OpenFixture Takes the Pain Out of Pogo Pins

[Elliot] (no relation, but hey, cool name!) wrote in with his OpenFixture model for OpenSCAD. It’s awesome because it takes a small problem, that nonetheless could consume an entire day, and solves it neatly. And that problem is making jigs to test assembled electrical products: a PCB test fixture.

In the PCB design software, you simply note down the locations of the test points and feed these into the OpenSCAD model. ([Elliot] shows you exactly how to do it using KiCAD.) There are a few more parameters of the model that you can tweak to match your particulars, but you should have a DXF outline for a test jig in short order. Cut that out, assemble, and test.

If you have to make more than a few handfuls of a complicated circuit, it becomes worth it to start thinking about testing them systematically. And with this OpenSCAD model, you can have the test jig up and running before the first prototype boards are back in from the fab. How cool is that?

Scanning Parts Into KiCad

You do not know how to make a PCB unless you can make your own parts. [Jan] knows this, but like everyone else he checked out the usual online sources for a footprint for an SD card socket before making his own. It turns out, this SD card socket bought from an online marketplace was completely undocumented. Not only was an Eagle or KiCad footprint unavailable, but CAD files showing the dimensions of the part were non-existent. A solution had to be devised.

Instead of taking calipers and finely measuring all the pads on this SD card socket – a process that would surely fail – [Jan] decided to use a flatbed scanner to trace out the part. The part was placed on the glass and scanned at 300 dpi with a convenient reference object (a public transport card) in the same picture. This picture was imported into a CAD package, scaled to the correct ratio, and exported as a DXF. Since KiCad readily accepts importing DXFs, the CAD file was easily accessed, traced over, and a new part created.

From start to finish, making the footprint for this no-name, off-brand SD card socket took fifteen minutes. That’s nothing compared to the time it would take to manually measure each of the pads, draw a footprint, and print out the footprint at 1:1 scale to see if it matched up several times. It’s awesome work, and a great reminder that the best tools are usually right in front of you.

Hackaday Links: September 11, 2016

You know about the Hackaday Superconference, right? It’s the greatest hardware con ever, and it’s happening on November 5+6. Details incoming shortly.

The Hackaday Retro Edition exists. It’s the Hackaday blog, HTML-1-izized for weird and old computers? Why did I do this? Because Google is the quickest page to load on a Powerbook 180. There’s a new Retro Success, this time coming from @LeSpocky and his Nokia 3109c phone from 2008.

This is your official notice. The Open Hardware Summit is less than a month away. It’s going down in Portland, OR. Why Portland? The Vaporwavescene, of course. Hackaday, Tindie, and the rest of the crew will be out in Portland next month getting the latest news on the state of Open Hardware. We won’t be sitting in church pews this year, but then again there is no lady made out of soap.

Speaking of OHS, [Dave] just solved all their problems. The ‘problem’ with Open Hardware, if you can call it that, is that people use it as a bullet point on a sales deck. That neat gear logo can be marketing wank, without any of the sources, schematics, or anything else that makes a project Open Hardware. Last year, OSHWA announced they would be creating a certification process, with a trademarked logo, so they can sue people who don’t post schematics and mechanical designs (slightly inaccurate, but that’s the jist of the program). [Dave] is suggesting keeping the cool gear logo, but adding letters the teeth of the gear to designate what makes something Open Hardware. Add an S for schematic, add a B for a BOM, sort of like the creative commons logo/license. Is it a good idea? If OSHWA keeps using the gear logo for the ‘official’ Open Hardware logo/designation, there’s no recourse for when people misuse it. I’m of several minds.

[Colin Furze] is famous for his zany builds. His latest Youtube is anything but. It’s a shed. Of course, it’s the entry for his underground bunker, but this is a quality shed with a concrete pad, a few bits to keep it off the ground, and insulation. The roof is slate (because why not?), but if your design decisions are based on the phrase, ‘you only live once,’ copper may be a better choice.

The ESP32 has been released. The ESP32 is the follow-on to the very popular ESP8266. The ’32 features WiFi and Bluetooth, dual core processors, and a few undisclosed things that will make it very interesting. You can buy ESP32 modules right now, but no one has them on their workbench quite yet. To get you started when they finally arrive, [Adam] created an ESP32 KiCad Library for the ESP32 chip, and the ESP32-WROOM and ESP3212 modules.

Compact ePaper Business Card

Is your business card flashy? Is it useful in a pinch? Do they cost $32 each and come with an ePaper display? No? Well, then feast your eyes on this over-the-top business card with an ePaper display by [Paul Schow]. Looking to keep busy and challenge himself with a low-power circuit in a small package, he set about making a business card that can be updated every couple of months instead of buying a new stack whenever he updated his information.

Having worked with ePaper before, it seemed to be the go-to option for [Schow] in fulfilling the ultra-low power criteria of his project — eventually deciding on a 2″ display. Also looking to execute this project at speed, he designed the board in KiCad over a few hours after cutting it down to simply the power control, the 40-pin connector and a handful of resistors and capacitors. In this case, haste made waste in the shape of the incorrect orientation of the 40-pin connector and a few other mistakes besides. Version 2.0, however, came together as a perfect proof-of-concept, while 3.0 looks sleek and professional.

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Power Glove Takes Over Quadcopter Controls

Gerrit and I were scoping out the Intel booth at Bay Area Maker Faire and we ran into Nolan Moore who was showing of his work to mash together a Nintendo Power Glove with an AR Drone quadcopter. Not only did it work, but the booth had a netted cage which Nolan had all to himself to show off his work. Check the video clip below for that.

The control scheme is pretty sweet, hold your hand flat (palm toward the ground) to hover, make a fist and tilt it in any direction to affect pitch and roll, point a finger up or down to affect altitude, and point straight and twist your hand for yaw control. We were talking with Nolan about these controls it sounded sketchy, but the demo proves it’s quite responsive.

The guts of the Power Glove have been completely removed (that’s a fun project log to browse through too!) and two new boards designed and fabbed to replace them. He started off in Eagle but ended up switching to KiCAD before sending the designs out for fabrication. I really enjoy the footprints he made to use the stock buttons from the wrist portion of the glove.

A Teensy LC pulls everything together, reading from an IMU on the board installed over the back of the hand, as well as from the flex sensors to measure what your fingers are up to. It parses these gestures and passes appropriate commands to an ESP8266 module. The AR Drone 2.0 is WiFi controlled, letting the ESP8266 act as the controller.

It’s Time to Finally Figure Out How to Use KiCAD

KiCAD has been making leaps and bounds recently, especially since CERN is using it almost exclusively. However, while many things are the same, just enough of them are different from our regular CAD packages that it’s hard to get started in the new suite.

[Chris Gammell] runs Contextual Electronics, an online apprenticeship program which goes from concept to assembled electronics covering everything in between. To take the course you pay a nominal fee, but [Chris] posted a very excellent ten-part video series made during the last run of classes which you can watch without charge. The videos go through the basics of KiCAD while hitting the major points to consider when designing and manufacturing your electronics.

The project [Chris] chose is a simple circuit that blinks an LED with a 555. The first videos cover navigating KiCAD’s component schematic editor and library system. Next comes creating circuit schematics and component footprint creation. [Chris] covers PCB layout, the generation of Gerber files, and finally ordering the design from OSH Park — the purveyors of purple boards we’ve come to know and love. The series finishes up with simulating the circuit in LTSpice, ordering the parts, and finally soldering and debugging of the board. If all goes correctly you should now have a single blinking LED.

If the bright summer sun is burning your delicate skin, and you’d rather be locked inside with solder fumes, add this to your watch list now!

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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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