What the Flux: How Does Solder Work Anyway?

I’ve been soldering for a long time, and I take pride in my abilities. I won’t say that I’m the best solder-slinger around, but I’m pretty good at this essential shop skill — at least for through-hole and “traditional” soldering; I haven’t had much practice at SMD stuff yet. I’m confident that I could make a good, strong, stable joint that’s both electrically and mechanically sound in just about any kind of wire or conductor.

But like some many of us, I learned soldering as a practical skill; put solder and iron together, observe results, repeat the stuff that works and avoid the stuff that doesn’t. Seems like adding a little inside information might help me improve my skills, so I set about learning what’s going on mechanically and chemically inside a solder joint.

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SHAttered — SHA-1 is broken in

A team from Google and CWI Amsterdam just announced it: they produced the first SHA-1 hash collision. The attack required over 9,223,372,036,854,775,808 SHA-1 computations, the equivalent processing power as 6,500 years of single-CPU computations and 110 years of single-GPU computations. While this may seem overwhelming, this is a practical attack if you are, lets say, a state-sponsored attacker. Or if you control a large enough botnet. Or if you are just able to spend some serious money on cloud computing. It’s doable. Make no mistake, this is not a brute-force attack, that would take around 12,000,000 single-GPU years to complete.

SHA-1 is a 160bit standard cryptographic hash function that is used for digital signatures and file integrity verification in a wide range of applications, such as digital certificates, PGP/GPG signatures, software updates, backup systems and so forth. It was, a long time ago, proposed as a safe alternative to MD5, known to be faulty since 1996. In 2004 it was shown that MD5 is not collision-resistant and not suitable for applications like SSL certificates or digital signatures. In 2008, a team of researchers demonstrated how to break SSL based on MD5, using 200 Playstations 3.

Early since 2005 theoretical attacks against SHA-1 were known. In 2015 an attack on full SHA-1 was demonstrated (baptized the SHAppening). While this did not directly translate into a collision on the full SHA-1 hash function due to some technical aspects, it undermined the security claims for SHA-1. With this new attack, dubbed SHAttered, the team demonstrated a practical attack on the SHA-1 algorithm, producing two different PDF files with the same checksum.

The full working code will be released in three months, following Google’s vulnerability disclosure policy, and it will allow anyone to create a pair of PDFs that hash to the same SHA-1 sum given two distinct images and some, not yet specified, pre-conditions.

For now, recommendations are to start using SHA-256 or SHA-3 on your software. Chrome browser already warns if a website has SHA-1 certificate, Firefox and the rest of the browsers will surely follow. Meanwhile, as always, tougher times are ahead for legacy systems and IoT like devices.

Suddenly, Wireless Power Transmission Is Everywhere

Wireless power transfer exists right now, but it’s not as cool as Tesla’s Wardenclyffe tower and it’s not as stupid as an OSHA-unapproved ultrasonic power transfer system. Wireless power transfer today is a Qi charger for your phone. It’s low power – just a few amps — and very short range. This makes sense; after all, we’re dealing with the inverse square law here, and wireless power transfer isn’t very efficient.

Now, suddenly, we can transfer nearly two kilowatts wirelessly to electronic baubles scattered all over a room. It’s a project from Disney Research, it’s coming out of Columbia University, it’s just been published in PLOS one, and inexplicably it’s also an Indiegogo campaign. Somehow or another, the stars have aligned and 2017 is the year of wirelessly powering your laptop.

disney-research-quasistatic-cavity-roomThe first instance of wireless power transfer that’s more than just charging a phone comes from Disney Research. This paper describes quasistatic cavity resonance (QSCR) to transfer up to 1900 Watts to a coil across a room. In an experimental demonstration, this QSCR can power small receivers scattered around a 50 square meter room with efficiencies ranging from 40% to 95%. In short, the abstract for this paper promises a safe, efficient wireless power transfer that completely removes the need for wall outlets.

In practice, the QSCR from Disney Research takes the form of a copper pole situated in the center of a room with the walls, ceiling, and floor clad in aluminum. This copper pole isn’t continuous from floor to ceiling – it’s made of two segments, connected by capacitors. When enough RF energy is dumped into this pole, power can be extracted from a coil of wire. The video below does a good job of walking you through the setup.

As with all wireless power transmission schemes, there is the question of safety. Using finite element analysis, the Disney team found this room was safe, even for people with pacemakers and other implanted electronics. The team successfully installed lamps, fans, and a remote-controlled car in this room, all powered wirelessly with three coils oriented orthogonally to each other. The discussion goes on to mention this setup can be used to charge mobile phones, although we’re not sure if charging a phone in a Faraday cage makes sense.

motherbox-charging-phone-squareIf the project from Disney research isn’t enough, here’s the MotherBox, a completely unrelated Indiegogo campaign that was launched this week. This isn’t just any crowdfunding campaign; this work comes straight out of Columbia University and has been certified by Arrow Electronics. This is, by all accounts, a legitimate thing.

The MotherBox crowdfunding campaign promises true wireless charging. They’re not going for a lot of power here – the campaign only promises enough to charge your phone – but it does it at a distance of up to twenty inches.

