A graph of current versus time for circuits with and without inductors

A Deep Dive Into Inductors

February 5, 2026 by No comments

[Prof MAD] runs us through The Hidden Power of Inductors — Why Coils Resist Change.

The less often used of the passive components, the humble and mysterious inductor is the subject of this video. The essence of inductance is a conductor’s tendency to resist changes in current. When the current is steady it is invisible, but when current changes an inductor pushes back. The good old waterwheel analogy is given to explain what an inductor’s effect is like.

There are three things to notice about the effect of an inductor: increases in current are delayed, decreases in current are delayed, and when there is no change in current there is no noticeable effect. The inductor doesn’t resist current flow, but it does resist changes in current flow. This resistive effect only occurs when current is changing, and it is known as “inductive reactance”.

After explaining an inductor’s behavior the video digs into how a typical inductor coil actually achieves this. The basic idea is that the inductor stores energy in a magnetic field, and it takes some time to charge up or discharge this field, accounting for the delay in current that is seen.

There’s a warning about high voltages which can be seen when power to an inductor is suddenly cut off. Typically a circuit will include snubber circuits or flyback diodes to help manage such effects which can otherwise damage components or lead to electric shock.

[Prof MAD] spends the rest of the video with some math that explains how voltage across an inductor is proportional to the rate of change of current over time (the first derivative of current against time). The inductance can then be defined as a constant of proportionality (L). This is the voltage that appears across a coil when current changes by 1 ampere per second, opposing the change. The unit is the volt-second-per-ampere (VsA-1) which is known as the Henry, named in honor of the American physicist Joseph Henry.

Inductance can sometimes be put to good use in circuits, but just as often it is unwanted parasitic induction whose effects need to be mitigated, for more info see: Inductance In PCB Layout: The Good, The Bad, And The Fugly.

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Gimmick Sunglasses Become Easy Custom Helmet Visor

February 5, 2026 by 3 Comments

[GizmoThrill] shows off a design for an absolutely gorgeous, high-fidelity replica of the main character’s helmet from the video game Satisfactory. But the best part is the technique used to create the visor: just design around a cheap set of full-face “sunglasses” to completely avoid having to mold your own custom faceplate.

One of the most challenging parts of any custom helmet build is how to make a high-quality visor or faceplate. Most folks heat up a sheet of plastic and form it carefully around a mold, but [GizmoThrill] approached the problem from the other direction. After spotting a full-face sun visor online, they decided to design the helmet around the readily-accessible visor instead of the other way around.

The first thing to do with the visor is cover it with painter’s tape and 3D scan it. Once that’s done, the 3D model of the visor allows the rest of the helmet to be designed around it. In the case of the Satisfactory helmet, the design of the visor is a perfect match for the game’s helmet, but one could easily be designing their own custom headgear with this technique.

The hexagon grid pattern? It’s actually a clear vinyl sticker and doesn’t obstruct vision at all. Another clever touch.

With the helmet 3D printed, [GizmoThrill] heads to the bandsaw to cut away any excess from the visor, and secure it in place. That’s all there is to it! Sure, you don’t have full control over the visor’s actual shape, but it sure beats the tons and tons of sanding involved otherwise.

There’s a video tour of the whole process that shows off a number of other design features we really like. For example, metal mesh in the cheek areas and in front of the mouth means a fan can circulate air easily, so the one doesn’t fog up the inside of the visor with one’s very first breath. The mesh itself is concealed with some greebles mounted on top. You can see all those details up close in the video, embedded just below.

The helmet design is thanks to [Punished Props] and we’ve seen their work before. This trick for turning affordable and somewhat gimmicky sunglasses into something truly time-saving is definitely worth keeping in mind.

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Toybox Tractor: Plywood, Lathe Hacks, And 350W Of Fun

February 5, 2026 by 3 Comments

When you think of a toy tractor, what probably comes to mind is something with fairly simple lines, maybe the iconic yellow and green, big rear tires, small front ones. Well, that’s exactly what [James] built, with simple, clean lines and a sturdy build that will hold up to driving around off-road in the garden. This Tractor is a great build, combining CAD, metal and wood work, some 3D printing, and electronics.

