Voicebox FX Is A Blueprint For CircuitPython I2S Audio

September 5, 2026 by Donald Papp 1 Comment

[Adafruit]’s Voicebox FX gadget is a fun, well-documented project that serves another useful purpose: being a fantastic reference design for audio on CircuitPython, with I²S audio components. Be sure to check it out if you have a project that involves any of that and could use a few pointers, or if you just want to jog a few ideas loose.

I²S (Inter-IC Sound) is a protocol aimed squarely at moving audio data between components as digital signals. Our own [Jenny List] can tell you everything you need to know about I²S. It’s a relatively simple interface that is not at all fussy about actually being used for audio, and that has led to it being put to some unusual uses.

The Voicebox FX uses an I²S microphone, an I²S amplifier, and an RP2350 microcontroller to record and play sound as well as offer a variety of effects controlled by physical inputs. It’s all wrapped up in a slick 3D printed case, and while it’s a fantastic reference design, it looks like a fun toy in its own right.

Continue reading “Voicebox FX Is A Blueprint For CircuitPython I2S Audio” →

Parchment Paper Paired With 3D-Printed Grid Gives A Nice Glow

September 4, 2026 by Donald Papp 14 Comments

This custom enclosure for a 64×64 RGB LED matrix by [Davisan1001] not only provides a mount point for a Raspberry Pi, but presents a clean and smooth face with square pixels thanks to a 3D-printed grid, some parchment paper, and a sheet of clear plastic.

The first clever thing in this design is the way [Davisan1001] created the grid that acts as a light blocker for each LED in the matrix, preventing light from “spilling” over into its neighbors. Instead of designing the grid from scratch, the solution was just to leverage slicer settings. By printing a flat square with a grid pattern infill and zero solid top and bottom layers, the slicer creates the grid all by itself. A little trial and error was required to get the spacing just right, but it seems to have worked out fine. We’re not sure it’s better than designing a grid in CAD, but it was certainly a clever way to avoid having to do so.

[Davisan1001] also struggled to find an effective and economical solution for a diffuser. Certainly, high-quality diffuser films are available for sale, as are specialty acrylic sheets, but surely there was some household DIY option to do the trick. A sheet of plain white paper blocks too much light. Wax paper handles poorly, and off-angle viewing is poor. The sweet spot was parchment paper.

Parchment paper is commonly used in baking and is thin, easy to handle, flat and even in color, and just opaque enough to act as an effective diffuser while still transmitting enough light to not impede clarity. Cover the LED matrix with the 3D-printed grid, lay parchment paper over that, cover with a sheet of clear plastic, and the job is done.

Light diffusion can be tricky to get just right in a DIY project, and what works for one application won’t necessarily work for another. Our community had loads of suggestions on different solutions, so consider this one more idea to try the next time you have a project that calls for it.

3D Printed Cubes Provide Passive Cooling

September 4, 2026 by Donald Papp 31 Comments

Passive evaporative cooling has been used for centuries to reduce temperatures. Heat is drawn off as water evaporates, which in turn reduces temperature. The more efficiently this process happens the greater the temperature differential, and that’s exactly what the 3D-printed structure pictured above aims for. Created at the Graz University of Technology in Austria, the cubes noticeably reduce surrounding air temperature thanks to their careful construction. As long as they’re kept wet, anyway.

The key is exposing the maximum amount of water to the maximum amount of airflow, and there are two ways the prototype cooling wall — which is 3D printed from a special clay mixture — does this.

First, the macro design of the 3D-printed blocks maximizes surface area. If the cube in the image above looks familiar, that’s because it’s the gyroid infill pattern. Gyroid is a porous pattern with no “dead ends” or closed sections, and the fact that it 3D prints cleanly with no supports also makes it an ideal structural candidate.

The second advantage is the clay used for the blocks themselves. Firing clay at a low temperature keeps it porous, but this particular mixture goes even further. It’s a bio-inspired formulation of clay, fungal mycelium, and wood chips. After printing, the cubes are fired and the fungus and wood chips burn away, leaving a network of thread-like capillaries with occasional larger pockets throughout.

The result is a porous ceramic cube with a massive evaporative surface area relative to its size. A practical test in a hot attic showed the air near a water-laden cube was nearly 7º C lower, a noticeable difference.

A home experimenter might not have access to fancy mycelium-laced clay mixtures, but it still strikes us as something that could be tried out at home. After all, clever hackers have successfully made DIY versions of passive cooling paint.

Take Tool Photo, Generate Custom Gridfinity Bin

September 4, 2026 by Donald Papp 21 Comments

What if the organization and storage benefits of tool shadowing could be had and improved with a modular, semi-automated process? Tracefinity attempts that by generating custom Gridfinity bins from photos of tools, and has quite a few nifty features that are worth a look.

Maintaining a library of tools makes it easy to create project-based custom layouts.

The basic workflow is this: place one or more tools on a sheet of paper, take a photo, then upload the photo and have the system trace and save the outline and add it to a private tool library. When one is ready to create some bins, use the library of saved tool outlines to generate custom Gridfinity layouts.

