Steve showing a circuit built with spintronics blocks

Electronics Explained With Mechanical Devices

It can be surprisingly hard to find decent analogies when you’re teaching electronics basics. The water flow analogy, for instance, is decent for explaining Ohm’s law, but it breaks down pretty soon thereafter.

Hydraulics aren’t as easy to set up when you want an educational toykit for your child to play with, which leaves them firmly in the thought experiment area. [Steve Mould] shows us a different take – the experimentation kit called Spintronics, which goes the mechanical way, using chains, gears, springs and to simulate the flow of current and the effect of potential differences.

Through different mechanical linkages between gears and internal constructs, you can implement batteries, capacitors, diodes, inductors, resistors, switches, transistors, and the like. The mechanical analogy is surprisingly complete. [Steve] starts by going through the ways those building blocks are turned into mechanical-gear-based elements. He then builds one circuit after another in quick succession, demonstrating just how well it maps to the day-to-day electronic concepts. Some of the examples are oscillators, high-pass filters, and amplifiers. [Steve] even manages to build a full-bridge rectifier!

In the end, he also builds a flip-flop and an XOR gate – just in case you were wondering whether you could theoretically build a computer out of these. Such a mechanical approach makes for a surprisingly complete and endearing analogy when teaching electronics, and an open-source 3D printable take on the concept would be a joy to witness.

Looking for something you could gift to a young aspiring mind? You don’t have to go store-bought – there are some impressive hackers who build educational gadgets, for you to learn from.

Harmonic Analyzer Does It With Cranks And Gears

Before graphic calculators and microcomputers, plotting functions were generally achieved by hand. However, there were mechanical graphing tools, too. With the help of a laser cutter, it’s even possible to make your own!

The build in question is nicknamed the Harmonic Analyzer. It can be used to draw functions created by adding sine waves, a la the Fourier series. While a true Fourier series is the sum of an infinite number of sine waves, this mechanical contraption settles on just 5.

This is achieved through the use of a crank driving a series of gears. The x-axis gearing pans the notepad from left to right. The function gearing has a series of gears for each of the 5 sinewaves, which work with levers to set the magnitude of the coefficients for each component of the function. These levers are then hooked up to a spring system, which adds the outputs of each sine wave together. This spring adder then controls the y-axis motion of the pen, which draws the function on paper.

It’s a great example of the capabilities of mechanical computing, even if it’s unlikely to ever run Quake. Other DIY mechanical computers we’ve seen include the Digi-Comp I and a wildly complex Differential Analyzer. Video after the break.

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Teach Computing The Old-School Way With A Digi-Comp II

Ubiquitous computing has delivered a world in which there seem to be few devices left that no longer contain a microprocessor of some sort. Thus should a student wish to learn about the inner workings of a computer they can easily do so from a multitude of devices. For an earlier generation though this was not such a straightforward process, in the 1950s or 1960s you could not simply buy a microcomputer and set to work. Instead a range of ingenious teaching aids providing the essentials of computing without a computer were created, and those students saw their first computational logic through the medium of paper, ball bearings, or flashlight bulbs.

The DigiComp II was just such a device, performing logic tasks through ball bearings rolling down trackways. Genuine machines are now particularly rare, so [Mike Gardi] created a modern 3D printed replica that delivers all the fun without the cost. It’s a complicated build with a multitude of parts and wire linkages, and there is an element of fine tuning of its springs required to achieve reliable operation. You’ll neither run a Beowulf cluster of DigiComp IIs nor will you mine any Bitcoin with one, but it’s definitely one of the more unusual computing devices you could have in your collection.

Of course, should you need a truly authentic period computing device, there is always the slide rule.

Via Hacker News.

VCF East: Before There Was Arduino, We Had Balls

Today, if you want to teach kids the art of counting to one, you’re going to drag out a computer or an iPad. Install Scratch. Break out an Arduino, or something. This is high technology to solve the simple problem of teaching ANDs and ORs, counting to 0x0F, and very basic algorithms.

At the Vintage Computer Festival East this year, System Source, proprietors of a fantastic museum of not-quite-computing equipment brought out a few of their best exhibits. These include mechanical calculators, toys from the 60s, and analog computers that are today more at home in a CS departments’ storage closet than a classroom. It’s fantastic stuff, and shows exactly how much you can learn with some very cleverly designed mechanical hardware.

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Differential Analyzer Cranks Out Math Like A Champ At VCF 2016

Here at VCF, we stumbled across a gigantic contraption that spanned several tables. Rube Goldberg machine this was not. Instead, this device actually does something useful! [Tim Robinson’s] differential analyzer can solve differential equations through several stages of mechanical integrators. The result is a pen-plot graph of the solution to the input equation, input by displacing a rod as a function of time.

Differential analyzers have been around for over a century. [Tim’s] claim to fame is that this particular DA is constructed entirely from Meccano-branded parts. We’re thrilled to see Meccano, over 100 years old at this point, continue to find new uses outside the toy box.

diff_analyzer
The Torque Amplifier

The differential analyzer is riddled with mechanisms that are bound to swing some heads for a double-take. Since the input shaft that transmits the input function f(x), has very little friction, the result can only be carried through the remainder of the machine with some means of torque amplification. To do so, [Tim], and most other DA designers implement a torque analyzer. For [Tim], though, this feat proved to be more difficult (and more triumphant) than other solutions, since he’s using a set of parts that are entirely from Meccano. In fact, this feature took [Tim] through about 20 iterations before he was finally satisfied.

VCF West continues to run through the end of the weekend at the Computer History Museum in Mountain View, CA. If you haven’t already packed your bags for DEF CON, stop by for a few more bewildering brain teasers.

1980s Toy Robot Arm Converted To Steam And Other Explorations

We were doing our daily harvest of YouTube for fresh hacks when we stumbled on a video that eventually led us to this conversion of a 1980s Armatron robot to steam power.

The video in question was of [The 8-bit Guy] doing a small restoration of a 1984 Radio Shack Armatron toy. Expecting a mess of wiring we were absolutely surprised to discover that the internals of the arm were all mechanical with only a single electric motor. Perhaps the motors were more expensive back then?

The resemblance is uncanny.
The resemblance is uncanny.

The arm is driven by a Sarlacc Pit of planetary gears. These in turn are driven by a clever synchronized transmission. It’s very, very cool. We, admittedly, fell down the google rabbit hole. There are some great pictures of the internals here. Whoever designed this was very clever.

The robot arm can do full 360 rotations at every joint that supports it without slip rings. The copper shafts were also interesting. It’s a sort of history lesson on the prices of metal and components at the time.

Regardless, the single motor drive was what attracted [crabfu], ten entire years ago, to attach a steam engine to the device. A quick cut through the side of the case, a tiny chain drive, and a Jensen steam engine was all it took to get the toy converted over. Potato quality video after the break.

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Laser Cut Mechanical Logic Gates

When you create logic circuits using ICs or FPGAs, you can’t easily visualize their operation without special tools. But if you’ve ever seen a mechanical computer (like the Computer History Museum’s Babbage engine) operate, you know you don’t have that problem. Just like it is fascinating to watch a 3D printer or CNC machine, watching mechanical logic gates work can be addictive.

[Anthony] wanted to build some mechanical logic gates and set out designing them using Inkscape. Unlike some common mechanical gate schemes, [Anthony’s] gates use gears to implement the logic operations. He sent the designs off to a laser cutter service and got back parts cut from 3mm acrylic.

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