Image Credit: https://3dp.se/2018/04/17/3dmeetup-lockade-entusiaster-i-alla-aldrar/

Remembering Sanjay Mortimer, Pioneer And Visionary In 3D Printing

December 1, 2021 by 24 Comments

Over the weekend, Sanjay Mortimer passed away. This is a tremendous blow to the many people who he touched directly and indirectly throughout his life. We will remember Sanjay as pioneer, hacker, and beloved spokesperson for the 3D printing community.

If you’ve dabbled in 3D printing, you might recall Sanjay as the charismatic director and co-founder of the extrusion company E3D. He was always brimming with enthusiasm to showcase something that he and his company had been developing to push 3D printing further and further. But he was also thoughtful and a friend to many in the community.

Let’s talk about some of his footprints.

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The supersonic trebuchet being modeled in software

Supersonic Projectile Exceeds Engineers Dreams: The Supersonic Trebuchet

December 1, 2021 by 62 Comments

Have you ever sat down and thought “I wonder if a trebuchet could launch a projectile at supersonic speeds?” Neither have we. That’s what separates [David Eade] from the rest of us. He didn’t just ask the question, he answered it! And he documented the entire build in a YouTube video which you can see below the break.

The trebuchet is a type of catapult that was popular for use as a siege engine before gunpowder became a thing. Trebuchets use a long arm to throw projectiles farther than traditional catapults. The focus has typically been on increasing throwing distance for the size of the projectile, or vice versa. But of course you’re here to read about the other thing that trebuchets can be used for: speed.

How fast is fast? How about a whip-cracking, sonic-booming speed in excess of 450 meters per second! How’d he do it? Mostly wood and rubber with some metal bits thrown in for safety’s sake. [David]’s video explains in full all of the engineering that went into his trebuchet, and it’s a lot less than you’d think. There’s a very satisfying montage of full power trebuchet launches that make it audibly clear that the projectile being thrown is going well past the speed of sound, with a report quite similar to that of a small rifle.

[David]’s impressive project and presentation makes it clear that all one has to do to build a supersonic trebuchet is to try. Just be careful, and watch where you shoot that thing before you put somebody’s eye out, ok?

Speaking of things that can go unexpectedly fast, check out these unpowered RC gliders that approach the speed of sound just feet off the ground. And thanks to [Keith] for the awesome Tip!

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The Medieval History Of Your Favourite Dev Board

December 1, 2021 by 20 Comments

It’s become something of a trope in our community, that the simplest way to bestow a level of automation or smarts to a project is to reach for an Arduino. The genesis of the popular ecosystem of boards and associated bootloader and IDE combination is well known, coming from the work of a team at the Interaction Design Institute Ivrea, in Northern Italy. The name “Arduino” comes from their favourite watering hole, the Bar di Re Arduino, in turn named for Arduin of Ivrea, an early-mediaeval king.

As far as we can see the bar no longer exists and has been replaced by a café, which appears on the left in this Google Street View link. The bar named for Arduin of Ivrea is always mentioned as a side note in the Arduino microcontroller story, but for the curious electronics enthusiast it spawns the question: who was Arduin, and why was there a bar named after him in the first place?

The short answer is that Arduin was the Margrave of Ivrea, an Italian nobleman who became king of Italy in 1002 and abdicated in 1014. The longer answer requires a bit of background knowledge of European politics around the end of the first millennium, so if you’re ready we’ll take Hackaday into a rare tour of medieval history.

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3D Printed Generator Build Highlights The Scientific Method

December 1, 2021 by 6 Comments

Sometimes we build to innovate, and sometimes we build just to have the satisfaction of saying we made it ourselves. Yet there is another reason to construct something ourselves: To learn, just as [Fraens] has done with this 3D-printed generator. (Video, embedded below.)

[Fraens] starts off with a jig for winding the individual coils, but then the jig itself snaps into a the stator ring. The stator ring is sandwiched by two rotors which rotate on a brass shaft suspended by needle bearings. With the exception of the hardware, all the structural parts are 3d printed.

