A Mechanical Calculator For The Modern Age

There was a brief period through the 1960s into the 1970s when the last word in electronics was the calculator. New models sold for hundreds of dollars, and owning one made you very special indeed. Then the price of the integrated circuit at their heart fell to the point at which anyone could afford one, and a new generation of microcomputers stole their novelty for ever. But these machines were by no means the first calculators, and [What Will Makes] shows us in detail the workings of a mechanical calculator.

His machine is beautifully made with gears hand-cut from plywood, and follows a decimal design in which the rotation of a gear with ten teeth represents the numbers 0 to 9. We’re taken through the mechanical processes behind addition, subtraction, multiplication, and division, showing us such intricacies as the carry lever or a sliding display mechanism to implement a decimal equivalent of a bitwise shift multiplication.

We have to admit to be particularly impressed by the quality of the work, more so because these gears are hand made. To get such a complex assembly to work smoothly requires close attention to tolerance, easy with a laser cutter but difficult by hand. We heartily recommend watching the video, which we’ve placed below the break.

Meanwhile if you’d like more mechanical calculators, take a look at one of the final generation of commercial models.

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The TimeChi Never Shipped, But You Can Build One From Scratch

What do you do when a crowdfunded product you really liked gets cancelled? Naturally, you take the idea and build your own version of it. That’s what [Salim Benbouziyane] did when the TimeChi project on Kickstarter saw its launch cut short. This device allows you to set a ‘no distractions’ timer, during which notifications on one’s phone and elsewhere are disabled, making it something similar to those Pomodoro timers. What this dial also is supposed to do is integrate with home automation to set up clear ‘focus’ periods while the timer runs.

A quick prototype of the newly minted Focus Dial project was set up using an ESP32 and other off-the-shelf components. The firmware has to run the timer, toggle off notifications on iOS and trigger firewall traffic rules to block a batch of social media addresses. Automating this with iOS was the hardest part, as Apple doesn’t make such automation features easy at all, ultimately requiring a Bluetooth audio board just to make iOS happy.

After this prototyping phase, the enclosure and assembly with the modules were drawn up in Autodesk Fusion 360 before the plastic parts were printed with a resin printer. The end result looks about as good as the Kickstarter one did, but with a few changes, because as [Salim] notes, if you are going to DIY such a failed crowdfunding project, why not make it work better for you?

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Battery-Electric Ships: Coming Soon To A Harbor Near You?

When ships moved from muscle- and wind power to burning coal and other fossil fuels for their propulsion, they also became significantly faster and larger. Today’s cargo ships and ferries have become the backbone of modern civilization, along with a range of boat types. Even though tugs and smaller pleasure vessels are a far cry from a multi-thousand ton cargo or cruise ship, one would be hard-pressed to convert these boats back to a pure muscle or wind-based version. In short, we won’t be going back to the Age of Sail, but at the same time the fossil fuel-burning engines in these boats and ship come with their own range of issues.

Even if factors like pollution and carbon emissions are not something which keep you up at night, fuel costs just might, with these and efficiency regulations increasing year over year. Taking a page from alternative propulsions with cars and trucks, the maritime industry has been considering a range of replacements for diesel and steam engines. Here battery-electric propulsion is somewhat of an odd duck, as it does not carry its own fuel and instead requires on-shore recharging stations. Yet if battery-electric vehicles (BEVs) can be made to work on land with accompanying low ‘refueling’ costs, why not ships and boats?

A recent study by Lawrence Berkeley National Laboratory (LBNL) researchers Hee Seung Moon et al. as published in Nature Energy claims that a significant part of US maritime traffic can be electrified this way. Yet as a theoretical model, how close does it hit to the harsh realities imposed by this physical world which we live in?

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Blinded By The Light: The Problem With LED Headlights

Having a good set of (working) headlights is a crucial feature of any motor vehicle, assuming you want to be able to see the road ahead of you when there’s a lack of sunshine. Headlights are also essential to be noticed by other cars and traffic participants, but if installed improperly they can end up blinding an opposing driver with potentially fatal results. This is a major worry with LED lamps that are increasingly being installed in cars, often replacing the old-style halogen bulbs that have a very different color spectrum and beam patterns, to the dismay of fellow road participants.

