Screwless Eyeballs Are A Lesson In Design-For-Assembly

June 8, 2024 by Dan Maloney 9 Comments

[Will Cogley] makes eyeballs; hey, everyone needs a hobby, and we don’t judge. Like all his animatronics, his eyeballs are wondrous mechanisms, but they do tend toward being a bit complex, especially in terms of the fasteners needed to assemble them.

But not anymore. [Will] redid his eyeball design to be as easy to assemble as possible, and the results are both impressive and instructive. His original design mimics real eyeballs quite well, but takes six servos and a large handful of screws and nuts, which serve both to attach the servos to the frame and act as pivots for the many, many linkages needed. The new design has snap-fit pivots similar to Lego Technic axles printed right into the linkage elements, as well as snap connectors to hold the servos down. This eliminates the need for 45 screws and cuts assembly time from 30 minutes to about six, with no tools required. And although [Will] doesn’t mention it, it must save a bunch of weight, too.

Everything comes at a cost, of course, and such huge gains in assembly ease are no exception. [Will] details this in the video below, including printing the parts in the right orientation to handle the forces exerted both during assembly and in use. And while it’s hard to beat a five-fold reduction in assembly time, he might be able to reduce that even more with a few print-in-place pivots.

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A screenshot of the website, showing various parts from Western manufacturers

How Many Western ICs Are There In Russia’s Weapons?

June 8, 2024 by Arya Voronova 60 Comments

Recently, the Ukrainian government has published a database of Western components being used in recently produced Russian armaments, and it’s a fascinating scroll. Just how much does Russia rely on Western manufacturers’ parts? It turns out, a surprising amount. For instance, if you are wondering which ICs are used to build Iran-produced Shahed drones, it seems that it’s a whole bunch of Texas Instruments parts, as well as some Maxim, Intel, and Xilinx ones. Many of the parts in the lists are MCUs and FPGAs, but it’s also surprising how many of the components are jelly bean parts with multiple suppliers.

There appear to be thousands of parts listings, compiled from a good few dozen pieces of equipment that volunteers appear to have taken apart and scrupulously documented – just take a look at the dropdowns at the top of the page. The Ukrainian government is advocating for parts restrictions to be implemented based upon this data – as we all remember, it’s way harder to produce hardware when you can’t buy crucial ICs.

Even for a regular hacker, this database is worth a scroll, if only to marvel at all the regular parts we wouldn’t quite associate with military use. Now, all that’s left is to see whether any of the specific chips pictured have been sold to washing machine manufacturers.

Gas-Tight FDM 3D Printing Is Within Your Grasp

June 8, 2024 by Jenny List 65 Comments

The widespread availability of inexpensive 3D printers has brought about a revolution in what can be easily made at home. However these creations aren’t perfect, particularly when it comes to the adhesion between their layers. Aside from structural failures along the layer lines there is also the question of those joins being permeable, limiting the possibility for waterproof or gas proof prints. It’s something [German Engineer] has tackled in a new video, in which he’s looking at the design and preparation of small propane tanks.

A blurry image of a red 3d-printed part exploding — This is the frame at which the 3D printed tank explodes

The attraction of propane as a fuel is that it liquefies easily on compression, so a propane cylinder or tank will be an equilibrium of liquid propane with pressurized gas above it, whose pressure depends on the ambient temperature. This means that any tank must be expected to have a working pressure somewhere between 150 and 200 PSI, with of course a design pressure far exceeding that for safety reasons.

Filling a 3D printed tank immediately results in the propane escaping, as he demonstrates by putting one of his prints under water. He solves this with a sealant, Diamant Dichtol, which is intended to polymerize in the gaps between layers and create a gas-tight tank. A range of three tanks of different thicknesses are treated this way, and while the 1 mm thick variety bursts, the thicker ones survive.

It’s clear that this technique successfully creates gas-tight prints, and we can see the attraction of a small and lightweight fuel tank. But we can’t help worrying slightly about the safety, for even when the material is a lightweight 3D print, high pressure equipment is not to be trifled with. Tanks do burst, and when that happens anyone unfortunate enough to be close by sustains nasty, even life-threatening injuries. Use the technique, but maybe don’t hit it with high pressures.

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Happy Birthday, Tetris!

June 8, 2024 by Elliot Williams 6 Comments

Porting DOOM to everything that’s even vaguely Turing complete is a sport for the advanced hacker. But if you are just getting started, or want to focus more on the physical build of your project, a simpler game is probably the way to go. Maybe this explains the eternal popularity of games like PONG, Tetris, Snake, or even Pac-Man. The amount of fun you can have playing the game, relative to the size of the code necessary to implement them, make these games evergreen.

Yesterday was Tetris’ 40th birthday, and in honor of the occasion, I thought I’d bring you a collection of sweet Tetris hacks.

On the big-builds side of things, it’s hard to beat these MIT students who used colored lights in the windows of the Green Building back in 2012. They apparently couldn’t get into some rooms, because they had some dead pixels, but at that scale, who’s complaining? Coming in just smaller, at the size of a whole wall, [Oat Foundry]’s giant split-flap display Tetris is certainly noisy enough.

