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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Harmonographs Generate Geometric Images Unique as Fingerprints

When my elder brother and I were kids back in the late 1970’s, our hacker Dad showed us this 1960-61 catalog of the Atlas Lighting Co (later Thorn Lighting) with an interesting graphic design on the cover. He told us to do a thought experiment, asking us to figure out how it would be possible to have a machine that would draw the design on that catalog cover.

Incorrectly, our first thought was that the design was created with a Spirograph. A spirograph has two main parts: a large ring with gear teeth on the inside and outside circumferences and a set of smaller, toothed wheels with holes in them for inserting a drawing instrument — usually a ball point pen. You hold the big ring, insert the pen in the smaller wheel, and then mesh and rotate the smaller wheel around the big ring. But spirographs can’t be used to draw irregular, asymmetrical figures. You could always recreate a design. Because of the nature of gears, none of them were unique, one off, designs.

A spirograph set like this cannot make the image above[Image credit: Multicherry CC-BY-SA 3.0]
A spirograph set like this cannot make the image above [Image credit: Multicherry CC-BY-SA 3.0]
We figured adding some lever arms, and additional geared wheels (compound gears) could achieve the desired result. It turns out that such a machine is called a Cycloid Drawing Machine. But even with this kind of machine, it was possible to replicate a design as often as required. You would fix the gears and levers and draw a design. If the settings are not disturbed, you can make another copy. Here’s a video of a motorized version of the cycloid machine.

The eventual answer for making such designs was to use a contraption called as the harmonograph. The harmonograph is unique in the sense that while you can make similar looking designs, it would be practically impossible to exactly replicate them — no two will be exactly the same. This thought experiment eventually led to my brother building his own harmonograph. This was way back when the only internet we had was the Library, which was all the way across town and not convenient to pop in on a whim and fancy. This limited our access to information about the device, but eventually, after a couple of months, the project was complete.

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Friday Hack Chat: Security for IoT

securityforiot-01Over the last few weeks, our weekly Hack Chats on hackaday.io have gathered a crowd. This week, we’re talking about the greatest threat humanity has ever faced: toasters with web browsers.

The topic of this week’s Hack Chat is Security for IoT, because someone shut down the Internet with improperly configured webcams.

This chat is hosted by the Big Crypto Team at the University of Pittsburgh. [Wenchen Wang], [Ziyue Sun], [Brandon Contino], and [Nick Albanese] will be taking questions about lightweight devices connected to the Internet. Discussion will include building things that connect to larger networks securely.

The Big Crypto team at UP are thinking about the roadblocks people have to implement security in their projects, and if apathy or ignorance is the main reason security isn’t even considered in the worst IoT offenders.

The Hack Chat is scheduled for Friday, February 24th at noon PST (20:00 GMT).

Here’s How To Take Part:

join-hack-chatOur Hack Chats are live community events on the Hackaday.io Hack Chat group messaging.

Log into Hackaday.io, visit that page, and look for the ‘Join this Project’ Button. Once you’re part of the project, the button will change to ‘Team Messaging’, which takes you directly to the Hack Chat.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Upcoming Hack Chats

These Hack Chats are becoming very popular, and that’s due in no small part to the excellent lineup of speakers we’ve hosted. Already, we’ve had [Lady Ada], [Sprite_tm], and [bunnie] — engineers, hackers, and developers who are at the apex of their field. We’re not resting on our laurels, though: in a few weeks we’ll be hosting Hack Chats with [Roger Thornton], an engineer with Raspberry Pi, and Fictiv, masters of mechanical manufacturing.

Ask Hackaday: Is Owning A 3D Printer Worth It?

3D printers are the single best example of what Open Hardware can be. They’re useful for prototyping, building jigs for other tools, and Lulzbot has proven desktop 3D printers can be used in industrial production. We endorse 3D printing as a viable tool as a matter of course around here, but that doesn’t mean we think every house should have a 3D printer.

Back when Bre was on Colbert and manufacturing was the next thing to be ‘disrupted’, the value proposition of 3D printing was this: everyone would want a 3D printer at home because you could print plastic trinkets. Look, a low-poly Bulbasaur. I made a T-rex skull. The front page of /r/3Dprinting. Needless to say, the average consumer doesn’t need to spend hundreds of dollars to make their own plastic baubles when WalMart and Target exist.

The value proposition of a 3D printer is an open question, but now there is some evidence a 3D printer provides a return on its investment. In a paper published this week, [Joshua Pearce] and an undergraduate at Michigan Tech found a 3D printer pays for itself within six months and can see an almost 1,000% return on investment within five years. Read on as I investigate this dubious claim.

