New Years Circuit Challenge: Make This RFID Circuit

December 31, 2024 by Jenny List 9 Comments

A 125kHz PCB antenna, a spiral pattern on a PCB. — The Proxmark3 PCB 125kHz antenna., GNU GPL version 2, GitHub link.

Picture this: It’s the end of the year, and a few hardy souls gather in a hackerspace to enjoy a bit of seasonal food and hang out. Conversation turns to the Flipper Zero, and aspects of its design, and one of the parts we end up talking about is its built-in 125 kHz RFID reader.

It’s a surprisingly complex circuit with a lot of filter components and a mild mystery surrounding the use of a GPIO to pulse the receive side of its detector through a capacitor. One thing led to another as we figured out how it worked, and as part of the jolity we ended up with one member making a simple RFID reader on the bench.

Just a signal generator making a 125 kHz square wave, coupled to a two transistor buffer pumping a tuned circuit. The tuned circuit is the coil scavenged from an old RFID card, and the capacitor is picked for resonance in roughly the right place. We were rewarded with the serial bitstream overlaying the carrier on our ‘scope, and had we added a filter and a comparator we could have resolved it with a microcontroller. My apologies, probably due to a few festive beers I failed to capture a picture of this momentous event. Continue reading “New Years Circuit Challenge: Make This RFID Circuit” →

Release Your Inner Ansel Adams With The Shitty Camera Challenge

December 30, 2024 by Jenny List 18 Comments

Social media microblogging has brought us many annoying things, but some of the good things that have come to us through its seductive scrolling are those ad-hoc interest based communities which congregate around a hashtag. There’s one which has entranced me over the past few years which I’d like to share with you; the Shitty Camera Challenge. The premise is simple: take photographs with a shitty camera, and share them online. The promise meanwhile is to free photography from kit acquisition, and instead celebrate the cheap, the awful, the weird, and the wonderful in persuading these photographic nonentities to deliver beautiful pictures.

Where’s The Hack In Taking A Photo?

Of course, we can already hear you asking where the hack is in taking a photo. And you’d be right, because any fool can buy a disposable camera and press the shutter a few times. But from a hardware hacker perspective this exposes the true art of camera hacking, because not all shitty cameras can produce pictures without some work.

The #ShittyCameraChallenge has a list of cameras likely to be considered shitty enough, they include disposables, focus free cameras, instant cameras, and the cheap plastic cameras such as Lomo or Holga. But also on the list are models which use dead film formats, and less capable digital cameras. It’s a very subjective definition, and thus in our field everything from a Game Boy camera or a Raspberry Pi camera module to a home-made medium format camera could be considered shitty. Ans since even the ready-made shitty cameras are usually cheap and unloved second-hand, there’s a whole field of camera repair and hacking that opens up. Finally, here’s a photography competition that’s fairly and squarely on the bench of Hackaday readers. Continue reading “Release Your Inner Ansel Adams With The Shitty Camera Challenge” →

Do You Know Vail Code?

December 27, 2024 by Al Williams 26 Comments

We talk about Morse code, named after its inventor, Samuel Morse. However, maybe we should call it Vail code after Alfred Vail, who may be its real inventor. Haven’t heard of him? You aren’t alone. Yet he was behind the first telegraph key and improved other parts of the fledgling telegraph system.

The story starts in 1837 when Vail visited his old school, New York University, and attended one of Morse’s early telegraph experiments. His family owned Speedwell Ironworks, and he was an experienced machinist. Sensing an opportunity, he arranged with Morse to take a 25% interest in the technology, and in return, Vail would produce the necessary devices at the Ironworks. Vail split his interest with his brother George.

By 1838, a two-mile cable carried a signal from the Speedwell Ironworks. Morse and Vail demonstrated the system to President Van Buren and members of Congress. In 1844, Congress awarded Morse $30,000 to build a line from Washington to Baltimore. That was the same year Morse sent the famous message “What Hath God Wrought?” Who received and responded to that message? Alfred Vail.

The Original Telegraph

Telegraphs were first proposed in the late 1700s, using 26 wires, one for each letter of the alphabet. Later improvements by Wheatstone and Cooke reduced the number of wires to five, but that still wasn’t very practical.

Samuel Morse, an artist by trade, was convinced he could reduce the number of wires to one. By 1832, he had a crude prototype using a homemade battery and a relatively weak Sturgeon electromagnet.

