Calculus And A Calculator

July 4, 2018 by Al Williams 7 Comments

Earlier this year, [Dan Maloney] went inside mechanical calculators. Being the practical sort, [Dan] jumped right into the Pascaline invented by Blaise Pascal. It couldn’t multiply or divide. He then went into the arithmometer, which is arguably the first commercially successful mechanical calculator with four functions. That was around 1821 or so. But [Dan] mentions it used a Leibniz wheel. I thought, “Leibniz? He’s the calculus guy, right? He died in 1716.” So I knew there had to be at least a century of backstory to get to the arithmometer. Having a rainy day ahead, I decided to find out exactly where the Leibniz wheel came from and what it was doing for 100 years prior to 1821.

If you’ve taken calculus you’ve probably heard of Gottfried Wilhelm Leibniz (who would have been 372 years old on July 1st, by the way). He’s the guy that gave us the notation we use in modern calculus and oddly was one of two people who apparently figured out calculus, the other being Issac Newton. Both men, by the way, accused each other of stealing, although it is more likely they both built on the same prior work. When you are struggling to learn calculus, it is sometimes amazing that not only did someone think it up, but two people thought it up at one time. However, Leibniz also built what might be the first four function calculator in 1694. His “stepped reckoner” used a drum and some cranks and the underlying mechanism found inside of it lived on until the 1970s in other mechanical calculating devices. Oddly, Leibniz didn’t use the term stepped reckoner but called the machine Instrumentum Arithmeticum.

Many of us remember when a four function electronic calculator was a marvel and not even very inexpensive. Nowadays, you’d have to look hard to find one that only had four functions and simple calculators are cheap enough to give away like ink pens. But in 1694, you didn’t have electronics and integrated circuits necessary to pull that off.

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Retrotechtacular: Constructing A Car Engine

July 4, 2018 by Jenny List 18 Comments

Oxford is a city world-famous for its university, and is a must-see stop on the itinerary of many a tourist to the United Kingdom. It features mediaeval architecture, unspoilt meadows, two idylic rivers, and a car plant. That’s the part the guide books don’t tell you, if you drive a BMW Mini there is every chance that it was built in a shiny new factory on the outskirts of the historic tourist destination.

A 1930s Morris Ten Series II. Humber79 [CC BY-SA 3.0].

The origins of the Mini factory lie over the road on a site that now houses a science park but was once the location of the Morris Motors plant, at one time Britain’s largest carmaker. In the 1930s they featured in a British Pathé documentary film which we’ve placed below the break, part of a series on industry in which the production of an internal combustion engine was examined in great detail. The music and narration is charmingly of its time, but the film itself is not only a fascinating look inside a factory of over eight decades ago, but also an insight into engine manufacture that remains relevant today even if the engine itself bears little resemblance to the lump in your motor today.

Morris produced a range of run-of-the-mill saloon cars in this period, and their typical power unit was one of the four-cylinder engines from the film. It’s a sidevalve design with a three-bearing crank, and it lacks innovations such as bore liners. The metallurgy and lubrication in these engines was not to the same standard as an engine of today, so a prewar Morris owner would not have expected to see the same longevity you’d expect from your daily.

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These Capacitors Are A Cheap Gimmick

July 3, 2018 by Al Williams 31 Comments

If you search through an electrical engineering textbook, you probably aren’t going to find the phrase “gimmick capacitor” but every old ham radio operator knows about them. They come in handy when you need a very small capacitor of unknown value. For example, if you are trying to balance the stray capacitance in a circuit, you might not know exactly what value you need, but you know it won’t be very much. That’s when you want a gimmick capacitor.

A gimmick capacitor is made by taking two strands of insulated wire and twisting them together; the length and the tightness of the twist determine the capacitance. Tightening or loosening the twist, or trimming some of the wire off, makes it tunable.

These are most commonly found in RF equipment or high-speed logic because of the small capacitance involved — usually about 1 to 2 pF per inch of twist or so. The thicker the insulation, the less capacitance you’ll get, so it is common to use magnet wire or something else with a thin insulating layer. You can take this one step further and decrease the spacing by stripping down one wire as long as it isn’t going to touch anything else.

Obviously, the insulation needs to be good enough for the voltage on them, an important consideration in tube circuits, for instance. But other than that, a gimmick capacitor is a straightforward tool to have in your box of design tricks. Can we take this further? Continue reading “These Capacitors Are A Cheap Gimmick” →

Video Quick-Bit: The Things That Move Robots

July 2, 2018 by Mike Szczys 1 Comment

Magenta Strongheart returns for a look at some of the coolest robotic entries from this year’s Hackaday Prize. Each of these answered the challenge for modular designs that will help supercharge new robot projects.

We think that cheap and abundant motor designs are poised to revolutionize robotics and several of the entries thought along those same lines. [Masahiro Mizuno] came up with a great 3D printed servo design based around a 6mm DC motor. Also in this ballpark, a team of two — Giovanni Leal and Jonathan Diaz — used 3D printing to turn some tiny metallic servos into linear actuators.

Picking stuff up is a difficult thing for a machine to do. We’ve long enjoyed seeing jamming grippers which do it with an inflatable bladder around a granular material (watch the video… it’s amazing). Two of these were demonstrated as part of the challenge. The Universal Jamming Gripper focuses on the entire mechanism, while Programmable Air took aim at the pneumatic actuation system and can adapt to other soft-robotics uses.