Smaller still, although only a little bit less noisy, this flip-dot Tetris is at home on the coffee table, while this one by [Electronoobs] gives you an excuse to play around with RGB LEDs. And if you need a Tetris for your workbench, but you don’t have the space for an extra screen, this oscilloscope version is just the ticket. Or just play it (sideways) on your business card.

All of the above projects have focused on the builds, but if you want to tackle your own, you’ll need to spend some time with the code as well. We’ve got you covered. Way back, former Editor in Chief [Mike Szczys] ported Tetris to the AVR platform. If you need color, this deep dive into the way the NES version of Tetris worked also comes with demo code in Java and Lua. TetrOS is the most minimal version of the game we’ve seen, coming in at a mere 446 bytes, but it’s without any of the frills.

No Tetris birthday roundup would be complete without mentioning the phenomenal “From NAND to Tetris” course, which really does what it says on the package: builds a Tetris game, and your understanding of computing in general, from the ground up.

Can you think of other projects to celebrate Tetris’ 40th? We’d love to see your favorites!

Baffle The Normies With This Binary Thermometer

June 8, 2024 by Dan Maloney 9 Comments

We think it’s OK to admit that when someone puts a binary display on a project, it’s just a thinly veiled excuse to get more blinkenlights into the world. That and it’s a way to flex a little on the normies; you’ve gone pretty far down the tech rabbit hole to quickly decipher something like this binary-display thermometer, after all.

Don’t get us wrong, we think those are both perfectly valid reasons for going binary. And all things considered, a binary display for a thermometer like [Clovis Fritzen]’s is much simpler to decode than, say, a clock. Plus, it seems a bit that this build was undertaken at least partially as an exercise in Charlieplexing, which [Clovis] uses to drive the six-bit LED display using only three lines of GPIO from the Digispark ATtiny85 board running the show.

The temperature sensor is a DHT11, whose output is read by the microcontroller before being converted to binary and sent to the six-bit display. The 64-degree range is perfect for displaying the full range of temperatures most of us would consider normal, although we’d find 63°C a touch torrid so maybe there’s a little too much resolution on the upper end of the scale. Then again, switching to Fahrenheit would shift it toward the hypothermia end of the scale, which isn’t helpful. And you can just forget about Kelvin.

The Cheap CNC3018 Gets A Proper Revamp

June 8, 2024 by Dave Rowntree 24 Comments

Many people have been attracted to the low price and big dreams of the CNC3018 desktop CNC router. If you’re quick, you can pick one up on the usual second-hand sales sites with little wear and tear for a steal. They’re not perfect machines by any stretch of the imagination, but they can be improved upon, and undoubtedly useful so long as you keep your expectations realistic.

[ForOurGood] has set about such an improvement process and documented their journey in a whopping eight-part (so far!) video series. The video linked below is the most recent in the series and is dedicated to creating a brushless spindle motor on a budget.

As you would expect from such a machine, you get exactly what you pay for. The low cost translates to thinner than ideal metal plates, aluminium where steel would be better, lower-duty linear rails, and wimpy lead screws. The spindle also suffers from cost-cutting, as does the size of the stepper motors. But for the price, all is forgiven. The fact that they can even turn a profit on these machines shows the manufacturing prowess of the Chinese factories.

We covered the CNC 3018 a while back, and the comments of that post are a true gold mine for those wanting to try desktop CNC. Warning, though: It’s a fair bit harder to master than 3D printing!

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The End Of BLHeli_32: Long Live AM32?

June 7, 2024 by Maya Posch 11 Comments

An essential part of drones are the Electronic Speed Controller (ESC) which translate the commands from the flight computer into responses by the connected brushless motors (generally BLDCs). As the ESC determines a lot of the performance characteristics of a drone, it has its own firmware, which for (FPV) drones is overwhelmingly BLHeli, specifically the 32-bit version (BLHeli_32). Now the Norwegian company (BLHeli AS) behind this closed source firmware has thrown in the towel, citing illegal use of its firmware by sanctioned countries like Russia for purposes like warfare. This news and its implications are covered in detail in a video by the [Mads Tech] YouTube channel, including the message sent to customers by the company’s lawyer.

So far the GitHub repository is still online, featuring binary images for BLHeli_32, as well as the open source BLHeli (8-bit Atmel/Silabs) firmware and BLHeli_S (multirotor 8-bit Silabs) firmware. Due to the open source nature of these earlier projects forks already exist, such as BlueJay for BLHeli_S, and with the AM32 project there is an open source 32-bit ESC alternative. For 8-bit platforms it would thus seem that even with BLHeli_32 vanishing there is no impact at all, while for 32-bit platforms AM32 seems to be largely a drop-in solution.

Regardless of the reasons behind BLHeli_32 vanishing like this, the community and businesses can now hopefully move their (financial) support over to the AM32 project, making this more of a blip than an outright disaster for those who are into their high-end multicopter drones.

Thanks to [Frank Zhao] for the tip.

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