Keeping Kids In School The Smart Way

September 30, 2019 by Sharon Lin 44 Comments

For institutions with high traffic, such as schools and movie theaters, it can be difficult to keep track of individuals moving in and out, especially without a critical mass of security. For schools especially, keeping track of student attendance and preventing kids from leaving campus in the middle of the day can be a costly problem.

The solution that Tunisian engineers [Michael Djimeli], [Darius Koliou], and [Jinette Tankoua] came up with was to create a smart gate that only turns when checks are carried out by designated security officers. The design is retrofitted to existing school turnstiles in his hometown of Monastir, Tunisia, and uses an RFID card, biometric devices, and a host of access controls to ensure that the student attempting to turn the turnstile is validated first.

The smart gate uses a few methods for identification – either by RFID, fingerprint, facial recognition, or by reading a QR code. An external database stores each user’s data and their transaction history, effectively storing their attendance data. In addition to relaying the information to an administrator, the smart gate also checks the credit of the user — whether they’ve paid the entrance fee for a movie theater, or whether they’re permitted to exit school grounds as a student.

A Raspberry Pi is used as the card collector, relaying information on transaction data over WiFi. Meanwhile local identification information via biometric devices and key fobs are relayed to the processor over Bluetooth. There are also plans to develop a mobile app to track the status of the smart gate remotely.

While the full systems integration isn’t published yet, there are several photos of the control box, which shows the components used for the first smart gate. The mechanical design was successfully tested on the IUC Douala Cameroon university campus (with 35-45 students identified per minute), and the project will hopefully be repeated within more schools in the coming year.

Off-World Cement Tested For The First Time

September 30, 2019 by Tom Nardi 54 Comments

If the current Administration of the United States has their way, humans will return to the surface of the Moon far sooner than many had expected. But even if NASA can’t meet the aggressive timeline they’ve been given by the White House, it seems inevitable that there will be fresh boot prints on the lunar surface within the coming decades. Between commercial operators and international competition, we’re seeing the dawn of a New Space Race, with the ultimate goal being the long-term habitation of our nearest celestial neighbor.

Schmitt's dusty suit while retrieving samples from the Moon — An Apollo astronaut covered in lunar dust

But even with modern technology, it won’t be easy, and it certainly won’t be cheap. While commercial companies such as SpaceX have significantly reduced the cost of delivering payloads to the Moon, we’ll still need every advantage to ensure the economical viability of a lunar outpost. One approach is in situ resource utilization, where instead of transporting everything from Earth, locally sourced materials are used wherever possible. This technique would not only be useful on the Moon, but many believe it will be absolutely necessary if we’re to have any chance of sending a human mission to Mars.

One of the most interesting applications of this concept is the creation of a building material from the lunar regolith. Roughly analogous to soil here on Earth, regolith is a powdery substance made up of grains of rock and micrometeoroid fragments, and contains silicon, calcium, and iron. Mixed with water, or in some proposals sulfur, it’s believed the resulting concrete-like material could be used in much the same way it is here on Earth. Building dwellings in-place with this “lunarcrete” would be faster, cheaper, and easier than building a comparable structure on Earth and transporting it to the lunar surface.

Now, thanks to recent research performed aboard the International Space Station, we have a much better idea of what to expect when those first batches of locally-sourced concrete are mixed up on the Moon or Mars. Of course, like most things related to spaceflight, the reality has proved to be a bit more complex than expected.

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Alternative Photography Hack Chat

September 30, 2019 by Dan Maloney 3 Comments

Join us on Wednesday, October 2 at noon Pacific for the Alternative Photography Hack Chat with Pierre-Loup Martin!

It seems like the physics of silicon long ago replaced the chemistry of silver as the primary means of creating photographs, to the point where few of us even have film cameras anymore, and home darkrooms are a relic of the deep past. Nobody doubts that the ability to snap a quick photo or even to create a work of photographic genius with a tiny device that fits in your pocket is a wonder of the world, but still, digital photographs can lack some of the soul of film photography.