What really separates the generator build isn’t how it’s built, but rather how [Fraens] has put it to use as tool for learning and experimentation. By plotting input torque vs electrical output, [Fraens] is able to calculate efficiencies in multiple configurations, and has some interesting conclusions to share toward the end of the video. We appreciate how the documentation and analysis help iterate the design towards higher efficiency and will inform the next build.

With some more work, we can see this going straight into a Vertical Axis Wind Turbine or attached to a Pelton Wheel for an off-grid hydro-power setup. Thanks to [Shabab] for the great Tip!

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Ask Hackaday: Why Don’t Automakers Make Their Own EV Batteries?

December 1, 2021 by 88 Comments

Sales of electric vehicles continue to climb, topping three million cars worldwide last year. All these electric cars need batteries, of course, which means demand for rechargeable cells is through the roof.

All those cells have to come from somewhere, of course, and many are surprised to learn that automakers don’t manufacture EV batteries themselves. Instead, they’re typically sourced from outside suppliers. Today, you get to Ask Hackaday: why aren’t EV batteries manufactured by the automakers themselves? Continue reading “Ask Hackaday: Why Don’t Automakers Make Their Own EV Batteries?” →

Korean Facial Recognition Project Faces Opposition

December 1, 2021 by 20 Comments

It was discovered last month that a South Korean government project has been providing millions of facial images taken at Incheon International Airport to private industry without the consent of those photographed. Several civic groups called this a “shocking human rights disaster” in a 9 Nov press conference, and formally requested that the project be cancelled. In response, the government has only promised that “the project would be conducted at a minimum level to ensure personal information is not abused”. These groups are now planning a lawsuit to challenge the project.

Facial information and other biometric data aren’t easily altered and are unique to the individuals concerned. If this data were to be leaked, it would constitute a devastating infringement upon their privacy. It’s unheard of for state organizations — whose duty it is to manage and control facial recognition technology — to hand over biometric information collected for public purposes to a private-sector company for the development of technology.

The program itself wasn’t secret, and had been publicly announced back in 2019. But the project’s scope and implementation weren’t made clear until a lawmaker recently requested documents on the project from the responsible government agencies. The system, called the Artificial Intelligence and Tracking System Construction Project, was a pilot program set to run until 2022. Its goals were to simplify the security and immigration screening of passengers, improve airport security, and to promote the local AI industry in South Korea. If the project proves successful, the plan is to expand it to other airports and ports in the country.

Current systems at the airport do one-to-one facial recognition. For example, they try to determine whether the face of the person presenting a passport matches the photo in the passport. The goal of this new project was to develop one-to-many matching algorithms, which can match one face against the plethora of faces in an airport, track the movement of a face within the airport, and flag “suspicious” activities which could be a security concern.

The groups protesting the project note that the collection and sharing of these images without the travelers’ consent is prohibited by the Personal Information Protection Act, the South Korean law which governs such things. Under this act, a project like this would ordinarily require consent of the participants. But the government’s interpretation relies on an exception in the act, specifically, Article 15 Section 3, which states:

A personal information controller may use personal information without the consent of a data subject within the scope reasonably related to the initial purpose of the collection

Basically they are saying that since the images were collected at the security and immigration checkpoints, and that the project will be using them to improve the security and immigration checkpoints, no consent is required.

  • Foreigners: 120 million individuals, face image, nationality, gender, age
  • Korean citizens: 57.6 million individuals, face image, nationality, gender, age
  • Other: unknown number of individuals, images and videos of atypical behavior and travelers in motion

The breakdown of the numbers above reveals that 57 million Korean citizens are in the data set, a bit surprising to many since the collection of biometric data on Korean citizens at immigration is prohibited by law. The project circumvented this by only collecting data from citizens who participate in the automated Smart Entry service, a voluntary program which uses fingerprints and facial recognition. It’s interesting to note that the number of passengers using Incheon airport since May 2019 (the program was announced 30 Apr 2019) is only 62 million, so the average passenger appears approximately three times in the data set.

Are there any similar programs in your region? How do they handle the issue of consent, if at all? Let us know in the comments below.

[Banner image: “Customer uses facial recognition as identification at TSA security checkpoint” by DeltaNewsHub, CC BY 2.0  — Yes, it’s from another country with similar problems, but much less public outcry. Discuss in the comments!]