At the heart of the MotherBox is a set of three coils oriented perpendicular to each other. The argument, or sales pitch, says current wireless chargers only work because the magnetic fields are oriented to each other. The coil in the phone case is parallel to the coil in the charging mat, for instance. With three coils arranged perpendicular to each other, the MotherBox allows for ‘three-dimensional charging’.

Does the MotherBox work? Well, if you dump enough energy into a coil, something is going to happen. The data for the expected charging ranges versus power delivered is reasonably linear, although that doesn’t quite make sense in a three-dimensional universe.

Is it finally time to get rid of all those clumsy wall outlets? No, not quite yet. The system from Disney Research works, but you have to charge your phone in a Faraday cage. It would be a great environment to test autonomous quadcopters, though. For MotherBox, Ivy League engineers started a crowdfunding campaign instead of writing a paper or selling the idea to an established company. It may not be time to buy a phone case so you can charge your phone wirelessly at Starbucks, but at least people are working on the problem. This time around, some of the tech actually works.

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Own the Night with this Open Source Night Vision Monocular

If you’ve always wanted to see in the dark but haven’t been able to score those perfect Soviet-era military surplus night vision goggles, you may be in luck. Now there’s an open-source night vision monocular that you can build to keep tabs on the nighttime goings-on in your yard.

Where this project stands out is not so much the electronics — it’s really just a simple CCD camera module with the IR pass filter removed, an LCD screen to display the image, and a big fat IR LED to throw some light around. [MattGyver92] seemed to put most of his effort into designing a great case for the monocular, at the price of 25 hours of 3D printer time. The main body of the case is nicely contoured, the eyepiece has a comfortable eyecup printed in NinjaFlex, and the camera is mounted on a ball-and-socket gimbal to allow fine off-axis angle adjustments. That comes in handy to eliminate parallax errors while using the monocular for nighttime walks with both eyes open. One quibble: the faux mil-surp look is achieved with a green filter over the TFT LCD panel. We wonder if somehow eliminating the red and blue channels from the camera might not have been slightly more elegant.

Overall, though, we like the way this project came out, and we also like the way [MattGyver92] bucked the Fusion 360 trend and used SketchUp to design the case. But if walking around at night with a monocular at your face isn’t appealing, you can always try biohacking yourself to achieve night vision.

Plasma Cutter Jig Notches Tubing Quickly and Cleanly

It may be [MakeItExtreme]’s most ambitious build to date. There are a lot of moving parts to this plasma cutter tubing notcher, but it ought to make a fine addition to the shop and open up a lot of fabrication possibilities.

We have to admit to a certain initial bafflement when watching the video below for the first time. We can usually see where [MakeItExtreme]’s builds are going right from the first pieces of stock that get cut, but the large tube with the pressed-in bearing had us scratching our heads. The plan soon became clear — a motorized horizontal rotary table with a hollow quill for the plasma torch leads. There’s a jig for holding the torch itself that can move in and out relative to the table. Cams made of tube sections can be bolted to a fixed platen; a cam follower rides on the cams and moves the torch in and out as the table rotates. This makes the cuts needed to properly fit tubes together — known as fish mouth cuts or saddle cuts. The cams can be removed for straight cuts, and the custom pipe vise can be adjusted to make miter cuts.

All in all a sturdy and versatile build that ought to enable tons on new projects, especially when teamed up with [MakeIt Extreme]’s recent roll bender.

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Keep the Peace in the Bedroom with a Snore Stopping Sleep Mask

Despite what my wife says, I have absolutely no evidence that I snore. After all, I’ve never actually heard me snoring. But I’ll take her word for it that I do, and that it bothers her, so perhaps I should be a sport and build this snore-detecting vibrating sleep mask so she can get a few winks more.

Part wearable tech and part life hack, [mopluschen]’s project requires a little of the threadworker’s skill. The textile part of the project is actually pretty simple, and although [mopluschen] went with a custom mask made from fabric and foam shoulder pads, it should be possible to round up a ready-made mask that could be easily modified. The electronics are equally simple – an Arduino with a sound sensor module and a couple of Lilypad Vibe boards. The mic rides just above the snore resonating chamber and the vibrators are right over the eyes. When your snore volume exceeds a preset threshold, the motors wake you up.

Whether this fixes the underlying problem or just evens the score with your sleep partner is debatable, but either way there’s some potential here. And not just for snore-correction – a similar system could detect a smoke alarm and help rouse the hearing impaired. But if the sewing part of this project puts you off, you should probably check out [Jenny List]’s persuasive argument that sewing is not just for cosplayers anymore.

Radio and Phone Speaker has Style

Building a crystal radio isn’t exactly rocket science. Some people who build them go for pushing them technically as far as they can go. Others, like [Billy Cheung], go for style points. The modular radio and phone speaker looks like it came out of the movie Brazil. The metallic gramophone-like speaker horn adds to the appeal and mechanically amplifies the sound, too.

The video (see below) isn’t exactly a how-to, but if you watch to the end there is enough information that you could probably reproduce something at least similar. There are actually several horns. One is made from copper, another from paper, and one from a plastic bottle.

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