SOL75 Uses AI To Design Standard Mechanical Parts

July 19, 2021 by 19 Comments

[Francesco] developed a parametric design tool called SOL75 which aims to take the drudgery out of designing the basic mechanical parts used in projects. He knows how to design things like gears, pulleys, belts, brackets, enclosures, etc., but finds it repetitive and boring. He would rather spend his time on the interesting and challenging portions of his project instead.

The goal of SOL75 is to produce OpenSCAD and STL files of a part based on user requirements. These parameters go beyond the simple dimensional and include performance characteristics such as peak stress, rigidity, maximum temperature, etc. The program uses OpenSCAD to generate the geometries and a core module to evaluate candidate designs. In an attempt to overcome the curse of dimensionality, [Francesco] has trained an AI oracle to quickly accept or reject candidate solutions.

In the realm of parametric design aids, you have projects like NopSCADlib which dimensionally parameterize a large collection of common objects by numbers alone ( a 100 cm long, 6.35 mm diameter brass tube with 1.22 mm wall thickness ) or industry standard specifications ( a 10 mm long M3 socket head cap screw ). This approach doesn’t take into account whether the object will hold up in your application nor does it consider any 3D printing issues. At the other extreme, there are the generative design and optimization tools found in professional packages like Fusion 360 and SolidWorks which can make organic-looking items that are optimized precisely for the specified conditions.

SOL75 seems to fall in the middle, combine characteristics of both approaches. It gives you the freedom to select dimensional parameters and performance requirements, yet bounds the solution space by only offering objects that have been prepared ahead of time by domain experts — if you ask for an L-bracket, you’ll get an L-bracket and not something that looks like a spider web or frog leg.

Once you compile the design, SOL75 generates the OpenSCAD and/or STL files and a bill of materials. But wait — there’s more– it also makes a thorough design handbook documenting the part in great detail, including the various design considerations and notes on printing. Here is a demonstration link for an electronics enclosure which is pretty interesting. There is also an example of using SOL75 to make a glider, which you can read about on the Hackaday.io project page.

For now, [Francesco] has only made SOL75 available in a register-by-email online Beta version, as he’s still undecided on what form the final version will be. Do you have any success (or failure) stories regarding generative designs? Let us know in the comments below.

Hackaday Podcast 127: Whippletree Clamps, Sniffing Your Stomach Radio, Multimeter Hum Fix, And C64 Demo; No C64

July 16, 2021 by No comments

Hackaday editors Mike Szczys and Elliot Williams help you get caught up on a week of wonder hacks. We don’t remember seeing a floppy drive headline the demoscene, but sure enough, there’s a C64 demo that performs after the computer is disconnected. What causes bench tools to have unreliable measurements? Sometimes a poor crystal choice lets AC ruin the party. We dive into the ongoing saga of the Audacity open source project’s change of ownership, and talk about generator exciter circuits — specifically their role in starting grid-scale generators from shutdown.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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Hackaday Links: June 27, 2021

June 27, 2021 by 24 Comments

When asked why he robbed banks, career criminal Willie Sutton is reported to have said, “Because that’s where the money is.” It turns out that a reporter made up the quote, but it’s a truism that offers by extension insight into why ATMs and point-of-sale terminals are such a fat target for criminals today. There’s something far more valuable to be taken from ATMs than cash, though — data, in the form of credit and debit card numbers. And taking a look at some of the hardware used by criminals to get this information reveals some pretty sophisticated engineering. We’d heard of ATM “skimmers” before, but never the related “shimmers” that are now popping up, at least according to this interesting article on Krebs.

While skimmers target the magnetic stripe on the back of a card, simmers are aimed at reading the data from card chips instead. Shimmers are usually built on flex PCBs and are inserted into the card slot, where traces on the device make contact with the chip reader contacts. The article describes a sophisticated version of shimmer that steals power from the ATM itself, rather than requiring a separate battery. The shimmer sits inside the card slot, completely invisible to external inspection (sorry, Tom), and performs what amounts to man-in-the-middle attacks. Card numbers are either stored on the flash and read after the device is retrieved, or are read over a Bluetooth connection; PINs are stolen with the traditional hidden camera method. While we certainly don’t condone criminal behavior, sometimes you just can’t help but admire the ingenuity thieves apply to their craft.

