pcb

633 Articles

Tidy Board Rework Uses Flex PCBs, No Wires

December 17, 2019 by 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!

Journey Through The Inner Workings Of A PCB

December 10, 2019 by 20 Comments

Most electronics we deal with day to day are comprised of circuit boards. No surprise there, right? But how do they work? This might seem like a simple question but we’ve all been in the place where those weird green or black sheets are little slices of magic. [Teddy Tablante] at Branch Eduction put together a lovingly crafted walkthrough flythrough video of how PCB(A)s work that’s definitely worth your time.

[Teddy]’s video focuses on unraveling the mysteries of the PCBA by peeling back the layers of a smartphone. Starting from the full assembly he separates components from circuit board and descends from there, highlighting the manufacturing methods and purpose behind what you see.

What really stands out here is the animation; at each step [Teddy] has modeled the relevant components and rendered them on the PCBA in 3D. Instead of relying solely on hard to understand blurry X-ray images and 2D scans of PCBAs he illustrates their relationships in space, an especially important element in understanding what’s going on underneath the solder mask. Even if you think you know it all we bet there’s a pearl of knowledge to discover; this writer learned that VIA is an acronym!

If you don’t like clicking links you can find the video embedded after the break. Credit to friend of the Hackaday [Mike Harrison] for acting as the best recommendation algorithm and finding this gem.

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How Safe Is That Ultrasonic Bath For Flux Removal?

December 5, 2019 by 30 Comments

How do you clean the residual flux off your boards? There are plenty of ways to go about the job, ranging from “why bother?” to the careful application of isopropyl alcohol to every joint with a cotton swab. It seems like more and more people are turning to ultrasonic cleaners to get the job done, though, and for good reason: just dunk your board and walk away while cavitation does the work for you.

But just how safe is it to sonically blast the flux off your boards? [SDG Electronics] wanted to know, so he ran some cleaning tests to get to the bottom of things. On the face of it, dunking a PCB in an aqueous cleaning solution seems ill-advised; after all, water and electricity famously don’t mix. But assuming all the nooks and crannies of a board can be dried out before power is applied, the cleaning solution itself should be of little concern. The main beef with ultrasonic cleaning seems to be with the acoustic energy coupling with mechanical systems on boards, such as crystal oscillators or micro-electrical-mechanical systems (MEMS) components, such as accelerometers or microphones. Such components could resonate with the ultrasonic waves and be blasted to bits internally.

To test this, [SDG Electronics] built a board with various potentially vulnerable components, including the popular 32.768-kHz crystal, cut for a frequency quite close to the cleaner’s fundamental. The video below goes into some detail on the before-and-after tests, but the short story is that nothing untoward happened to any of the test circuits. Granted, no components with openings as you might find on some MEMS microphones were tested, so be careful. After all, we know that ultrasound can deal damage, and if it can levitate tiny styrofoam balls, it might just do your circuit in.

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Creating Easy Glass Circuit Boards At Home

December 1, 2019 by 41 Comments

This tip for creating glass substrate circuit boards at home might hew a bit closer to arts and crafts than the traditional Hackaday post, but the final results of the method demonstrated by [Heliox] in her recent video are simply too gorgeous to ignore. The video is in French, but between YouTube’s attempted automatic translation and the formidable mental powers of our beloved readers, we don’t think it will be too hard for you to follow along after the break.

The short version is that [Heliox] loads her Silhouette Cameo, a computer-controlled cutting machine generally used for paper and vinyl, with a thin sheet of copper adhered to a backing sheet to give it some mechanical strength. With the cutting pressure of the Cameo dialed back, the circuit is cut out of the copper but not the sheet underneath, and the excess can be carefully peeled away.

Using transfer paper, [Heliox] then lifts the copper traces off the sheet and sticks them down to a cut piece of glass. Once it’s been smoothed out and pushed down, she pulls the transfer paper off and the copper is left behind.

From there, it’s just a matter of soldering on the SMD components. To make it a little safer to handle she wet sands the edges of the glass to round them off, but it’s still glass, so we wouldn’t recommend this construction for anything heavy duty. While it might not be the ideal choice for your next build, it certainly does looks fantastic when mounted in a stand and blinking away like [Heliox] shows off at the end.

Ironically, when compared to some of the other methods of making professional looking PCBs at home that we’ve seen over the years, this one might actually be one of the easiest. Who knew?

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DeepPCB Routes Your KiCAD PCBs

December 1, 2019 by 36 Comments

Computers can write poetry, even if they can’t necessarily write good poetry. The same can be said of routing PC boards. Computers can do it, but can they do it well? Of course, there are multiple tools each with pluses and minuses. However, a slick web page recently announced deeppcb.ai — a cloud-based AI router — and although details are sparse, there are a few interesting things about the product.

First, it supports KiCAD. You provide a DSN file, and within 24 hours you get a routed SES file. Maybe. You get three or four free boards –apparently each week — after which there is some undisclosed fee. Should you just want to try it out, create an account (which is quick and free — just verify your e-mail and create a password). Then in the “Your Boards” section there are a few examples already worked out.

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Add A Bit Of PCB Badge Glamour To Your Boring ID Badge

November 18, 2019 by 6 Comments

When we talk about badges and printed circuit boards, it is usually in the context of the infinite creativity of the Badgelife scene, our community’s own art form of electronic conference badges. It’s easy to forget when homing in on those badges that there are other types of badge, and thus [Saimon]’s PCB badge holder is an entertaining deviation from our norm. His workplace requires employees to carry their credit-card-sized ID pass with them at all times, but the plastic holder that came with his had broken. So he did what any self-respecting engineer would do, and designed his own holder using PCBs.

It’s a three-way sandwich with identical front and back PCBs featuring a nice design, but the clever bit is the middle PCB. It is U-shaped to slide the card in from the side, but to retain the card it has a couple of springy milled PCB arms each with a small retaining tooth on the end. This is an ingenious solution, with just enough give to bend, but not so much as to break.

The three boards are glued together, it seems his original aim was to reflow solder them but this was not successful. The result is an attractive and functional badge holder, which if Hackaday required us to have a corporate ID you can be sure we’d be eyeing up for ourselves.

Beam Me Up To The PCB Space Ship

October 19, 2019 by 15 Comments

This project would fit in perfectly with #BadgeLife if someone could figure out a way to hang it from their neck. Inspired by Star Trek’s Starship Enterprise, [bobricius] decided to design and assemble a miniature space ship PCB model, complete with 40 blinking LEDs controlled by an ATtiny85.

While the design uses 0603, 0802, 3014, 4014, and 0805 LEDs, some substitutions can be made since the smallest LEDs can be difficult to solder. The light effects include a green laser, plasma coils, a deflector with scrolling blue LEDs, and the main plate and bridge for the space ship.

The LEDs are controlled by charlieplexing, a technique for driving LED arrays with relatively few I/O pins, different from traditional multiplexing. Charlieplexing allows n pins to drive n2−n LEDs, while traditional multiplexing allows n pins to drive (n/2)2 LEDs. (Here is the best explanation of Charlieplexing we’ve ever seen.)

Especially with the compiled firmware running on the MCU, the PCB model makes for an impressive display.

The only catch? Your Starship Enterprise can’t actually fly.

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