A white woman with a long ponytail in a green apron looks down at a mannequin head with pasta coming out of its chin. There is an orange pasta gun sticking out of the back of its head and a chef's hat on its head. It looks vaguely like a bust of Ramses.

Goatee Pasta Maker Makes Us Hunger For Hair

March 4, 2024 by Navarre Bartz 9 Comments

Some hacks are pure acts of whimsy, and [Simone Giertz] is back to her roots with this Goatee Pasta Maker.

If violence to mannequin heads is upsetting, the video may be a bit NSFW (to warn you now that you already clicked on it). What started out as a pasta-making version of those Play-Doh hair people quickly morphed into a more scaled-back endeavor with simply extruding pasta through the mannequin’s chin to create pasta hair.

Initial attempts at using a basketball to extrude clay (used as a pasta stand-in) through holes in a mannequin’s head were unsuccessful, so [Giertz] turned to a more conventional pasta gun to handle the pasta extrusion. Since the gun didn’t have the volume necessary to produce a full head of hair, or even a respectable mustache, the next mannequin’s chin was subjected to multiple drill holes for pasta to escape in a hairy tangle.

The results aren’t exactly appetizing, but it definitely does make edible pasta. If you’re looking for more pasta hacks, how about ramen in an edible package, flat pack pasta, or Barilla’s Open Source pasta tool?

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Accelerate Your Large Builds Locally With Distcc

March 4, 2024 by Dave Rowntree 20 Comments

The motto of Sun Microsystems back in the day was “The Network Is The Computer” which might be kind of relevant when CPUs were slower and single-core affairs, but lately to get a faster compile, you’d simply throw more cores and memory at the problem. The thing is, most of us don’t do huge compilations all that often, we can’t remember the last time we even attempted a Linux kernel build. However if you do find yourself with a sudden need to do so, and have access to a pile of machines hooked to a network, then why not check out distcc: the fast distributed C/C++ Compiler? We’ve seen a few mentions in comments and a HaD links article referencing it, but never explicitly covered the tool. So here we go.

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Design Tips To Hide Layer Lines In 3D Printed Parts

March 4, 2024 by Donald Papp 31 Comments

[Slant 3D] knows a lot about optimizing 3D prints so that they can be cranked out reliably with minimal need for post-processing, and in this short video he uses a cube as a simple example of how a few design changes can not only optimize for production, but can even hide layer lines pretty effectively.

Just to be perfectly clear, layer lines cannot be eliminated entirely without some kind of post-processing. But [Slant 3D]’s tips sure goes a long way toward making a part lose that obvious 3D-printed “look”. They also dovetail nicely with advice on how to optimize cranking out high numbers of parts in a print farm.

Adding texture to the outer layer is especially effective when combined with non-traditional part orientations.

One simple way to avoid visible layer lines is to put some kind of texture onto the part. This can be modeled into the part’s surface, or the slicer software can be used to modify the exterior of the print to add a texture such as a geometric pattern or by applying a fuzzy skin modifier.

Printing a texture onto the exterior is great, but the outcome can be even further improved by also printing the object in a non-traditional orientation.

Using a cube as an example, printing the cube on a corner has the advantage of putting the layer lines in a different orientation as well as minimizing the contact area on the print bed. This applies the texture across more of the part, and looks less obviously 3D printed in the process. Minimizing bed adhesion also makes parts much easier to remove, which has obvious benefits for production. [Slant 3D] points out that performing these operations on a 3D-printed part is essentially free.

A few other optimizations for production involve rounding sharp corners to optimize tool travel paths, and putting a slight chamfer on the bottom of parts to avoid any elephant foot distortion (Elephant’s foot can be compensated for, but simply putting a slight chamfer on a part is a design change that helps avoid accounting for machine-to-machine variance.)

Even if one has no need to optimize for high production volume, the tips on hiding layer lines with design changes is great advice. Watch it all in action in the short video, embedded below.

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Optical Guitar Pickup Works With Nylon Strings

March 4, 2024 by Lewin Day 67 Comments

Electric guitar pickups rely on steel strings interfering with a magnetic field, the changes in which are picked up with coils of wire. That doesn’t work with nylon strings, because they don’t tend to perturb magnetic fields nearly as much, beyond some infinitesimal level that some quantum physicist could explain. So what do you do? You follow [Simon]’s example, and build an optical pickup instead.

