Author: Jenny List

3538 Articles

Flux Gate Magnetometers Make A Special Current Probe

September 21, 2019 by 11 Comments

There are moments when current measurement is required on conductors that can’t be broken to insert a series resistor, nor encircled with a current transformer. These measurements require a completely non-invasive technique, and to satisfy that demand there are commercial magnetometer current probes. These probes are however not for the light of wallet, so [ensgoldmine] has created a much cheaper alternative.

The Texas Instruments GRV425 flux gate magnetometer integrated circuit on its TI evaluation module provides the  measuring element placed at the tip of a probe as close as possible to the conductor to be measured, with another GRV425 module at the head of the probe to measure ambient magnetic field for calibration purposes.  An Arduino Due measures and processes the readings, chosen due to its higher-resolution ADC than the more ubiquitous Arduino Uno.

The write-up is interesting even if you have no need for a current probe, because of its introduction to these sensing elements. Because it’s a rare first for Hackaday, we’ve never taken a close look at them before other than as an aside when talking about a scientific instrument on Mars.

British Cops Catch Shooter-Printing Villain

September 20, 2019 by 84 Comments

It’s a perennial of breathless British tabloid scare reporting that 3D printers will unleash a tide of weapons upon the streets. But perhaps it might actually be time for Brits lock up their children, because London’s Metropolitan Police have announced their first prosecution for 3D printing a handgun. The gun pictured appears to be a Repringer 5-shot .22 revolver, and was found by police during a drugs raid.

The UK has significantly restrictive firearms legislation and shooting incidents are extremely rare in the country, so while this might not raise any eyebrows on the other side of the Atlantic it’s an extremely unusual event for British police. It appears that the builder was not the type of libre firearms enthusiast who has made the news with similar work in the USA, so it has to be assumed that it was printed purely as a means to secure an illegal firearm however rough-and-ready or indeed dangerous it might be.

Stepping aside from the firearm aspect of the story, it should be of concern for any British 3D printer enthusiasts. As we’ve reported over the years with respect to drone incidents they can sometimes throw reason to the wind when faced with unfamiliar technology, indeed we’ve already seen them imagining RepRap parts to be for a firearm. We’d counsel all parties to keep sane heads, and hope that both the sentence for today’s criminal proves to be a suitable deterrent, and that no clueless fool decides to download and print another weapon for the hell of it. As always, we’ll bring you developments as they happen.

3D Print A Complete Wind Generator

September 19, 2019 by 22 Comments

For many of us our landscapes are dotted with wind turbines, the vast majority of which are horizontally aligned as if they were giant aircraft propellers. A much rarer sight is the vertical wind turbine, which remains a staple of the wind power experimenter. [Troy] and his brother have posted a video showing a small wind 3D printed vertical turbine, which unusually includes an alternator made from scratch as well as the rotor itself.

The machine adopts a Savonius rotor design with three scoops, which offers simplicity and high torque at a lower rotational speed than some of the alternatives. The scoops are assembled from a number of 3D-printed sections, and directly drive the generator which uses a large number of coils on a stator encircled by a rotor containing an array of magnets. A simple rectifier and three-terminal regulator produces a 5-volt output.

Sadly there was not enough wind to give it a decent test for the video, but they demonstrate it with a very large fan standing in. We like the alternator design but we’d be interested to see how the sectional rotors hold up in outdoor conditions, and perhaps that regulator could benefit from a switch-mode component. If you fancy a go he says he’ll release the files as open source if there’s enough interest. We’re interested [Troy], please do!

Many wind turbines have passed through these pages over the years, and for contrast here’s a horizontal 3D printed example.

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That Game Cartridge Isn’t As Straightforward As You’d Think

September 19, 2019 by 11 Comments

Classic games consoles played their games from cartridges, plastic bricks that held a PCB with the game code on it ready to be run by the console hardware. You might therefore expect them to be an easy prospect for emulation, given that the code can be extracted from whatever ROM they contain. But as anyone with an interest in the subject will tell you, some cartridges included extra hardware to boost the capabilities of their games, and this makes the job of an emulator significantly more complex.

[Byuu] has penned an article exploring this topic across a variety of consoles, with in-depth analyses of special-case cartridges. We see the obvious examples such as the DSP coprocessors famously used on some SNES games, as well as Nintendo’s Super Game Boy that contained an entire Game Boy on a chip.

But perhaps more interesting are the edge-case cartridges which didn’t contain special hardware. Capcom’s Rockman X had a copy protection feature that sabotaged the game if it detected RAM at a frequently used save game address emulated by copiers. Unfortunately this could also be triggered accidentally, so every one of the first generation Rockman X cartridges had a manually attached bodge wire that a faithful emulator must replicate. There is also the case of the Sega Genesis F22 Interceptor, which contained an 8-bit ROM where most cartridges for this 68000-powered platform had a 16-bit part. Simple attempts to copy this cartridge result in the upper 8 bits having random values due to the floating data lines, which yet again an emulator must handle correctly.