If you’re unfamiliar, Gridfinity is a modular system of standardized bins and baseplates designed with 3D printing in mind, making it an ideal match for highly-customized organization tasks and a particularly natural fit for a tool-tracing system like this one.

The idea of taking a photo of a tool and generating a custom bin is a compelling one, and a couple years ago we covered a project that did just that. Tracefinity seems like a natural evolution of the idea, and includes handy features like easy design adjustments, optional magnet holes, and we really like the concept of a tool library from which individual tools are scanned once then later selected to create specific, project-based layouts.

Tracefinity takes advantage of new software capabilities like machine learning to improve and streamline the tracing process, but that doesn’t mean it relies on any external services. It can be entirely self-hosted and by default uses a local, CPU-friendly object detection model for tool tracing. There is an option to provide a API key to use Google Gemini instead, but it’s not required. It can come in handy for especially complex tool outlines or dealing with non-ideal source photos, however.

Corners Lifting On 3D Prints? Guide Gives Prevention Tips

September 3, 2026 by Donald Papp 17 Comments

Large prints have a risk of warping, by which we mean corners can lift off the print bed as the object sort of curls inward on itself. It’s not always due to poor filament quality or an unclean build plate. Sound like something you’ve dealt with? Check out this handy roundup to understand why it happens, and learn ways to prevent it.

A big flat area with sharp corners is susceptible to warping. Breaking the footprint into a grid pattern helps distribute stresses instead of concentrating them at the corners.

The reason some objects have trouble while others don’t is physics. Deposited plastic shrinks ever so slightly as it cools, and some shapes — like wide, flat surfaces with sharp corners — are worse for this than others. This sort of problem is what the guide addresses with a number of techniques.

Some are simple, like turning on brims which increases an object’s footprint. This increased surface area offers more adhesion, but also increases heat transfer from the print bed into the model, slowing the cooling process. Thinner walls and an altered infill pattern is another option. Other techniques are more complex.

The most effective methods involve modifying the model itself to reduce or eliminate stress points. One such method is to break the model’s footprint into multiple zones with a shallow grid. Instead of one big flat bottom, the object has multiple smaller ones. Because big flat areas are more susceptible to warping than small ones, turning the bottom into a grid pattern helps spread those stresses out and prevent lifting.

If you design your own models, you’ll find several design tips worth keeping in mind. It’s always smart to practice good DFM (Design For Manufacturability) which means taking 3D printer strengths and weaknesses into account when designing an object. In this case, it can help prevent print failures. Good DFM can also make parts much, much stronger just by designing in the right features.

Reactive Heat And Wind Come To VR, Thanks To Smart Plugs

September 1, 2026 by Donald Papp 6 Comments

Want to feel the heat of nearby fire, explosions, or radiation? Or even just the gentle warmth and breeze of a sunny day in the wasteland? If you said yes, you’re in luck because [GingasVR] created an immersive heat mod and wind mod for the VR version of Fallout 4 that leverages economical smart outlets and game scripting to do just that.

The heart of this hack lies in gluing two things that don’t normally go together. In this case [GingasVR] uses a bit of game scripting to control TP-Link HS100 or HS110 Smart Plugs, allowing virtual events to control things in the real world. An ordinary fan in a smart plug creates wind on demand, and heat comes from a 250 watt infrared heat lamp aimed toward the player. For heat, an IR lamp is the way to go because it’s highly directional, can be quickly cycled on and off, and responds rapidly.

The range of immersive effects opened up by this is pretty compelling. Sunny weather yields a gentle glow of warmth, but nearby explosions cause a short full-blast flash of heat. The heat of fires also grows and fades with proximity. This being Fallout, [GingasVR] ensured local radiation has an effect on the heat level as well. Want to see it in action? She briefly explains around the 3:20 mark in this video.

Using ordinary appliances and smart plugs controlled from within VR to modify environmental effects is clever, and we like that it’s entirely nondestructive. The scripting mod for the game doesn’t overwrite any game files, and the hardware used requires no modifications.

Not into Fallout? [GingasVR] has similar Skyrim VR mod, if that’s more your bag. And if you’re modding Skyrim VR anyway, consider adding a “meditation device” headband to make magic respond to your actual state of mind.

Low(er)-Cost Humanoid Robot Leverages DIY Actuators

August 30, 2026 by Donald Papp 11 Comments

Humanoid robots, even scaled-down ones, tend to be expensive. The Berkeley Humanoid Lite offers a more accessible and economical option by centering the design around 3D printed actuators that make up the bulk of the robot’s frame.

The actuators are made by combining motors with printed cycloidal gearboxes and an embedded magnetic encoder. They’re modular, so even if one has no desire to recreate the whole robot it might be worth checking out the actuator design details to see if they might be useful in some other way.

The Berkeley Humanoid Lite isn’t a finished product so much as an open-source, easily customized reference design. The GitHub repository contains everything one might need, and you can watch some basic demonstrations, including VR-driven teleoperation, in the video embedded below.

At a total hardware cost of under $5,000 USD it’s still expensive, but much more economical than other humanoid robots, open-source or not. As mentioned, even if one doesn’t plan to build one, the modular actuator design is worth keeping in mind for other purposes.
Continue reading “Low(er)-Cost Humanoid Robot Leverages DIY Actuators” →