Multi-Material Printing Enables Low Cost Silicone Prototypes

September 4, 2024 by Tom Nardi 9 Comments

While it’s the ideal choice for mass production, injection molding is simply no good for prototyping. The molds are expensive and time-consuming make, so unless you’ve got the funding to burn tens of thousands of dollars on producing new ones each time you make a tweak to your design, they’re the kind of thing you don’t want to have made until you’re absolutely sure everything is dialed in and ready. So how do you get to that point without breaking the bank?

That’s not always an easy question, but if you’re working with silicone parts, the team at OpenAeros thinks they might have a solution for you. As demonstrated through their OpenRespirator project, the team has developed a method of 3D printing single-use molds suitable for large silicone parts that they’re calling Digital-to-Silicone (D2S).

In the video below, [Aaron] and [Jon] explain that they started off by simply printing injection molds in the traditional style. This worked, but the molds can get quite complex, and the time and effort necessary to design and print them wasn’t a great fit for their iterative development cycle. They wanted to be able to do from design to prototype in a day, not a week.

Eventually they realized that if they printed the mold out of a water-soluble filament, they could simplify its design greatly. They’ve documented the design process in detail, but the short version is that you essentially subtract the 3D model of the design you want to produce from a solid shape in your CAD package, and add a few holes for injecting the silicone. Once the silicone has cured, the mold can be dissolved away in warm water to reveal the finished part.

They then took this concept a step further. Thanks to the multi-material capabilities offered by some of the latest 3D printers, it’s possible to print structures within the mold. Once the silicone is injected, these structures can become part of the finished part. For the OpenRespirator, this lets them add PETG stiffening rings around where the filters to snap into the silicone mask body.

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2024 Business Card Challenge: Adding Some Refinement To Breadboard Power Supplies

May 26, 2024 by Bryan Cockfield 6 Comments

For small electronics projects, prototyping a design on a breadboard is a must to iron out kinks in the design and ensure everything works properly before a final version is created. The power supply for the breadboard is often overlooked, with newcomers to electronics sometimes using a 9V battery and regulator or a cheap USB supply to get a quick 5V source. We might eventually move on to hacking together an ATX power supply, or the more affluent among us might spring for a variable, regulated bench supply, but this power supply built specifically for breadboards might thread the needle for this use case much better than other options.

The unique supply is hosted on a small PCB with two breakout rails that connect directly to the positive and negative pins on a standard-sized breadboard. The power supply has two outputs, each of which can output up to 24V DC and both are adjustable by potentiometers. To maintain high efficiency and lower component sizes, a switch-mode design is used to provide variable DC voltage. A three-digit, seven-segment display at the top of the board keeps track of whichever output the user selects, and the supply itself can be powered by a number of inputs, including USB-C or lithium batteries.

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Adding AI To NPCs Is Easy, Doing It Well Is Hard

January 10, 2024 by Donald Papp 18 Comments

Adding natural language interfaces to software is easier than ever, and that led [creikey] to prototype a game that hinges on communicating with NPCs. The prototype went through multiple iterations during which he mainly discovered things that did not work well. Ultimately, it led to [creikey] settling on a western-themed game called Dante’s Cowboy which he hopes to release as an experiment. He begins talking about the game around the 4:43 mark in the video, which directly precedes a recording of a presentation he gives at as an indie developer.

Games typically revolve around the player manipulating entities in an environment in order to make things happen. This interaction drives engagement and interesting decisions. But while adding natural language AI to NPCs makes them easy to talk with, talking by itself is a shallow interaction. Convincing NPCs to do things? That’s complex and far more difficult to implement. [creikey] realized the limitations large language models (LLMs) had and worked to overcome them to make a unique game experience.

The challenges boil down to figuring out how to drive meaningful interaction, aligning AI behavior with the gameplay context, and managing API costs. In his words, “it’s been a learning experience to figure out where [natural language AI] even belongs in a game, if it belongs at all.”

We’ve previously seen ChatGPT used to grant NPCs the ability to communicate naturally which is a fascinating tech demo, but gameplay-wise can boil down to being a complicated alternative to pressing a button. As [creikey] discovered, adding this technology into games in a way that feels meaningful takes a new kind of work.

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Weird Lens Allows Light Field Passthrough For VR Headset

August 10, 2023 by Donald Papp 16 Comments

Light Fields are a subtle but critical element to making 3D video look “real”, and it has little to do with either resolution or field of view. Meta (formerly Facebook) provides a look at a prototype VR headset that provides light field passthrough video to the user for a more realistic view of their surroundings, and it uses a nifty lens and aperture combination to make it happen.

