Rising To The Occasion: A Brief History Of Crewed High Altitude Balloons

April 28, 2023 by Al Williams 11 Comments

Piccard inspects an instrument on his balloon (Image: Bundesarchiv, Bild 102-10382 / CC-BY-SA 3.0)

We think of human flight as a relatively modern affair, with a few claims to the first airplane all around the turn of the last century. But people flew much earlier than that by using hot air balloons as well as gas-filled ones. While the Montgolfier brothers get most of the credit for hot air ballooning in 1783, there are some reports that a Brazilian priest may have lifted himself with a balloon as early as 1709.

Regardless, we’ve had balloons a good century earlier than winged flight, if not longer. While the device is deceptively simple, it is possible to get a balloon to very high altitudes without a lot of specialized technology. Airplanes at high altitudes need a way to get enough oxygen to fuel their engines, or they have to rely on rockets. Either way, there are plenty of design and operational challenges.

Balloons, of course, can simply rise to the occasion. Auguste Piccard and an assistant took a gas-filled balloon to 15,781 meters in 1931. Their gondola was pressurized, and they were the first humans to see the curvature of the Earth and the dark sky above. That record wouldn’t stand for long, though.

CCCP-1

The Soviet Union was keenly interested in Piccard’s flight, and the Soviet Air Force set about to build a research vessel, CCCP-1 (in English, USSR-1), that flew in 1933. The envelope was a large amount of thin fabric impregnated with latex and filled with hydrogen. The air-tight gondola presented several challenges in design. Most of the science experiments were outside, of course, and in 1933, you didn’t have an Arduino and RC servos to control things.

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Smoke Some Weeds: Lasers Could Make Herbicide Obsolete

April 26, 2023 by Lewin Day 53 Comments

We’ve all tangled with unwelcome plant life at one point or another. Whether crabgrass infested your lawn, or you were put on weeding duty in your grandfather’s rose patch, you’ll know they’re a pain to remove, and a pain to prevent. For farmers, just imagine the same problem, but scaled up to cover thousands of acres.

Dealing with weeds typically involves harsh chemicals or excessive manual labor. Lasers could prove to be a new tool in the fight against this scourge, however, as covered by the BBC.

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FET: The Friendly Efficient Transistor

April 25, 2023 by Arya Voronova 57 Comments

If you ever work with a circuit that controls a decent amount of current, you will often encounter a FET – a Field-Effect Transistor. Whether you want to control a couple of powerful LEDs, switch a USB device on and off, or drive a motor, somewhere in the picture, there’s usually a FET doing the heavy lifting. You might not be familiar with how a FET works, how to use one and what are the caveats – let’s go through the basics.

Here’s a simple FET circuit that lets you switch power to, say, a USB port, kind of like a valve that interrupts the current flow. This circuit uses a P-FET – to turn the power on, open the FET by bringing the GATE signal down to ground level, and to switch it off, close the FET by bringing the GATE back up, where the resistor holds it by default. If you want to control it from a 3.3 V MCU that can’t handle the high-side voltage on its pins, you can add a NPN transistor section as shown – this inverts the logic, making it into a more intuitive “high=on, low=off”, and, you no longer risk a GPIO!

This circuit is called a high-side switch – it enables you to toggle power to a device at will through a FET. It’s the most popular usecase for a FET, and if you’re wondering more about high-side switches, I highly recommend this brilliant article by our own [Bil Herd], where he shows you high-side switch basics in a simple and clear way. For this article, you can use this schematic as a reference of how FETs are typically used in a circuit.

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Gen Tojo’s Teeth: Morse Code Shows Up In The Strangest Places

April 21, 2023 by Al Williams 43 Comments

The Baader-Meinhof effect is the common name for what scientists call frequency illusion. Suppose you are watching Star Trek’s Christopher Pike explain how he makes pasta mama, and you’ve never heard of it before. Immediately after that, you’ll hear about pasta mama repeatedly. You’ll see it on menus. Someone at work will talk about having it at Hugo’s. Here’s the thing. Pasta mama was there all along (and, by the way, delicious). You just started noticing it. We sometimes wonder if that’s the deal with Morse code. Once you know it, it seems to show up everywhere.

One of the strangest places we’ve ever heard of Morse code appearing is the infamous case of Tojo’s teeth. If you don’t remember, General Hideki Tojo was one of the main “bad guys” in the Pacific part of World War II. In particular, he is thought to have approved the attack on Pearl Harbor, which started the American involvement in the war globally. Turns out, Tojo would be inextricably tied to Morse code, but he probably didn’t realize it.

The Honorable Attempt

At the end of the war, the US military had a list of people they wanted to try, and Tojo was near the top of their list of 40 top-level officials. As prime minister of Japan, he had ordered the attack that brought the US into the war. He remained prime minister until 1944, when he resigned, but the US had painted him as the face of the Japanese enemy. Often shown in caricature along with Hitler and Mussolini, Tojo was the face of the Japanese war machine to most Americans.

In Allied propaganda, Tojo was one of the “big three”

When Americans tried to arrest him, though, he shot himself. However, his suicide attempt failed. Reportedly, he apologized to the American medics who resuscitated him for failing to kill himself. Held in Sugamo Prison awaiting a trial, he requested a dentist to make him a new set of dentures so he could speak clearly during the trial.

