A Look At 3D Printed Professional LED Signage

January 27, 2024 by Lewin Day 30 Comments

Customer perception is everything when you’re running a business, particularly in retail. High-quality signage can go a long way into creating a good impression in this respect. [king process] decided to show us how professional-grade LED signage is made in a Korean shop that specializes in the work.

The signs we’re shown are custom builds that are matched to the shape of a company’s logo. No rectangular printed lightboxes here, this is fully custom stuff. To that end, a 3D printer is the perfect tool for the job, as it lets the shop produce signs in any shape desired with no need for custom tooling.

The 3D printers that build up the signs have seriously large build volumes, though more so in the X and Y dimensions rather than the Z. We see a whole fleet of printers working away to allow multiple signs to be produced quickly. The first step is to produce the outline of a sign, which serves as a base for the build. Cavities in the sign are then filled with a translucent silicone solution to act as diffuser material. Once cured, these various sections are colored by hand as required. LED strips are then installed on a backing plate to illuminate the sections of the sign.

The final result is a sign with clean, bright glowing lines. It’s vaguely reminiscent of a neon sign, but without any of the limitations of the glass tubes influencing how it looks. It’s also neat to see the techniques a professional shop uses to make things right the first time, without dinging or marring any of the parts along the way.

Indeed, it seems the classical neon sign is, these days, bested by a variety of alternative technologies.

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A General-Purpose PID Controller

January 27, 2024 by Bryan Cockfield 19 Comments

For those new to fields like robotics or aerospace, it can seem at first glance that a problem like moving a robot arm or flying an RC airplane might be simple problems to solve. It turns out, however, that control of systems like these can get complicated quickly; so much so that these types of problems have spawned their own dedicated branch of engineering. As controls engineers delve into this field, one of their initial encounters with a control system is often with the PID controller, and this open source project delivers two of these general-purpose controllers in one box.

The dual-channel PID controller was originally meant as a humidity and temperature controller and was based on existing software for an ATmega328. But after years of tinkering, adding new features, and moving the controller to an ESP32 platform, [knifter] has essentially a brand new piece of software for this controller. Configuring the controller itself is done before the software is compiled, and it includes a GUI since one of the design goals of the project was ease-of-use. He’s used it to control humidity, temperature and CO2 levels in his own work at the University of Amsterdam, but imagines that it could see further use outside of his use cases in things like reflow ovens which need simple on/off control or for motors which can be controlled through an H-bridge.

The PID controller itself seems fairly robust, and includes a number of features that seasoned controls engineers would look for in their PID controllers. There are additionally some other open-source PID controllers to take a look at like this one built for an Arduino, and if you’re still looking for interesting use cases for these types of controllers one of our favorites is this PID controller built into a charcoal grill.

In Praise Of “Simple” Projects

January 27, 2024 by Elliot Williams 9 Comments

When I start off on a “simple” project, experience shows that it’s got about a 10% chance of actually remaining simple. Sometimes it’s because Plan A never works out the way I think it will, due to either naivety or simply the random blockers that always get in the way and need surmounting. But a decent percentage of the time, it’s because something really cool happens along the way. Indeed, my favorite kind of “simple” projects are those that open up your eyes to a new world of possibilities or experiments that, taken together, are nothing like simple anymore.

Al Williams and I were talking about water rockets on the podcast the other day, and I realized that this was a perfect example of an open-ended simple project. It sounds really easy: you put some water in a soda bottle, pressurize it a bit with air, and then let it go. Water gets pushed down, bottle flies up. Done?

Oh no! The first step into more sophistication is the aerodynamics. But honestly, if you make something vaguely rocket-shaped with fins, it’ll probably work. Then you probably need a parachute release mechanism. And then some data logging? An accelerometer and barometer? A small video camera? That gets you to the level of [ARRO]’s work that spawned our discussion.

But it wasn’t ten minutes into our discussion that Al had already suggested making the pressure vessel with carbon fiber and doctoring the water mix to make it denser. You’d not be surprised that these and other elaborations have been tried out. Or you could go multi-stage, or vector-thrust, or…

In short, water rockets are one of those “simple” projects. You can get one basically working in a weekend day, and then if you’re so inclined, you could spend an entire summer of weekends chasing down the finer points, building larger and larger tubes, and refining payloads. What’s your favorite “simple” project?

A Hydroelectric Dam, Built Out Of LEGO

January 27, 2024 by Lewin Day 10 Comments

Hydroelectric dams are usually major infrastructure projects that costs tens of millions of dollars to construct. But they don’t have to be — you can build your own at home, using LEGO, as [Build it with Bricks] demonstrates!

