Author: Dan Maloney

3373 Articles

Big Chemistry: Ultrapure Water

July 7, 2022 by 53 Comments

My first job out of grad school was with a biotech company in Cambridge, Massachusetts. It was a small outfit, and everyone had a “lab job” in addition to whatever science they were hired to do — a task to maintain the common areas of the lab. My job was to maintain the water purification systems that made sure everyone had an ample supply of pure, deionized water to work with. The job consisted of mainly changing the filter and ion-exchange cartridges of the final polishing units, which cleaned up the tap water enough for science.

When I changed the filter packs, I was always amazed and revolted by the layers of slime and sediment in them. A glimpse out the window at the banks of the river Charles — love that dirty water — was enough to explain what I was seeing, and it was a lesson in just how much other stuff is mixed in with the water you drink and cook with and bathe in.

While we humans can generally do pretty well with water that rates as only reasonably pure, our industrial processes are quite another thing. Everything from power plants to pharmaceutical manufacturing facilities needs water of much, much higher purity, but nothing requires purer water than the specialized, nanometer-scale operations of a semiconductor fab. But how does ordinary tap water get transformed into a chemical of such purity that contaminants are measured in parts per trillion? And how do fabs produce enough of this ultrapure water to meet their needs? With some big chemistry.

Continue reading “Big Chemistry: Ultrapure Water” →

Scratch-Built Electric Buggy Tears Up The Dunes

July 5, 2022 by 14 Comments

It’s a fair bet to say that the future of personal transportation will probably be electric. In support of that, every major car manufacturer either has an electric drivetrain option available now, or they’re working furiously on developing one. And while it’s good that your suburban grocery grabber will someday be powered by the sun, what about the pressing need for EVs that are just plain fun to drive?

To fill the fun gap, at least for now, [James Biggar] built what you can’t buy: an all-electric dune buggy. And lest you think this was a kit build, be assured that the summary video below shows this little sand rail was 100% scratch-built. The chassis is fabricated from bent tubing, and welded up using a clever plywood template to get the angles just right. The buggy has four-wheel independent suspension and a wide, aggressive stance to handle rough terrain. The body panels are sheet aluminum bent on a custom-built brake, which was also used to form the Plexiglas windshield with a little help from a heat gun.

While the bodywork makes the buggy pretty sick looking, the drivetrain is just as impressive. [James] used an ME1616, a liquid-cooled 55-kW beast. A chain drive couples the motor to a differential from a Honda CR-V which has a limited-slip modification installed. The batteries are impressive, too — 32 custom-made lithium-iron-phosphate batteries made from 32650 cells in vacuum-formed ABS plastic shells that nest together compactly. It all adds up to a lot of fun in the dirt; skip to 23:37 in the video to see what this thing can do.

Honestly, the level of craftsmanship here is top-notch, and is all the more impressive in that it’s not fancy — just good, solid methods and lots of hard work. We’d love to have the time and resources to put into something like this — although a drop-in crate motor EV might be a satisfying build too.

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A 3D Printer Big Enough To Print A Kayak

July 4, 2022 by 43 Comments

When one of your design goals for a 3D printer is “fits through standard doors,” you know you’re going to be able to print some pretty big stuff. And given that the TAUT ONE printer by [Nathan Brüchner] could easily be mistaken for a phone booth, we’d say it’ll be turning out some interesting prints.

The genesis for this beast of a printer came from the Before Times, with the idea of printing a kayak. [Nathan] leveraged his lowdown time to make it happen, going through three prototypes. Each featured a print bed of 1,000 mm x 550 mm with 1,100 mm of Z-height, and the overall footprint fits a standard Euro-pallet. It uses a CoreXY design to move the dual-filament hot end, which has ducting for taking cooling air from outside the cabinet. And the machine has all the bells and whistles — WiFi, an internal camera, filament sensors, and a range of environmental controls.

In a nod to making it easier to build, [Nathan] kept all the custom parts either laser cut or 3D-printed — no mill or lathe required. He also points out that he used only quality components, which shows in the price — about 3,000€. That seems like a lot to be able to print kayaks that you can buy for fraction of that amount, but we certainly appreciate the potential of this printer, and the effort that went into making it work.