This headlight glare can also be simulated in driving simulators, as in a 2019 article by [B.C. Haycock] et al. where the effect is of course diminished because displays can only get so bright. Of note is that it’s not just LED lights themselves, but also taller vehicles and misaligned headlights, all of which makes it important that the angle of your car’s headlights is proper. You want to see the road in front of you, after all, not illuminate every house in the nearest settlement two klicks away.

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Tech In Plain Sight: Incandescent Bulbs

While they are dying out, you can still find incandescent bulbs. While these were once totally common, they’ve been largely replaced by LEDs and other lighting technology. However, you still see a number of them in special applications or older gear. If you are above a certain age, you might be surprised that youngsters may have never seen a standard incandescent lightbulb. Even so, the new bulbs are compatible with the old ones, so — mechanically, at least — the bulbs don’t look different on the outside.

You might have learned in school that Thomas Edison invented the light bulb, but the truth is much stranger (public domain)

It has been known for a long time that passing a current through a wire creates a glow. The problem is, the wire — the filament — would burn up quickly. The answer would be a combination of the right filament material and using an evacuated bulb to prevent the filament degrading. But it took over a century to get a commercially successful lightbulb.

We were all taught in school that Thomas Edison invented the light bulb, but the truth is much more complicated. You can go back to 1761 when Ebenezer Kinnersley first caused a wire to glow. Of course, wires would quickly burn up in the air. By the early 19th century, limelight was fairly common in theaters. Limelight — also known as the Drummond light — heated a piece of calcium oxide using a gas torch — not electric, but technically incandescence. Ships at sea and forts in the U.S. Civil War used limelights to illuminate targets and, supposedly, to blind enemy troops at night. Check out the video below to see what a limelight looks like.

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OpenWRT, But On An Unsupported Router

Everyone likes something cheap, and when that cheap thing is a router that’s supported by OpenWRT, it sounds like a win. [Hennung Paul] ordered a Wavlink WL-WN586X3 for the princely sum of 39 Euros, but was disappointed to find his device a rev. 2 board rather than the rev.1 board supported by the Linux distribution. Toss it on the failed projects pile and move on? Not at all, he hacked together a working OpenWRT for the device.

It’s fair to say that a majority of Hackaday readers will  have familiarity with Linux, but that’s something which runs on a sliding scale from “Uses Ubuntu a bit” all the way to “Is at one with the kernel”. We’d rate ourselves somewhere around halfway along that scale in terms of having an in-depth knowledge of userland and a working knowledge of some of the internals which make the operating system tick even if we’re apprehensive about tinkering at that level. [Henning] has no such  limitations, and proceeds to take the manufacturer’s distribution, itself a heavily modified OpenWRT, and make it his own. Booting over tFTP we’re used to, and we’re particularly impressed to see him using a Raspberry Pi as a surrogate host for the desoldered Flash chip over SPI.

It’s a long path he takes to get the thing working and we’re not sure we could follow it all, but we hope that the result will be a new device added to OpenWRT’s already extensive support list. It’s sometimes a shock to find this distro is now over two decades old.

Open Source Lemontron 3D Printer Is Ready To Build

In this era of cheap turn-key machines, the idea of actually building your own desktop 3D printer might seem odd to some. But if you’re looking for a challenge, and want to end up with a printer that legitimately sets itself apart from what they’re stocking on Amazon these days, then take a look at the Lemontron.

We’ve been keeping tabs on the development of this open source 3D printer for some time now, and just before Christmas, the files finally were released for anyone who wants to try putting one together themselves. There’s currently no formal kit available, but once you’ve printed out all the parts, there’s a very nice bill of materials you can find on the website which will tell you everything you need to complete the assembly — and critically — where you can get it.

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