Hand Cranking the Malevolent Mechanical Pumpkin

Meet Marty. He’s a pumpkin that has been fitted out with a moving eyes, tongue and an expression of malevolent glee. You would probably assume that this is all driven by servos, right? Nope: Marty is driven by an old-fashioned crank mechanism, designed and built by [Ben Brandt].

He wanted to make something that could be driven by a hand crank. Of course, there is nothing stopping you from throwing a motor on the back to drive the mechanism, but [Ben] wanted the internals to be fireproof so he could light it with a candle. His mechanism, built from old bits of wire and sheet metal, is not flammable or adversely affected by heat like a motor and power supply would be. He succeeded admirably, and he has also done an excellent job of documenting the process to providing handy tips on creating a mechanical pumpkin-based monstrosity.

Those hackers down with a little electronic wet work you should start building their LED-integrated Jack-O-Lantern now. These things take a lot of time turn out.

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Mechanical Watch Hacker Gets an Apple Watch

Mechanical watch enthusiasts see the Apple watch as a threat to the traditional gear train. It does not tick, requires frequent re-charging, and it’s certainly not the most attractive of watches. But it can direct you to the local coffee shop, allow you to communicate with friends anywhere in the world, get you onto an airplane after the most awkward of arm gestures, and keep you apprised of the latest NCAA basketball scores. Is the advent of the smart watch the end to the mechanical watch?
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A Different Kind of Plastic Shredder for 3D Filament Making

Haven’t you heard? You can make your own 3D filament nowadays from plastic granules (10X cheaper than filament), or even by recycling old plastic! Except if you’re recycling plastic you will have to shred it first…

[David Watkins] came up with a different way of shredding plastic. Typically we’ve seen shrunken versions of giant metal shredders used to dice up plastic into granules that can be melted down and then extruded back into filament. These work with a series of sharp toothed gears that kind of look like a stack of circular saw blades put together inside of a housing.

But that can be rather pricey. [David’s] method is super cheap, and you can do it at home with minimal tools, and maybe $10 or less worth of parts?

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Jacquard Loom Becomes A Display

The world’s leading expert on mechanical computers wasn’t [Charles Babbage]; sure, he could design stuff, but eventually you need to actually build something. We are now graced with the expertise of [Chris Fenton]. He’s built mechanical calculators, a mechanical digital computer, and now a mechanical display inspired by the Jacquard loom.

[Chris] calls his creation the PixelWeaver, and the name isn’t far from the truth; it’s a 32-hook Jacquard style punch card reader that could be mounted over a small loom. Instead of weaving rugs and fabric, the PixelWeaver controls a 6×5 black and white display.

The PixelWeaver is built out of t-slot aluminum, 3D printed parts, and a web of thread to transfer motion from rotating cams to ratchets and pixels. The display itself is heavily inspired by a Lego mechanical display, and the cards that store the data for the display are laser-cut plywood. Interestingly, there’s nothing in this machine that couldn’t have been made 150 years ago; it’s the same technology used to weave rugs, although the necessity of a bitmap display in the Victorian era is a bit questionable.

You can see a few videos of the PixelWeaver below. If you’re wondering what else has come out of [Chris]’ mechanical computing lab, check out his digital computer and Fibonacci calculating set of gears. For a real treat, here’s a machine that will calculate all primes under 1000 in 30 years.

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14 Wheel Drive Vehicle Climbs Over Most Things

What do you get when you cross 7 hobby gearboxes with 14 wheels and a LiPo battery? Instead of speculating an answer, we can just check out one of [rctestflight’s] projects.

He came across those hobby gearboxes and thought it would be fun to build a 14 wheel drive contraption. Each gearbox has its own motor and is wrapped up in a nice tidy package also including the axle and wheels. All of the wheels mounted on a straight board wouldn’t be much fun so [rctestflight] used heavy duty zip ties that act as a flexible frame to connect one gearbox to the next. This allows the vehicle to bend and climb over obstacles while keeping as many wheels in contact with the ground as possible.

14 Wheel Drive

All 7 motors are powered by a single cell LiPo battery. In the video after the break it appears the vehicle can steer or that it is remotely controlled, but that is not the case. Once the battery is plugged in it just goes forward. This isn’t the first time one of [rctestflight’s] projects has been featured on Hackaday, check out his Free Falling Quadcopter Experiment.

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DIY Thermal Insert Press

You might not know what a threaded insert is, but chances are you’ve seen one before. Threaded inserts are small metal (typically brass) inserts that are pressed into plastic to give a strong point of attachment for bolts and screws. These inserts are a huge step up from screwing or bolting directly into tapped plastic holes since the brass threads are very strong compared to the plastic. The only major downside to these inserts is that the press to install them is incredibly expensive. Thankfully, [Alex Rich] came up with a cheap solution: a modified soldering iron mounted to an Arbor press.

Commercial threaded insert presses typically use ultrasonic welding or heat welding to fuse inserts with plastic. [Alex] chose the simple route and went with heat welding, which (as you might imagine) is way simpler than ultrasonic welding. To provide the heat, [Alex] mounted a 100W Weller soldering iron to the press, which he says handles the impact with no problem. Unfortunately the copper tips of the Weller just wouldn’t hold up to the impact, so [Alex] made his own tips out of some brass he turned on a lathe.

If, like most people, you don’t have the capability of making injection-molded cases, let alone an Arbor press on hand, you’re not out of luck! Using this same technique people have successfully added thermal inserts to 3d-printed parts using a soldering iron and much smaller DIY presses. Have any ideas on how you could use thermal inserts in your 3d prints? Let us know in the comments.

4-bit Adder Built from Mechanical Relays


Would you consider this to be doing math the old-fashioned way? Instead of going with silicon-based switching (ie: transistors) this 4-bit adder uses mechanical relays. We like it for its mess of wires (don’t miss the “assembly” page which is arguably the juiciest part of the project). We like it for the neat and tidy finished product. And we like it for the clicky-goodness which surely must bloom from its operation; but alas, we didn’t find a video to stand as testament to this hypothesis.

The larger of the two images seen above is from the register memory stage of the build. The black relay in the bottom right is joined by a ring of siblings that are added around the perimeter of the larger relays before the entire thing is planted in the project box.

Sure, simulators are a great way to understand building blocks of logic structures like an adder. But there’s no better way to fully grip the abstraction of silicon logic than to build one from scratch. Still hovering on our list of “someday” projects is this wooden adder.

[Thanks Alex]