Rounding out this update, make sure to take a peek at the PCB stepper motor [Bobricius] built after being inspired by [Carl Bugeja’s] PCB motor. You’ll also want to see the entry that is taking on industrial farming. Imaging slow-rolling behemoths that use computer vision and spinning tillers to take care of weeds, cutting down on herbicide use.

Right now we’re in the thick of the Power Harvesting Challenge. Show us how you’re getting power from an interesting source and you’ll be on the way to the finals. Twenty power harvesting entries will get that honor, along with a $1,000 cash prize. The five top entries of the 2018 Hackaday Prize will split $100,000!

Spy Tech: How An Apollo Capsule Landed In Michigan After A Layover In The USSR

July 2, 2018 by Al Williams 44 Comments

There’s an Apollo module on display in Michigan and its cold-war backstory is even more interesting than its space program origins.

Everyone who visits the Van Andel Museum Center in Grand Rapids, Michigan is sure to see the Apollo Command Module flanking the front entrance. Right now it’s being used as a different kind of capsule: a time capsule they’ll open in 2076 (the American tricentennial). If you look close though, this isn’t an actual Command Module but what they call a “boilerplate.”

Technically, these were mass simulators made cheaply for certain tests and training purposes. A full spacecraft costs a lot of money but these — historically made out of boilerplate steel — could be made with just the pieces necessary and using less expensive materials. What you might not know is that the boilerplate at the Van Ardel — BP 1227 — has a cold war spy history unlike any other boilerplate in the fleet.

The early life of BP 1227 is a little sketchy. It appears the Navy was using it for recovery training somewhere between the Azores and the Bay of Biscay in early 1969. We don’t know for sure if the picture to the left is BP 1227 or not. Comparing it to the one at the museum, it probably isn’t, but then again the museum’s does have a fresh paint job and possibly a top cap. Regardless, the picture to the left was from 1966 in the Atlantic, giving us an idea of how boilerplate capsules were put into service.

In those days — the height of the cold war — Naval ships were often followed by Soviet “fishing trawlers.” These were universally understood to be spy ships — Auxiliary, General Intelligence or AGI vessels.

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Hackaday Links: July 1, 2018

July 1, 2018 by Brian Benchoff 32 Comments

Remember when computer mice didn’t have scroll wheels? The greatest mouse of all time, the Microsoft Intellimouse Explorer 3.0, is back in production. This mouse was released in 2003, before the popularity of ‘gaming’ mice from the likes of Razer, and at the time it was the standard mouse for RTS and FPS professional gamers. After producing a few million of these mice, the molds died or the sensors were out of stock, Microsoft stopped shipping the Intellimouse Explorer 3.0, and the ones that were out in the wild slowly died. Now this fantastic mouse is back, and it’s only going to set you back $40. Believe me when I say this is one of the greatest user interface devices ever created, right up there with the Model M keyboard.

Another week, another update on building an airplane in a basement. [Peter Sripol] has basically finished the fuselage of his homebuilt ultralight with working elevator, rudder, and landing gear that looks like it might hold up.

The Pebble was one of the most successful crowdfunding campaigns ever, and now it’s dead. Pebble was bought by Fitbit for $40M, and now the Pebble servers are off, as of June 30th. Of course there are community-based projects to keep the Pebble working, notably the rebble project.

It’s time for Steam’s summer sale, and your wallet is crying. The standout deal is the Steam Link, a sort of ‘thin client for Steam’ that plugs into your TV, looks on the network for your battlestation, and allows you to play Fortnite or whatever on the big screen. The Steam Link normally sells for $50, but with the summer sale it’s two dollars and fifty cents.

Here are a few experiments in CNC joinery. [Mirock] has a CNC machine and a few pieces of wood, and explored what is possible when you want to join two boards at ninety degrees to each other. Why is this interesting? One of the joints on this simple box project consists of a circle with a hole on one board, and a pin on the other. This is basically a Knapp joint, a ‘dovetail’ of sorts that was developed in the 1860s. This was the first popular machine-made joint in woodworking, and if you ever see it on an antique, it solidly dates that piece to any time between 1870-1900. Of course, now that you can just buy a CNC router, an infinite variety of joints are possible, and [Mirock] can experiment with all sorts of combinations of pins and tails and mortises and tenons.

How Etak Paved The Way To Personal Navigation

June 29, 2018 by Dan Maloney 29 Comments

Our recent “Retrotechtacular” feature on an early 1970s dead-reckoning car navigation system stirred a memory of another pre-GPS solution for the question that had vexed the motoring public on road trips into unfamiliar areas for decades: “Where the heck are we?” In an age when the tattered remains of long-outdated paper roadmaps were often the best navigational aid a driver had, the dream of an in-dash scrolling map seemed like something Q would build for James Bond to destroy.

And yet, in the mid-1980s, just such a device was designed and made available to the public. Dubbed Etak, the system was simultaneously far ahead of its time and doomed to failure by the constellation of global positioning satellites being assembled overhead as it was being rolled out. Given the constraints it was operating under, Etak worked very well, and even managed to introduce some of the features of modern GPS that we take for granted, such as searching for services and businesses. Here’s a little bit about how the system came to be and how it worked.

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