3D Printed Sensor For Finding Wind Direction And Likely Much More

January 11, 2022 by Ryan Flowers 35 Comments

Have you ever wondered how an electronic wind vane translates a direction into a unique signal? It seems as though it might be very complicated, and indeed some of them are. [martinm] over at yoctopuce.com has an excellent writeup about measuring wind direction using just a single, easily printed disk and some phototransistors.

Commercial weather vanes often use complicated multi-tracked disks with magnets and reed switches, conductive traces and brushes, or some other means of getting a fine resolution. Unfortunately some of these are prone to wear or are otherwise more complicated than they need to be.

What makes [martinm]’s solution unique is that they have applied previous research on the subject to a simple and durable 3d printed wind vane that looks like it’ll be able to handle whatever global warming can throw at it. The encoder’s simplicity means that it could likely be used in a large number of applications where low resolution position sensing is more than enough- the definition of a great hack!

Adding more tracks or even more disks would enable higher resolution, but the 12 degree resolution seems quite good for the purpose. Such a neat wind vane design will surely be welcome if you want to 3d print your own weather station. Thanks to [Adrian] for the great tip!

Honda Ignition Coils Sing The Song Of Their People

January 11, 2022 by Tom Nardi 7 Comments

High-voltage experimenters have been using automotive ignition coils to generate impressive sparks in the home lab for decades, and why not? They’re cheap, easily obtainable, and at the end of the day, producing sparks is literally what they’re designed to do. But that doesn’t mean there isn’t room for improvement.

In his latest Plasma Channel video [Jay Bowles] revisits this classic experiment, bringing to bear the considerable high-voltage experience he’s gained over the last several years. Building on an earlier setup that used a single Honda ignition coil, this new dual-coil version can produce up to 60,000 volts and is driven by a cleaner and more reliable circuit based on the iconic 555 timer. A pair of potentiometers on the front of the driver can adjust its square wave output from 1 to 10 kilohertz manually, while a commercial Bluetooth audio receiver tied into the 555 circuit allows the output to be modulated by simply playing audio from a paired device.

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Electronic Drum Toy Built From Scratch

January 11, 2022 by Lewin Day 9 Comments

Drum kits used to be key to any serious band, however, these days, much of our music is created on computer or using a drum machine instead. [spanceac] has built a simple example of the latter, using a microcontroller to build a basic sample-based drum toy.

The brains of the operation is the STM32F100VET6B, which comes complete with a 12-bit DAC for outputting sound. It’s also got a healthy 512 KB of flash, enabling it to store the drum samples onboard without the need for extra parts. Samples are stored at a sample rate of 22,050 Hz in 16-bit resolution – decent quality for a tiny little build, even if the DAC chops that back down to 12-bits later.

[spanceac] was sure to code proper mixing into the drum machine, so that triggering a second sample doesn’t stop the first one playing. With a kick, snare, two toms, and crash and ride samples onboard, there’s plenty to get a solid beat going on the kit. It’s all built up on a small PCB with tactile buttons to activate each sound.

The demo video shows the kit performing ably; it’s not clear if there’s an issue with latency on the samples or that’s just from the difficulty of [spanceac] playing one-handed. If the former, likely some code tweaks or simply trimming silence at the start of samples would be all that was needed. Overall, it’s a neat little groovebox, and the kind of thing that’s great fun to use when jamming with other musicians. Video after the break.

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3D Printering: Soldering A Heated Bed

January 11, 2022 by Al Williams 62 Comments

There’s an old saying about something being a “drop in the ocean.” That’s how I felt faced with the prospect of replacing a 12 V heated bed on my printer with a new 24 V one. The old bed had a nice connector assembled from the factory, although I had replaced the cable long ago due to heating issues with that particular printer. The new bed, however, just had bare copper pads.

I’m no soldering novice: I made my first solder joint sometime in the early 1970s. So I felt up to the challenge, but I also knew I wouldn’t be able to use my usual Edsyn iron for a job like this. Since the heated bed is essentially a giant heatsink for these pads, I knew it would require the big guns. I dug out my old — and I mean super old — Weller 140 W soldering gun. Surely, that would do the trick, right?

