Hackaday Links: It’s Mother’s Day And You Forgot

[AvE] noticed someone was having trouble with their Nepeploid Shilden Inversker, and after a sinusoidal lambda deplanarization test, noticed the dinglebop wouldn’t pass through the grumbo. [AvE] is probably just some guy who wears overalls to bed, but he does know a polyfractal magnetorestrictor when he sees one. To wit, he has a novel application of Eularian magnetronics resulting in a friction factor over unityGame changing stuff here, from the guy who brought you the beer stein made out of an oil filter.

It was soft launched at the Midwest RepRap Festival this year, and now Lulzbot’s TAZ 6 is finally out. The biggest new feature? The electronics ‘brain box’ holds everything, including the power supply. This tower of brain box makes the Taz 6 harder to build from source, but there are unconfirmed reports that Lulzbot may sell this brainbox separately.

Boldport, and founder [Saar Drimer] are the cream of the crop when it comes to artistic PCBs. Boldport’s catalog and [Saar]’s portfolio include a tribute to [Bob Pease], a beautiful board with multicolor solder masks, and an emergency business card. Now Boldport is doing a beautiful PCB of the month club. It’s called Boldport Club, and each three-month membership gets you three months of pretty PCBs. The shop will also stop taking orders for the Boldport club 25 hours after this post goes live. If you missed the boat on the club, you can still get in on the pretty PCB action – we have the Boldport cordwood puzzle available in the Hackaday store.

The Apple IIgs was the last gasp of the Apple II before that platform was phased out for the Macintosh. Despite being mostly forgotten, except for thousands of units in middle school computer labs until the 2000s, it was a very interesting machine, with a wavetable synth, real multitasking, a GUI, and very high resolution graphics. After 30-odd years the IIgs now has quadraphonic sound. The 4soniq card was introduced at the WOzFest III conference last month, and it will give an Apple IIgs with four channels of audio output.

There’s a lot of stuff happening next weekend, and Hackaday is going to be there. If you’re at the Maker Faire Bay Area, Hackaday is taking over a pub. It’s on Saturday night, so it doesn’t conflict with the bring-a-hack at an undisclosed location on Sunday night. Me? I’m going to hamvention, mostly for the purposes of documenting the two parking lots full of swap meet. Find me and I’ll get you some Hackaday swag.

Hackaday Prize Entry: A Cheaper Soldering Solution

Everyone goes through a few phases during their exploration of electrons, and nowhere is this more apparent than the choice of soldering iron. The My First Soldering Iron™ is an iron that plugs directly into the wall, and doesn’t have temperature control. They’re cheap, and electronics isn’t for everyone, giving the quitters the opportunity to take up woodburning as a hobby. The next step up is a temperature controlled iron, probably an Aoyue or Hakko. The best soldering iron? You’re looking at a Metcal or Weller, and your wallet will become a few hundred dollars lighter.

Your My First Soldering Iron™ need not be terrible, though. For his project for The Hackaday Prize, [HP] is working on a soldering iron that is cheap, accurate, and uses the very nice Weller RT tips. No, it’s not as good as a Metcal or proper Weller, but it’s good enough for some fine soldering work and will give the Aoyues and Hakkos a run for their money.

If price is a reasonable measure of the quality of a soldering iron, the irons that use these Weller RT tips are the best irons around. The tips, though, are pretty cheap: about $30, which gets you a heater and thermistor and not much else. There have been numerous reverse engineering efforts for this iron ([1] and [2]), and even a few Arduino-based circuits that replicate the functionality of the Weller base unit.

[HP] is going in a different direction to heat these iron tips. Instead of building a big box to hold the electronics, he’s building everything into the handle of the soldering iron. With brains donated from an ATMega168, a few op-amps, MOSFETS, and a single power jack, [HP] can heat up this soldering iron tip in a compact, hand-held unit.

For his Hackaday Prize entry, [HP] did a rundown of soldering pen in a video. You can check that out below.

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Clever And Elegant Tilt Sensors From Ferrofluid

Let’s talk about tilt sensors for a second. The simplest tilt sensors – the dead simplest – are a few ball bearings rolling around in a small metal can. When the can is tilted, the balls roll into a pair of electrical contacts, completing the circuit. How about a drop of mercury in a glass ampule with a few contacts? Same thing. You can get more expensive tilt sensors, including a few that are basically MEMS gyros, but they’re all pretty much the same. For [Aron]’s project for the Hackaday Prize, he’s come up with a tilt sensor that is so clever, so innovative, and so elegant, we’re gobsmacked by his creativity.

5700111461442877186Instead of electrical contacts or gyroscopes, [Aron] is using induction to measure the tilt of a sensor. By wrapping a tube with one long primary winding of copper wire, and several secondary windings in various places, [Aron] built a Linear Variable Differential Transformer. If you insert an iron rod inside this transformer, different voltages will be induced in the primary. Simple, and this device is effectively a position sensor for any ferrous material.

