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Hackaday Links: February 13, 2022

February 13, 2022 by 31 Comments

If you need evidence that our outwardly peaceful little neck of the solar system is actually a dangerous place, look no further than the 40 newly launched Starlink satellites that were just clobbered out of orbit. It seems that the SpaceX launch on February 3 was ill-timed, as it coincided with the arrival of energetic plasma from a solar storm that occurred a few days before. The coronal mass ejection followed an M-class flare on the Sun, which was aimed just right to hit just as the 49-satellite addition to the Starlink constellation was being released. This resulted in an expansion of the upper atmosphere sufficient to increase drag on the newborn satellites — up to 50% more drag than previous launches had encountered. Operators put the satellites into safe mode, but it appears that 40 of them have already met a fiery demise, or soon will. Space is a tough place to make a living.

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Servo Larson scanner

No LEDs Required For This Servo-Controlled Larson Scanner

February 13, 2022 by 31 Comments

All things considered, it’s pretty easy to get one LED is a strip to light up sequentially, and have it bounce back and forth. Turning that simple animation into a real Larson scanner, with smooth transitions and controlled fade-out, is another thing entirely. And forgetting the LEDs altogether and making a servo-operated Larson scanner is — well, let’s just call it an interesting lesson in hardware abstraction.

The Larson scanner, named after famed TV producer Glen A. Larson for his penchant for incorporating it into shows like Battlestar Galactica and Knight Rider, is actually hard to execute in hardware thanks to the fading tail that follows the lead pixel as it dances back and forth across the display. [Eric Gunnerson] decided to make this and other animation effects easier to achieve with Fade, a custom framework for LED animations that runs on an ESP32.

LED animations are fine, but what about servos? Could Fade be modified to support them? This turned out to be a fairly easy mod thanks to Fade’s architecture and [Eric]’s existing support for non-addressable LEDs via PWM signals. And it was even possible to support more than the 16 PWM channels on an ESP32by adding a UDP connection that puts multiple ESP32s under the control of a central microcontroller.

The video below shows [Eric]’s demo of servo support, with an eight-channel electromechanical Larson scanner. Each “pixel” is a painted ping pong ball swinging back and forth on a hobby servo, and the whole thing sounds just about as awful as you’d expect it to. If you squint just right, the effect looks pretty convincing, but that’s hardly the point. The real story here is [Eric]’s thoughtful architecture, which made the mods easier than starting from scratch.

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Pump Up The Resin

February 13, 2022 by 13 Comments

Sometimes the best ideas are simple and seem obvious after you’ve heard them. [Danny] showed us a great idea that fits that description. He uses a peristaltic pump to move resin in and out of his print bed. (Video, embedded below.) Normally, you remove the tank and pour the resin out into a container. With the pump, you can leave the tank where it is and simply pull the resin through a tube. The process is slower than pouring, but not as messy and doesn’t risk damage to your FEP film.

You can also use the pump like a vacuum to clean up resin. According to [Danny], the biggest value is when working with very large printers. He shows a Peopoly Phenom which has a huge tank compared to the other printers he shows in the video.

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Weather Station Predicts Air Quality

February 13, 2022 by 7 Comments

Measuring air quality at any particular location isn’t too complicated. Just a sensor or two and a small microcontroller is generally all that’s needed. Predicting the upcoming air quality is a little more complicated, though, since so many factors determine how safe it will be to breathe the air outside. Luckily, though, we don’t need to know all of these factors and their complex interactions in order to predict air quality. We can train a computer to do that for us as [kutluhan_aktar] demonstrates with a machine learning-capable air quality meter.

The build is based around an Arduino Nano 33 BLE which is connected to a small weather station outside. It specifically monitors ozone concentration as a benchmark for overall air quality but also uses an anemometer and a BMP180 precision pressure and temperature sensor to assist in training the algorithm. The weather data is sent over Bluetooth to a Raspberry Pi which is running TensorFlow. Once the neural network was trained, the model was sent back to the Arduino which is now capable of using it to make much more accurate predictions of future air quality.

The build goes into quite a bit of detail on setting up the models, training them, and then using them on the Arduino. It’s an impressive build capped off with a fun 3D-printed case that resembles an old windmill. Using machine learning to help predict the weather is starting to become more commonplace as well, as we have seen before with this weather station that can predict rainfall intensity.

3D Printing Rainbows

February 13, 2022 by 18 Comments

[The Action Lab] had a very serious technical problem. His daughter wanted to 3D print sparkly unicorns. But how do you make a 3D print sparkly? Turns out, he had used a diffraction grating before to make rainbow-enhanced chocolate.

The method turns out to be surprisingly simple. Using a diffraction grating as a print bed, puts the pattern on the bottom of the 3D print and — thanks to how a diffraction grating works — the 3D print now works like a grating, too.

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Sticker Brings The Heat

February 13, 2022 by 17 Comments

[Carl] is always looking at making heater plates for PCB reflow and other applications. In his latest video, he shows how he is using thin flexible PCBs with adhesive backs as stickers that get hot. You can find gerber files and design files on GitHub.

You might think that this is a pretty simple thing to do with a flex PCB, but it turns out while the PCB might be flexible, the traces aren’t and so the typical long traces you see in a heater won’t allow the sticker to bend, which is a problem if you want to wrap it around, say, a coffee mug.

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Epoxy Resin Night Light Is An Amazing Ocean-Themed Build

February 12, 2022 by 17 Comments

We’ve all seen those “river” tables where a lovely old piece of tree is filled with some blue resin to create a water-like aesthetic. This project from [smartyleowl] takes that basic idea, but pushes it further, and the result is a beautiful build that is as much a diorama as it is a simple lamp.

First up, an appropriate rough piece of unprepared wood is chosen to create a cliff for the underwater scene. Speckles of UV-reactive blue powder are scattered on to the wood and some little plastic coral and marine plants are stuck down as well. A mold is then constructed around the wood using acrylic. Small whale and diver figurines are dangled in place, and blue resin poured in to complete the underwater scene. Once the resin has hardened, it’s polished to a clear sheen and its edges are nicely beveled. It’s then placed on a illuminated base which lights the scene from below, giving it a somewhat ethereal underwater quality.

It’s not a complicated project by any means, but it’s a great example of the beautiful things one can create with the creative application of colored resin. Producing a lamp that looks this good obviously takes some skill, of course – getting a bubble-free resin pour and a nice shiny finish on the wood isn’t easy. However, there’s no reason you can’t start learning today! Video after the break.

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