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Tech In Plain Sight: Incandescent Bulbs

December 26, 2024 by Al Williams 58 Comments

While they are dying out, you can still find incandescent bulbs. While these were once totally common, they’ve been largely replaced by LEDs and other lighting technology. However, you still see a number of them in special applications or older gear. If you are above a certain age, you might be surprised that youngsters may have never seen a standard incandescent lightbulb. Even so, the new bulbs are compatible with the old ones, so — mechanically, at least — the bulbs don’t look different on the outside.

You might have learned in school that Thomas Edison invented the light bulb, but the truth is much stranger (public domain)

It has been known for a long time that passing a current through a wire creates a glow. The problem is, the wire — the filament — would burn up quickly. The answer would be a combination of the right filament material and using an evacuated bulb to prevent the filament degrading. But it took over a century to get a commercially successful lightbulb.

We were all taught in school that Thomas Edison invented the light bulb, but the truth is much more complicated. You can go back to 1761 when Ebenezer Kinnersley first caused a wire to glow. Of course, wires would quickly burn up in the air. By the early 19th century, limelight was fairly common in theaters. Limelight — also known as the Drummond light — heated a piece of calcium oxide using a gas torch — not electric, but technically incandescence. Ships at sea and forts in the U.S. Civil War used limelights to illuminate targets and, supposedly, to blind enemy troops at night. Check out the video below to see what a limelight looks like.

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Atoms For Peace: The US Nuclear Fleet Build-Out And Modern-Day Revival

December 23, 2024 by Maya Posch 24 Comments

By the end of World War II the world had changed forever, as nuclear weapons were used for the first and – to this date – only time in anger. Although the use of these weapons was barely avoided during the Korean War in the early 1950s, the dawning of the Atomic Age had come in the form of obliterated cities and an increasing number of these weapons being test fired around the world. It was against this background that on December 8, 1953, US President Dwight D. Eisenhower held his ‘Atoms for Peace’ speech, during which he would not only promote the peaceful use of nuclear technologies but also lay the groundwork for what would become the International Atomic Energy Agency (IAEA), as announced in the full speech.

Under the Eisenhower administration the US became one of the world’s nuclear power pioneers, as it competed with the UK and later others in establishing world’s firsts in commercial nuclear power. Dresden Generating Station would become the first purely commercial boiling water reactor (BWR) in 1960 and Yankee-Rowe, the first pressurized water reactor (PWR) in 1961. Following these, the number of new reactors planned and constructed kept increasing year over year, setting the trend for the few decades of the US nuclear power industry.

Today the US operates 94 reactors, which generate nearly 20% of the country’s electricity. Exactly how did the US build so many reactors before 1990, and how does this compare to the recent revival with both new builds and retired plants being put back into service?

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Subchannel Stations: The Radio Broadcasts You Didn’t Know Were There

December 20, 2024 by Lewin Day 31 Comments

Analog radio broadcasts are pretty simple, right? Tune into a given frequency on the AM or FM bands, and what you hear is what you get. Or at least, that used to be the way, before smart engineers started figuring out all kinds of sneaky ways for extra signals to hop on to mainstream broadcasts.

Subcarrier radio once felt like the secret backchannel of the airwaves. Long before Wi-Fi, streaming, and digital multiplexing, these hidden signals beamed anything from elevator music and stock tickers to specialized content for medical professionals. Tuning into your favorite FM stations, you’d never notice them—unless you had the right hardware and a bit of know-how.

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Human Civilization And The Black Plastic Kitchen Utensils Panic

December 19, 2024 by Maya Posch 98 Comments

Recently there was a bit of a panic in the media regarding a very common item in kitchens all around the world: black plastic utensils used for flipping, scooping and otherwise handling our food while preparing culinary delights. The claim was that the recycled plastic which is used for many of these utensils leak a bad kind of flame-retardant chemical, decabromodiphenyl ether, or BDE-209, at a rate that would bring it dangerously close to the maximum allowed intake limit for humans. Only this claim was incorrect because the researchers who did the original study got their calculation of the intake limit wrong by a factor of ten.

This recent example is emblematic of how simple mistakes can combine with a reluctance to validate conclusions can lead successive consumers down a game of telephone where the original text may already have been wrong, where each node does not validate the provided text, and suddenly everyone knows that using certain kitchen utensils, microwaving dishes or adding that one thing to your food is pretty much guaranteed to kill you.

How does one go about defending oneself from becoming an unwitting factor in creating and propagating misinformation?

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