LED Tester Also Calculates Resistor For Target Voltage

December 2, 2023 by Donald Papp 12 Comments

[mircemk] built a slick-looking LED tester with a couple handy functions built in. Not only can one select a target current to put through an LED, but by providing a target voltage, the system will automatically calculate the necessary series resistor. If for example the LED is destined for 14 V, this device will not only show how the LED looks at the chosen current, but will calculate the required resistor to get the same results on a 14 V system.

The buttons on the left control the target current and the voltage of the destination system. Once an LED is connected it will light up and the display indicates the LED’s forward voltage, the LED current, and the calculated series resistor value to obtain the same result at the selected target voltage. It’s a handy way to empirically dial in LED brightness values without needing to actually set up any particular test environment.

On the inside there’s little more than a handful of passive components, an Arduino, an LCD display, and a few buttons. This kind of tool reminds us of the highly clever component testers that hit the hobbyist scene years ago, showing what kind of advanced tricks a modern microcontroller is capable of with the right programming. (Here’s a look at how those work, if you’re interested in some deeper details.)

[mircemk] demonstrates his tool in the video, embedded below. We particularly like the attention he paid to the enclosure, giving it a very functional layout. It goes to show that when designing something, it’s never too early to consider enclosure and UI layout.

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Radio Emissions Over Sunspots Challenge Models Of Stellar Magnetism

December 1, 2023 by Donald Papp 1 Comment

Sustained radio emissions originating from high over a sunspot are getting researchers thinking in new directions. Unlike solar radio bursts — which typically last only minutes or hours — these have persisted for over a week. They resemble auroral radio emissions observed in planetary magnetospheres and some stars, but seeing them from about 40,000 km above a sunspot is something new. They don’t seem tied to solar flare activity, either.

The signals are thought to be the result of electron cyclotron maser (ECM) emissions, which involves how electrons act in converging geometries of magnetic fields. These prolonged emissions challenge existing models and ideas about how solar and stellar magnetic processes unfold, and understanding it better could lead to a re-evaluation of existing astrophysical models. Perhaps even leading to new insights into the behavior of magnetic fields and energetic particles.

This phenomenon was observed from our very own sun, but it has implications for better understanding distant stellar bodies. Speaking of our sun, did you know it is currently in it’s 25th Solar Cycle? Check out that link for a reminder of the things the awesome power of our local star is actually capable of under the right circumstances.

Absolutely Everything About The Coleco Adam, 8-bit Home Computer

November 30, 2023 by Donald Papp 21 Comments

[Thom Cherryhomes] shared with us an incredible resource for anyone curious about the Coleco Adam, one of the big might-have-been home computers of the 80s. There’s a monstrous 4-hour deep dive video (see the video description for a comprehensive chapter index) that makes a fantastic reference for anyone wanting to see the Coleco Adam and all of its features in action, in the context of 8-bit home computing in the 80s.

The Adam aimed to be an all-in-one computer package, targeting a family audience for both education and gaming purposes, with a price target around $600, a pretty compelling pitch.

The video is a serious in-depth look at the Adam, providing practical demonstrations of everything in various scenarios. This includes showcasing commercials from the period, detailing the system’s specs and history, explaining the Adam’s appeal, discussing specific features, comparing advertisement promises to real costs, and giving a step-by-step tutorial on how to use the system. All of the talk notes are available as well, providing a great companion to the chapter index.

Manufactured by the same Coleco responsible for the ColecoVision gaming console, the Adam had great specs, a great price, and a compelling array of features. Sadly, it was let down badly at launch and Coleco never recovered. However, the Adam remains of interest in the retrocomputing scene and we’ve even seen more than one effort to convert the Adam’s keyboard to USB.

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G-code Goes Binary With Proposed New Format

November 28, 2023 by Donald Papp 66 Comments

G-code is effective, easily edited, and nearly ubiquitous when it comes to anything CNC. The format has many strengths, but space efficiency isn’t one of them. In fact, when it comes to 3D printing in particular file sizes can get awfully large. Partly to address this, Prusa have proposed a new .bgcode binary G-code format. You can read the specification of the new (and optional) format here.