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Music Typewriter

April 20, 2023 by Kristina Panos 4 Comments

This edition’s community build comes from the Yes They Could, But Should They Have? file. Well, I ultimately say yes, this is intriguing. Redditor [dj_edit] looked at the venerable Model M and thought, this buckling-spring masterpiece can yet be improved upon. Yeah! Well, to each their own. I must say that it does sound great, especially with the solenoid feedback enabled via rotary encoder. Just check out the typing test.

To be clear, this is essentially a new keyboard that fits inside a Model M case, but that alone is quite a feat, especially if you consider the curvature of the backplate. Because of this hurdle, [dj_edit] went with 1 mm FR4 for the switch PCB, which is a nice compromise of sturdiness and flexibility.

Underneath those stunning reproduction keycaps are Kailh box white switches, which are pretty chonky-sounding on their own. But turn on that sweet solenoid action and you really get noisy.

Those box whites are sitting in hot-swap sockets, a design decision that kind of made things difficult because of the curvature. [dj_edit] ended up using an acrylic plate that gets bent to match the curvature by the switches themselves.

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Vintage Computer Festival East Was A Retro Madhouse

April 19, 2023 by Tom Nardi 36 Comments

The Vintage Computer Festival East took place last weekend at the InfoAge Science and History Museum in New Jersey, and by any metric you care to use, it was a phenomenal success. Everyone you spoke with, from the the exhibitors and attendees, to the veteran volunteers who put this incredible show together, all said the same thing: they’d never seen a turnout like this before.

Of course, such success is not without cost. The exhibit rooms were so packed that moving through them was a challenge, the line to get food or browse the consignment area occasionally stretched outside the building, and at one point the event’s electronic payment system buckled under the pressure.

Yet even the folks who waited the better part of an hour to rummage through boxes of dusty treasures, only to find themselves left standing with armfuls of heavy gear they couldn’t pay for until the technical issues were resolved couldn’t really complain. I should know, I was one of them. It would be like going to a concert and getting upset that the music was too loud — the event was advertised as a festival, and that’s exactly what it was.

No matter where you went, you’d find throngs of excited people who were eager to chat about the golden age of computing. So even if you were stuck in a long line, or had to step outside of the exhibit area to get some fresh air, you were always in excellent company. Seeing such a large and diverse number of people come out for what’s ultimately a niche event was exceptionally gratifying. At the end of the day, if the price we have to pay for this kind of community response is a few long lines and tight squeezes, it’s well worth it.

Each time I cover an event like this for Hackaday, I do so with the caveat that there’s really no substitute for being there in person. No matter how many articles you read and YouTube recaps you watch, you’ll never be able to see all the things you would have had you been able to walk the show floor yourself. It’s a bit like exploring the Moon or Mars: remotely controlled robots are capable of capturing terabytes of data and beaming it back to Earth, but even still, there’s the potential to learn so much more by putting boots on the ground.

The same is true of VCF East 2023 — what I bring you here is just the tip of the iceberg in terms of what was on display at this year’s event. On the other hand, you have the advantage of being able to peruse these images without having to stand in line. Is it worth the trade? Only you can be the judge of that. But for my money, I’ll gladly get back in line when VCF East 2024 rolls around.

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PUF Away For Hardware Fingerprinting

April 17, 2023 by Matthew Carlson 9 Comments

Despite the rigorous process controls for factories, anyone who has worked on hardware can tell you that parts may look identical but are not the same. Everything from silicon defects to microscopic variations in materials can cause profoundly head-scratching effects. Perhaps one particular unit heats up faster or locks up when executing a specific sequence of instructions and we throw our hands up, saying it’s just a fact of life. But what if instead of rejecting differences that fall outside a narrow range, we could exploit those tiny differences?

This is where physically unclonable functions (PUF) come in. A PUF is a bit of hardware that returns a value given an input, but each bit of hardware has different results despite being the same design. This often relies on silicon microstructure imperfections. Even physically uncapping the device and inspecting it, it would be incredibly difficult to reproduce the same imperfections exactly. PUFs should be like the ideal version of a fingerprint: unique and unforgeable.

Because they depend on manufacturing artifacts, there is a certain unpredictability, and deciding just what features to look at is crucial. The PUF needs to be deterministic and produce the same value for a given specific input. This means that temperature, age, power supply fluctuations, and radiation all cause variations and need to be hardened against. Several techniques such as voting, error correction, or fuzzy extraction are used but each comes with trade-offs regarding power and space requirements. Many of the fluctuations such as aging and temperature are linear or well-understood and can be easily compensated for.

Broadly speaking, there are two types of PUFs: weak and strong. Weak offers only a few responses and are focused on key generation. The key is then fed into more traditional cryptography, which means it needs to produce exactly the same output every time. Strong PUFs have exponential Challenge-Response Pairs and are used for authenticating. While strong PUFs still have some error-correcting they might be queried fifty times and it has to pass at least 95% of the queries to be considered authenticated, allowing for some error. Continue reading “PUF Away For Hardware Fingerprinting” →