Introducing The Periodic Table Of US Electrical Receptacles

September 16, 2026 by 3 Comments

Although things may seem simple on the North American grid as an end-user if you limit yourself to just 120 VAC and NEMA 1-15 and 5-15 connectors, there is a veritable zoo of different voltages and receptacles out there in the NEMA connector catalogue. Recently [Practical Engineering] decided to not only take a look at how many of these defined standards are actually used, but also put them in a nice periodic table style graphic.

Responsible for these standards is the National Electrical Manufacturers Association (NEMA), which as the name says is a collection of manufacturers. Founded in 1926, this US trade association also affects outlet standards in countries like Canada, Mexico, Japan and so on. The caveat here is that compatibility between e.g. a similar looking Japanese 1-15-style plug and a US 1-15 outlet is not guaranteed, even if you ignore voltage and grid frequency differences.

In an ideal world everyone would agree on a set of reasonable connector designs and we could move on, but we live in a world where even today designing your own national connector instead of picking something like the ubiquitous Type F is considered to be reasonable. At least it’s not susceptible to the ‘penny challenge‘ flaw that the NEMA 5-15 connector suffers from, but that’s small comfort.

NEMA connectors are also unique in that they are often polarized, while Type E/F and others rarely are, putting the onus of dealing with AC polarity on the device. This already shows why the NEMA connector diversity exists, as this trade association wanted to have specific connectors for different polarities, different current limits and also the nearly half a dozen of different voltages commonly used throughout the US.

This ‘one connector for a specific combination’ approach means that quite a few of them are not really used in real life, though from a European perspective where you deal with Type C (‘euro plug’) and Type E/F (‘Schuko’)  on ~240 VAC and triple-phase 440 VAC connectors if you run a heavy machine shop or want to fast-charge an EV at home, it’s still a bewildering number of active combinations.

Continue reading “Introducing The Periodic Table Of US Electrical Receptacles” →

A man in white and black railroad overalls rides a short one wheel platform suspended between two rail wheels on a steel axle.

Ride The Rails On A OneWheel

September 16, 2026 by 13 Comments

The US has tons of abandoned rail, especially in urban environments, so it seems a shame to let it go to waste. [OneWheel] decided to modify one of their boards to ride the rail behind their office.

The stock OneWheel frame was sectioned and CNC cut mounts were placed in the center to raise the motor above the deck. Steel rail wheels sourced from eBay were then attached to an axle run through where the original wheel was mounted in the center. The motor housing was turned down on a lathe for better clearance, and then a bike sprocket was attached to chain drive the train axle.

While not everyone has a hydraulic press and a CNC for that professional look, we don’t see any reason you couldn’t bodge something similar together at home. Be sure to watch [Bradley Gawthrop]’s Supercon talk on the Personal Electric Vehicle Revolution for some ideas on what you need to get started.

Dream of riding the rails yourself? You should checkout this tiny rail riding pod car or this more minimalist example. Definitely make sure you’re riding on a truly abandoned line or get a rail warrant though!

Continue reading “Ride The Rails On A OneWheel” →

A 3D Rasterizer For Embedded Devices

September 16, 2026 by 6 Comments

Once upon a time, doing graphics on a microcontroller was challenging, to say nothing of the concept of going into three dimensions. But modern microcontrollers are far more powerful, and you might find yourself wanting to do all sorts of graphical wizardry with one. To that end, you might find Jet useful.

Created by [CubeCoders], Jet is a compact 3D rasterizer built for modern chips like the ESP32 and STM32. It’s dependency free, relatively tiny, and is written in C++17 with an eye towards working well on memory-limited platforms. It runs entirely in software, uses only integer arithmetic, and is built around 16-bit RGB565 color — intended to make it easy to use with parts like the ST7796, ILI9488, and other similar displays interfaced via SPI.

As a point of reference, on a ESP32-S3 Jet can render around 650 on-screen triangles (post-culling) at 60 frames per second on a 480×320 display, or 1300 triangles at 30 FPS. The developers note that 3D performance lands somewhere between the Sega 32X and Sega Saturn — not bad for a microcontroller you can buy for under $20. The Wipeout-like demo shows off the capabilities of Jet rather fantastically, we think.

You’d be foolish to expect your next microcontroller project to render Crysis. However, if you want some retro 3D graphics for your next ESP32-based build, you might just consider exploring what Jet can do for you.

