Slicer Settings For “Indestructible” Battle-Bot Worthy PLA Parts

If you follow [Maker’s Muse] on YouTube, you know he’s as passionate about robot fights these days as he is about the tools he uses to make the robots. Luckily for us, he’s still got fame as a 3D printing YouTuber, as this has given him the platform to share his trade secrets for strong, robot-combat-worthy prints.

He fights robots in a ‘plastic ant-weight’ division, which restricts not only the weight of the robot but also the materials used. Not only must they be primarily plastic, but only certain plastics are allowed: PLA is in, but engineering filaments, Nylon, and TPU are out. Since necessity is the mother of invention, this has led to strong evolutionary pressure to figure out how to print the most impact-resilient PLA parts for armor and spinners.

He’s using the latest OrcaSlicer and shares the profile as a pay-what-you-want 3MF file. It’s all about solidity: a solid part with solidly fused walls and solidly linked layers. It makes sense: if you’re going to be hammering on or with these parts, you don’t want any internal voids that could either collapse or pull open.

The infill density is obviously 100%, and you’ll want a concentric pattern — this makes it look like you’re just printing walls, but it allows you to use another trick. To make sure those walls don’t all align, creating a potential weakness, OrcaSlicer’s “alternate extra wall” will put one extra wall every second layer. The extra wall causes the infill pattern to stagger and lock together.

Also helping lock it together, he’s playing with extrusion widths, with the suggested rule-of-thumb being the line width on the walls be one-half that of the internal fill — and as wide as possible. In his case, with a 0.4 mm nozzle, that means 0.4 mm wide walls and 0.8 mm for the infill. OrcaSlicer 2.3.2 also lets you play with specific flow ratios, allowing you to overextrude only the internals for strength, without overextruding on the walls and potentially ruining dimensional accuracy. He also irons all top surfaces, but admits that that’s mostly about aesthetics. The iron may make those layers a little bit stronger, though, so why not?

Would brick layers make these parts even stronger? That’s very likely; [Maker’s Muse] mentions them in the video but does not use them because they’re not implemented in-slicer, and he wants something accessible to all. On the other hand, this post-processing script seems accessible enough for our crowd.

This video/profile is exclusively about fully-solid parts. When you want strong parts that aren’t fully solid, it looks like the answer is walls.

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You Wouldn’t Download A Combustion Engine

Although 3D printing it a great tool for making all sorts of things, the nature of the plastics used in most desktop FDM printers means it isn’t the first tool most would think of to build an internal combustion engine. [Alexander] is evidently not most people, as he’s on his third generation 3D printed engine.

There are 3D printed pumps to distribute coolant water and oil, plus some clever engineering in the head to make sure they don’t mix — a problem with a previous iteration. As you probably guessed, the engine isn’t fully printed. Assembling it requires add-on hardware for things like bearings, belts, and filters.

But it’s still impressive just how much of this beast is actually made of plastic. Not even fancy engineering plastic, either — there are a few CF-Nylon parts, but most of it is apparently good old ASA and ABS.

If you’re looking for “cheats”, the plastic engine block does get a stainless steel sleeve, and the head is CNC’d aluminum, but we hesitate to call anything that gets a homemade engine running a “cheat”. It’s hard enough using all the ‘right’ materials. Just like another 3D printed engine we featured, the carb is also an off-the-shelf component.

Still, it’s the dancing bear all over again: it’s not how well it runs that impresses, but the fact that it runs at all. We’ve also seen hackers use 3D printing to make steam engines, hot-air Stirling engines, and electric motors— all with varying amounts of non-printed parts.

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Time Frog Color Is A Game Boy Color On Your Wrist

Handheld consoles are great for gaming on the go, but who wants to hold onto things all the time? Would it not be easier to strap the game to your wrist? Well, not in its current form factor, but [LeggoMyFroggo], aka [
Chris Hackmann] has you covered, because he turned the Gameboy Color into a (relatively smart) watch.