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Hackaday Links: July 3, 2022

July 3, 2022 by 10 Comments

Looks like we might have been a bit premature in our dismissal last week of the Sun’s potential for throwing a temper tantrum, as that’s exactly what happened when a G1 geomagnetic storm hit the planet early last week. To be fair, the storm was very minor — aurora visible down to the latitude of Calgary isn’t terribly unusual — but the odd thing about this storm was that it sort of snuck up on us. Solar scientists first thought it was a coronal mass ejection (CME), possibly related to the “monster sunspot” that had rapidly tripled in size and was being hyped up as some kind of planet killer. But it appears this sneak attack came from another, less-studied phenomenon, a co-rotating interaction region, or CIR. These sound a bit like eddy currents in the solar wind, which can bunch up plasma that can suddenly burst forth from the sun, all without showing the usually telltale sunspots.

Then again, even people who study the Sun for a living don’t always seem to agree on what’s going on up there. Back at the beginning of Solar Cycle 25, NASA and NOAA, the National Oceanic and Atmospheric Administration, were calling for a relatively weak showing during our star’s eleven-year cycle, as recorded by the number of sunspots observed. But another model, developed by heliophysicists at the U.S. National Center for Atmospheric Research, predicted that Solar Cycle 25 could be among the strongest ever recorded. And so far, it looks like the latter group might be right. Where the NASA/NOAA model called for 37 sunspots in May of 2022, for example, the Sun actually threw up 97 — much more in line with what the NCAR model predicted. If the trend holds, the peak of the eleven-year cycle in April of 2025 might see over 200 sunspots a month.

So, good news and bad news from the cryptocurrency world lately. The bad news is that cryptocurrency markets are crashing, with the flagship Bitcoin falling from its high of around $67,000 down to $20,000 or so, and looking like it might fall even further. But the good news is that’s put a bit of a crimp in the demand for NVIDIA graphics cards, as the economics of turning electricity into hashes starts to look a little less attractive. So if you’re trying to upgrade your gaming rig, that means there’ll soon be a glut of GPUs, right? Not so fast, maybe: at least one analyst has a different view, based mainly on the distribution of AMD and NVIDIA GPU chips in the market as well as how much revenue they each draw from crypto rather than from traditional uses of the chips. It’s important mainly for investors, so it doesn’t really matter to you if you’re just looking for a graphics card on the cheap.

Speaking of businesses, things are not looking too good for MakerGear. According to a banner announcement on their website, the supplier of 3D printers, parts, and accessories is scaling back operations, to the point where everything is being sold on an “as-is” basis with no returns. In a long post on “The Future of MakerGear,” founder and CEO Rick Pollack says the problem basically boils down to supply chain and COVID issues — they can’t get the parts they need to make printers. And so the company is looking for a buyer. We find this sad but understandable, and wish Rick and everyone at MakerGear the best of luck as they try to keep the lights on.

And finally, if there’s one thing Elon Musk is good at, it’s keeping his many businesses in the public eye. And so it is this week with SpaceX, which is recruiting Starlink customers to write nasty-grams to the Federal Communications Commission regarding Dish Network’s plan to gobble up a bunch of spectrum in the 12-GHz band for their 5G expansion plans. The 3,000 or so newly minted experts on spectrum allocation wrote to tell FCC commissioners how much Dish sucks, and how much they love and depend on Starlink. It looks like they may have a point — Starlink uses the lowest part of the Ku band (12 GHz – 18 GHz) for data downlinks to user terminals, along with big chunks of about half a dozen other bands. It’ll be interesting to watch this one play out.

Reverse Engineering An Apollo-Era Module With X-Ray

June 29, 2022 by 9 Comments

The gear that helped us walk on the Moon nearly 60 years ago is still giving up its mysteries today, with some equipment from the Apollo era taking a little bit more effort to reverse engineer than others. A case in point is this radiographic reverse engineering of some Apollo test gear, pulled off by [Ken Shirriff] with help from his usual merry band of Apollo aficionados.

