A 65-in-1 The 2024 Way

If necessity is the mother of invention, nostalgia must be its stepmother, or its aunt at the very least. The desire to recreate long-obsolete devices simply because they existed while we were growing up is a curious trait, but one that’s powerful enough to drive entire categories of hardware hacking — looking at you, retrocomputing buffs.

Hardware nostalgia isn’t all about 6502s and Z80s, though. Even more basic were the electronic toys of the 1970s, such as the Radio Shack 65-in-1 kit that [Tom Thoen] is currently recreating. The 65-in-1 was a breadboarding kit aimed at the budding electrical engineer, with components mounted to colorful cardboard by spring terminals. The included “lab manual” had circuits that could be quickly assembled using a handful of jumper wires. It was an endlessly fascinating toy that undoubtedly launched many careers, present company included.

The original 65-in-1 was $21.95 in 1976, or about $120 today.

While the passage of time may not have dulled [Tom]’s memories of his original 65-in-1, technology has marched on, meaning that certain allowances had to be made to create a modern version. He wisely eschews the cardboard for PCBs, one for each of the major component blocks provided in the original, and uses female header connectors in place of the springs. Component choice is tailored for the times; gone are the ferrite rod antenna and variable capacitor of the original, as well as the incandescent lamp, which is replaced by an LED that would have been a significant fraction of the kit’s $21.95 price back in 1976. There’s no BOM yet, so we can’t say for sure if any of the transistors are germanium, but it’s clear that there aren’t any of the old TO-1 cans. But dismay not, originalists, for the meter, relay, CdS photocell, and “solar battery” all made the final cut.

[Tom] has done some beautiful work here, with more to come. We imagine that 3D printing could be used to recreate some details like the original Morse key and speaker grille. We love the laser-engraved backing board, too, as it captures some of the charm of the original’s wooden box. This isn’t the only love for the “Science Fair” brand we’ve seen lately, either; the nostalgia seems to be contagious.

A Classroom-Ready Potentiometer From Pencil And 3D Prints

If you need a potentiometer for a project, chances are pretty good that you’re not going to pick up a pencil and draw one. Then again, if you’re teaching someone how a variable resistor works, that old #2 might be just the thing.

When [HackMakeMod] realized that the graphite in pencil lead is essentially the same thing as the carbon composition material inside most common pots, the idea for a DIY teaching potentiometer was born. The trick was to build something to securely hold the strip while making contact with the ends, as well as providing a way to wipe a third contact across its length. The magic of 3D printing provided the parts for the pot, with a body that holds a thin strip of pencil-smeared paper securely around its inner diameter. A shaft carries the wiper, which is just a small length of stripped hookup wire making contact with the paper strip. A clip holds everything firmly in place. The video below shows the build process and the results of testing, which were actually pretty good.

Of course, the construction used here isn’t meant for anything but demonstration purposes, but in that role, it performs really well. It’s good that [HackMakeMod] left the body open to inspection, so students can see how the position of the wiper correlates to resistance. It also makes it easy to slip new resistance materials in and out, perhaps using different lead grades to get different values.

Hats off to a clever build that should be sure to help STEM teachers engage their students. Next up on the lesson plan: a homebrew variable capacitor.

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Kitchen Steganography With Turmeric

It is a classic rite of passage for nerdy kids to write secret messages using lemon juice. If you somehow missed that, you can’t see the writing until you heat the paper up with, say, an old-fashioned light bulb. If you were a true budding spy, you’d write a boring normal letter with wide spacing and then fill in the blanks between the lines with your important secrets written in juice. This is a form of steganography — encoding secret messages by hiding them in plain sight. [Randomona] shares a different technique that seems to be way cooler than lemon juice using, of all things, turmeric. This isn’t like the invisible ink of our childhood.

That’s probably a good thing. We doubt an LED bulb makes enough heat to develop our old secret messages. [Ranomona’s] ink doesn’t use heat, but it uses a developer. That means you must make two preparations: the ink and the developer. The results are amazing, though, as shown in the video below.

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Hackaday Prize 2023: Tiny RC Aircraft Built Using Foam And ESP12

Once upon a time, a radio controlled plane was a hefty and complex thing. They required small nitro engines, support equipment, and relatively heavy RC electronics. Times have changed since then, as this lightweight RC build from [Ravi Butani] demonstrates.

The body of the plane is lightweight foam, and can be assembled in two ways. There’s a relatively conventional layout, using a main wing, tailplane, and rudder, or a pusher model with the main wing at the rear and a canard up front. The open hardware electronics package, which [Ravi] calls VIMANA, consists of an ESP12 module with a pair of MOSFETs to act as two independent motor drivers — allowing the plane to be flown and steered with differential thrust.

For more advanced flight control, it can also command a pair of servos to control ailerons, a rudder, canards, or elevons, depending on configuration. There’s also potential to install an IMU to set the plane up with flight stabilization routines.

Thanks to the low-cost of the VIMANA board, [Ravi] hopes it can be used in STEM education programs. He notes that it’s not limited just to aircraft, and could be used for other motorized projects such as boats and cars. We’ve featured an early version of his work before, but the project has come a long way since then.

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Machine Learning Helps Electron Microscopy

Machine learning is supposed to help us do everything these days, so why not electron microscopy? A team from Ireland has done just that and published their results using machine learning to enhance STEM — scanning transmission electron microscopy. The result is important because it targets a very particular use case — low dose STEM.

The problem is that to get high resolutions, you typically need to use high electron doses. However, bombarding a delicate, often biological, subject with high-energy electrons may change what you are looking at and damage the sample. But using reduced electron dosages results in a poor image due to Poisson noise. The new technique learns how to compensate for the noise and produce a better-quality image even at low dosages.

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Supercon 2022: Tap Your Rich Uncle To Fund Your Amateur Radio Dreams

Imagine you had a rich uncle who wanted to fund some of your projects. Like, seriously rich — thanks to shrewd investments, he’s sitting on a pile of cash and is now legally obligated to give away $5,000,000 a year to deserving recipients. That would be pretty cool indeed, but like anything else, if it sounds too good to be true, it probably is, right?

Well, maybe not. It turns out that we in the amateur radio community — and even amateur radio adjacent fields — have a rich uncle named Amateur Radio Digital Communications (ARDC), a foundation with a large endowment and a broad mission to “support amateur radio, funds scholarships and worthy educational programs, and financially support technically innovative amateur radio and digital communications projects.” As the foundation’s Outreach Manager John Hayes (K7EV) explained at Supercon 2022, ARDC is a California-based 501(c)3 non-profit organization that has been in the business of giving away money to worthy projects in the amateur radio space since 2021.

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STEM Award Goes To Accessible 3D Printing Project

When you are a 15-year old and you see a disabled student drop the contents of their lunch tray while walking to a table, what do you do? If you are [Adaline Hamlin], you design a 3D printed attachment for the trays to stop it from happening again.

The work was part of “Genius Hour” where [Hamlin’s] teacher encouraged students to find things that could be created to benefit others. An initial prototype used straws to form stops to fit plates, cups, and whatever else fit on the tray. [Zach Lance], a senior at the school’s 3D printing club, helped produce the actual 3D printed pieces.

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