Ask Hackaday: What’s Your Worst Soldering Job?

February 24, 2022 by Lewin Day 114 Comments

Soldering! It’s the primary method for attaching one component to another in the world of electronics. Whether you’re free-forming a circuit, attaching connectors to cables, or populating a PCB, you’ll eventually find yourself doing some soldering, whether by hand, reflow, or maybe even a fancy wave soldering machine.

It’s a fundamental skill that nevertheless remains one of the biggest hurdles for newcomers to overcome when diving into the electronics hobby. Difficult jobs with tiny components or with large heat sinks can up the challenge for even well-practiced hands. Thus, today we ask the question: What’s your worst soldering job?
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Don’t Miss The VCF Indoor Swap Meet This Weekend

February 24, 2022 by Tom Nardi 1 Comment

We don’t need to tell you that these last couple of years have been a real drag for in-person events. But at long last, after a bit of a false start last summer, it seems like we can finally start peeking our heads out and getting back to doing the things we love. So why not celebrate by taking part in that most sacred of geek pastimes: poring through boxes of dusty old gear in search of some electronic treasure?

On Saturday the Vintage Computer Federation (VCF) is holding an indoor swap meet at the InfoAge Science and History Museum in New Jersey, and everyone’s invited. Vintage computers will naturally be the main attraction, but if their previous events are any indication, you should expect the tables to be filled with a healthy mix of general electronics, classic games, and amateur radio gear as well. The doors open up at 8 AM sharp and it’s free to get in, so we’d suggest showing up early for the best selection.

A little less than a year ago we visited the previous VCF swap meet, which back then had to be held outdoors due to COVID-19 concerns, and were blown away by the selection of weird and wonderful hardware up for grabs. From arcade cabinets to luggable PCs and 3D printers, there was a little something for everyone, and all at rock-bottom prices. The only real gripe we had was the lack of on-site food and beverage, which according to the VCF website, has been addressed this time around. No word on whether or not there’s an ATM handy though, so you might want to stop and get some cash before heading to the relatively remote Camp Evans site.

After the swap meet wraps up at 2 PM, be sure to check out the Vintage Computer Federation’s permanent collection at InfoAge, as well as all the incredible exhibits and mini-museums the site has to offer. If nothing else, we strongly recommend you take the walk down the road to the TLM-18 Space Telemetry Antenna that Princeton University currently operates as Linux-powered software defined radio telescope.

The fine folks of the VCF are also hard at work putting together their annual East Coast Vintage Computer Festival, which will take place at InfoAge on April 22nd to the 24th, so mark your calendars.

An “unbusy” USB-C Port Doubles-up For JTAG Programming

February 24, 2022 by Sonya Vasquez 12 Comments

Board space is a premium on small circuit board designs, and [Alvaro] knows it. So instead of adding a separate programming port, he’s found a niche USB-C feature that lets him use the port that he’s already added both for its primary application and for programming the target microcontroller over JTAG. The result is that he no longer needs to worry about spending precious board space for a tiny programming port; the USB-C port timeshares for both!

In a Twitter thread (Unrolled Link), [Alvaro] walks us through his discovery and progress towards an encapsulated solution. It turns out that the USB-C spec supports a “Debug-Accessory Mode” specification, where some pins are allowed to be repurposed if pins CC1 and CC2 are pulled up to Logic-1. Under these circumstances, the pin functions are released, and a JTAG programmer can step in to borrow them. To expose the port to a programmer, [Alvaro] cooked up a small breakout board with a USB-C plug and separate microcontroller populated on it.

This board also handles a small quirk. Since [Alvaro’s] choice of programming pins aren’t reversible, the USB-C plug will only work one of the two ways it can be plugged in. To keep the user informed, this breakout board sports a red LED for incorrect orientation and a green LED for correct orientation–nifty. While this design quirk sacrifices reversibility, it preserves the USB 2.0 D+ and D- pins while also handling some edge cases with regard to the negotiating for access to the port.

Stick through [Alvaro]’s Twitter thread for progress pics and more details on his rationale behind his pin choices. Who knows? With more eyes on the USB-C feature, maybe we’ll see this sort of programming interface become the norm?

[Alvaro] is no stranger to Hackaday. In fact, take a tour back to our very first Supercon to see him chat about shooting lasers at moving targets to score points on a DEFCON challenge in the past

Finding Lo-fi In All The Strange Places

February 23, 2022 by Matthew Carlson 12 Comments

If you haven’t heard any lo-fi music yet, it stands for low-fidelity music. Lofi music today is characterized by audio imperfections such as cable noise or tape hiss. To get a pleasantly warm imperfect sound, many artists turn to vintage equipment. [HAINBACH] found an excellent instrument, the obsolete classroom tool known as magnetic card audio recorders.

