Build Yourself A Little Mangonel, You Deserve One

If you’re of a certain age, you almost certainly learned about mangonels by playing Age of Empires II. Any intermediate player will tell you they are a powerful siege weapon that nevertheless cannot destroy trees (in game). However, why limit yourself to experiencing this capable siege engine in digital form? With the help of [Arry Koster’s] design, you can build a little mangonel of your very own!

A good-looking siege engine is, more often than not, a well-performing one.

The build is intended for a student or hobbyist audience, and is for a mangonel roughly the size of a shoebox. That’s big enough to have some fun, without being so large as to get you into trouble. The project also comes complete with a useful spreadsheet that lets you simulate the performance of a mangonel hurling a projectile so you can better understand the physics involved.

The mangonel is constructed out of wood, just as medieval examples were. The guide explains how to put the the design together, including the use of graphite to lubricate moving parts — a technique also used historically. Beyond building the siege weapon itself, there are also instructions on how to instrument it with an Arduino to measure its performance accurately.

The only thing this project is missing is a brilliant video of the titchy siege machine in action. We want to see it knocking down some appropriately-sized castles! If you happen to be building your own siege engines, miniature or otherwise, don’t hesitate to drop us a line. Do include some excellent footage of your antics, to boot!

An Apple ][ With A Pendulum

Clocks are a favourite project here, and we can say we’ve seen all conceivable types over the years. Just a software clock on a retrocomputer perhaps isn’t the coolest among them, but [Willem van der Jagt ]’s Apple][ clock has a little bit extra. It takes its time reference from a real pendulum, on an antique wall clock.

A proximity sensor next to a metal pendulum gives an easy way to generate a digital pulse on each pass, but leaves the question of how to transfer it to the computer. With computers of this age the circuitry is surprisingly simple, and in this case he’s sending an interrupt to the machine which the software can pick up for its timing. There is a small logic circuit between the sensor and the interrupt allowing him to gate the pendulum line, triggered from one of the output lines exposed on the Apple’s game port.

The code is written in assembly, and counts the number of pendulum swings before incrementing the number of minutes. It’s an enjoyable reminder of the days when the architecture of a computer was this accessible, and for those of us whose past lies in the Sinclair world it’s also been a little peek into something of how the Apple works.

We think this is the first pendulum-driven retrocomputer clock we’ve seen here at Hackaday, as you might understand when a clock has a pendulum it’s usually a more traditional design.

Building Robots With A 20×20 Grid

On autonomous robots, the most difficult challenges usually lie in the software and electronic realms, but the mechanics can also be very time consuming. To help address this challenge, [Nikodem Bartnik] is working on the Open Robotic Platform (ORP), a modular robotics chassis system designed to make prototyping as easy and affordable as possible. Video after the break.

The ORP is governed by a set of design rules to maintain interchangeability. Most of the design rules are very open, but the cornerstone of ORP is its standardized mounting plates featuring a 20 mm grid pattern of 3.5 mm mounting holes. These plates can be stacked using connecting rods, creating a versatile foundation upon which various components can be mounted.

[Nikodem] is on a mission to create and collect an entire library of these modular components. From custom 3D-printed holders that accommodate sensors, motors, wheels and dev boards to homemade PCBs that snap directly onto the chassis, everything to get your robot rolling as soon as possible. While manufacturing methods and materials are not limited, 3D printing and laser cutting will likely be the most popular manufacturing technologies for making your own parts.

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A white male in a green shirt sitting next to a tall rectangular robot made of green and black components with an aluminum frame. In front of him are a variety of components from several windshield wiper motor assemblies. Casings, gearboxes, and the like are strewn across the wooden table.

A Wiper Motor 101

Need a powerful electric motor on the cheap? [Daniel Simu] and his friend [Werner] show us the ins and outs of using windshield wiper motors.