Continue reading “A 3D Rasterizer For Embedded Devices” →

FLOSS Weekly Episode 882 With OSADL: Better Together

September 16, 2026 by No comments

This week Jonathan chats with Jan Altenberg of the Open Source Automation Development Lab, a cooperative of nerds that care about Linux and Open Source! Jan and OSADL helped push Real Time Linux across the finish line, are looking at safety critical hardening, and general cooperating to make Open Source and Industry work better together.

Continue reading “FLOSS Weekly Episode 882 With OSADL: Better Together” →

A Cheap And Easy Control Screen For Home Assistant

September 16, 2026 by 5 Comments

Home Assistant is a great way to rig up and manage your smart home and its many and varied devices. You can of course control the system from your smartphone or a computer, but you might like to have a dedicated interface too. In that regard, [Max Gramser]’s project may come in handy.

At heart, it’s a Home Assistant control screen that you can lay out yourself. It’s intended to run on ESP32 hardware. Most specifically, it’s built to run on the Cheap Yellow Display which combines an ILI9341 display with an XPT2046 resistive touchscreen, or a Guition ESP32-S3-4848S040, which has a ST7701S RGB display combined with a capacitive GT911 touchscreen. You merely need to load the firmware on to one of these units, and you’ll have a configurable and customizable touchscreen interface for your own Home Assistant setup.

The GUI used is clean, attractive, and flexible. You can have it display weather, time, and date widgets, populate the screen with buttons for activating lights and appliances, or even command a compatible robot vacuum. Whatever you might want to do with Home Assistant, you can almost certainly create a quick control for it on the display so it’s always on the wall, ready to go when you need it.

If you’ve always dreamed of your house having a futuristic control panel like we used to dream of in the 1980s, well… now it’s a reality. You just need to drop a few bucks on a touchscreen ESP32 rig and you’re ready to go. There’s plenty more you can do with a Cheap Yellow Display, too, so don’t hesitate to check out some of the previous builds we’ve featured with it!

Heat Domes: Meet The Quiet And Oppressive Take On The Thunderdome

September 16, 2026 by 24 Comments

One of the nice things about the weather is that even if it’s bad right now, it’ll definitely be changing soon and maybe even for the better. There is one exception to this rule, however, and that comes in the form of heat domes, which are weather systems whereby a region of air becomes isolated from the surrounding systems. This creates effectively a greenhouse, with hot air remaining trapped and moisture unable to get in.

Although until recently not very common, this weather phenomenon poses a major challenge to any flora and fauna that finds itself trapped in a heat dome. With nights being about as hot and stifling as the days with their blue skies unbroken by any cloud cover and no rain for potentially weeks on end, it poses severe hydration, cardiovascular, and other challenges to any affected lifeforms.

Continue reading “Heat Domes: Meet The Quiet And Oppressive Take On The Thunderdome” →

Full-Color Looks Great On 3D Printed Sliding Puzzles

September 16, 2026 by 4 Comments

[Angus] of [Maker’s Muse] shows off both a parametric, print-in-place sliding puzzle design he created, and the results of UV printing full-color designs on the same. The results look beautiful, and there was a whole lot of trial and error involved in the process.

The design includes a pop-out tile, which can be re-inserted to a finished puzzle.

Creating a good print-in-place sliding puzzle depends a lot on tolerances. Today’s 3D printers are much more capable in this regard than they were ten or so years ago, but getting the right feel to the pieces was still a long learning process. It’s not at all easy to get all the different characteristics in the right balance. On one hand, if the pieces are too tight they won’t slide easily. But if they are too loose, the puzzle can bind because the pieces have too much play. It may also flex enough to pop apart. And of course, the shape of the pieces and their mating surfaces are constrained to angles and shapes that 3D print reliably. [Angus] persevered and succeeded, and shows off everything from cute 3 x 3 units to a massive scaled-up 11 x 11 puzzle, printed on his Prusa XL.

Getting the color onto the print is the work of a desktop UV ink printer, the same model our own Tom Nardi had a hands-on look at last year. [Angus] shows how printing a single color image onto the puzzle is pretty easy and looks great, but what’s even better is a textured relief image with some real tactile depth to it. Expect a lot more work to do for that, because thick layers of ink gum the puzzle up with overspray unless one avoids printing over the gaps in the tiles.

Watch both the puzzles and the color printing in action in his video, embedded just below.

Continue reading “Full-Color Looks Great On 3D Printed Sliding Puzzles” →