In a bit of foreshadowing into how weird 2020 was going to be, back in January of that year we mentioned reports of swarms of mysterious UAVs moving in formation at night across the midwest United States. We never heard much else about this — attention shifted to other matters shortly thereafter — but now there are reports out of Arizona of a “super-drone” that can outrun law enforcement helicopters. The incidents allegedly occurred early this year, when a Border Patrol helicopter pilot reported almost colliding with a large unmanned aerial system (UAS) over Tucson, and then engaged them in a 70-mile chase at speeds over 100 knots. The chase was joined by a Tucson police helicopter, with the UAS reaching altitudes of 14,000 feet at one point. The pilots didn’t manage to get a good look at it, describing it only as having a single green light on its underside. The range on the drone was notable; the helicopter pilots hoped to exhaust its batteries and force it to land or return to base, but they themselves ran out of fuel long before the drone quit. We have to admit that we find it a little fishy that there’s apparently no photographic evidence to back this up, especially since law enforcement helicopters are fairly bristling with sensors, camera, and spotlights.

When is a backup not a backup? Apparently, when it’s an iCloud backup. At least that’s the experience of one iCloud user, who uses a long Twitter thread to vent about the loss of many years of drawings, sketches, and assorted files. The user, Erin Sparling, admits their situation is an edge case — he had been using an iPad to make sketches for years, backing everything up to an iCloud account. When he erased the iPad to loan it to a family member for use during the pandemic, he thought he’s be able to restore the drawings from his backups, but alas, more than six months had passed before he purchased a new iPad. Apparently iCloud just up and deletes everythign if you haven’t used the account in six months — ouch! We imagine that important little detail was somehere in the EULA fine print, but while that’s not going to help Erin, it may help you.

And less the Apple pitchfork crowd think that this is something only Cupertino could think up, know that some Western Digital external hard drive users are crying into their beer too, after a mass wiping of an unknown number of drives. The problem impacts users of the WD My Book Live storage devices, which as basically network attached storage (NAS) devices with a cloud-based interface. The data on these external drives is stored locally, but the cloud interface lets you configure the device and access the data from anywhere. You and apparently some random “threat actors”, as WD is calling them, who seem to have gotten into some devices and performed a factory reset. While we feel for the affected users, it is worth noting that WD dropped support for these devices in 2015; six years without patching makes a mighty stable codebase for attackers to work on. WD is recommending that users disconnect these devices from the internet ASAP, and while that seems like solid advice, we can think of like half a dozen other things that need to get done to secure the files that have accumulated on these things.

And finally, because we feel like we need a little palate cleanser after all that, we present this 3D-printed goat helmet for your approval. For whatever reason, the wee goat pictured was born with a hole in its skull, and some helpful humans decided to help the critter out with TPU headgear. Yes, the first picture looks like the helmet was poorly Photoshopped onto the goat, but scroll through the pics and you’ll see it’s really there. The goat looks resplendent in its new chapeau, and seems to be getting along fine in life so far. Here’s hoping that the hole in its skull fills in, but if it doesn’t, at least they can quickly print a new one as it grows.

 

Mechanical 7-Segment Display Uses A Single Motor

June 27, 2021 by 29 Comments

Seven-segment displays have been around for a long time, and there is a seemingly endless number of ways to build them. The latest of is a mechanical seven-segment from a master of 3D printed mechanisms, [gzumwalt], and can use a single motor to cycle through all ten possible numbers.

The trick lies in a synchronized pair of rotating discs, one for the top four segments and another for the bottom three segments. Each disc has a series of concentric cam slots to drive followers that flip the red segments in and out of view. The display can cycle through all ten states in a single rotation of the discs, so the cam paths are divided in 36° increments. [gzumwalt] has shown us a completed physical version, but judging by CAD design and working prototype of a single segment, we are pretty confident it will. While it’s not shown in the design, we suspect it will be driven by a stepper motors and synchronized with a belt or intermediate gear.

Another 3D printed mechanical display we’ve seen recently is a DIY flip dot, array, which uses the same electromagnet system as the commercial versions. [gzumwalt] has a gift for designing fascinating mechanical automatons around a single motor, including an edge avoiding robot and a magnetic fridge crawler.

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1700 Regulatory Approvals Revoked In South Korea

June 19, 2021 by 40 Comments

For the first time since its inception, the Korea Communications Commission this week revoked the regulatory approvals of 1,696 telecommunications devices from 378 companies, both foreign and domestic. Those companies must recall unsold inventory from the shelves, and prove conformity of existing products already sold. In addition, the companies may not submit new applications for these items for one year. It’s not clear what would happen to already-sold equipment if the manufacturer is unable to prove conformity as requested — perhaps a recall? Caught up in this are CCTV products, networking equipment, Bluetooth speakers, and drones from companies like Huawei, DJI, and even Samsung.

The heart of the issue are what’s known as Mutual Recognition Agreements (MRAs) between countries to officially recognize of each other’s certification testing laboratories (or Conformity Assessment Bodies, CAB, in the lingo of the industry). Currently ten countries (USA, Canada, Mexico, UK, Israel, Japan, Korea, Singapore, Vietnam, and Australia), the 27 member states of the EU, Taiwan and Hong Kong all have MRAs with each other. Based on these MRAs, a Korean manufacturer could have a product tested by a laboratory in Israel, for example, and all would be kosher with the KCC.