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Hackaday Links: February 19, 2017

The ESP-32 is the Next Big Chip. This tiny microcontroller with WiFi and Bluetooth is the brains of the GameBoy on your keychain, emulates an NES, and does Arduino. There are ESP32 modules that are somewhat easy to acquire, but so far the bare chips have been unobtanium. Now you can buy them. One supplier has them for $3.60 USD/piece. That’s a lot of computational power, WiFi, and Bluetooth for not much money. What are you going to build?

What is the power of artisanal product videos? The argument for this trend cites [Claude C. Hopkins] and how he told consumers what no one else would tell them. In other words, if you and your competitors have product designers working on the enclosure, tell the consumer you have product designers working on the enclosure before your competitors do coughapplecough. In other words, marketing your product as ‘artisanal’ is simply telling consumers what all products in your market do, and this type of advertising is the easiest to create. See also: music with whistling, clapping, a ukulele, and a Fisher Price xylophone – it’s popular because it’s very easy to make.

Over on hackaday.io, [Michael Welling] is stuffing a BeagleBone in one of those mini Altoids tins. This build is based on the Octavo Systems OSD3358, otherwise known as the BeagleBone on a Chip. This is an absurdly small build, but surprisingly something we’ve seen before. Before the Octavo chip was released, [Jason Kridner] built a mini BeagleBone breakout for this chip in the mini Altoids form factor. [Jason] did it in Eagle, [Michael] is doing it in KiCad. Awesome work, and just what you need if you want Linux in your pocket.

Every month or so, Hackaday (or at least the Hackaday Overlords) hold events in LA, NYC, and San Francisco. These events are free, there’s usually pizza, and there’s always a speaker or two giving a talk on a very interesting topic. Waaaaaay back in July, we had the monthly Hardware Developers Didactic Galactic meetup in SF, with two great talks. [Jason Cerundulo], a CastAR engineer gave a talk about various ways of driving a LED. [Werner Johansson], a former Sony designer, talked about software-defined power supplies. There’s mention of a ‘transverter design’ which sounds like excellent Berman-era Trek technobabble but is really a power converter without a transformer. Both of these talks can be seen below.

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LTC4316 is the I2C Babelfish

The LTC4316 is something special. It’s an I²C address translator that changes the address of a device that would otherwise conflict with another on the same I²C bus. Not a hack? Not so fast. Exactly how this chip does this trick is clever enough that I couldn’t resist giving it the post it rightfully deserves.

On-the-Fly Translation

What’s so special? This chip translates the address on-the-fly, making it transparent to the I²C protocol. Up until this point, our best bet for resolving address collisions was to put the clashing chip on a separate I²C bus that could be selectively enabled or disabled. In that department, there’s the PCA9543 and PCA9547 demultiplexers which we’ve seen before. Both of these devices essentially act like one-way check valves. To address any devices downstream, we must first address the multiplexer and select the corresponding bus. While these chips resolve our address collision problems, and while there’s technically a way to address a very large number of devices if we’re not time-constrained, the control logic needed to address various bus depths can get clunky for nested demultiplexers.

What’s so classy about the LTC4316 is that is preservers simplicity by keeping all devices on the same bus. It prevents us from having to write a complicated software routine to address various sections of a demultiplexed I²C bus. In a nutshell, by being protocol-transparent, the LTC4316 keeps our I²C master’s control logic simple.

How it Works

I mocked up a quick test setup to have a go at this chip in real life. Continue reading “LTC4316 is the I2C Babelfish”

Hands On With Variable Layer Height

3D printers are an exercise in compromise. Generally, you don’t want a lot of mass on your tool head, as that can lead to ringing and other mechanical artifacts on your print. However, direct drive extruders are better for many filaments, and the decision on what printer to build ultimately comes down to a choice between speed, build area, and the ability to print in exotic filaments.

Even in slicing a 3D model, a 3D printing enthusiast must balance the quality of a print versus how long the print will take to squirt out of a nozzle. Now, just about any printer can produce fantastic models at a very high layer height, but no one wants to wait several days for the print to finish.

This balance between print time and print quality has, for the last few years, been completely ignored. One of the best solutions to this we’ve seen is variable layer height slicing. Basically, if you’re printing something without much detail, you don’t need small layers in your 3D print. Think of it as printing the neck of a bust at 0.3mm layer height, and the face at 0.1mm.

Yes, there were a few papers from a decade ago laying the conceptual foundations of variable layer height slicing. 3D printers weren’t exactly common back then, though. Recently, Autodesk’s Integrated Additive Manufacturing Team released Varislice for automatic generation of variable layer heights on a 3D printed object. So far, though, there’s no good automated solution for variable layer height slicing, and the tools for manual configuration of variable layer height slicing are terrible.

For the past few months, Prusa Research has been working on their own edition of Slic3r that includes an easy to use interface for variable layer height slicing. This version of Slic3r was just released, and now it’s time for the hands-on. Does variable layer height slicing work?

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