Peltier Snow Globe Features Snowman Who Dresses Himself In Real Frost

December 24, 2021 by Dan Maloney 22 Comments

We doubt that few of us ever thought that snow globes contain real snow, but now that we’ve seen a snow globe that makes its own snow, we have to admit the water-filled holiday decorating mainstay looks a little disappointing.

Like a lot of the Christmas decorations [Sean Hodgins] has come up with over the years, this self-frosting snowman is both clever in design and cute in execution. The working end is a piece of aluminum turned down into the classic snowman configuration; the lathe-less could probably do the same thing by sticking some ball bearings together with CA glue. Adorned with 3D-printed accessories, the sculpture sits on a pedestal of Peltier coolers, stacked on top of a big CPU cooler. Flanking the as-yet underdressed snowman is a pair of big power resistors, which serve as heating elements to fill the globe with vapor. [Sean]’s liquid of choice is isopropyl alcohol, and it seems to work very well as the figurine is quickly enrobed with frost.

But wait, there’s more — as [Sean] points out, the apparatus is 90% of the way to being a cloud chamber. Maybe we’ll see a less festive version after the holidays. Until then, enjoy his ornament that prints other ornaments, his blinkenlight PCB tree-hangers, or his tiny TV that plays holiday commercials.

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FlyBrainLab: Google Earth But For A Drosophila Fly’s Brain

December 24, 2021 by Maya Posch 6 Comments

In biology there are a couple of truly crucial model animals and insects. Not that they’re particularly good students, or pick up their own trash, but in the sense that they have become standard model organisms for research. Aside from genetic research, the FlyEM project seeks to fully map a little fly’s brain’s neural connections. This common fly, called drosophila melanogaster (or ‘lesser fruit fly’) has been the subject of a lot of genetic studies, but this study of its brain structure may provide insights in how our brain works as well.

Based on electron microscope images of thin slices of a drosophila brain, the three-dimensional structure of this tiny brain is reconstructed to not only determine the location of each neuron, but also their connections with other neurons. We know that about two-thirds of their brain is dedicated to processing the visual information from their relatively advanced compound eyes, but a lot is still unknown about how this is done, or how the brain’s structure develops.

If it’s always been your dream to tinker with a little fruit fly’s brain, you can do so yourself using the open source FlyBrainLab tool provided, along with the freely available data sources. This tool does not just allow one to visualize the drosophila brain in great detail, but also to create executable circuits and study their functionality. With neurobiology still a largely unexplored territory, this makes for an amazing tool to make this research accessible to anyone.

(Thanks for the tip, [Hernandi Krammes])

DIY bagpipe made from a latex glove and some straws.

Ring In The New Year With DIY Bagpipes

December 23, 2021 by Kristina Panos 14 Comments

Remember early on in the pandemic when people would don protection just short of a full hazmat suit to go out, and wore rubber gloves to the grocery store? Was that just us? The point is, we are surely not alone in having an excess of latex gloves left over, and pitifully few uses for them aside from the usual — gross jobs around the house, and making hand-shaped ice cubes.

Well, here’s something a little more fun: DIY bagpipes. No matter how you feel about the sounds they produce, the way that bagpipes work is pretty interesting. In the video embedded after the break, [Charlie Engelman] shows us how they work and compares them to saxophonist Kenny G’s little jazz mouth.

See, Mr. G can circular breathe, which means he can hold a note for as long as he wants. Basically, he is able to keep a reserve of air in his mouth for playing the thing, while at the same time inhaling new air.

If we bring this back around to bagpipes, the bladder is akin to Kenny G’s mouth. It always contains air, so it perpetually releases air through the sound pipes that stick up. In the case of the glove pipe, the glove is the bladder, and the pipes are made of drinking straws. Check it out after the break — we think the sound is far more tolerable than real bagpipes.

We’ve seen bagpipes made from common household items before (if you consider a couple of plastic recorders to be common household items), and we’ve also seen real bagpipes go electromechanical.

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Lisp In 436 Bytes

December 23, 2021 by Al Williams 26 Comments

You would assume that any programming language available back in the 1960s would be small enough to easily implement on today’s computers. That’s not always true though, since old languages sometimes used multiple passes. But in some cases, you can implement what would have been a full language decades ago in a tiny footprint. A case in point is a pretty good implementation of Lisp — including garbage collection — in 436 bytes.

SectorLISP claims to be the tiniest real language, beaten only by toy languages that are not really very useful. If you want to, you can try it in your browser, but that version has better error messages and persistent bindings, so it hogs up a whole 509 bytes.

