Hackaday Links: September 1, 2024

September 1, 2024 by Dan Maloney 21 Comments

Why is it always a helium leak? It seems whenever there’s a scrubbed launch or a narrowly averted disaster, space exploration just can’t get past the problems of helium plumbing. We’ve had a bunch of helium problems lately, most famously with the leaks in Starliner’s thruster system that have prevented astronauts Butch Wilmore and Suni Williams from returning to Earth in the spacecraft, leaving them on an extended mission to the ISS. Ironically, the launch itself was troubled by a helium leak before the rocket ever left the ground. More recently, the Polaris Dawn mission, which is supposed to feature the first spacewalk by a private crew, was scrubbed by SpaceX due to a helium leak on the launch tower. And to round out the helium woes, we now have news that the Peregrine mission, which was supposed to carry the first commercial lander to the lunar surface but instead ended up burning up in the atmosphere and crashing into the Pacific, failed due to — you guessed it — a helium leak.
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Film, As You Have Never Had It Explained Before

September 1, 2024 by Jenny List 17 Comments

For all the advances in digital photography, there remains a mystique for photographers and filmmakers about chemical film. Using it presents an artistic and technical challenge, and it lends an aesthetic to your work which is difficult to find in other ways. But particularly when it comes to moving pictures, how many of us have ever ventured beyond the Super 8 cartridge? If you’re not lucky enough to have a Spielberg budget, [Stand-Up Maths] is here with a video taking the viewer through the various movie film formats. He claims it’s the first video shot for YouTube in 35mm, and given that his first point is about the costs involved, we can see why.

In particular it serves as an introduction to the various film terms and aspect ratios. We all know what full frame and IMAX are, but do many of us know what they really mean in camera terms. A particularly neat demonstration comes when he has two cameras side by side with the same stock as a split screen, one 35mm and the other 16mm. The cheaper smaller framed format is good quality, but using a profession resolution chart you can see some of the differences clearly. The full film is below the break, and we’d suggest you watch it in the full 4K resolution if you are able to.

Meanwhile, some of us have been known to dabble in 8mm film, and even sometimes shoot footage with it.

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Two tools for placing magnets with ease, one for each polarity.

An Attractive Magnet Insertion Tool

September 1, 2024 by Kristina Panos 9 Comments

Magnets are pretty nice little tools. [EmGi] has used them in many a cool 3D printed build with great success. But getting them where you want can be really tricky. More often than not, you end up with glue all over your fingers, or the magnets fly out of place, or they stick together when you don’t want them to.

Well, [EmGi] created a mighty fine magnet insertion tool that you can print for yourself. It’s finger-operated and uses a single embedded magnet to place magnets wherever they’re needed.

This thing went through several designs before [EmGi] ever printed it out. Originally, there were two magnets, but there was an issue where if the tool wasn’t lifted off perfectly, it would send the magnet flying.

But now it works great, and [EmGi] even deposited an array of 64 magnets without using glue to test it out before printing a second one to handle the other polarity. Check out the build/demo video after the break.

While you’re printing and placing magnets, why not make yourself a couple of magnetic switches? You can even make ’em for keyboards.

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CL-32: The Minimum Possible For A Useful Handheld Computer

September 1, 2024 by Jenny List 19 Comments

For almost as long as there have been microcomputers, there have been attempts with varying success to make tiny handheld microcomputers. Sometimes these have been very good, and other times they’ve missed the mark in some way. Latest to find its way to us is the CL-32 from [Moosepr], it’s a handheld computer with an ESP32 as brains, an electronic paper display, and a QWERTY keyboard in its smart printed case.

The hardware is relatively standard, save for the keyboard which is a dome-switch design in which the membrane carrying the domes is hand-made. We like this, and don’t think we’ve seen anyone else doing that. Expansion is taken care of by a novel socket arrangement in which boards nestle in a recess in the surface. Some experimentation was required as always to drive the display, but the result is a functional computer.

