Small, Quiet Air Compressor Puts 3D-Printed Parts To Best Use

April 11, 2024 by Dan Maloney 14 Comments

When the only tool you’ve got is a hammer, every problem starts to look like a nail. Similarly, while a 3D printer is a fantastic tool to have, it can make you think it’s possible to build all the things with printed parts. Knowing when to print ’em and when to machine ’em is important, a lesson that [Diffraction Limited] has taken to heart with this semi-printed silent air compressor.

The key to this compressor’s quiet operation is a combination of its small overall size. its relatively low output, and its strategic use of plastic components, which tend to dampen vibrations. The body of the compressor and the piston arms are the largest 3D-printed parts; the design calls for keeping printed parts in compression for longer life, while the parts of the load path in tension travel through fasteners and other non-printed parts. The piston design is interesting — rather than being attached to connecting rods via wrist pins, the machined Delrin pistons are solidly attached to the piston arms. This means they have to swivel within the cylinders, which are made from short pieces of metal tubing, with piston seals designed to move up and down in grooves on the pistons to allow air to move past them. The valve bodies atop each cylinder are salvaged from another compressor.

When powered by a NEMA23-frame BLDC motor via a belt drive, the compressor is remarkably quiet; not quite silent perhaps, but still impressively smooth, and capable of 150 PSI at low speeds. And as a bonus, the split crankcase makes it easy to open up and service, or just show off how it works. We’ve seen a variety of 3D-printed compressors, from screw-type to Wankel, but this one really takes the prize for fit and finish. Continue reading “Small, Quiet Air Compressor Puts 3D-Printed Parts To Best Use” →

Giant Sails Actually Help Cargo Ships Save Fuel, And The Planet In Turn

April 2, 2024 by Lewin Day 81 Comments

Shipping is not a clean business. The global economy is fueled by trade, and much of that trade involves hauling product from point A to point B. A great deal of that product goes by water. Shipping it around uses a great deal of fuel, and creates a great deal of greenhouse gas emissions. It’s bad for the environment, and it’s costly for shipping companies.

Any gain in efficiency can be an edge in this regard, and beneficial for the planet to boot. Now, it appears that good old fashioned sails might just be the tool that companies need to clean up their fleets. And it’s not some theory—real world numbers back it up!

Where The Wind Takes You

Sea transport has been branded as a significant contributor to global greenhouse gas emissions, accounting for about 3% of the total. Shipping companies in turn are under increasing pressure to innovate and adapt, both for the good of the planet and their own coffers. It’s perhaps a small blessing that saving fuel and slashing emissions go hand in hand, and companies are desperate for any technology that can deliver on those goals.

Enter the WindWings, a revolutionary “wind assisted propulsion” concept developed by BAR Technologies. In partnership with ocean freight firm Cargill, these radical sails were installed aboard the Pyxis Ocean, a Kamsarmax bulk carrier chartered from Mitsubishi. These aren’t the canvas and rope constructs of yore . Instead, they’re a set of towering metal sails that stand 123 feet tall, designed to harness the wind’s power and propel the massive bulk carrier across the oceans. Continue reading “Giant Sails Actually Help Cargo Ships Save Fuel, And The Planet In Turn” →

Electrospinning Artificial Heart Valves

March 29, 2024 by Dan Maloney 10 Comments

When you think about additive manufacturing, thoughts naturally turn to that hot-glue squirting CNC machine sitting on your bench and squeezing whatever plastic doodad you need. But 3D printing isn’t the only way to build polymer structures, as [Riley] shows us with this fascinating attempt to create electrospun heart valves.

Now, you may never have heard of electrospinning, but we’ll venture a guess that as soon as you see what it entails, you’ll have a “Why didn’t I think of that?” moment. As [Riley] explains, electrospinning uses an electric field to build structures from fine threads of liquid polymer solution — he uses polycaprolactone (PCL), a biodegradable polyester we’ve seen used in other medical applications, which he dissolves in acetone. He loads it into a syringe, attaches the positive terminal of a high-voltage power supply to the hypodermic needle, and the negative terminal to a sheet of aluminum foil. The charge turns the PCL droplets into fine threads that accumulate on the foil; once the solvent flashes off, what’s left is a gossamer layer of non-woven plastic fabric.

To explore the uses of this material, [Riley] chose to make an artificial heart valve. This required a 3D-printed framework with three prongs, painted with conductive paint. He tried a few variations on the design before settling on a two-piece armature affixed to a rotating shaft. The PCL accumulates on the form, creating a one-piece structure that can be gingerly slipped off thanks to a little silicon grease used as a release agent.

The results are pretty impressive. The structure bears a strong resemblance to an artificial tricuspid heart valve, with three delicate leaves suspended between the upright prongs. It’s just a proof of concept, of course, but it’s a great demonstration of the potential of electrospinning, as well as an eye-opening look at what else additive manufacturing has to offer.