Starting at the power plant for the build, [James] went with a 350W DC motor powered by a 36V Li-ion battery from an e-bike. The motor turns a solid rear axle he made on a mini-lathe, connected to a set of riding lawn mower wheels. The mini-lathe spindle bore was too small to accommodate the shaft, and the lathe was not long enough to use the tailstock, so [James] had to get creative, using a vice and a piece of wood to make a stand–in tailstock, allowing him to turn this custom rear axle. The signature smoothly curved bonnet was made possible with plywood and body filler, rather than the sheet metal found on full-sized tractors. In fact, most of the build’s frame used plywood, giving it plenty of strength and, once painted, helping give it the appearance of a toy pulled out of a toybox.

This build had a bit of many domains in it, and all combined into a fantastic final result that no doubt will bring a smile to any face that gets to take the Tractor for a ride. Thanks [James] for documenting your build process, the hacks needed to pull off the tough bits along the way in making this fun toy. If you found this fun, be sure to check out another tractor related project.

Big Heat Pumps Are Doing Big Things

February 5, 2026 by 25 Comments

The heat pump has become a common fixture in many parts of modern life. We now have reverse-cycle air conditioning, heat pump hot water systems, and even heat pump dryers. These home appliances have all been marketed as upgrades over simpler technologies from the past, and offer improved efficiency and performance for a somewhat-higher purchase price.

Heat pumps aren’t just for the home, though. They’re becoming an increasingly important part of major public works projects, as utility providers try to do ever more with ever less energy in an attempt to save the planet. These days, heat pumps are getting bigger, and will be doing ever grander things in years to come. Continue reading “Big Heat Pumps Are Doing Big Things” →

Three Decades Of ReactOS

February 5, 2026 by 6 Comments

Over the past couple of years with the Jenny’s Daily Drivers series, we’ve looked at a number of unusual or noteworthy operating systems. Among them has been ReactOS, an open source clone of a millennium-era Windows OS, which we tried back in November. It’s one of those slow-burn projects we know has been around for a long time, but still it’s a surprise to find we’ve reached the 30th anniversary of the first ReactOS code commit.

The post is a run through the project’s history, and having followed it for a long time we recognize some of the milestones from the various ISOs we downloaded and tried back in the day. At the end it looks into the future with plans to support more up-to-date hardware as well as UEFI, which we hope will keep it relevant.

When we tried it, we found an OS which could indeed be a Daily Driver on which a Hackaday article could be written — even if it wasn’t the slickest experience on the block. It doesn’t matter that it’s taken a while, if you’re used to Windows XP this has become a usable replacement. We came to the conclusion that like FreeDOS it could find a niche in places where people need a modern version of the old OS to run older software, but perhaps as it now moves towards its mature phase it will move beyond that. We salute the ReactOS developers for bringing it this far, and for not giving up.

You can read our Daily Drivers review of a recent ReactOS build here.

How Industrial Robot Safety Was Written In Blood

February 5, 2026 by 17 Comments

It was January 25th of 1979, at an unassuming Michigan Ford Motor Company factory. Productivity over the past years had been skyrocketing due to increased automation, courtesy of Litton Industry’s industrial robots that among other things helped to pick parts from shelves. Unfortunately, on that day there was an issue with the automated inventory system, so Robert Williams was asked to retrieve parts manually.

As he climbed into the third level of the storage rack, he was crushed from behind by the arm of one of the still active one-ton transfer vehicles, killing him instantly. It would take half an hour before his body was discovered, and many years before the manufacturer would be forced to pay damages to his estate in a settlement. He only lived to be twenty-five years old.

Since Robert’s gruesome death, industrial robots have become much safer, with keep-out zones, sensors, and other safety measures. However this didn’t happen overnight; it’s worth going over some of the robot tragedies to see how we got here.

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