Tidy Board Rework Uses Flex PCBs, No Wires

December 17, 2019 by Donald Papp 26 Comments

PCB rework for the purpose of fixing unfortunate design problems tends to involve certain things: thin wires (probably blue) to taped or glued down components, and maybe some areas of scraped-off soldermask. What are not usually involved are flexible PCBs, but [Paul Bryson] shows us exactly how flex PCBs can be used to pull off tricky rework tasks.

It all started when [Paul] had a run of expensive PCBs with a repeated error; a design mistake that occurred in several places in the board. Fixing with a bunch of flying wires leading to some glued-on components just wasn’t his idea of tidy. A more attractive fix would be to make a small PCB that could be soldered in place of several of the ICs on the board, but this idea had a few problems: the space available into which to cram a fix wasn’t always the same, and the footprints of the ICs to be replaced were too small to accommodate a PCB with castellated mounting holes as pads anyway.

It’s about then that he got a visit from the Good Idea Fairy, recalling that fab houses have recently offered “flex” PCBs at a reasonable cost. By mounting the replacement parts on a flex PCB, the board-level connection could reside on the other end of an extension. Solder one end directly to the board, and the whole flexible thing could be bent around or under on a case-by-case basis, and secured in whatever way made sense. Soldering the pads of the flex board to the pads on the PCB was a bit tricky, but easy enough to pull off reliably with a bit of practice. A bonus was that the flex PCB is transparent, so solder bridges are easy to spot. He even mocked up a solution for QFP packages that allows easy pin access.

Flex PCBs being available to hobbyists and individuals brings out fresh ideas and new twists on old ones, which is why we held a Flexible PCB Design Contest earlier this year. Repairs were definitely represented as applications, but not to the extent that [Paul] has shown. Nice work!

Quick-Turn PCB Fab Hack Chat

July 29, 2019 by Dan Maloney No comments

Join us on Wednesday, July 31st at noon Pacific for the Quick-Turn PCB Fab Hack Chat with Mihir Shah!

We’ve all become used to designing a PCB and having it magically appear at our doorstep – after a fashion. Modern PCB fabs rely on economies of scale to deliver your design cheaply, at the expense of time – the time it takes to put enough orders onto a panel, and the time it takes to ship the finished boards from Far, Far Away.

Not everyone has that kind of time to burn, though. That’s where quick-turn fabs come in. These manufacturers specialize in getting boards to their customers as quickly as possible, helping them deal with sudden design changes or supporting specialty applications for customers.

It’s a niche industry, but an important one, and Royal Circuits is at the forefront. Mihir Shah is Director of Special Projects there, and he’s deep into the business of getting PCBs to customers as quickly as possible. He’ll drop by the Hack Chat to answer all your questions about how the quick-turn industry fits into the electronics manufacturing ecosystem, and to show off some of the tools of the future that they’re developing and investing in to streamline PCB design and analysis – from DebuggAR to PCBLayout.com, and more.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday July 31 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

FlexLED Is A Unique Take On Persistence Of Vision

July 9, 2019 by Lewin Day 13 Comments

Many hackers have experimented with the persistence of vision effect. Whip around a bunch of LEDs, flash them at just the right times, and it’s possible to make images to appear to hang in the air. There’s plenty of ways to do this, whether by manually shaking the LEDs by hand, spinning them around, or even putting them on your bike wheels. [Carl Bugeja] went a different route, taking advantage of the possibilities created by flex PCBs.

[Carl]’s project goes by the name FlexLED. This aptly describes the build, which, in prototype form, mounts a single LED on the end of a flex PCB. The PCB itself has a pattern of traces creating a coil, which enable it to interact with magnetic fields more strongly. By passing the right current through the coil, the flexible PCB can be made to flap up and down, moving the LED on the end at a rapid rate. By then controlling the flashing of the LED, it’s possible to create a persistence of vision effect.

Currently fitted with only one LED, capable of 3 colors, the visual display of the FlexLED is somewhat limited. However, [Carl] reports the effect is more impressive in person than on camera, and is already working on plans to scale up the project to a multi-LED diplay.

POV technology can do some pretty impressive things – even volumetric displays are possible. If you’re working on something yourself, be sure to let us know. Video after the break.