Sadly there’s little detail in terms of what the software will be, and no hardware files as yet. But what we can see is promising enough to make this one to watch, so we’ll look forward to what they come up with. If an ESP32 OS is a problem, there’s always badge.team, who have been continuously improving theirs since 2017.

The Trashiest Of Mains Inverters

August 31, 2024 by Jenny List 21 Comments

Switch-mode technology has made inverters which take a low DC voltage and turn it into a usable mains voltage within the reach of everybody. But still, there might be moments when a mains supply is needed and you’re not lucky enough to have AliExpress at your fingertips, and for that, here’s [Rulof] with a mains inverter that is simultaneously awful and awesome. He’s made a rotary converter, from trash and off the shelf parts.

While a switch-mode converter operates using PWM at many times the output frequency for efficiency, we’re guessing that most readers will be familiar enough with how AC works to see how a low frequency converter turns DC into AC. A set of switches repeatedly flip the polarity, and the resulting square wave is fed into a transformer to step up to the final voltage. The switches can be mechanical as with old-style converters that used vibrating reeds or rotary armatures, or they can be electronic using power transistors. In this case they are a set of microswitches actuated by a set of cams on a shaft driven by a small motor, and the transformer comes from a surplus UPS.

We’re guessing that the frequency will be only a few Hz and the microswitches will suffer from switching such an inductive load, but as you can see in the video below the break it does light a mains bulb, and we’re guessing it would be enough to activate most wall-wart switching power supplies. We’re not so sure though about his use of the IEC sockets from the UPS to carry 12 volts, as the current may be a little much for them.

Meanwhile if you thirst for more of this kind of thing, we have you covered.

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A milling machine with an attached pantograph following the various intricate patterns of a spirograph on the bench next to it. The spirograph is a series of acrylic gears and brass connecting bars mounted on a wooden base.

Taking A Spirograph Mill For A Spin

August 31, 2024 by Navarre Bartz 3 Comments

Spirographs can make some pretty groovy designs on paper, but what if you want to take it a step further? [Uri Tuchman] has used the pantograph on his milling machine to duplicate the effect in harder materials.

[Tuchman] starts with a quick proof-of-concept using an actual plastic Spirograph toy to make sure it isn’t a totally unworkable idea. Unsurprisingly, the plastic is too flexible to give a highly detailed result on the MDF test piece, so he laser cut an acrylic version as the next prototype. This provided much better stiffness, but he needed to adjust gear ratios and ergonomics to make the device more usable.

The final iteration uses a combination of laser cut acrylic and machined brass components to increase rigidity where needed. A hand-turned knob for the crank adds a classy touch, as does the “Spiromatic 2000” brass plate affixed to the wooden base of the mechanism.

This isn’t the first spirograph-related project we’ve seen. How about one made of LEGO Mindstorms, another using Arduino, or one that makes these patterns on your oscilloscope?

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Make Your Own Point Contact Transistor

August 31, 2024 by Jenny List 22 Comments

Beyond the power variant, it sometimes seems as though we rarely encounter a discrete transistor these days, such has been the advance of integrated electronics. But they have a rich history, going back through the silicon era to germanium junction transistors, and thence to the original devices. if you’ve ever looked at the symbol for a transistor and wondered what it represents, it’s a picture of those earliest transistors, which were point contact devices. A piece of germanium as the base had two metal electrodes touching it as the emitter or collector, and as [Marcin Marciniak] shows us, you can make one yourself (Polish language, Google Translate link).

These home made transistors sacrifice a point contact diode to get the small chip of germanium, and form the other two electrodes with metal foil glued to paper. Given that germanium point contact diodes are themselves a rarity these days we’re guessing that some of you will be wincing at that. The video below is in Polish so you’ll have to enable YouTube’s translation if you’re an Anglophone — but we understand that the contact has to be made by passing a current through it, and is then secured with a drop of beeswax.

A slight surprise comes in how point contact transistors are used, unlike today’s devices their gain in common emitter mode was so poor that they took instead a common base configuration. There’s a picture of a project using three of them, a very period radio receiver with bulky transformers between all stages.

If you’re interested in more tales of home made early transistors, read our feature on Rufus Turner.

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