Now for the real trick: put ferrofluid in the core of that transformer. Liquids always find their level, and different tilts will induce different voltages in the primary. Brilliant. Continue reading “Clever And Elegant Tilt Sensors From Ferrofluid”

Designing Flat Flexible PCBs

You can find flex PCBs in just about every single piece of consumer electronics. These traces of copper laminated in sheets of Kapton are everywhere, and designing these cables, let alone manufacturing them, is a dark art for the garage electronics wizard. Having these flat flex cables and PCBs manufactured still requires some Google-fu or a contact at a fab house, but at least now designing these cables is a solved problem.

[Oli] needed a way to connect two PCBs together over a moving part. Usually this means some sort of connector or cable, but he’s developed an even better solution – flexible PCB connections. To generate these copper traces sandwiched between a few layers of Kapton, [Oli] wrote a Python script to take a set of parameters, and produces an design for Eagle that includes all the relevant bits.

Of course, with a flexible PCB layout, the question of how to get these manufactured comes up. we’ve seen a few creative people make flexible PCBs with a 3D printer and there’s been more than one Hackaday Prize project using these flex PCBs. [Oli] says any manufacturer of flexible circuits should be able to reproduce everything generated from his script without much thinking at all. All we need now is for OSH Park to invent purple Kapton.

You can grab [Oli]’s script on his GitHub.

JIT Learning Using Expert Systems

Chris Gammell is a guy that should need no introduction around these parts. He’s a co-host on The Amp Hour, and the guy behind Contextual Electronics, a fabulous introduction to electronics and one of the best ways to learn KiCad. If you want to talk about the pedagogy of electronics, this is the guy you want.

Chris’ talk at the Hackaday | Belgrade conference was on just that – the pedagogy of electronics. Generally, there are two ways to learn how to blink an LED. The first, the bottom-up model taught in every university, is to first learn Ohm’s law, resistance, current, voltage, solve hundreds of resistor network problems, and eventually get around to the ‘electrons and holes’ description of a semiconductor. The simplest semiconductor is a diode, and sometime in the sophomore or junior year, the student will successfully blink a LED.

The second, top-down method is much simpler. Just wire up a battery, resistor, switch, and LED to a breadboard. This is the top-down model of electronics design; you don’t need to know everything to get it to work. You don’t need to do it with a 555, and you certainly don’t have to derive Maxwell’s equations to make something glow. Chris is a big proponent of the top-down model of learning, and his Belgrade talk is all about the virtues of not knowing everything.

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An Open Source Lead Tester

If you’ve ever needed an example of colossal failure of government actors, you need only to look at Flint, Michigan’s water crisis. After the city of Flint changed water supplies from Detroit to the Flint river, city officials failed to add the correct corrosion inhibitors. This meant that lead dissolved into the water, thousands of children were exposed to lead in drinking water, a government coverup ensued, [Erin Brockovich] showed up, the foreman of the Flint water plant was found dead, and the City Hall office containing the water records was broken into.

Perhaps inspired by Flint, [Matthew] is working on an Open Source Lead Tester for his entry into the 2016 Hackaday Prize.

[Matthew]’s lead tester doesn’t test the water directly. Instead, it uses a photodiode and RGB LED to look at the color of a lead test strip. These results are recorded, and with a bit of a software backend, an entire city can be mapped for lead contamination in a few days with just a few of these devices.

One problem [Matthew] has run into is the fact the Pi does not have analog to digital conversion, making reading a photodiode a little harder than just plugging a single part into a pin header and watching an analog value rise and fall. That really shouldn’t be a problem – ADCs are cheap, especially if you only need a single channel of analog input with low resolution. [Matthew] is also looking into using the Pi webcam for measuring the lead test strip. There are a lot of decisions to make, but any functional device that comes out of this project will be very useful in normal, functioning governments. And hopefully in Flint, Michigan too.

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Reverse Engineering An ATM Card Skimmer

While vacationing in Bali, [Matt South] walked into a nice, secure, air-conditioned cubicle housing an ATM. Knowing card skimmers are the bane of every traveller, [Matt] did the sensible thing and jiggled the card reader and the guard that hides your PIN when punching it into the numeric keypad. [Matt] found the PIN pad shield came off very easily and was soon the rightful owner of a block of injection molded plastic, a tiny camera, and a few bits of electronics.

The first thing that tipped [Matt] off to the existence of electronics in this brick of plastic was a single switch and a port with four contacts. These four pins could be anything, but guessing it was USB [Matt] eventually had access to a drive filled with 11GB of video taken from inside this PIN pad shield.

An investigation of the videos and the subsequent teardown of the device itself revealed exactly what you would expect. A tiny pinhole camera, probably taken from a ‘spy camera’ device, takes video whenever movement is detected. Oddly, there’s an audio track to these videos, but [Matt] says that makes sense; the scammers can hear the beeps made by the ATM with every keypress and correlate them to each button pressed.

Of course, the black hats behind this skimmer need two things: the card number, and the PIN. This tiny spy cam only gets the PIN, and there wasn’t a device over or in the card slot in the ATM. How did the scammers get the card number, then? Most likely, the thieves are getting the card number by sniffing the ATM’s connection to the outside world. It’s a bit more complex than sticking a magnetic card reader over the ATM’s card slot, but it’s harder to detect.