional load disconnect (voltage applied to output won’t leak into input), EMI reduction and efficiency modes, and it’s decently cheap. I put it on the Sony Vaio board among five other regulators, ordered the board, assembled it, powered it up, and applied a positive logic level onto the regulator’s EN pin.

Immediately, I saw the regulator producing 3 V output accompanied by loud buzzing noise – as opposed to producing 5 V output without any audible noise. Here’s how the regulator ended up failing, how exactly I screwed up the design, and how I’m creating a mod board to fix it – so that the boards I meticulously assembled, don’t go to waste.

Some Background… Noise

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Catching The BOAT: Gamma-Ray Bursts And The Brightest Of All Time

September 18, 2024 by Dan Maloney 12 Comments

Down here at the bottom of our ocean of air, it’s easy to get complacent about the hazards our universe presents. We feel safe from the dangers of the vacuum of space, where radiation sizzles and rocks whizz around. In the same way that a catfish doesn’t much care what’s going on above the surface of his pond, so too are we content that our atmosphere will deflect, absorb, or incinerate just about anything that space throws our way.

Or will it? We all know that there are things out there in the solar system that are more than capable of wiping us out, and every day holds a non-zero chance that we’ll take the same ride the dinosaurs took 65 million years ago. But if that’s not enough to get you going, now we have to worry about gamma-ray bursts, searing blasts of energy crossing half the universe to arrive here and dump unimaginable amounts of energy on us, enough to not only be measurable by sensitive instruments in space but also to effect systems here on the ground, and in some cases, to physically alter our atmosphere.

Gamma-ray bursts are equal parts fascinating physics and terrifying science fiction. Here’s a look at the science behind them and the engineering that goes into detecting and studying them.

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