Through many examples and disassembled components, the duo walk us through some of the potential uses of wiper motors to power a project. Some of the nuggets we get are the linear relationship of torque to current (10-15A max) and speed to voltage (12-15V DC) on these units, and some of the ways the wiring in these motors is a little different than a simple two wire DC motor.

They also discuss some of their favorite ways to control the motors ranging from a light switch to an Arduino. They even mention how to turn one into a big servo thanks to a project on Hackaday.io and a few modifications of their own. [Simu] also discusses some of the drawbacks of wiper motors, the most evident being that these motors use nylon gears which are prone to stripping or failing in other ways when subjected to high torque conditions for too long.

If you recognize [Simu], it may be from his robotic acrobat built with wiper motors. Want to see some more wiper motor hacks? How about a 3D scanner or making sure your wipers always keep the beat?

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Swapping Nunchucks For A Steering Wheel

Rather than chasing pure performance and high quality graphics like other gaming companies, Nintendo has made a name for themselves over the last few decades by favoring not only artistic design and gameplay, but the physical design of the game systems. Of course the hybrid handheld Switch console is among these, but it also includes things like the novel design of the Nintendo 64 controller and, of course, the Wii nunchuck controllers. They’re not always met with resounding approval, though. Some of us tend to prefer more traditional gamepad design, and will go to extreme lengths to get it like this D-pad for playing Mario Kart Wii.

Rather than simply building a compatible controller for the Wii, or even using a GameCube controller, this controller setup takes a more roundabout approach. A Wiimote is placed in a holster built from Lego, and the game is set up to recognize it as if it were being used in its steering wheel mode. The Lego holster has a servo attached which can tilt the Wiimote from side to side, mimicking a player holding it to play the game, with another set of servos set up to press the various buttons. To control the controller, a homebrew D-pad built on perfboard with an Arduino at its core is used to send commands to the servos, allowing for a more standard controller layout to be used for the classic kart racing game than the steering wheel Wiimote allows.

While it’s quite obvious that there are simpler, easier solutions that avoid the sometimes awkward nature of using Wiimotes, we certainly appreciate the Rube Goldberg-like approach to setting up your gaming experience exactly the way you like. Whether that’s setting up an antique CRT effect for the authentic retro gaming experience or building a complete racing simulator from scratch, the gaming experience is ripe for personalization and unique builds like this one.

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Hackaday Podcast Episode 254: AI, Hijack Guy, And Water Rockets Fly

This week Hackaday Editors Elliot Williams and Al Williams chew the fat about the Haier IOT problem, and all other top Hackaday stories of the week. Want to prove your prowess at C programming? Take a quiz! Or marvel at some hairy display reverse engineering or 3D-printed compressor screws. On the lighter side, there’s an immense water rocket.

After Al waxes nostalgic about the world of DOS Extenders and extended memory, the guys talk about detective work: First detecting AI-written material, and finally, a great detective story about using science to finally (maybe) crack the infamous DB Cooper hijacking case.

Follow along with the links below. Don’t forget to tell us what you think about this episode in the comments!

Here’s a string of bits containing the podcast that looks suspiciously like an MP3!

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All I Want For Mr. Christmas Is Some New Music

It’s true — you really can find anything (except maybe LEGO) in thrift stores. When [thecowgoesmoo] picked up a Mr. Christmas Symphonium music box one day, they knew they wanted to make it play more than just the standard Christmas and classical fare that ships with the thing.

So they did what any self-respecting hacker would do, and they wrote a MATLAB script that generates new disk silhouette images that they then cut from cardboard with a laser cutter. They also used various other materials like a disposable cutting mat. Really, whatever is lying around that’s stiff enough and able to be cut should work. You know you want to hear Van Halen’s “Jump” coming from a tinkling music box, don’t you? Be sure to check out the video demonstration after the break.

If you don’t want to wait around until a Mr. Christmas lands in your lap, why not make your own hand-cranked music box and accompanying scores?

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