Why “relatively” smart? Well, we say that because he’s using the original Game Boy Color CPU, a Sharp SOC based on the Z80 that is far less powerful than modern smartwatch platforms. That SOC is helped out by an RP2040 that translates the chip’s parallel RGB output into something a modern watch-sized display can comprehend via its PIOs. [Chris] refers to it as a “poor man’s FPGA” which isn’t a bad way of thinking about it in this context. Yes, he could have just stuck an emulator on that chip, but what’s the fun in that?

The controls are squeezed into the sides of the watch — the four face buttons on one side, and a tiny D-pad on the other — but that’s easy enough because this thing is 15 mm thick. Since [LeggoMyFroggo] is a purist, he insists on loading the games via cartridge, which does not help thin it out. Game Boy carts are not not watch-friendly, so the cartridges are custom PCBs that plug into an M.2 slot, but with the original (or at least compatible) ROM.

If it wasn’t for the cartridge slot, maybe a battery would have fit. But it doesn’t, which leads to our favorite part of the hack: the battery is in the watch strap. This is both kind of crazy, but also brilliant. The band is cast in silicone, so he’s able to embed a flexi-PCB inside. As for the watch body, that’s CNC’d out of 6061 aluminum before being anodized to a very Nintendo-esque purple.

[Chris] evidently has a soft spot for the Game Boy Color — we featured his FrogBoy re-imagining of the handheld a few years back. The project is just up on YouTube as of this writing, but the watch will join the FrogBoy on [Chris]’s GitHub so we can all get in on the fun once he’s finished the documentation.

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Muon Magnetic Moment Matches Model, Making Major Malaise

Sometimes, a major discovery is exactly what you were hoping not to find. That’s the case with a team at Penn State who seem to have recently closed the door on any new physics stemming from a longstanding discrepency in the magnetic moment of the muon. It turns out, the model was fine, and we just needed better calculations.

The Muon is a heavier cousin to the electron. Like the electron, it has an intrinsic magnetic moment, but the traditional methods to calculate it did not quite match experiments, which was very exciting because it made us hope our models could be improved. Rather than try the traditional approximation methods for the unsolvable equations, the group at Penn State set up what you can think of as the Quantum Chromodynamic equivalent of a Finite Element Model (FEM) simulation–a grid of discrete steps in space and time. Tiny ones, of course, because the muon, like the electron, is a point-like particle with no lower size limit. In any case, according to their paper in Nature, after a decade of refinement and increasingly expensive supercomputer runs, the mystery can be put to bed. Instead of the discrepancy that so exited physicists 25 years ago when it was first found, theory and experiment now match to 11 digits, or a 0.5 sigma discrepancy, if you prefer.

Statistically, the Standard Model works– and that kind of sucks. It sucks, because it’s the gaps in the model where new physics are possible, and everyone has been pushing at those few gaps for the last 50 years to try and find what might be behind the standard model. Even [Zoltan Fodor], the principle investigator behind this project, is sad to see it work out. Sure, it’s a feather in his cap to get the calculations right at last–but ask anybody in the field, and they’d rather keep the door open to new physics than be right. We were certainly hoping it was something novel, last time the topic came up.

You might think muons are the last thing a hacker would ever encounter, but since there’s a steady rain of them from the sky in the form of cosmic rays, it’s not only easy to interact with them, you can actually put them to practical use– like muon tomography, or navigation indoors and underground.

Header Image Credit: Dani Zemba / Penn State

Reviving Nintendo’s Early Arcade Game, Wild Gunman

There’s retrogaming, and then there’s retro gaming. This next project falls into the second category, as [Callan] of 74XX Arcade Repair digs into the original Wild Gunman, first released by Nintendo way, way back in 1974 — on 16 mm film. Yes, it was a film-based arcade machine, but how else were you going to get realistic graphics just two years after PONG?

