Five-minute(ish) Beanie Is The Fastest We’ve Seen Yet

July 8, 2025 by Tyler August 15 Comments

Yes, you read that right– not benchy, but beanie, as in the hat. A toque, for those of us under the Maple Leaf. It’s not 3D printed, either, except perhaps by the loosest definition of the word: it is knit, by [Kevr102]’s motorized turbo knitter.

The turbo-knitter started life as an Addi Express King knitting machine. These circular knitting machines are typically crank-operated, functioning with a cam that turns around to raise and lower special hooked needles that grab and knit the yarn. This particular example was not in good working order when [Kevr102] got a hold of it. Rather than a simple repair, they opted to improve on it.

A 12 volt motor with a printed gear and mount served for motorizing the machine. The original stitch counter proved a problem, so was replaced with an Arduino Nano and a hall effect sensor driving a 7-digit display. In theory, the Arduino could be interfaced with the motor controller and set to run the motor for a specific number of stitches, but in practice there’s no point as the machine needs babysat to maintain tension and avoid dropping stitches and the like. Especially, we imagine, when it runs fast enough to crank out a hat in under six minutes. Watch it go in the oddly cropped demo video embedded below.

Five minutes would still be a very respectable time for benchy, but it’s not going to get you on the SpeedBoatRace leaderboards against something like the minuteman we covered earlier.

If you prefer to take your time, this knitting machine clock might be more your fancy. We don’t see as many fiber arts hacks as perhaps we should here, so if you’re tangled up in anything interesting in that scene, please drop us a line.

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Oscillator Negativity Is A Good Thing

July 8, 2025 by Al Williams 5 Comments

Many people who get analog electronics still struggle a bit to design oscillators. Even common simulators often need a trick to simulate some oscillating circuits. The Barkhausen criteria state that for stable oscillation, the loop gain must be one, and the phase shift around the feedback loop must be a multiple of 360 degrees. [All Electronics Channel] provides a thorough exploration of oscillators and, specifically, negative resistance, which is punctuated by practical measurements using a VNA. Check it out in the video below.

The video does have a little math and even mentions differential equations, but don’t worry. He points out that the universe solves the equation for you.

In an LC circuit, you can consider the losses in the circuit as a resistor. That makes sense. No component is perfect. But if you could provide a negative resistance, it would cancel out the parasitic resistance. With no loss, the inductor and capacitor will go back and forth, electrically, much like a pendulum.

So, how do you get a negative resistance? You’ll need an active device. He presents some example oscillator architectures and explains how they generate negative resistances.

Crystals are a great thing to look at with a VNA. That used to be a high-dollar piece of test gear, but not anymore.

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3 yellow modules are connected with bees filling 2 out of 3

View A Beehive Up Close With This 3D Printed Hive

July 8, 2025 by Ian Bos 24 Comments

Bees are incredible insects that live and die for their hive, producing rich honey in complicated hive structures. The problem is as the average beekeeper, you wouldn’t see much of these intricate structures without disturbing the hive. So why not 3D print an observation hive? With [Teddy Hatcher]’s 3D printing creativity, that is exactly what he did.

Hexagonal sections allow for viewing of entire panels of hexagonal cells, growing new workers, and storing the rich syrup we all enjoy. Each module has two cell panels, giving depth to the hive for heat/humidity gradients. The rear of a module has a plywood backing and an acrylic front for ample viewing. [Teddy] uses three modules plus a Flow Hive for a single colony, enough room for more bees than we here at Hackaday would ever consider letting in the front door.

As with many 3D printed projects involving food or animals, the question remains about health down the line. Plastic can bio-accumulate in hives, which is a valid concern for anyone wanting to add the honey to their morning coffee. On the other hand, the printed plastic is not what honey is added to, nor what the actual cell panels are made from. When considering the collected honey, this is collected from the connected Flow Hive rather than anything directly in contact with 3D printed plastic.

Beehives might not always need a fancy 3D printed enclosure; the standard wooden crates seem to work just fine for most, but there’s a time and place for some bio-ingenuity. Conditions in a hive might vary creating problems for your honey production, so you better check out this monitoring system dedicated to just that!

