The work of one such research project caught the eye of Greg Davill recently, when a paper written by Fereshteh Shahmiri and Paul H Dietz was published, after being submitted for the 2020 ACM Conference on Human Factors in Computing Systems (CHI 2020).
This paper goes by the title of “ShArc:A Geometric Technique for Multi-Bend/Shape Sensing,’ and proposes a novel contour sensor, comprised of a flexible, capacitive PCB sensor, a suitable capacitance-to-digital converter, and some subsequent signal processing, allowing a two-layer polyamide FPC circuit to cleverly capture the contours of the shape it is stuck to.
That’s the operation in a nutshell, so why are we covering all this here on Hackster? Well, it’s all about accessibility! This research isn’t relegated to labs where we’ll never see sight of it, until commercialized into a product. Far from it. Davill has shown just how easily we here at home can play along with this project, using the same tools and services that we’d normally look at for our own hobby projects!
He’s not only managed to recreate the capacitance to digital converter needed for this application, but perhaps more of note, he’s even turned his hand to having a go at the flexible sensor electrodes themselves, all fabricated by the one stop shop, whose services seem to keep on growing— our favorite board fab house, OSH Park!
We were exited to see this use of a flex PCB to create a backplane for the RC2014:
RC2014 is a simple 8 bit Z80 based modular computer originally built to run Microsoft BASIC. It is inspired by the home built computers of the late 70s and computer revolution of the early 80s. It is not a clone of anything specific, but there are suggestions of the ZX81, UK101, S100, Superboard II and Apple I in here. It nominally has 8K ROM, 32K RAM, runs at 7.3728MHz and communicates over serial at 115,200 baud.
This time around i give you the DimeDuino. Its a Flex PCB based which utilizes the ATMEGA328P. Using this MCU allows for the installation of the Arduino bootloader. Hence the Duino in the name. These will come pre-programmed with the bootloader. One portion of the circle is just for programming. There is a GND, VCC,RXI, TXO and DTR & RST depending on your programmer.
As soon as its available ill post it here and on Twitter.
Atmega328 running at 3.3v/8MHz or 5v/16MHz
Power LED (Green)
User LED (D13– Color may vary but mainly Blue)
3.3v(AP2112K) or 5v (AP7335A) Linear step down
Flash 32KB (2KB is Bootloader)
20 I/O Pins (A6 & A7 are not used here. Input Only anyway)
In the beginning, there was hot glue. Plus some tape, and a not inconsiderable amount of Bondo. In general, building custom portable game consoles a decade or so in the past was just a bit…messier than it is today. But with all the incredible tools and techniques the individual hardware hacker now has at their disposal, modern examples are pushing the boundaries of DIY.
This Zelda: Ocarina of Time themed portable N64 by [Chris Downing] is a perfect example. While the device is using a legitimate N64 motherboard, nearly every other component has been designed and manufactured specifically for this application. The case has been FDM 3D printed on a Prusa i3, the highly-detailed buttons were printed in resin on a Form 3, and several support PCBs and interface components made the leap from digital designs to physical objects thanks to the services of OSH Park.
Today, those details are becoming increasingly commonplace in the projects we see. But that’s sort of the point. In the video after the break, [Chris] breaks down the evolution of his portable consoles from hacked and glued together monstrosities (we mean that in the nicest way possible) to the sleek and professional examples like his latest N64 commission. But this isn’t a story of one maker’s personal journey through the ranks, it’s about the sort of techniques that have become available to the individual over the last decade.
Case in point, custom flexible flat cables (FFC). As [Chris] explains, when you wanted to relocate the cartridge slot on a portable console in the past, it usually involved tedious point-to-point wiring. Now, with the low-volume production capabilities offered by companies like OSH Park, you can have your own flexible cables made that are neater, faster to install, and far more reliable.
I wish I could say that it hasn’t been two years since this project was commissioned…I also wish I could say this wasn’t the second time the job was completed…but if I didn’t have too, this beauty would have never existed. Kinda funny how that works.
But that said, after two years since the original agreement and a total remake of the original failure, Project 15 has come to light in the most beautiful portable console I’ve ever made. But not only has this been a technical achievement for me in many respects, but I’m very proud of the video I’ve made to accompany it.
You don’t have to scroll down very far in past posts to see what prompted this rebuild but at this point I can honestly say I’m glad it happened!
And on the subject of reliability, low volume FFC PCB’s have become available through services like OSH Park which have allowed some very time and space saving options that do wonders for the assembly.
Earrings have been a hackers’ target for electronic attachment for quite a while, but combining the needed components into a package small enough to wear in that finicky location is quite a challenge. If [Sawaiz Syed]’s Art Deco Earrings are anything to go by, ear computers have a bright future ahead of them!
This is a project unusually well described by its name. It is in fact an earring, with art deco styling. But that sells it way too short. This sliver of a flex circuit board is double sided to host an ATtiny, accelerometer, LDO, and eight 2020 formfactor controller-integrated LEDs. Of course it’s motion sensitive, reacting to the wearer’s movement via LED pattern. [Sawaiz] makes reference to wearing it while dancing, and we can’t help but imagine an entire ballroom all aglow with tiny points of LED light.
This action plugin adds and deletes teardrops to a PCB.
This implementation uses zones instead of arcs. This allows to comply with DRC rules by simply rebuild all zones. You can also modify their shape by simply modifying the zone outline (like any other zone). Teardrops created with this script use a specific priority (0x4242) to be recognized as teardrops.
You also need to be careful that there is not copper on the same layer too close to the zone. For example, the text was too close to the teardrop zone on this via, so I moved the text down and the zone now fills correctly:
An open GitHub issue is that the teardrop zone does not align perfectly for SMD pads that are not circles (like rectangles, squares, rounded rectangles). The work around I used was to move the zone after it is filled to align with my SMD pad:
I hope you have fun with this plugin and leave a comment if you use it your own design!
The last two years has been a particularly exciting time for KiCad, for users, casual contributors, and for the core developers too. Even so, there are many cool new features that are still in process. One bottleneck with open-source development of complex tools like KiCad is the limited amount of time that developers can devote for the project. Action plugins stand to both reduce developer load and increase the pace of development by making it easier to add your own functionality to the already extensible tool.
Since version 5.0, we’ve seen an explosion of extremely useful action plugins for KiCad that have added some very useful bells and whistles. The KiCad website lists a couple of external tools, but there’s a lot of action happening out there, so we decided to round up some of the more useful ones.
In the early days, PCB fabs often had yield issues due to offset drill holes, particularly on vias and micro-vias. One trick that PCB designers used to mitigate this problem was to use “teardrops”. The area around the pad or via that connected to the track was made into a teardrop shape, ostensibly in the hope that it would improve matters. Fabs nowadays do a pretty good job due to improved processes and accurate machines, so the jury is still out on the use of teardrops, but KiCad does have a Teardrop plugin, in case anyone wants to use it. Combined with smooth, rounded tracks, we’re guessing teardrops would be pretty helpful in the artistic PCBs department.