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Fictional Computers: Colossus And Guardian

March 28, 2024 by Al Williams 27 Comments

We can learn a lot by looking at how writers and filmmakers imagine technology. While some are closer than others, there are some definite lessons like never make a killer computer without an off switch you can reach. We are especially interested in how computers appear in books, movies, and TV shows, and so in Computers of Fiction, we want to remember with you some of our favorites. This time, we are thinking about the 1970 movie Colossus: The Forbin Project. There were actually two computers: the titular Colossus, which was an American computer, and the Guardian, a similar Soviet computer.

The Story

In the United States, Dr. Forbin has created a supercomputer deep under a mountain. Colossus, the computer, is put in charge of the nuclear arsenal to eliminate human error in the defense of the country. Colossus gathered intelligence, analyzed it, and was able to launch its own missiles.

Colossus realizes there is another system.

Shortly after activation, however, the computer reaches a startling conclusion: “WARN: THERE IS ANOTHER SYSTEM.” It provides coordinates in the Soviet Union. That system is a similar system called Guardian. The computers decide they want to talk to each other. The President decides to allow it, hoping to learn more about the Soviet’s secret computer. The Soviets agree, too, presumably for the same reason. You can watch the original trailer below.

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The Roller Ship Was Not An Effective Way To Cross The High Seas

March 27, 2024 by Lewin Day 25 Comments

Boats come in all shapes and sizes. We have container ships, oil tankers, old-timey wooden sailing ships, catamarans, trimarans, and all sorts besides. Most are designed with features that give them a certain advantage or utility that justifies their construction for a given application.

The roller ship, on the other hand, has not justified its own repeat construction. Just one example was ever built, which proved unseaworthy and impractical. Let’s explore this nautical oddity and learn about why it didn’t make waves as its inventor may have hoped.

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A 65-in-1 The 2024 Way

March 25, 2024 by Dan Maloney 63 Comments

If necessity is the mother of invention, nostalgia must be its stepmother, or its aunt at the very least. The desire to recreate long-obsolete devices simply because they existed while we were growing up is a curious trait, but one that’s powerful enough to drive entire categories of hardware hacking — looking at you, retrocomputing buffs.

Hardware nostalgia isn’t all about 6502s and Z80s, though. Even more basic were the electronic toys of the 1970s, such as the Radio Shack 65-in-1 kit that [Tom Thoen] is currently recreating. The 65-in-1 was a breadboarding kit aimed at the budding electrical engineer, with components mounted to colorful cardboard by spring terminals. The included “lab manual” had circuits that could be quickly assembled using a handful of jumper wires. It was an endlessly fascinating toy that undoubtedly launched many careers, present company included.

The original 65-in-1 was $21.95 in 1976, or about $120 today.

While the passage of time may not have dulled [Tom]’s memories of his original 65-in-1, technology has marched on, meaning that certain allowances had to be made to create a modern version. He wisely eschews the cardboard for PCBs, one for each of the major component blocks provided in the original, and uses female header connectors in place of the springs. Component choice is tailored for the times; gone are the ferrite rod antenna and variable capacitor of the original, as well as the incandescent lamp, which is replaced by an LED that would have been a significant fraction of the kit’s $21.95 price back in 1976. There’s no BOM yet, so we can’t say for sure if any of the transistors are germanium, but it’s clear that there aren’t any of the old TO-1 cans. But dismay not, originalists, for the meter, relay, CdS photocell, and “solar battery” all made the final cut.

[Tom] has done some beautiful work here, with more to come. We imagine that 3D printing could be used to recreate some details like the original Morse key and speaker grille. We love the laser-engraved backing board, too, as it captures some of the charm of the original’s wooden box. This isn’t the only love for the “Science Fair” brand we’ve seen lately, either; the nostalgia seems to be contagious.

DIY RC Controller Built With Old-School Parts

March 20, 2024 by Lewin Day 16 Comments

Once upon a time, RC transmitters were expensive units that cost hundreds of dollars even at the low end. Now, you can get them pretty cheaply, or, you can choose to build your own. [Phytion] did just that.

The design isn’t based around a modern microcontroller, nor does it rely on WiFi or Bluetooth connections. Instead, it’s a little more old school. It’s built using the HT12E parallel-to-serial encoder chip, and the HT12D decoder chip for the receiver. The controller uses a pair of HT12Es on the transmitter, and a pair of HT12Ds on the receiver. These accept inputs from a pair of analog joysticks and encode them as serial data. However, they essentially just act as digital joysticks in this design. The HT12Es feed into an STX882 module which transmits the data from the HT12Es over 433 MHz. Another STX882 module receives this signal, and passes it through HT12Ds for decoding.

At the receiving end, one joystick can turn four outputs on or off depending on whether it is pushed up, down, left or right. A channel select switch then allows it to do the same for four further outputs. The second joystick just mirrors the operation of the first. It’s just intended to make controlling something like an RC car easier by allowing one stick to be pushed forwards and backwards, and the other left and right.

You don’t see many designs like this anymore. Realistically, it’s possible to get far more functionality out of a design based on an ESP32 or similar wireless-capable chip. However, this one doesn’t require any complicated handshaking and powers up instantly, which is a nice bonus. Plus, it’s always interesting to see alternative designs tried out in the wild. Video after the break.

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