Don’t Need A Weatherman To Know Which Way The Wind Blows On Mars

NASA’s latest Mars lander has a very precise weather package, and you can check the daily conditions on Elysium Planitia online. The data however has apparently led to a bit of a mystery. According to Ars Technica, every day at 7AM and 7PM local time, there’s an unexplained atmospheric pressure spike.

The TWINS (Temperature and Wind for InSight) package provided by Spain’s Centro de Astrobiología shows the little spikes regularly since the lander hit the ground in November. They seem to correspond to local sunrise and sunset. Keep in mind, the pressure on Mars is very low — about 1% of Earth’s atmosphere — and scientists have already ruled out instrument problems.

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OptoGlitch Is An Optocoupler Built For Distortion

When we are concerned with the accurate reproduction of a signal, distortion and noise are the enemy that engineers spend a great deal of time eliminating wherever possible. However, humans being the imperfect creatures that we are, we sometimes desire a little waviness and grain in our media – typically of the analog variety, as the step changes of digital distortion can be quite painful. Tired of Instagram filters and wanting to take a different approach, [Patrick Pedersen] built the OptoGlitch – a hardware solution for analog distortion.

Changing the number of samples per pixel varies the accuracy of reproduction of the original image, left.

The concept of operation is simple – pixel values of a digital image are sent out by varying the intensity of an LED, and are then picked up by a photoresistor and redigitized. The redigitized image then bears a variety of distortion and noise effects due to the imperfect transmission process.

In the OptoGlitch hardware, the LED and photoresistor are intentionally left open to ambient light to further allow noise and distortion to happen during the transmission process. A variety of calibration methods are used to avoid the results being completely unrecognizable, and there are various timing and sampling parameters that can be used to alter the strength of the final effect.

It’s possible to introduce distortion more intentionally, too – such as this project that hides metadata in malformed glyphs.

DIY X-Ray Machine Becomes CT Scanner

Once you’ve built your own X-ray machine to take 2D images of the insides of stuff, there’s really only one logical next step: building your own computed tomography (CT) scanner to get 3D reconstructions instead. That’s exactly what [Fran Piernas] has done, and documented over on hackaday.io. While the original X-ray machine build dealt with scary hardware stuff such as high voltage and ionizing radiation, this time it’s the turn of scary mathematics like inverse radon transforms.

The original build, which we wrote about in December, uses a commercial dental X-ray tube and a home-made 65 kV power supply to send X-rays through objects. Transmitted X-rays are viewed using an intensifying screen that converts the rays to visible light. The result is a 2D image similar to that we’re all familiar with.

To create a 3D reconstruction of an object, you need a number of X-ray images taken from different angles. If you’ve ever been unlucky enough to need a medical CT scan, you’ll remember staying motionless in the tunnel while the X-ray apparatus rotated around you. In this build, [Fran] rotates the object instead, using a motor that may have once been part of a microwave oven (one of those “mystery motors” we all have laying around). The required sequence of images is simply obtained by recording video of the X-ray screen while the motor rotates the object.

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Retrotechtacular: How Not To Design With Transistors

Consider the plight of a mid-career or even freshly minted electrical engineer in 1960. He or she was perched precariously between two worlds – the proven, practical, and well-supported world of vacuum tube electronics, and the exciting, new but as yet unproven world of the transistor. The solid-state devices had only started making inroads into electronic products relatively recently, and mass production techniques were starting to drive the cost per unit down enough to start including them in your designs. But, your company has a long history with hot glass and no experience with flecks of silicon. What to do?

To answer that question, you might have turned to this helpful guide, “Tubes and Transistors: A Comparative Guide” (PDF link). The fancy booklet, with a great graphic design that our own [Joe Kim] would absolutely love, was the product of the Electron Tube Information Council, an apparently defunct group representing the interests of the vacuum tube manufacturers. Just reading the introduction of this propaganda piece reveals just how worried companies like RCA, General Electric, and Westinghouse must have been as the 1950s turned into the 1960s. The booklet was clearly aimed directly at engineers and sought to persuade them of the vacuum tube’s continued relevance and long-term viability. They helpfully explain that tubes are a reliable, proven technology that had powered decades of designs, and that innovations such as heaterless cathodes and miniaturization were just around the corner. Transistors, we’re told, suffer from “spread of characteristics” that correctly describes the state of materials engineering of silicon and germanium at the time, a thornier problem than dealing with glass and wires but that they had to know would be solved within a few years.