As humans move our eyes (or our heads, for that matter) to take in a scene, we see things from slightly different perspectives in the process. These differences are important cues for our brains to interpret our world. But when cameras capture a scene, they capture it as a flat plane, which is different in a number of important ways from the manner in which our eyes work. A big reason stereoscopic 3D video doesn’t actually look particularly real is because the information it presents lacks these subtleties.

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Simple Cubes Show Off AI-Driven Runtime Changes In VR

May 30, 2023 by Donald Papp 6 Comments

AR and VR developer [Skarredghost] got pretty excited about a virtual blue cube, and for a very good reason. It marked a successful prototype of an augmented reality experience in which the logic underlying the cube as a virtual object was changed by AI in response to verbal direction by the user. Saying “make it blue” did indeed turn the cube blue! (After a little thinking time, of course.)

It didn’t stop there, of course, and the blue cube proof-of-concept led to a number of simple demos. The first shows off a row of cubes changing color from red to green in response to musical volume, then a bundle of cubes change size in response to microphone volume, and cubes even start moving around in space.

The program accepts spoken input from the user, converts it to text, sends it to a natural language AI model, which then creates the necessary modifications and loads it into the environment to make runtime changes in Unity. The workflow is a bit cumbersome and highlights many of the challenges involved, but it works and that’s pretty nifty.

The GitHub repository is here and a good demonstration video is embedded just under the page break. There’s also a video with a much more in-depth discussion of what’s going on and a frank exploration of the technical challenges.

If you’re interested in this direction, it seems [Skarredghost] has rounded up the relevant details. And should you have a prototype idea that isn’t necessarily AR or VR but would benefit from AI-assisted speech recognition that can run locally? This project has what you need.

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Prototyping The Prototype

November 29, 2022 by Bryan Cockfield 28 Comments

For basic prototyping, the go-to tool to piece together a functioning circuit is the breadboard. It’s a great way to prove a concept works before spending money and time on a PCB. For more complex tasks we can make use of simulation software such as SPICE. But there hasn’t really been a tool to blend these two concepts together. That’s what CRUMB is hoping to solve as a tool that allows simulating breadboard circuits.

Currently, most basic circuit functions are working for version 1.0. This includes passive components like resistors, capacitors, switches, some LEDs, and potentiometers, as well as some active components like transistors and diodes. There are some logic chips available such as 74XX series chips and 555 timers, which opens up a vast array of circuit building. There’s even an oscilloscope feature, plus audio output to incorporate buzzers into the circuit simulation. Currently in development is an LCD display module and improvements to the oscilloscope.

Besides prototyping, this could be useful for anyone, students included, who is learning about circuits without the need to purchase any hardware. The major downside to this project is that it there doesn’t seem to have a free or trial version, the source is not available, and it’s only for sale on Steam, Apple Store, and Google Play. That being said, there is a forum available for users to discuss problems and needs for future versions, so it’s possible that a community could build up around it. We’ve seen previously non-free versions of circuit simulation software become more open after some time, so it’s not out of the realm of possibility.

Thanks to [Thomas] for the tip!

Several shelf boxes of various widths are held together by brightly-colored plus-sign-shaped connectors.

3D Printed Shelf Connector

November 8, 2022 by Navarre Bartz 15 Comments

Sometimes, you really need a custom shelf. Whether you have a weird-shaped space, weird-shaped stuff, or just want something different, making your own shelving can make your place more like home. The Plus Shelf by [shurly] aims to make building your own shelves a little easier with a 3D printed bracket.

These connectors aren’t just sitting flush against the wood of the shelf. Each end of the + sign actually sits in a 3/8″ drilled recess, giving a more secure fit. The pieces were printed on an Objet and then dyed in various bright shades to really make the shelving pop. The cubbies were assembled with biscuits after cutting down a sheet of plywood to the appropriate sizes. The 45˚ angles around the edges of the cubbies make the whole shelf system that much nicer.

The final shelf has a little wobble, but that’s probably because dying the shelf connectors made them “bendy.” Because of the instability with the friction fit, the shelf connectors were super glued into the shelf boxes. [shurly] hopes that a metal version of the connectors might be able to eliminate these problems in the future.

This shelving system not your cup of tea? Maybe you’d prefer this Vintage Adjustable Shelving Method or this MP3 Player Shelf.