The item in question is a test set used for ground testing of the Up-Data Link, which received digital commands from mission controllers. Contrary to the highly integrated construction used in Apollo flight hardware, the test set, which was saved from a scrapyard, used more ad hoc construction, including cards populated by mysterious modules. The pluggable modules bear Motorola branding, and while they bear some resemblance to ICs, they’re clearly not.

[Ken] was able to do some preliminary reverse-engineering using methods we’ve seen him employ before, but ran into a dead end with his scope and meter without documentation. So the modules went under [John McMaster]’s X-ray beam for a peek inside. They discovered that the 13-pin modules are miniature analog circuits using cordwood construction, with common discrete passives stacked vertically between parallel PCBs. The module they imaged showed clear shadows of carbon composition resistors, metal-film capacitors, and some glass-body diodes. Different angles let [Ken] figure out the circuit, which appears to be part of a square wave to sine wave converter.

The bigger mystery here is why the original designer chose this method of construction. There must still be engineers out there who worked on stuff like this, so here’s hoping they chime in on this innovative method.

Homebrew Optical Sensor Helps Your Diesel Pass The Smoke Test

June 27, 2022 by 50 Comments

We’ve all heard of the smoke test, and we know that it’s the lowest possible bar for performance of an electronic device. If it doesn’t burst into flames when power is applied, you’re good to go for more functional testing. But the smoke test means something else for cars, especially those powered by diesel fuel. And passing diesel exhaust tests can become something of a chore.

To make passing these tests a little easier, [Janis Alnis] came up with this diesel exhaust monitor that measures the opacity of his car’s emissions. The sensor itself is quite simple, and mimics what commercial exhaust analyzers use: a LED and a photodiode at opposite ends of a tube of a specified length. Soot particles in exhaust passing through the tube will scatter light in a predictable way, and the numbers work out that a passing grade is anything greater than 53% transmission.

The sensor body is cobbled together from brass pipe fittings with glass windows epoxied into each end. Exhaust enters via a tee fitting attached to a hose and sampling tube, and exits through another tee. One window of the sensor has a cheap battery-powered flashlight as a light source, while the other end has a Texas Instruments OPT101 photodiode sensor. The sensor is connected to one of the analog inputs of an Arduino, which also runs a 128×64 pixel LCD display — inspired by this air quality meter — to show the current smokiness both graphically and as a percentage. The video below shows the sensor at work.

While there were some issues with soot buildup and water vapor condensation, using the sensor [Janis] discovered that a little bit of a warm-up drive got things hot enough to clear up his ride’s tendency to smoke a bit, allowing him to pass his inspection. Continue reading “Homebrew Optical Sensor Helps Your Diesel Pass The Smoke Test” →

Odd Inputs And Peculiar Peripherals: RoenDi Smart Knob Thinks Outside The Box

June 27, 2022 by 19 Comments

When it comes to design decisions, we’re often advised to “think outside the box.” It’s generally good advice, if a bit abstract — it could really mean anything. But it appears that someone took it quite literally with this nifty little smart knob display and input device.

[Dimitar]’s inspiration for RoenDi — for “rotary encoder and display” — came from an unusual source: a car dashboard, and specifically, the multipurpose knobs that often crop up in a car’s climate control cluster. Designed for ease of use while driving while causing as little distraction as possible, such knobs often combine a rotary encoder with one or more indicators or buttons. RoenDi builds on that theme by putting a 1.7″ round LCD display in the middle of a ring attached to an Alps rotary encoder, allowing the knob to be customized for whatever you want it to represent. The backplane sports a powerful STM32 microcontroller with a lot of the GPIO pins broken out, so customization and interfacing are limited only by your imagination. The design is open source, so you can either build your own or support the project via Crowd Supply.

Unlike the haptic smart knob we’ve been seeing a bit about lately, which also features a round LCD at its center, RoenDi’s feedback is via the physical detents on the encoder. We think both devices are great, and they fill different niches in the novel input ecosystem.

Continue reading “Odd Inputs And Peculiar Peripherals: RoenDi Smart Knob Thinks Outside The Box” →