Recapturing the look of old school photography is a passion for a relatively small group of dedicated photographers, who ply their craft with equipment and chemistries that haven’t been in widespread use for a hundred years. The tools of this specialty trade are hard to come by commercially, so practitioners of alternate photographic processes are by definition hackers, making current equipment bend to the old ways. Pierre-Loup is one such artist, working with collodion plates, hacked large-format cameras, pinholes camera, and chemicals and processes galore – anything that lets him capture a unique image. His photographs are eerie, with analog imperfections that Photoshop would have a hard time creating.

Join us as Pierre-Loup takes us on a tour through the world of alternative photography. We’ll look at the different chemistries used in alternative photography, the reasons why anyone would want to try it, and the equipment needed to pull it off. Photography was always a hack, until it wasn’t; Pierre-Loup will show us how he’s trying to put some soul back into it.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 2 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

The Legacy Of The Floppy Still Looms Over Windows

September 30, 2019 by Jenny List 56 Comments

We no longer use floppy disks on the vast majority of computers, but a recent Old New Thing blog post from Microsoft sheds light on one of their possible unexpected legacies. It seems Windows disk cache items expire after two seconds, and as the post explains this has its origin in the development of MS-DOS 2.0.

Disks, especially floppy disks, are slow compared to computer memory. A disk cache is a piece of memory into which the operating system puts frequently loaded items to speed up access and avoid its having to repeatedly access the disk. They have an expiry time to ensure that the cache doesn’t become clogged with data that hasn’t been needed for a while.

IBM PC floppy drives didn’t implement any form of notification for a disk eject, so it became quite possible for a disk to be ejected while the operating system still believed cached data from it to be valid. Thus a pair of Microsoft engineers tried their hardest to swap floppy discs as fast as they could, and it was discovered to be an impossible task in under two seconds. This became the cache expiry time for a Microsoft OS, and thus we’re told the floppy’s legacy lives on as more than just the ‘save’ icon.

As this is being written the Internet is abuzz with a viral Tweet about railroad gauges having an origin in the width of a Roman horse, that rail historians are debunking with a reference to the coal tramways of [George Stephenson’s] Northern England. It’s thus sometimes dangerous to take simple soundbite origin stories at face value, but since in this case our source is Microsoft themselves we think we can take it as being close to the horse’s mouth. Even if it isn’t a Roman horse.

IBM floppy drive image: Michael Holley [Public domain].

What On Earth Is A Pickle Fork And Why Is It Adding To Boeing’s 737 Woes?

September 30, 2019 by Jenny List 88 Comments

It’s fair to say that 2019 has not been a good year for the aircraft manufacturer Boeing, as its new 737 MAX aircraft has been revealed to contain a software fault that could cause the aircraft to enter a dive and crash. Now stories are circulating of another issue with the 737, some of the so-called “Pickle forks” in the earlier 737NG aircraft have been found to develop cracks.

It’s a concerning story and there are myriad theories surrounding its origin but it should also have a reassuring angle: the painstaking system of maintenance checks that underpins the aviation industry has worked as intended. This problem has been identified before any catastrophic failures have occurred. It’s not the story Boeing needs at the moment, but they and the regulators will no doubt be working hard to produce a new design and ensure that it is fitted to aircraft.

The Role of the Pickle Fork

For those of us who do not work in aviation though it presents a question: what on earth is a pickle fork? The coverage of the story tells us it’s something to do with attaching the wing to the fuselage, but without a handy 737 to open up and take a look at we’re none the wiser.

Fortunately there’s a comprehensive description of one along with a review of wing attachment technologies from Boeing themselves, and it can be found in one of their patents. US9399508B2 is concerned with an active suspension system for wing-fuselage mounts and is a fascinating read in itself, but the part we are concerned with is a description of existing wing fixtures on page 12 of the patent PDF.

A cross-section of the aircraft wing fixing, in which we've highlighted the role of the pickle forks. (Boeing) — A cross-section of the aircraft wing fixing, in which we’ve highlighted the role of the pickle forks. (Boeing)

The pickle fork is an assembly so named because of its resemblance to the kitchen utensil, which attaches firmly to each side of the fuselage and has two prongs that extend below it where they are attached to the wing spar.