The concept is simple. You place an LED and a phototransistor in a U-shaped channel, and place it so that the string runs through it. You repeat this for each string. Thus, as a string vibrates, it interrupts the light travelling from the LED to the phototransistor. This generates a voltage that varies with the frequency of the string’s vibration. Funnily enough, this type of pickup will work just fine on both nylon and steel strings, if you were so inclined to try it.

[Simon] designed a nifty PCB with six LED-phototransistor pairs (using off-the-shelf interruptor sensors) for use with a nylon-stringed guitar. He reports that sound from the strings comes through clearly, but that there is some noise that is evident in the pickup’s output, too. Listening to the demo, it seems to capture the sound of the nylon strings well, it’s just a shame that the noise floor is so high.

If you prefer your guitar pickups to be the regular magnetic kind, you can always wind your own from scrap. Demo after the break.

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Retrotechtacular: The Free Piston Engine

March 4, 2024 by Jenny List 20 Comments

We all know how a conventional internal combustion engine works, with a piston and a crankshaft. But that’s by no means the only way to make an engine, and one of the slightly more unusual alternatives comes to us courtesy of a vintage Shell Film Unit film, The Free Piston Engine, which we’ve placed below the break. It’s a beautiful period piece of mid-century animation and jazz, but it’s also an introduction to these fascinating machines.

We’re introduced to the traditional two-stroke diesel engine as thermally efficient but not smooth-running, and then the gas turbine as smooth but much more inefficient. The free piston engine, a design with opposed pistons working against compressed air springs and combining both compression and firing strokes in a single axis, doesn’t turn anything in itself, but instead works as a continuous supplier of high pressure combustion gasses. The clever part of this arrangement is that these gasses can then turn the power turbine from a gas turbine engine, achieving a smooth engine without compromising efficiency.

This sounds like a promising design for an engine, and we’re introduced to a rosy picture of railway locomotives, ships, factories, and power stations all driven by free piston engines. Why then, here in 2024 do we not see them everywhere? A quick Google search reveals an inordinately high number of scientific review papers about them but not so many real-world examples. In that they’re not alone, for alternative engine designs are one of those technologies for which if we had a dollar for every one we’d seen that didn’t make it, as the saying goes, we’d be rich.

It seems that the problem with these engines is that they don’t offer the control over their timing that we’re used to from more conventional designs, and thus the speed of their operation also can’t be controlled. The British firm Libertine claim to have solved this with their line of linear electrical generators, but perhaps understandably for commercial reasons they are a little coy about the details. Their focus is on free piston engines as power sources for hybrid electric vehicles, something which due to their small size they seem ideally suited for.

Perhaps the free piston engine has faced its biggest problem not in the matter of technology but in inertia. There’s an old saying in the computer industry: “Nobody ever got fired for buying IBM“, meaning that the conventional conservative choice always wins, and it’s fair to guess that the same applies anywhere a large engine has been needed. A conventional diesel engine may be a complex device with many moving parts, but it’s a well-understood machine that whoever wields the cheque book feels comfortable with. That’s a huge obstacle for any new technology to climb. Meanwhile though it offers obvious benefits in terms of efficiency, at the moment its time could have come due to environmental concerns, any internal combustion engine has fallen out of fashion. It’s possible that it could find a life as an engine running on an alternative fuel such as hydrogen or ammonia, but we’re not so sure. If new free piston engines do take off though, we’ll be more pleased than anyone to eat our words.

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High Vacuum Hack Chat

March 4, 2024 by Dan Maloney 3 Comments

Join us on Wednesday, March 6 at noon Pacific for the High Vacuum Hack Chat with Niklas from Advanced Tinkering!

To the casual observer, there’s not much that goes on in experimental physics that doesn’t require at least a partial vacuum. It makes sense when you think about it; our atmosphere is so thick and so loaded with water vapor and reactive oxygen that it just has to play havoc with experiments. Even when the goal is more applied than empirical, getting rid of all those pesky molecules is often the first step in getting good results.

But pulling a vacuum is rarely an easy task. Sure you can pump out some of the air, but that just makes the rest of the atmosphere try really hard to get back inside and ruin your day. It takes a lot of specialized equipment, a lot of precision-machined stainless steel fittings, and quite a bit of experience not only to pull a vacuum, but to then be able to work within it and do something useful.

One place where we’ve seen a lot of high-vacuum action is over on Advanced Tinkering on YouTube. The channel has a wealth of interesting experiments, many of which need a good vacuum to get going. To that end, channel owner Niklas has assembled a nice collection of vacuum gear, and we asked him to drop by the Hack Chat to talk about what he’s learned by embracing the suck.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 6 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.