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Fixing A Freezer Design Flaw With A Little Bit Of Heat

December 23, 2021 by Maya Posch 41 Comments

As a shining example of the law of unintended consequences, [Lou] demonstrates how certain types of freezer/refrigerator combinations fail to work in a cold environment, such as a garage during the winter. As [Lou] points out in his video (also linked after the break) – using the freezer unit in his own garage – the problem lies with devices that put the temperature sensor in the refrigerator section, but circulate cold air starting in the freezer section.

This works great in a home environment with a room temperature comfortable for humans, as the refrigerator will constantly warm up slightly due to heat from the outside, triggering the cooling cycle and ensuring the freezer section will stay nice and cold. When placed in, say, a garage when it’s around freezing, the refrigerator section will not warm up, and thus no more cooling cycle gets triggered.

As obviously the freezer section is supposed to stay significantly colder than roughly around 0°C, the freezer section can warm up enough to allow frozen goods to thaw out. The easy fix here as [Lou] demonstrates, is to add a constant source of warmth inside the refrigerator section, such as by keeping the refrigerator light on constantly.

Obvious complaints about the lack of energy efficiency and this combo unit’s optimistically broken sensor design aside, it is a fairly simple and effective fix. Even so, perhaps trading such a combo unit for one with a dedicated temperature sensor in the freezer section would prevent headaches like these.

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WS2812s On A 6502

December 23, 2021 by Elliot Williams 40 Comments

We can still remember when the WS2812 LED first came into our consciousness, way back in the mists of time. The timing diagrams in the datasheet-of-questionable-veracity made it sound quite tricky, with tight timing tolerances and essentially a high-speed two-bit PWM data protocol at 500 kHz. It was a challenge to bit-bang with an ATtiny85 back then, but there’s no way something as old and crusty as an Apple II would be up to snuff, right?

[Anders Nielsen] took up the challenge of getting the venerable 6502 processor to drive Neopixels and won! After all, if the chip is good enough for Bender and the Terminator T-800, it should be able to blink some colored LEDs, right? The secret sauce is shift registers!

Specifically, [Anders] abuses the 74LS165 parallel-in, serial-out shift register for his dirty work. Instead of bit-banging the WS2812’s “long high is a 1, short high is a 0” signal directly, the first few bits of the shift register are hard-wired to VCC and the last few to GND.

The bits in the middle determine if the pulse shifted out is long or short, and they’re set by the 6502, through a 6522 VIA chip, just like the Apple II would have. Clocking the data out of the shift register handles the timing-critical stuff. Very clever!

Video below the break.

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Eric Strebel peeks through his Pfaff 463 industrial sewing machine.

Simple Upgrades Make An Old Industrial Sewing Machine New Again

December 23, 2021 by Kristina Panos 30 Comments

Well, this is a pleasant surprise: it seems that industrial designer [Eric Strebel] recently got a hold of an industrial sewing machine to tackle the softer side of prototyping. What doesn’t surprise us is that he did some upgrades to make it more user-friendly. Check them out in the video embedded below.

So, what’s the difference between a machine like this and what you might have around the house? Domestic sewing machines have a motor about the size of your fist, and it’s inside the machine’s body. Modern domestics can do light-duty work, but they can’t handle making bags and upholstery or sewing a bunch of layers of any material together. Industrial machines have either clutch or servo motors that are easily five times the size of a domestic’s motor, and are built into the table along with the machine.

[Eric] found this Pfaff 463 on Craigslist. It was built somewhere around 1950, and it only does one thing — a single-needle, straight stitch, forward or reverse — but it will do it through damn near anything you want (unlike those computerized hunks of plastic made for home use nowadays). Again, these machines are always built into a table, and they come with a lamp. While the machine itself may be a workhorse, the light is wimpy, so [Eric] replaced it with a goose-neck LED light that has a magnet for sticking it anywhere light is required around the machine.

No matter the size, electric sewing machines are driven with a foot pedal. On a domestic, the pedal is loose and you just put it on the floor wherever you want, but industrial foot pedals are built into the table frame. [Eric] drilled a bunch of new holes in the side of the pedal so he can move the connecting rod closer to the pivot point. This gives him better control with less footwork.

The biggest, baddest upgrade [Eric] did was to the motor. Although there was nothing wrong with the original clutch motor, it makes the machine go very fast so that garment workers can fulfill their quotas. Because of this, it’s difficult to control. He upgraded to a brushless DC servo motor for greater precision and easier prototyping. He got really lucky, too, because it mounted directly into the old holes.

We agree wholeheartedly with [Eric]’s sentiment about old sewing machines, or any old machine for that matter. They tend to be overbuilt because planned obsolescence wasn’t a thing yet. If you can’t afford or find an industrial, an old Singer or something similar will likely serve your purpose, as long as you use the right needle.

If you already have an old domestic machine sitting around, you might be able to breathe new life into it with a 3D printer.

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