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These Projects Bent Over Backward To Win The Flexible PCB Contest

June 19, 2019 by Dan Maloney 7 Comments

Back in March, the call went out: take your wiggliest, floppiest, most dimensionally compliant idea, and show us how it would be better if only you could design it around a flexible PCB. We weren’t even looking for a prototype; all we needed was an idea with perhaps a sketch, even one jotted on the legendary envelope or cocktail napkin.

When we remove constraints like that, it’s interesting to see how people respond. We have to say that the breadth of applications for flex PCBs and the creativity shown in designing them into projects was incredible. We saw everything from circuit sculpture to wearables. Some were strictly utilitarian and others were far more creative. In the end we got 70 entries, and with 60 prizes to be awarded, the odds were ever in your favor.

Now that the entries have been evaluated and the winners decided, it’s time to look over the ways you came up with to put a flexible PCB to work. Normally we list all the winners in our contest wrap-ups, but with so many winners we can’t feature everyone. We’ll just call out a few of the real standout projects here, but you really should check the list of winning projects to see the full range of what this call for flexibility brought out in our community.

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Flex PCB Saves Lens From The Junk Pile

May 31, 2019 by Jenny List 16 Comments

There’s a piece of tech that many of us own, but very few of us have dissected. This is strange, given our community’s propensity for wielding the screwdriver, but how many of you have taken apart a camera lens. Even though many of us have a decent camera, almost none of us will have taken a lens to pieces because let’s face it, camera lenses are expensive!

[Anthony Kouttron] has taken that particular plunge though, because in cleaning his Olympus lens he tore its internal ribbon cable from the camera connector to the PCB. Modern lenses are not merely optics in a metal tube, their autofocus systems are masterpieces of miniaturised electronics that penetrate the entire assembly.

In normal circumstances this would turn the lens from a valued photographic accessory into so much junk, but his solution was to take the bold path of re-creating the torn cable in KiCad and have it made as a flexible PCB, and to carefully solder it back on to both connector and autofocus PCB. We applaud both the quality of his work, and thank him for the unusual glimpse into a modern lens system.

Lens repairs may be thin on the ground here, but we’ve had another in 2015 with this Nikon aperture fix.

Flexible Battery Meter Bends Over Backward To Work

November 2, 2018 by Dan Maloney 7 Comments

A lithium-ion battery tester seems like a simple project, at least electrically. But when you start thinking about the physical problem of dealing with a huge range of battery sizes, things get a little more complicated. Sure, you can 3D-print adapters and jigs to accommodate the different batteries, or you can cheat a bit and put the charger and tester circuit on a flexible PCB.

Maybe it’s the Kapton talking, but we really like the look of [Androkavo]’s project. The idea is simple – rather than use a rigid FR4 printed circuit board, a flexible polyimide film PCB a little longer than the biggest battery to be tested was fabricated. With large contacts on each end, the board can just be looped across the battery to take a reading. For charging, neodymium magnets on the other side of the board keep the charger in contact with the battery. The circuit itself is built around an STM8S003 8-bit microcontroller and a handful of discrete components. There’s a bar graph display for battery voltage that covers 2.0 to 4.9 volts, and a USB port for charging. The charger works with everything from the big 21700 cells down to the short 14500s. With the help of another magnet to keep the board from bending too sharply, even the diminutive 10180 can be charged. Check out the video below, which has some of the most relaxing music and best microscope shots of SMD soldering we’ve seen.

Flexible PCBs are versatile things. Not only can they make projects like this successful, but they can also wriggle around, swim, or even play music.

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Flexible PCB Becomes The Actuator

July 29, 2018 by Jenny List 13 Comments

An electromagnetic coil gun takes a line of electromagnets working together to form a moving electromagnetic field. These fields accelerate a project and boom, you have electricity moving matter, often at an impressive rate of speed.

[Carl Bugeja] has taken the idea and in a sense turned it upon its head with his flexible PCB actuator. Now the line of electromagnets are the moving part and the magnetic object the stationary one. There is still a line of flat PCB inductors in the classic coil gun configuration, but as the title suggests on a flexible substrate.

The result is a curiously organic motion reminiscent of some lizards, caterpillars, or snakes. It can move over the magnet in a loop, or flex in the air above it. It’s a novel moving part, and he’s treated us to a video which we’ve placed below the break.

He has plans to put it to use in some form of robot, though while it certainly has promise we’d be interested to know both what force it can produce and whether flexible PCB is robust enough for repeated operation. We salute him for taking a simple idea and so effectively proving the concept.

We’ve brought you [Carl]’s work before, most notably with his PCB motor.

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