It’s a subject with a variety as huge as the number of console developers and their games, and a field in which new quirks are constantly being unearthed. While most of us don’t spend our time peering into dusty cartridges, we’re grateful for this insight into that world.

We’ve visited the world of emulators a few times before, such as when we looked at combatting in-game lag.

AI Makes Hyperbolic Brain Hats A Reality

September 14, 2019 by 7 Comments

It isn’t often that the world of Hackaday intersects with the world of crafting, which is perhaps a shame because many of the skills and techniques of the two have significant overlap. Crochet for instance has rarely featured here, but that is about to change with [Janelle Shane]’s HAT3000 neural network trained to produce crochet hat patterns.

Taking the GPT-2 neural network trained on Internet text  and further training it with a stack of crochet hat patterns, she was able to generate AI-designed hats which her friends on the Ravelry yarn forum set to crochet into real hats. It’s a follow-up to a previous knitting-based project, and instead of producing the hats you might expect it goes into flights of fancy. Some are visibly hat-like while others turn into avant-garde creations that defy any attempt to match them to real heads. A whole genre of hyperbolic progressions of crochet rows produce hats with organic folds that begin to resemble brains, and tax both the stamina of the person doing the crochet and their supply of yarn.

Perhaps most amusingly the neural network retains the ability to produce text, but when it does so it now inevitably steers the subject back to crochet hats. A Harry Potter sentence spawns a passage of something she aptly describes as “terrible crochet-themed erotica“, and such is the influence of the crochet patterns that this purple prose can even include enough crochet instructions to make them crochetable. It would be fascinating to see whether a similar model trained with G-code from Thingiverse would produce printable designs, what would an AI make with Benchy for example?

We’ve been entertained by [Janelle]’s AI work before, both naming tomato varieties, and creating pie recipes.

Thanks [Laura] for the tip.

Stack Those Boards For An Extra-Special Backlit LED Effect

September 14, 2019 by 6 Comments

By now most of us should be used to backlit LEDs, in which a bare board with no copper or soldermask as an LED mounted on its reverse side to shine through as if with a diffuser. [Wim Van Gool] has created such an LED display with a twist, instead of reverse mounted LEDs his Shitty Add-On for Area3001 hackerspace in Leuven, Belgium has a set of WS2812 addressable LEDs shining upwards through a void in a stack of PCBs to the diffuser. The effect is of something that looks about the size and shape of a Kit-Kat finger with a glowing hackerspace logo on the front, and it breaks away from the SAO norm.

Full details are on the GitHub repository for the project, in which we find both large and small takes on the same idea. It appears that there is no onboard processor and that the WS2812s are driven from the host badge, but that doesn’t take away from the ingenuity of the design.

The through-PCB diffuser seems to be the badge must-have of the moment, we’ve seen quite a few such as the recent Numberwang badge. That’s the exciting thing about badge design though, one always knows that there will be a new twist along in the next crop of badges, to keep everything fresh.

A Conference Badge Breathes Life Into A Rotary Phone

September 14, 2019 by 4 Comments

We have covered the astonishing diversity of conference badges to a great extent over the years, and we are always pleased and surprised at the creativity and ingenuity that goes into their creation. But the saddest thing about so many badges is that after the event they go into the drawer and are never touched again, such a missed opportunity!

It’s a trend that [Dan] has reversed though, with his rotary dial phone brought to life with an EMF Tilda MkIV. This was the badge from last year’s EMF Camp 2018, and its defining feature was a built-in GSM mobile phone. We didn’t give it a full review at the time because it has problems with the GSM part at the event and it would have been unfair to display what was an amazing badge in a negative light, but once we got it home it was straightforward enough to put a commercial SIM in the slot and use the public networks with it.

[Dan]’s phone is an Eastern European model that came to him through his grandfather. Inside it’s a relatively conventional design, into which he’s patched a couple of the Tilda’s I/O lines from the dial through a debounce circuit. But simply selecting a couple of lines wasn’t enough, as most of those on its expansion port come via a port expander. He needed inputs that could generate an interrupt, so he hijacked a couple from the on-board joystick. He’s included Python code which you can see in action in the video below. It’s important to note that he’s yet to hook up the audio to the badge so this is a work in progress, but it’s an interesting project nevertheless.

Rotary phones hold a special place among hardware hackers, we’ve featured many projects including them. This isn’t the first GSM rotary phone we’ve brought you, and don’t forget they can also talk via Bluetooth.

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