Hand reaching for a 3d-printed hinge

One-piece Geared Hinge Can Take The Weight

3D printers have come a long way from cranking out things like bottle openers and coat pegs, and [E. Soderberg]’s Print in Place Geared Hinge is a pretty nifty demonstration of that. This hinge is designed as a print-in-place part, meaning it is 3D printed as a single piece, requiring no assembly. Not only that, but the herringbone gears constrain the sturdy device in a way that helps it support heavy loads.

Of course, hinges — even strong ones — are not particularly hard to find items. They’re available in a mind-boggling array of shapes and sizes. But what’s interesting about this design is that it shows what’s easily within the reach of just about any hobbyist nowadays. Not that long ago, designing and creating an object like this would not have been accessible to most home enthusiasts. Making it without a modern 3D printer would certainly have been a challenge in its own right.

It doesn’t always matter that a comparable (or superior) off-the-shelf part is available; an adequate part that can be created in one’s own workshop has a value all its own. Plus, it’s fun to design and make things, sometimes for their own sake. After all, things like 3D-printed custom switch assemblies would not exist if everyone were satisfied with the ability to just order some Cherry MX switches and call it a day.

The 3x0 in it's glory

Printing Your Own Exoskeleton

While not quite in a cave, the idea of making your own exoskeleton with limited tools does have a Tony Stark esque vibe. [Andrew Piccinno] is a mechanical engineer pursuing the dream of 3D printing a full-body exoskeleton called 3X0. It’s a project he’s been ruminating on since college, but the work really began in earnest about five months ago. Unfortunately, there are too many pictures to include here, but check out his Instagram or makeprojects for more photos.

To make sure parts fit, [Andrew] started with creating a mesh of his body. After running fifty pictures of himself holding relatively still through some photogrammetry software, he had a decent mesh. While measurements weren’t millimeter-accurate, the relative sizes of everything were reasonably accurate. While the design is modeled with his measurements in mind, all the different pieces are parametric, which in theory would allow someone to tweak the designs to fit their own body.

So far, all the parts have been entirely 3D printed, except for steel balls bearings, gas pistons, and tension bands. The non-3D printed parts are picked to be easy to obtain as the gas piston is just 100 N furniture pistons. The design process includes quite a bit of math, motion study, and simulation to make sure the part that he’s printing will not only fit but move correctly. Many parts, such as the shoulder, are built around a large custom bearing that allows the piece to move correctly with the user’s joints.

While still in the middle of development, [Andrew] has made some serious progress, and we’re looking forward to seeing it completed. The current design is primarily passive with just a few springs and pistons, but he is already looking forward to making it active to the degree that it can augment a user’s motions rather than just taking the load off. It’s clear that [Andrew] believes that exoskeletons are a look into a potential future, and we couldn’t agree more. In a similar vein, perhaps the techniques used in this powered exoskeleton arm on a budget could be used to power the 3X0?

HitClips Cartridge Hack

HitClips Custom Cartridge Hack Will Never Give Up, Let Down, Or Turn Around

In August 2000, Tiger Electronics released HitClips: Music cartridges and players designed to easily share 60 second low quality Clips of a youngster’s favorite Hits. Various players were available, and individual cartridges were inexpensive enough to collect. And it’s these toy music players that [Guy Dupont] has been hacking quite successfully on as you can see in the video after the break and on [Guy]’s Hackaday.io page.

HitClips Cartridge Hack
Two PCB’s make up the new cartridge

[Guy]’s main goal was to make cartridges of his own that could not just hold more music than the short clips in the commercially made product, but could make use of modern technology that has matured since HitClips came onto the scene more than 20 years go.

The project’s components are relatively simple, but beautifully executed. An ATTINY84 didn’t work out, so a SAM D09 controller was put it place to to read files from a microSD card and translate the WAV file into the HitClips player’s format. 3d printed cartridges and custom PCB’s complete the hack, ensuring that you can use any of the many HitClips players to play something new for a change.

The end result is quite good, considering that it’s still just 8 bit audio on a 20 year old toy player. Tiger Electronics made another toy that’s quite popular with hackers of the musical kind.

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Hidden Shaft And Gears Make This Hollow Clock Go

[shiura]’s Hollow Clock 3 is a fantastic 3D printed take on a clock movement that uses a hidden mechanism to pull off its unusual operation. The Hollow Clock has no face, just an open space with an hour and minute hand that move as expected. Only the longer minute hand has any apparent connection to the rest of the clock body, with the rest appearing to hang in the air.

Hidden shaft and gearing.