The newest version of PrusaSlicer has support for .bgcode, and a utility to convert ASCII G-code to binary (and back) is in the File menu. Want to code an interface of your own? The libbgcode repository provides everything needed to flip .gcode to .bgcode (with a huge file size savings in the process) and vice versa in a way that preserves all aspects of the data. Need to hand-edit a binary G-code file? Convert it to ASCII G-code, make your changes, then flip it right back.

Prusa are not the only ones to notice that the space inefficiency of the G-code file format is not ideal in all situations. Heatshrink and MeatPack are two other solutions in this space with their own strong points. Handily, the command-line tool in libgcode can optionally apply Heatshrink compression or MeatPack encoding in the conversion process.

In a way, G-code is the assembly language of 3D printers. G-code files are normally created when slicing software processes a 3D model, but there are some interesting tricks to be done when G-code is created directly.

Single-piece Tank Chassis Goes Robotic

November 27, 2023 by Donald Papp 8 Comments

[EXTREME3DPRINT] has a new version of their print-in-place tank chassis: the PiPBOT now accepts drop-in motors (in the form of 360° rotation servos), RC receiver, and battery pack to make a functional RC tank platform in no time flat. The design is entirely 3D printed with no supports needed.

This new version is a paid 3D model (and it includes STEP files, thankfully) but the original proof-of-concept print-in-place tank chassis is free and remains a highly clever piece of design that really shows off what is possible when one plays to a 3D printer’s strengths.

A better look at the design’s details can be found on the designer’s website, and a short video demonstrating assembly and operation is embedded below. We particularly like the attachment points on the top of the PiPBOT, which allows for securely mounting all kinds of customized payloads.

Interested in this style of printable RC platform, but want something a little more accessible? If race cars are more your thing, we’d like to also mention the Gamma 2.0 by [Under Engineered]. It’s a print-in-place RC car that needs minimal parts to get rolling and would make an excellent afternoon project.

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Tiny Speaker Busts Past Sound Limits With Ultrasound

November 27, 2023 by Donald Papp 15 Comments

Conventional speakers work by moving air around to create sound, but tiny speakers that use ultrasonic frequencies to create pressure and generate sound opens some new doors, especially in terms of maximum achievable volume.

A new design boasts being the first 140 dB, full-range MEMS speaker. But that kind of volume potential has less to do with delivering music at an ear-splitting volume and more to do with performing truly effective noise cancellation even in a small device like earbuds. Cancelling out the jackhammers of the world requires parts able to really deliver a punch, especially in low frequencies. That’s something that’s not so easy to do in a tiny form factor. The new device is the Cypress, from MEMS speaker manufacturer xMEMS and samples are aiming to ship in June 2024.

Combining ultrasonic waves to create audible sound is something we’ve seen show up in different ways, like using an array of transducers to focus sound like a laser beam. Another thing ultrasonics can do is cause sensors in complex electronics to become unhinged from reality and report false readings. Neato!

3D Printing A Nifty Sphere Without Supports

November 26, 2023 by Donald Papp 6 Comments

[DaveMakesStuff] demonstrates a great technique for 3D printing a sphere; a troublesome shape for filament-based printers to handle. As a bonus, it uses a minimum of filament. His ideas can be applied to your own designs, but his Giant Spiralized Sphere would also just happen to make a fine ornament this holiday season.

Printing two interlocking parts and using vase mode ensures a support-free print that uses a minimum of filament.

The trick is mainly to print the sphere in two parts, but rather than just split the sphere right down the middle, [Dave] makes two hollow C-shaped sections, like a tennis ball. This structure allows the halves to be printed in vase mode, which minimizes filament use while also printing support-free.

Vase (or spiral) mode prints an object using a single, unbroken line of extruded filament. The resulting object has only one wall and zero infill, but it’s still plenty strong for an ornament. Despite its size, [Dave]’s giant ball uses only 220 grams of filament.

A video (also embedded below) shows the design in better detail. If you’d like to experiment, we’ve previously covered how PETG’s transparency is best preserved when 3D printing by using vase mode, slightly overextruding, and printing at a higher temperature to ensure solid bonding between each layer. Continue reading “3D Printing A Nifty Sphere Without Supports” →