At the center of attention is the Bay Area Compliance Laboratories (BACL), established in 1996 and headquartered in Sunnyvale, California. BACL has laboratories all over the world (USA, Taiwan, Hong Kong, Vietnam, and mainland China). Except for those in mainland China, all BACL laboratories are acceptable per the MRAs. The KCC received a tip last year that some compliance test reports for some products might be defective.

A six-month investigation in cooperation with the US National Institute of Standards and Technology (NIST) resulted in the announcement this week. Korean companies, 378 of them to be exact, had submitted test reports from BACL Sunnyvale which appeared to be appropriate. But on further investigation, it was learned that the actual testing was done by BACL laboratories in mainland China and only the reports were prepared in Sunnyvale.

It’s not clear whether these companies were knowingly playing fast and loose with the rules, whether BACL was complicit, if it was just a misunderstanding of the intricacies of the regulations and MRAs, or a combination of all three. Regardless, the KCC said that intent doesn’t matter according the their rules. It also has not been suggested that the products themselves are problematic, nor has anyone suggested that BACL’s Chinese laboratories performed slipshod work — rather, the KCC says it has no choice but to proceed with the revocation based on the applicable laws.

Vacuum Tube Magic Comes To The 741

June 19, 2021 by 41 Comments

Some of you may remember a recent project that featured on these pages, a 555 timer reproduced using vacuum tubes. Its creator [Usagi Electric] was left at loose ends while waiting for a fresh PCB revision of the 555 to be delivered, so set about creating a new vacuum tube model of a popular chip, this time the ubiquitous 741 op-amp. (Video, embedded below.)

The circuit is fairly straightforward, using six small pentodes. The first two are  a long-tailed pair as might be expected, followed by two gain stages, then a final gain stage feeding a cathode follower with feedback. It’s neatly built on a PCB with IC-style “pins” made from more PCB material, then put in a huge replication of an IC socket on a wooden baseboard.

The result is an op-amp, but not necessarily a good one. He looks at the AC performance instead of the DC even though it’s a fully DC-coupled circuit, and finds that while it performs as expected in a classic op-amp circuit it still differs from the ideal at higher gain. The frequency response is poor too, something he rectifies by replacing the feedback capacitor with a smaller value. Sadly he doesn’t look at its common mode performance, though we’d expect that without close matching of the tubes it might leave something to be desired.

It’s obvious that this project would never be selected as an op-amp given the quality of even the cheapest silicon op-amp in comparison. But its value is in a novelty, a talking point, and maybe a chance to learn about op-amps. For that, we like it.

We covered the vacuum tube 555 when details of it emerged, but if op-amps are your bag we’ve looked at a simple one very closely indeed.

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Formula 1 TV Broadcasting In 1:87 Scale

June 18, 2021 by 11 Comments

[Gerrit Braun], co-founder of the [Miniatur Wunderland] model railway and miniature airport attraction in Hamburg, takes his model building seriously. For more than five years, he and his team have been meticulously planning, testing, and building a 1:87 scale of Formula 1’s Monaco Grand Prix. Models at the Wunderland are crafted to the Nth detail and all reasonable efforts, and some unreasonable ones, are taken to achieve true-to-life results. In the video down below, part of Gerrit’s diary of the project, he discusses the issues and solutions to simulating realistic television broadcasts (the video is in German, but it has English language subtitles).

The goal is to model the large billboard-sized monitor screens set up at viewing stands. In real life, these displays are fed with images coming in from cameras located all over the circuit, the majority of which are operated by a cameraman. The miniaturization of cameras has come a long way in recent years — the ESP32-CAM module or the Raspberry Pi cameras, for example. But miniaturizing the pan-and-tilt actions of a cameraman, while perhaps possible, would not be reliable over the long time (these exhibits at Wunderland are permanent and operate almost daily). Instead, the team is able to use software to extract a cropped window from high-resolution video, and moving the position of this cropped window simulates the pointing of the camera. More details are in the video.

The skill and creativity of [Gerrit] and his team is incredible. Other videos on this project cover topics like the sound system, PCB techniques used for the roads, and the eye-popping use of an electric standing desk to lift an entire city block so workers can gain access to the area. Fair warning — these are addictive, and the video below is #76 of an unfinished series. We wrote about Wunderland back in 2016 when [Gerrit] and his twin brother [Frank] teamed with Google Maps to make a street view of their replica cities. Thanks to [Conductiveinsulation] who sent us the tip, saying that the discussion about interconnected triangular PCB tiles on this week’s Podcast #122 reminded him of this for some reason. Have any of our readers visited Miniatur Wunderland before? Let us know in the comments below.

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