The game had two 16 mm projectors, with four different sets of film reels available, each depicting five gunmen. Unfortunately for [Callan], the film is all he has, so he’s not so much repairing as re-creating the historic game. Luckily, he had the manuals, so at least he knew how it was supposed to come together.

One projector did most of the work, showing the gunmen and a hidden timing signal for the game to know when the user could shoot; the other only activated if the user pulled the trigger at the correct time. Interestingly the ‘gun’ has an IR illuminator that bounced infrared light off the screen to a detector in the cabinet — much like later TV remotes. That makes for a rather large circular hitbox around the enemy gunslinger, which is perhaps not a bad thing for a game likely to be found in a bar.

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Encrypting Encrypted Traffic To Get Around VPN Bans

VPNs, Virtual Private Networks, aren’t just a good idea to keep your data secure: for millions of people living under restrictive regimes they’re the only way to ensure full access to the internet. What do you do when your government orders ISPs to ban VPNs, like Russia has done recently?  [LaserHelix] shows us one way you can cope, which is to use a ShadowSocks proxy.

If you’re not deep into network traffic, you might be wondering: how can an ISP block VPN traffic? Isn’t that stuff encrypted? Yes, but while the traffic going over the VPN is encrypted, you still need to connect to your VPN’s servers– and those handshake packets are easy enough to detect. You can do it at home with Wireshark, a tool that shows up fairly often on these pages. Of course if they can ID those packets, they can block them.

So, you just need a way to obfuscate what exactly the encrypted traffic you’re sending is. Luckily that’s a solved problem: Chinese hackers came up with something called Shadowsocks back in 2012 to help get around the Great Firewall, and have been in an arms-race with their authorities ever since.

Shadowsocks is not, in fact, a sibling of Gandalf’s horse as the name might suggest, but a tool to obfuscate the traffic going to your VPN. To invert a meme, you’re telling the authorities: we heard you don’t like encrypted traffic, so we put encryption in your encrypted traffic so you have to decrypt the packets before you recognize the encrypted packets.

What about the VPN? Well, some run their own shadowsocks service, while others will need to be accessed via a shadowsocks bridge: in effect, a proxy that then connects to the VPN for you. That means of course you’re bouncing through two servers you need to trust not to glow in the dark, but if you have to trust someone– otherwise it’s off to a shack in the woods, which never ends well.

Don’t forget that while VPNs can get you around government censorship, they do not provide anonymity on their own. If, like tipster [Keith Olson] –thanks for the tip, [Keith]!– you’re looking side-eyed at your government’s “think of the children!” rhetoric but don’t know where to start, we had a discussion about which VPNs to use last year.

Analog Circuitry Lets You Blow This LED Out

LED candles are neat, but they’re very suboptimal for wish-making: you can’t blow them out. Unless you take the circuit from [Andrea Console]’s latest project that lets you do just that, using only analog electronics— no microcontroller in sight.

He’s using the known temperature-voltage behaviour of the LED for control here– sort of like the project we saw in last year’s Component Abuse Challenge that let you illuminate the LED with a butane lighter. Here it’s a bit less dramatic, relying only on the small cooling effect your breath has on the LED.

There are two parts to the circuit, really– a latching section to turn the thing on from a single button press, and breath-detecting section. The breath-detecting section relies on an op-amp acting as a comparator, comparing the voltage across the LED’s current-limiting resistor, and a reference stored in a 100 µF capacitor. Blowing on the candle spikes the voltage on the LED, and thus the current-limiting resistor too fast for the capacitor’s voltage to change, so the comparator flips, triggering a reset of the latching circuit. Could you do it with an Arduino? No doubt, but the fact is you don’t have to and this is a more elegant solution than just another microcontroller.Check it out in action with the video embedded below.

It reminds us of the sort of circuit we’d have found in a project book, back in the day. [Andrea] seems to have a knack for that sort of thing, as seen with the half crystal/half regenerative radio we saw previously. Continue reading “Analog Circuitry Lets You Blow This LED Out”