For the curious engineer with no aviation experience the question is further answered by the patent’s figure 2, which provides a handy cross-section. The other wing attachment they discuss involves the use of pins, leading to the point of the patented invention. Conventional wing fixings transmit the forces from the wing to the fuselage as a rigid unit, requiring the fuselage to be substantial enough to handle those forces and presenting a problem for designers of larger aircraft. The active suspension system is designed to mitigate this, and we’d be fascinated to hear from any readers in the comments who might be able to tell us more.

We think it’s empowering that a science-minded general public can look more deeply at a component singled out in a news report by digging into the explanation in the Boeing patent. We don’t envy the Boeing engineers in their task as they work to produce a replacement, and we hope to hear of their solution as it appears.

[via Hacker News]

[Header image: AMX Boeing 737 XA-PAM by Jean-Philippe Boulet CC-BY 3.0]

Using PoE With A Raspberry Pi 3 For About Two Bucks

September 30, 2019 by Maya Posch 33 Comments

When the Raspberry Pi 3 Model B+ was announced in March of 2018, one of its new features was the ability to be (more easily) powered via Power-over-Ethernet (PoE), with an official PoE HAT for the low price of just twenty-one USA bucks. The thing also almost worked as intended the first time around. But to some people this just isn’t good enough, resulting in [Albert David] putting out a solution he calls “poor man’s PoE” together for about two bucks.

His solution makes it extra cheap by using so-called passive PoE, which injects a voltage onto the conductors of the network cable being used for PoE, without bothering with any kind of handshake. In general this is considered to be a very reliable (albeit non-standard) form of PoE that works great until something goes up in smoke. It’s also ridiculously cheap, with a PoE injector adapter (RJ-45 plug & 2.1×5.5 mm power jack to RJ-45 jack) going for about 80 cents, and a DC-DC buck converter that can handle the input of 12V for about 50 cents.

The rest of the $2 budget is mostly spent on wiring and heatshrink, resulting in a very compact PoE solution that plugs straight into the PoE header on the Raspberry Pi 3 board, with the buck converter outputs going into the ground and +5V pins on the Raspberry Pi’s GPIO header.

A fancier solution would implement any of the standard PoE protocols to do the work of negotiating a suitable voltage. Maybe this could be the high-tech, $5 solution featuring an MCU and a small PCB?

The Clickspring Playing Card Press Is A Work Of Art

September 30, 2019 by Dan Maloney 31 Comments

We have no idea what a playing card press is, nor do we care. All we know is that after watching [Chris] from Clickspring make his playing card press, we want it.

Digging a little deeper, [Chris] offered to make this card press for [Chris Ramsay], a magician who specializes in cardistry, or the art of illusions with cards. The feel of playing cards is crucial to performing with them, and a card press keeps a deck of cards in shape. Not a commonly available device, [Clickspring Chris] designed one in an elaborate style that brought in elements from [Chris Ramsay]’s logo.

Like all Clickspring videos, this one is a joy to watch, but in a departure, there’s no narration — just 30 minutes of precision machining and metal finishing. [Chris] has gotten into metal engraving in a big way, and used his skills to add details to everything from the stylized acorn at the top to the intricate press plate, all of which was done freehand. And those snakes! Made from brass rod and bent into shape by hand, they wrap around the side supports to form [Chris Ramsay]’s logo. All the brass ended up gold plated, while all the screws ended up with a heat-blued finish. Settle in and enjoy the video below.

It’s been a while since the Clickspring skeleton clock was finished, in which time [Chris] has been working on a reproduction of the Antikythera mechanism. His video output slowed considerably, though, when he made a new finding about the mechanism, an observation worthy of writing up as a scholarly paper. We can’t begrudge him the time needed to pursue that, and we’re glad he found time for this project too.

Continue reading “The Clickspring Playing Card Press Is A Work Of Art” →