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Better Solid State Heat Pumps Through Science

July 8, 2025 by Al Williams 22 Comments

If you need to cool something, the gold standard is using a gas compressor arrangement. Of course, there are definite downsides to that, like weight, power consumption, and vibrations. There are solid-state heat pumps — the kind you see in portable coolers, for example. But, they are not terribly efficient and have limited performance.

However, researchers at Johns Hopkins, working with Samsung, have developed a new thin-film thermoelectric heat pump, which they claim is easy to fabricate, scalable, and significantly more efficient. You can see a video about the new research below.

Manufacturing requires similar processes to solar cells, and the technology can make tiny heat pumps or — in theory — coolers that could provide air conditioning for large buildings. You can read the full paper in Nature.

CHESS stands for Controlled Hierarchically Engineered Superlattice Structures. These are nano-engineered thin-film superlattices (around 25 μm thick). The design optimizes their performance in this application.

The new devices claim to be 100% more efficient at room temperature than traditional devices. In practical devices, thermoelectric devices and the systems using them have improved by around 70% to 75%. The material can also harvest power from heat differences, such as body heat. The potential small size of devices made with this technology would make them practical for wearables.

We’ve looked at the traditional modules many times. They sometimes show up in cloud chambers.

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Budget Brilliance: DHO800 Function Generator

July 8, 2025 by Matt Varian 1 Comment

The Rigol oscilloscopes have a long history of modifications and hacks, and this latest from [Matthias] is an impressive addition; he’s been working on adding a function generator to the DHO800 line of scopes.

The DHO800 series offers many great features: it’s highly portable with a large 7-inch touchscreen, powered by USB-C, and includes plenty of other goodies. However, there’s room for enhancements. [Matthias] realized that while software mods exist to increase bandwidth or unlock logic analyzer functions, the hardware needed to implement the function generator—available in the more expensive DHO900 series—was missing.

To address this, he designed a daughterboard to serve as the function generator hardware, enabling features that software tweaks can unlock. His goal was to create an affordable, easy-to-produce, and easy-to-assemble interface board that fits in the space reserved for the official daughterboard in higher-end scopes.

Once the board is installed and the software is updated, the new functionality becomes available. [Matthias] clearly explains some limitations of his implementation. However, these shortcomings are outweighed by the tremendous value this mod provides. A 4-channel, 200 MHz oscilloscope with function generator capabilities for under $500 is a significant achievement. We love seeing these Rigol mods enhance tool functionality. Thanks, [Matthias], for sharing this project—great job bringing even more features to this popular scope.

Could Space Radiation Mutate Seeds For The Benefit Of Humanity?

July 8, 2025 by Lewin Day 32 Comments

Humans have forever been using all manner of techniques to better secure the food we need to sustain our lives. The practice of agriculture is intimately tied to the development of society, while techniques like selective breeding and animal husbandry have seen our plants and livestock deliver greater and more nourishing bounty as the millennia have gone by. More recently, more direct tools of genetic engineering have risen to prominence, further allowing us to tinker with our crops to make them do more of what we want.

Recently, however, scientists have been pursuing a bold new technique. Researchers have explored using radiation from space to potentially create greater crops to feed more of us than ever.

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Turning PET Plastic Into Paracetamol With This One Bacterial Trick

July 8, 2025 by Maya Posch 30 Comments

Over the course of evolution microorganisms have evolved pathways to break down many materials. The challenge with the many materials that we humans have created over just the past decades is that we cannot wait for evolution to catch up, ergo we have to develop such pathways ourselves. One such example is demonstrated by [Nick W. Johnson] et al. with a recent study in Nature Chemistry that explicitly targets PET plastic, which is very commonly used in plastic bottles.

The researchers modified regular E. coli bacteria to use PET plastic as an input via Lossen rearrangement, which converts hydroxamate esters to isocyanates, with at the end of the pathway para-aminobenzoate (PABA) resulting, which using biosynthesis created paracetamol, the active ingredient in Tylenol. This new pathway is also completely harmless to the bacterium, which is always a potential pitfall with this kind of biological pathway engineering.

In addition to this offering a potential way to convert PET bottles into paracetamol, the researchers note that their findings could be very beneficial to studies targeting other ‘waste’ products from biological pathways.

Thanks to [DjBiohazard] for the tip.