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

January 10, 2022 by Ryan Flowers 11 Comments

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.

[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

January 8, 2022 by Donald Papp 20 Comments

[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.

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 Power Has Never Been Easier

January 5, 2022 by Brian McEvoy 48 Comments

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.

3D Printed Model Roller Coaster Accurately Simulates The Real Thing

December 30, 2021 by Robin Kearey 11 Comments

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

December 25, 2021 by Matthew Carlson 5 Comments

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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3D Prints With A Mirror Finish

December 25, 2021 by Matthew Carlson 15 Comments

As anyone who has used a 3D printer before knows, what comes off the bed of your regular FSD printer is by no means a mirror finish. There are layers in the print simply by the nature of the technology itself, and the transitions between layers will never be smooth. In addition, printers can use different technology for depositing layers, making for thinner layers (SLA, for example). With those challenges in mind, [AlphaPhoenix] set out to create an authentic mirror finish on his 3D prints. (Video, embedded below.)

As the intro hints, mirrors need very flat/smooth surfaces to reflect light. To smooth his prints, [AlphaPhoenix] first did a light sanding pass and then applied very thick two-part epoxy, allowing surface tension to do the smoothing work for him. Once dried, silver was deposited onto the pieces via a few different sprays. First, a wetting agent is applied, which prevents subsequent solutions from beading up. Next, he sprays the two precursors, and they react together to deposit elemental silver onto the object’s surface. [AlphaPhoenix] asserts that he isn’t a chemist and then explains some of the many chemical reactions behind the process and theorizes why the solutions break down a while after being mixed.

He had an excellent first batch, and then subsequent batches came out splotchy and decided un-mirror-like. As we mentioned earlier, the first step was a wetting agent, which tended to react with the epoxy that He applied. Then, using a grid search with four variables, [AlphaPhoenix] trudged through the different configurations, landing on critical takeaways. For example, the curing time for the epoxy was essential and the ratio between the two precursor solutions.

Recently we covered a 3D printed mirror array that concealed a hidden message. Perhaps a future version of that could have the mirror integrated into the print itself using the techniques from [AlphaPhoenix]?

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Do You Need A Cycloidal Drive?

December 25, 2021 by Elliot Williams 10 Comments

A cycloidal gear drive is one of the most mesmerizing reduction gears to watch when it is running, but it’s not all just eye-candy. Cycloidals give decent gearing, are relatively compact and back-drivable, and have low backlash and high efficiency. You probably want one in the shoulder of your robot arm, for instance.

But designing and building one isn’t exactly straightforward. Thanks, then, to [How To Mechatronics] for the lovely explanation of how it works in detail, and a nice walkthrough of designing and building a cycloidal gear reducer out of 3D printed parts and a ton of bearings. If you just want to watch it go, check out the video embedded below.

The video is partly an ad for SolidWorks, and spends a lot of time on the mechanics of designing the parts for 3D printing using that software. Still, if you’re using any other graphical CAD tool, you should be able to translate what you learned.

It’s amazing that 3D printing has made sophisticated gearbox designs like this possible to fabricate at home. This stuff used to be confined to the high-end machine shops of fancy robotics firms, and now you can make one yourself this weekend. Not exotic or unreliable enough for you? Well, then, buy yourself some flexible filament and step on up to the strain wave, aka “harmonic drive”, gearbox.

Thanks to serial tipster [Keith] for the tip!

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