KiCad teardop plugin and flexible PCBs

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Thanks to Anool posting on Hackaday about KiCad plugins.  I decided to try out the Teardrop plugin by NilujePerchut:

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KiCad Teardrop Plugin

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.

Here is the result of my first experiment to use the Teardrop plugin on a flexible PCB to reduce the mechanical stress of flexing the trace:

The board is available as an OSH Park shared project and the KiCad design files are on GitHub.

The author of the plugin was very responsive to GitHub issues and I was able to get better results on my next flex design which is currently being manufactured:

My flex “business card” will fold over a coin cell battery to light a 0603 LED.

Curious how the plugin works?  It creates zones next to the vias and pads.  Here are the two teardrop zones that connect traces to a via:

Warning: you need create a schematic and generate a netlist before starting the PCB layout.  Otherwise the the zones the plugin creates won’t be filled:

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!

UPDATE: I joined Adafruit Show-n-Tell to talk about flex PCBs and the teardrop plugin at 10 min 51 sec mark

KiCad teardop plugin and flexible PCBs

KiCad Action Plugins

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.

Sometime around version 4.0.7 (correct us if we’re wrong), it was decided to introduce “action plugins” for KiCad, with the intention that the larger community of contributors can add features that were not on the immediate road map or the core developers were not working on. The plugin system is a framework for extending the capabilities of KiCad using shared libraries. If you’re interested in creating action plugins, check out documentation at KiCad Plugin System and Python Plugin Development for Pcbnew. Then head over to this forum post for a roundup of Tutorials on python scripting in pcbnew, and figure out how to Register a python plugin inside pcbnew Tools menu.

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.

via KiCad Action Plugins — Hackaday

Also, the Teardrop plugin could be useful for those using our 2 layer Flex service:

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.

 

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Introducing the “Arduflexboy”

Alasdair Allan writes on the Hackster.io blog about an awesome project using our OSH Park 2 Layer Flexible PCB service:

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Introducing the “Arduflexboy”

The Arduboy is a fantastic 8-bit game handheld video game platform built around a Microchip ATmega32U4 micro-controller. It’s open source, and there is a bunch of documentation that will help you build your own games. Since it crowdfunded itself into the retro-gaming scene back in 2015, it has become a staple of the community — and we’ve seen some impressive hacks.

But this one might beat them all, Kevin Bates has just built a flexible version.

A flexible Arduboy, the “Arduflexboy.” (📷: Kevin Bates)

While flexible PCBs have been around for a while, it’s only in the last few months that they’ve become readily available to the maker community with OSH Park introducing them as an option at the tail end of last year.

Bates made use of the OSH Park new flex service, and hiding all the Arduboy components behind the LCD screen, produced a flexible version that’s paper thin. Even the ‘bump’ of the screen is still only 2.5mm thick.

Introducing the “Arduflexboy”

Hackday launches Flexible PCB design contest

We are excited to see what people create in this new flexible PCB design contest on Hackaday.io:

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New Contest: Flexible PCBs

The now-humble PCB was revolutionary when it came along, and the whole ecosystem that evolved around it has been a game changer in electronic design. But the PCB is just so… flat. Planar. Two-dimensional. As useful as it is, it gets a little dull sometimes.

Here’s your chance to break out of Flatland and explore the third dimension of circuit design with our brand new Flexible PCB Contest.

We’ve teamed up with Digi-Key for this contest. Digi-Key’s generous sponsorship means 60 contest winners will receive free fabrication of three copies of their flexible PCB design, manufactured through the expertise of OSH Park. So now you can get your flex on with wearables, sensors, or whatever else you can think of that needs a flexible PCB.

HOW TO ENTER

Go over to Hackaday.io and create a project with images of your flexible circuit board design, and be sure to tell the story of how and why you came up with it. When the project is published, look for the “Submit project to…”  link in the left sidebar and submit it to the Flexible PCB contest.

AWARDS

  • 60 contest winners will receive an OSH Park code for 3 complimentary boards from OSH Park shipped to them (there’s a size limitation detailed below). Please allow 8 weeks after the close of this contest.
  • 3 Tindie gift certificates of $100 each will be awarded for:
    • Best Project
    • Best Social Media Picture or Video
      • You can post a picture or video of your device, of you working on your device, or anything related on Twitter, Facebook, Instagram, Youtube, or any other social platform. You must post a link to the video in the comments on this page.
    • Best Documentation

REQUIREMENTS

Here’s the small print on those free flexible PCB awards: If you’re one of the lucky 60 (yay, that’s a lot!) winners, you’ll receive a coupon that will cover the cost of a PCB up to 2 square inches (13 square centimeters) in size. If your design is larger you can still use this coupon and choose to pay the portion of the cost beyond that size. The best part is that OSH Park delivers three copies of the board from each order! See the contest page for complete rules.

WHAT SHOULD I BUILD?

Pretty much anything that needs a flexible PCB qualifies. Use your imagination! Folding cell phones are all the rage now, so use that for inspiration. Perhaps you’re into wearables, which are begging to be made from flexible materials. Repair a wonky laptop display with a new flexible connector? That counts. Working on something so small that a traditional PCB is just too bulky? We want to hear about it.

We’ve lined up some resources to help you get started. Check out OSH Park’s Flex PCB FAQ for all the technical details on flexible PCBs. If you’re new to PCB design, Brian Benchoff’s excellent Creating a PCB in Everything series covers everything you need to know.

Still stuck? Here are a few recent projects featuring flexible PCBs that might get the creative juices flowing (not all of which would necessarily fit the qualifications):

 

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