This is how it works: the longer minute hand is connected to the white ring, and it is in fact this ring that rotates, taking the attached minute hand with it. But how does the hour hand remain stationary while the rest turns? A concealed shaft and gear assembly takes care of that. For every full rotation of the minute hand (actually the white ring), the hour hand is only permitted a relative advancement of 1/12th of a rotation. It’s a clever system, and you can see the insides in the photo here.

Unlike clock projects that showcase their inner workings, the Hollow Clock works hard to conceal them. If you decide to make your own, [shiura] warns to expect to do a bit of tweaking to fine-tune the amount of friction between moving parts so that operation is smooth, and provides useful guidelines for doing so. Take a few minutes to watch the clock in action in the video, embedded below.

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USB to Dupont adapter by [PROSCH]

USB Power Has Never Been Easier

USB cables inevitably fail and sometimes one end is reincarnated to power our solderless breadboards. Of course, if the cable broke once, it is waiting to crap out again. Too many have flimsy conductors that cannot withstand any torque and buckle when you push them into a socket. [PROSCH] has a superior answer that only takes a couple of minutes to print and up-cycles a pair of wires with DuPont connectors. The metal tips become the leads and the plastic sheathing aligns with the rim.

The model prints with a clear plus sign on the positive terminal, so you don’t have to worry about sending the wrong polarity, and it shouldn’t be difficult to add your own features, like a hoop for pulling it out, or an indicator LED and resistor. We’d like to see one with a tiny fuse holder.

If you want your breadboard to have old-school features, like a base and embedded power supply, we can point you in the right direction. If you are looking to up your prototyping game to make presentation-worthy pieces, we have a host of ideas.

A model roller coaster

3D Printed Model Roller Coaster Accurately Simulates The Real Thing

While they don’t give the physical thrill of a real one, model roller coasters are always fun to watch. However, they actually make a poor analog of a full-sized ride, as gravitational force and aerodynamic drag don’t scale down in the same way, model roller coasters usually move way faster than the same design would in the real world. [Jon Mendenhall] fixed this deficiency by designing a model roller coaster that accurately simulates a full-sized ride.

The track and cart are all made of 3D printed pieces, which altogether took about 400 hours to print. The main trick to the system’s unique motion is that the cart is motorized: a brushless DC motor moves it along the track using a rack-and-pinion system. This means that technically this model isn’t a roller coaster, since the cart never makes a gravity-powered drop; it’s actually a small rack railway, powered by a lithium-ion battery carried on board the cart. An ESP32 drives the motor, receiving its commands through WiFi, while the complete setup is controlled by a Raspberry Pi that runs the cart through a predetermined sequence.

The design of the track was inspired by the Fury 325 roller coaster and simulated in NoLimits 2. [Jon] wrote his own software to generate all the pieces to be printed based on outputs from the simulator. This included all the track pieces as well as the large A-frames holding it up; some of these were too long to fit in [Jon]’s 3D printers and had to be built from smaller pieces. The physics simulation also provided the inputs to the controller in the form of a script that contains the proper speed and acceleration at each point along the track.

The end result looks rather slow compared to other model roller coasters, but actually feels realistic if you imagine yourself inside the cart. While it’s not the first 3D printed roller coaster we’ve seen, it’s probably the only one that accurately simulates the real thing. If you’re more interested in a roller coaster’s safety systems, we’ve featured them too.

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several chocolate figurines of various sizes

Cast Your Own Holiday Chocolate Bunny, Or Rather Mouse

The art of forming and using a mold is, well, an art. The already tricky process would be made even harder by using a fickle material, like chocolate. This is exactly where [Alexandre Chappel] found himself as he tried to cast his own chocolate figurines.

The starting point was a 3D low-poly model of everyone’s favorite fictional electric mouse. He tweaked the model to add offsets so that after the model was vacuum formed, there would be something to clamp onto. [Alexandre] was left with four different pieces, and he vacuum-formed them with 1 mm PETG plastic. Electing for white chocolate to add coloring, he started heating the chocolate. Adding too much colorant resulted in a seized mess, so the process was a bit of trial and error. Finally, he poured in chocolate and spun it around to form an even layer of chocolate as a shell. The flashing lines were easy to trim with a utility knife.

The last thing to add was a little splash of color via airbrush and food-grade paint. The results are stunning, and even though the techniques are simple, the results came together nicely. The files are available on his website if you’re curious about making your own. If you’re curious about more clever casting techniques with chocolate, take a look at the creative use of diffraction grating to get iridescent chocolate.

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