The basic mechanism of the device is that it reads and writes to the two tracks on the quarter-inch tape fed through it. One track is meant for the teacher and one track is meant for the student. Originally designed to assist language learners, we can see why it would be an ideal source of good lo-fi samples. The microphone and speaker need to be high quality to hear the nuances of the example sentence. [HAINBACH] also admires the general tone and timbre of the device as opposed to just using a cassette recorder.

The tape in question is glued to little plastic cards. With some modification, you can run the card backward, create a loop, or stitch sections together. With multiple machines, you can run the card from one machine directly into another. They were made by several companies and can be found relatively cheap on online auction houses. While we can’t credit [HAINBACH] for coming up with the idea as it was featured in the movie Baby Driver, it’s still an example of an awesome hack.

Magnetic tape has long been a fascination of musical instruments. This Crudman, which is a modern-day interpretation of the much older Mellotron from 1963, is a great example of that.

Video after the break.

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Pixelating Text Not A Good Idea

February 23, 2022 by Al Williams 63 Comments

People have gotten much savvier about computer security in the last decade or so. Most people know that sending a document with sensitive information in it is a no-no, so many people try to redact documents with varying levels of success. A common strategy is to replace text with a black box, but you sometimes see sophisticated users pixelate part of an image or document they want to keep private. If you do this for text, be careful. It is possible to unredact pixelated images through software.

It appears that the algorithm is pretty straightforward. It simply guesses letters, pixelates them, and matches the result. You do have to estimate the size of the pixelation, but that’s usually not very hard to do. The code is built using TypeScript and while the process does require a little manual preparation, there’s nothing that seems very difficult or that couldn’t be automated if you were sufficiently motivated.

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Bend It Like (Sonar) Beacon With A Phased Array

February 23, 2022 by Matthew Carlson 7 Comments

Ultrasonic transducers are incredible, with them you can detect distances, as well as levitate and peer through objects. They can emit and receive ultrasonic soundwaves (typically above 18khz) and just like all waves, they can be steered via a phased array. [Bitluni] was trying to accurately measure distances but found the large field of view of the sensor was just too imprecise, so he made a phased array of transducers.

The inspiration came from a Hackaday Supercon talk from 2019 about phased arrays. [Bitluni] walks through an excellent explanation of how the array works with a bucket of water and his finger, as well as a separate simulation. By changing the phase offset of the different array members, the beam can effectively be steered as interference muffs the undesired waves. Using a set of solenoids, he created a test bench to validate his idea in a medium he could see; water. The solenoids fire a single pulse into the water creating a wave. You can see the wave move in the correct direction in the water, which validates the concept. A simple PCB sent off to a fab house with a stencil offers a surface to solder the transducers and drivers onto. An ESP32 drives the 8 PWM signals that go to the transmitters and reads in the single receiver via a small amplifier. Still not content to let the idea be unproven, he sets up the receiver on his CNC gantry and plots the signal strength at different points, yielding beautiful “heat maps.”

It sweeps a 60-degree field in front of it at around 1-3 frames per second. As you might imagine, turning sound wave reflections into distance fields is a somewhat noisy affair. He projects the sonar display on top of what we can see in the camera and it is fun to see the blobs line up in the correct spot.

We noticed he built quite a few boards, perhaps in the future, he will scale it up like this 100 transducer array? Video after the break.

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Pulling Off A CRT Transplant Doesn’t Have To Be Tricky!

February 23, 2022 by Lewin Day 28 Comments

Whether it’s an engine swap in an old car or pulling a hard drive out of an old computer, we often find ourselves transplanting bits from one piece of hardware to another. [Emily Velasco] recently attempted this with a pair of CRTs, and came away with great success.

The donor was an old 1980s fishing sounder, which came complete with a rather fetching monochrome amber CRT display. [Emily]’s goal was to transplant this into the body of a early 2000s portable television. The displays were of a similar size and shape, though the Toshiba CRT from the 80s used a lot more glass in its construction.

The tube socket in the TV used to hook up the display matched the old CRT perfectly, so there were no hassles there. A bit of soldering was all that was needed to hook up the yoke, and [Emily] was ready to test. Amazingly, it powered up cleanly, displaying rolling amber static as you’d expect, given that analog television stations have been off the air for some time now.

After some perseverance, a VCR playing Mystic Pizza on VHS was able to deliver a video signal to the TV, proving that everything was working well. The next stage of the project is to get the television electronics to fit inside the 1980s fishing sounder housing, as it’s the more attractive of the two. Things were just built differently back in those days!

We’ve seen some other great vintage display swaps before, too. Video after the break.

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