The build is set up in an aquarium with a pump, which serves to simulate flow through a river system. The LEGO dam is installed in the middle of the aquarium, blocking the flow. It has a sluice gate in the lower section to feed water to a turbine for power generation. The gate is moved via a rack and pinion. It’s driven by a LEGO motor on a long shaft to keep it a safe distance from the wet stuff. The dam also gets a spillway to allow for overflow to be handled elegantly. Meanwhile, a second motor acts as a generator, fitted with a fairly basic turbine.

Hilariously, the first build fails spectacularly as the hydrostatic pressure of the water destroys the LEGO wall. A wider base and some reinforcements help solve the problem. There’s a better turbine, too. It’s all pretty leaky, but LEGO was never designed to be water tight. As you might imagine, it doesn’t generate a lot of power, but it’s enough to just barely light some LEDs.

It’s a fun way to learn about hydroelectric power, even if it’s not making major amounts of electricity. Video after the break.

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Soldering Holder From Old Lamps

January 27, 2024 by Al Williams 11 Comments

One of the neat things about 3D printing is that you can create custom parts to fit salvage to use in projects. For example, [Willyrags05] took a lamp — looks like something you might find at a resale shop — harvested the gooseneck tubes from it.

Before 3D printing, it would have required ingenuity to cobble together some way to secure base and add a clamp to the other end. A blob of epoxy wouldn’t look as nice and not everyone can machine nice round adapters. Don’t have the same lamp? No problem. You can easily modify the adapters or create new ones to print for yourself.

Outside of the 3D printer, the project required a way to cut the ends off the tubes. [Willy] used a chop saw, but it seems like a hacksaw or bolt cutters might work. Neatness doesn’t count since the printed adapter will cover all sins.

Once the tubes are ready, some glue, magnets, and alligator clips (why aren’t these crocodile clips?) complete the assembly. [Willy] mentions he needs stronger magnets, but we might have been tempted to make the bases wider with depressions for multiple magnets. This is probably a project you won’t duplicate exactly, but it may well inspire you to upcycle that old lamp in the attic.

Maybe you prefer a vise-like holder. There are plenty of other choices.

A ZX Spectrum Raytracer, In BASIC

January 26, 2024 by Dave Rowntree 12 Comments

[Gabriel Gambetta] knows a few things about ray tracers, being the author of Tiny Raytracer, a raytracer written in just 912 bytes of JavaScript. As a long-time fellow sufferer of the UK-designed ZX Spectrum, could these two love affairs be merged? Could the Tiny Raytracer fit on the ZX Spectrum? In BASIC? The answer is an affirmative, albeit with our beloved speccy’s many limitations.

Ray tracing with only 15 primary colours

The story starts with [Gabriel]’s Computer Graphics From Scratch (CGFS) raytracer algorithms and an existing code base that was ported to the ZX Spectrum’s very limited BASIC dialect, using VSCode for editing, BAS2TAP to generate a tape image file (essentially an audio track) and executed with FUSE. With the toolchain sorted, [Gabriel] adds just enough code to deal with the ray intersection equations of a sphere, and renders a three-sphere scene to a 32×22 pixel colour image, taking a mere 15 minutes of runtime. Fellow sufferers will remember the spectrum had a 32×22 block attribute array (or colour array) with two colour values for foreground and background pixels. Each attribute block contains 8×8 pixels, each of which could be foreground (on) or background (off.) The next stage was then to expand the code to handle pixels as well as blocks, by simply expanding the raytracing to the full 256×176 resolution, and for each block simply determine the two most common colours, and run with those for the whole block. It sort of works, in a very spectrum-esq ‘attribute clash’ kind of fashion.

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Nanotechnology In Ancient Rome? There Is Evidence

January 26, 2024 by Kristina Panos 47 Comments

Anything related to nanotechnology feels fairly modern, doesn’t it? Although Richard Feynman planted the seeds of the idea in 1959, the word itself didn’t really get formed until the 70s or 80s, depending on who you ask. But there is evidence that nanotechnology could have existed as far back as the 4th century in ancient Rome.

That evidence lies in this, the Lycurgus cup. It’s an example of dichroic glass — that is, glass that takes on a different color depending on the light source. In this case, the opaque green of front lighting gives way to glowing red when light is shining through it. The mythology that explains the scene varies a bit, but the main character is King Lycurgus, king of Edoni in Thrace.

So how does it work? The glass contains extremely small quantities of colloidal gold and silver — nanoparticles of gold to produce the red, and silver particles to make the milky green. The composition of the Lycurgus cup was puzzling until the 1990s, when small pieces of the same type of glass were discovered in ancient Roman ruins and analyzed. The particles in the Lycurgus cup are thought to be the size of one thousandth of a grain of table salt — substantial enough to reflect light without blocking it.

The question is, how much did the Romans know about what they were doing? Did they really have the means to grind these particles into dust and purposely infuse them, or could this dichroic glass have been produced purely by accident? Be sure to check out the videos after the break that discuss this fascinating piece of drinkware.

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