With cherry-picked facts and figures, the booklet makes what was probably in 1960 a persuasive case for sticking with tubes. But the Electron Tube Information Council was fighting a losing battle, and within a decade of swamping engineers with this book, the industry had largely shifted to the transistor. Careers were disrupted, jobs disappeared, and fortunes were lost, but the industry pressed forward as it always does. Still, it’s understandable why they tried so hard to stem the tide with a book like this. The whole PDF is worth a look, and we’d love to have a hard copy just for nostalgia’s sake.

Thanks to [David Gustafik] for the tip.

Badge.Team: Badges Get A Platform

Electronic conference badges are now an accepted part of the lifeblood of our community, with even the simplest of events now sporting a fully functional computer as an eye-catching PCB on a lanyard. Event schedules and applications are shipped on them, and the more sophisticated ones have app libraries and support development communities of their own.

The trouble is that so often those badges fail to live up to their promise, and one reason behind that stems from the enormity of the task facing a badge team when it comes to firmware for a modern badge. There is some fascinating news from the Netherlands  that might reduce some of those firmware woes though, badge.team is a freshly-launched project that provides a ready-made badge firmware with the promise of both stability and long-term support. If you’re making a badge, or even a one-off device using the ESP32, this is a project worth checking out.

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Love Inspires CD Player Hack

The heart is an impressive piece of hardware. It’s a rare pump that runs continuously for over 80 years in some cases. It’s also, for some reason or other, become a common human symbol of love and affection. In this vein, [Deepak Khatri] has built a beating electronic heart out of basic, readily available components.

The heart of the build (pun intended) is a lens assembly salvaged from a CD player, which uses a coil and permanent magnet to move the lens in order to read across a disc. In this case, the coil is instead fed pulses from an astable multivibrator circuit built with a hacker favourite, the 555 timer IC. It’s all assembled on a breadboard, which is a great way to build such projects that rely on experimentation through the swapping of component values.

The end result is rather satisfying. [Deepak] has also experimented with an Arduino driven version with a slightly different rhythm.

We haven’t seen too many projects using optical drive lens assemblies, but we’re sure there must be other applications. If you end up using one to agitate biological samples or build an awesome laser projector, be sure to hit up the tips line. Video after the break.

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The Woeful World Of Worldwide E-Waste

How large is the cache of discarded electronics in your home? They were once expensive and cherished items, but now they’re a question-mark for responsible disposal. I’m going to dig into this problem — which goes far beyond your collection of dead smartphones — as well as the issues of where this stuff ends up versus where it should end up. I’m even going to demystify the WEEE mark (that crossed out trashcan icon you’ve been noticing on your gadgets), talk about how much jumbo jets weigh, and touch on circular economies, in the pursuit of better understanding of the waste streams modern gadgets generate.

Our lives are encountering an increasing number of “how do I dispose of this [X]” moments, where X is piles of old batteries, LCDs, desktop towers, etc. This leads to relationship-testing piles of garbage potential in a garage or the bottom of a closet. Sometimes that old gear gets sold or donated. Sometimes there’s a handy e-waste campaign that swings through the neighborhood to scoop that pile up, and sometimes it eventually ends up in the trash wrapped in that dirty feeling that we did something wrong. We’ve all been there; it’s easy to discover that responsible disposal of our old electronics can be hard.

Fun fact: the average person who lives in the US generates 20 kg of e-waste annually (or about 44 freedom pounds). That’s not unique, in the UK it’s about 23 kg (that’s 23 in common kilograms), 24 kg for Denmark, and on and on. That’s quite a lot for an individual human, right? What makes up that much waste for one person? For that matter, what sorts of waste is tracked in the bogus sounding e-waste statistics you see bleated out in pleading Facebook posts? Unsurprisingly there are some common definitions. And the Very Serious People people at the World Economic Forum who bring you the definitions have some solutions to consider too.

We spend a lot of time figuring out how to build this stuff. Are we spending enough time planning for what to do with the gear once it falls out of favor? Let’s get to the bottom of this rubbish.
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