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Reusable Booster Rockets, Asian Roundup

January 11, 2022 by Chris Lott 28 Comments

The Space Shuttle’s solid rocket boosters were reusable, although ultimately the overall system didn’t prove cheaper than expendable launches. But given the successes of the Falcon 9 program — booster B1051 completed its 11th mission last month — the idea of a rocket stage returning to the launch site and being reused isn’t such a crazy proposition anymore. It’s not surprising that other space agencies around the world are pursuing this technology.

Last year the India Space Research Organization (ISRO) announced plans for a reusable launcher program based on their GSLV Mark III rocket. The Japan Aerospace Exploratory Agency (JAXA) announced last Fall that it is beginning a reusable rocket project, in cooperation with various industries and universities in Japan. The South Korean space agency, Korea Aerospace Research Institute (KARI), was surprised in November when lawmakers announced a reusable rocket program that wasn’t requested in their 2022 budget. Not in Asia, but in December France’s ArianeGroup announced a reusable rocket program called Maïa.

Speaking of South Korea’s rocketry program, we wrote about the Nuri rocket in October which failed to reach orbit because of a problem in the third stage. Kari recently completed a review of all the data, and concluded the problem was with the anchors of the helium tanks which are located inside the oxidizer tank.

Apparently the changing buoyancy of the submerged tanks with altitude wasn’t completely accounted for in the design of the mounting brackets. When they ultimately failed, the resulting broken piping caused a LOX leak and the subsequent 46-second premature engine shutdown. The next scheduled launch in May 2022 will very likely be delayed.

Haber-Bosch And The Greening Of Ammonia Production

January 11, 2022 by Dan Maloney 47 Comments

We here on Earth live at the bottom of an ocean of nitrogen. Nearly 80% of every breath we take is nitrogen, and the element is a vital component of the building blocks of life. Nitrogen is critical to the backbone of proteins that form the scaffold that life hangs on and that catalyze the myriad reactions in our cells, and the information needed to build these biopolymers is encoded in nucleic acids, themselves nitrogen-rich molecules.

And yet, in its abundant gaseous form, nitrogen remains directly unavailable to higher life forms, unusably inert and unreactive. We must steal our vital supply of nitrogen from the few species that have learned the biochemical trick of turning atmospheric nitrogen into more reactive compounds like ammonia. Or at least until relatively recently, when a couple of particularly clever members of our species found a way to pull nitrogen from the air using a combination of chemistry and engineering now known as the Haber-Bosch process.

Haber-Bosch has been wildly successful, and thanks to the crops fertilized with its nitrogenous output, is directly responsible for growing the population from a billion people in 1900 to almost eight billion people today. Fully 50% of the nitrogen in your body right now probably came from a Haber-Bosch reactor somewhere, so we all quite literally depend on it for our lives. As miraculous as Haber-Bosch is, though, it’s not without its problems, particularly in this age of dwindling supplies of the fossil fuels needed to run it. Here, we’ll take a deep dive into Haber-Bosch, and we’ll also take a look at ways to potentially decarbonize our nitrogen fixation industry in the future.

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LED Bubbles From The 1970s Tell The Time

January 11, 2022 by Al Williams 15 Comments

[CuriousMarc] is nothing if not curious. Finding some old TI timekeeping chips to reverse engineer, he set out to make a clock using old-fashioned “bubble LEDs.” You can see the result of his tinkering in the video below. For the uninitiated, bubble LEDs are 7-segment LEDs with magnifying bubbles over each digit. These were popular in calculators, watches, and other places that used LEDs before LCDs largely displaced them.

The history of these has to do with the power required to light an LED. You don’t technically need a magnifying lens, but larger LEDs take more power. These displays were relatively low power and used tiny LEDs with light pipes to make each dot a full segment. The lens made the segments larger and easier to see.

Beyond the TI chip and HP displays, there isn’t too much else needed. [Marc] just wired the whole thing using the IC as a substrate. Sort of dead bug construction using enameled wire. At first, it didn’t work but it turned out to be a battery issue. The device really wanted 2.5 V and not the 3 V provided by the battery. The solution required a little detective work.

We know this isn’t a very practical project, but we love seeing this old tech again and while the dead bug construction isn’t beautiful, there is something appealing about the look of it. Maybe one day people will build steampunk things and discopunk will be for the 1970s?

We’ve seen bubble LED projects before. If you want something more in a watch form factor, that exists, too.

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