Like many hackers, [Matthias Wandel] has a penchant for measuring the world around him, and quantifying the goings-on in his home is a bit of a hobby. And so when it came time to sense the current flowing in the wires of his house, he did what any of us would do: he built his own current sensing system.
What’s that you say? Any sane hacker would buy something like a Kill-a-Watt meter, or even perhaps use commercially available current transformers? Perhaps, but then one wouldn’t exactly be hacking, would one? [Matthias] opted to roll his own sensors for quite practical reasons: commercial meters don’t quite have the response time to catch the start-up spikes he was interested in seeing, and clamp-on current transformers require splitting the jacket on the nonmetallic cabling used in most residential wiring — doing so tends to run afoul of building codes. So his sensors were simply coils of wire shaped to fit the outside of the NM cable, with a bit of filtering to provide a cleaner signal in the high-noise environment of a lot of switch-mode power supplies.
Fed through an ADC board into a Raspberry Pi, [Matthias]’ sensor system did a surprisingly good job of catching the start-up surge of some tools around the shop. That led to the entertaining “Circuit Breaker Challenge” part of the video below, wherein we learn just what it really takes to pop the breaker on a 15-Amp branch circuit. Spoiler alert: it’s a lot.
One thing some of us here in the United States have always been jealous of is the WAGO connectors that seem so common in electrical wiring everywhere else in the world. We often wonder why the electrical trades here haven’t adopted them more widely — after all, they’re faster to use than traditional wire nuts, and time is money on the job site.
This print-in-place electrical connector is inspired by the WAGO connectors, specifically their Lever Nut series. We’ll be clear right up front that [Tomáš “Harvie” Mudruňka’s] connector is more of an homage to the commercially available units, and should not be used for critical applications. Plus, as a 3D-printed part, it would be hard to compete with something optimized to be manufactured in the millions. But the idea is pretty slick. The print-in-place part has a vaguely heart-shaped cage with a lever arm trapped inside it.
After printing and freeing the lever arm, a small piece of 1.3-mm (16 AWG) solid copper wire is inserted into a groove. The wire acts as a busbar against which the lever arm squeezes conductors. The lever cams into a groove on the opposite wall of the cage, making a strong physical and electrical connection. The video below shows the connectors being built and tested.
Most of us are familiar with the tools available to create circuit diagrams, as generally that’s the first step towards producing a custom PCB. But that about the cables and wiring harnesses that don’t live on your board? How do you easily document the rat’s nest perfectly logical wiring of your latest and greatest creation?
That’s precisely the question that led [Daniel Rojas] to create WireViz. This open source Python tool takes human readable input files and turns them into attractive and functional visualizations of where all the wires in your project are going. It can even be used to generate a Bill of Materials that documents the lengths of wire required and types of connectors needed to hook everything up.
If you’re still using pre-made cables to connect all of your components together, than you might not immediately see the benefit of a tool like this. But as we’ve talked about in the past, the creation of custom wiring harnesses is something that serious hardware hackers should become familiar with. Yes it takes more effort, but the end result is worth it. With a tool like WireViz, the creation of a bespoke harness for your next project just got a little bit easier.
Imagine you’re out behind enemy lines in WW2, setting up demolition charges that may save the lives of your fellow soldiers. How do we make a solid connection between wires that will last? One of the solutions that were used by the OSS and SOE, the predecessors to the CIA and British Secret Service, were self soldering sleeves that could be lit like a match. [ElementalMaker] managed to get his hands on a box of these sleeves, and found that they work incredibly well, even after more than half a century.
The sleeves consist of a copper tube with solder and flux inside, and wax-covered pyrotechnic compound around the outside. A small blob of striker compound similar to a match head is used to set the soldering process in motion, using the striker surface on the outside of the oversize matchbox that the sleeves are packed in. The pack that the [ElementalMaker] got was made in 1964, but is supposedly no different from those used in WW2.
When lit, the pyrotechnic compound does not create any flame, it only smolders, probably to make it safer to use, and avoid detection at night. As the solder inside the sleeve melts, the operator is supposed to push the wires further into the tube to make them overlap. Although [ElementalMaker] didn’t cut open the sleeves, it definitely looks like a good joint, with solder oozing from the ends. Check out the video after the break! If you want to get your hands on a pack of these sleeves, it looks like a military surplus store in the UK managed to source some.
If you’ve gone through the trouble of building your own customized mechanical keyboard, the last thing you want to do is plug it into your computer with some plebeian USB cable from the local electronics shop. Your productivity, nay livelihood, depends on all those 1s and 0s being reproduced with the crisp fidelity that’s only possible with a high-end USB cable. Anything less would be irresponsible.
Or at least, that’s what the advertising on the back of the package would say if we tried to sell the custom USB cables built by [Josef Adamčík]. But alas, he’s decided to give away all the details for free so that anyone can build their own delightfully overengineered USB cables. Do you need a paracord USB cable with GX12 aviation connectors in the middle? Of course not. But you still want one, don’t you?
As [Josef] admits in his blog post, there’s nothing particularly special about what he’s doing here. If you can splice wires together, you can build your own bespoke USB cables. But what attracted us to his write-up was the phenomenal detail he goes into. Every step is clearly explained and includes a nice, well-lit, photo to illustrate what he’s doing. Honestly, when the documentation for soldering some USB connectors onto a wire looks this good, there’s no excuse why more substantial projects get little more than a few blurry shots.
Of course, even for those of us who are no stranger to the ways of the soldering iron, there’s likely a few ideas you can pull from this project. We particularly liked his tip for taping the USB connector to the workbench while soldering it rather than trying to get it to stay in a vise, and his method for adding a coil the cable with a wooden jig and a heat gun is definitely something to file away for future use.
There are a lot of fun projects you can do with stepper motors salvaged from old printers or disk drives. However, it isn’t always clear how to connect to some strange motor with no markings or schematics. [Corvetteguy50] has a video showing his trick for working out the connections easily, and you can see it below.
The basic idea is simple. Using a special jig, he connects an LED across two random pins and spins the motor. If the LED lights, you’ve found a coil. You just don’t know which coil, yet. You can also short two wires and note when you feel resistance when you spin the shaft.
At some point in your electrical pursuits, you’ll need to make a connector. Maybe you’re designing something that will connect to another device, or maybe the spaghetti mess of wires coming out of your Raspberry Pi has become a pain to deal with. Whatever the reason, a proper connector can solve a lot of headaches in electronics projects.
Your first thought might be to run to your favorite component distributor and order the connectors, terminals, and crimping tool. Unfortunately, those tools can cost thousands of dollars. Maybe you’ll just solder the connectors instead? Don’t! It makes for easily damaged connections.
Fortunately, [Matt Millman] has a great guide on wire-to-board connectors. This guide will explain why you should never solder crimp terminals and then get into working with some of the most common wire-to-board connector families.
For example, the Mini-PV series (which often get called “Dupont”) are one of the most ubiquitous connectors in hobbyist electronics. They’re the connector on those rainbow colored jumper wire sets, and connect perfectly to 0.1″ pin headers. The connectors and terminals are cheap, but the official HT-0095 crimp tool costs over $1500. Most crimp tools make a mess of these terminals since they require a cylindrical jaw to crimp correctly. By using a combination of two unofficial tools, you can crimp these connectors properly for under $60.