Try It Out

October 7, 2023 by Elliot Williams 21 Comments

It’s like Star Wars versus Star Trek at a SciFi convention, or asking creamy or chunky at the National Peanut Butter Appreciation Festival. (OK, we made that one up.) When Jenny reviewed the 1.0 version of LibrePCB, it opened the floodgates. Only on Hackaday!

Of course it makes sense that in a community of hardware hackers, folks who are not unfamiliar with the fine art and engineering of designing their own PCBs, have their favorite tools. Let’s face it, all PCB design software is idiosyncratic, and takes some learning. But the more fluent you are with your tool of choice, the more effort you have invested in mastering it, leading to something like the sunk-cost phenomenon: because you’ve put so much into it, you can’t think of leaving it.

The beauty of open-source software tools is that there’s almost nothing, aside from your own psychology, stopping you from picking up another PCB program, kicking the proverbial tires with a simple design, and seeing how it works for you. That’s what Jenny did here, and what she’s encouraged me to do. Whether it’s beginner-friendly Fritzing (also recently in version 1.0), upstarts LibrePCB or Horizon EDA, heavyweight champion KiCAD, or the loose-knit conglomeration of tools in coralEDA, you have enough choices that something is going to fit your PCB hand like a glove.

I certainly wouldn’t risk a swap up to a new tool on something super complicated, or something with a tight deadline, but why not start up a fun project to test it out? Maybe follow Tom Nardi’s lead and make a Simple Add-on, for a badge or just as a blinky to put on your desk? Don’t be afraid to try something new!

Chip Shortage Engineering: Misusing DIP Packages

October 3, 2023 by Tom Nardi 57 Comments

After years of seeing people showing off and trading their badge Simple Add-Ons (SAOs) at Supercon, this year I finally decided to make one myself. Now for a first attempt, it would have been enough to come up with some cool PCB art and stick a few LEDs on it. But naturally I started with a concept that was far more ambitious than necessary, and before long, had convinced myself that the only way to do the thing justice was to have an onboard microcontroller.

My first thought was to go with the venerable ATtiny85, and since I already had a considerable stock of the classic eight-pin DIP MCUs on hand, that’s what I started prototyping with. After I had something working on the breadboard, the plan was to switch over to the SOIC-8 version of the chip which would be far more appropriate for something as small as an SAO.

Unfortunately, that’s where things got tricky. I quickly found that none of the major players actually had the SMD version of the chip in stock. Both DigiKey and Mouser said they didn’t expect to get more in until early 2024, and while Arrow briefly showed around 3,000 on hand, they were all gone by the time I checked back. But that was only half the problem — even if they had them, $1.50 a piece seems a hell of a lot of money for an 8-bit MCU with 8K of flash in 2023.

The whole thing was made all the more frustrating by the pile of DIP8 ATtiny85s sitting on the bench, mocking me. Under normal circumstances, using them in an SAO wouldn’t really be a problem, but eight hand-soldered leads popping through the front artwork would screw up the look I had in mind.

While brooding over the situation my eyes happened to fall on one of the chips I had been fiddling with, it’s legs badly bent from repeated trips through the programmer. Suddenly it occurred to me that maybe there was a way to use the parts I already had…

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Bespoke Implants Are Real—if You Put In The Time

September 6, 2023 by Brian McEvoy 23 Comments

A subset of hackers have RFID implants, but there is a limited catalog. When [Miana] looked for a device that would open a secure door at her work, she did not find the implant she needed, even though the lock was susceptible to cloned-chip attacks. Since no one made the implant, she set herself to the task. [Miana] is no stranger to implants, with 26 at the time of her talk at DEFCON31, including a couple of custom glowing ones, but this was her first venture into electronic implants. Or electronics at all. The full video after the break describes the important terms.

The PCB antenna in an RFID circuit must be accurately tuned, which is this project’s crux. Simulators exist to design and test virtual antennas, but they are priced for corporations, not individuals. Even with simulators, you have to know the specifics of your chip, and [Miana] could not buy the bare chips or find a datasheet. She bought a pack of iCLASS cards from the manufacturer and dissolved the PVC with acetone to measure the chip’s capacitance. Later, she found the datasheet and confirmed her readings. There are calculators in lieu of a simulator, so there was enough information to design a PCB and place an order.

The first batch of units can only trigger the base station from one position. To make the second version, [Miana] bought a Vector Network Analyzer to see which frequency the chip and antenna resonated. The solution to making adjustments after printing is to add a capacitor to the circuit, and its size will tune the system. The updated design works so a populated board is coated and implanted, and you can see an animated loop of [Miana] opening the lock with her bare hand.

Biohacking can be anything from improving how we read our heart rate to implanting a Raspberry Pi.

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Where Did Your PCB Go Wrong? KiRI Knows

August 21, 2023 by Matthew Carlson 5 Comments

When working on a PCB design in KiCad, it’s helpful that the files are all text and can easily be checked into Git or other source control. However, stepping back through the revisions to determine where precisely a trace got routed wrong can be tricky. [Leandro] started with a simple script that exported the KiCad project to an image for inspection — over time it grew into a full-blown visual diff tool named KiCad Revision Inspector (KiRI).

The primary mechanism exports the revisions of a KiCad 5, 6, or 7 project to SVG, which can then be compared via a handy onion skin view. As this is a tool written for those using KiCad, shortcuts are a huge part of the experience. A command line interface generates artifacts to view the diff in any web browser. As these outputs have the KiRI tooling baked in, it is relatively easy to archive the output as a build artifact and allow easy access to review design changes.

For the long-time reader, you might remember back in 2018 talked about another diffing tool called plotgitsch (which this KiRI uses for KiCad 5 projects). KiCad has grown significantly in the last five years. It might be time to update our tips to utilize Git better for your PCB designs.

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Easyeda2KiCad: Never Draw A Footprint Again

August 8, 2023 by Arya Voronova 38 Comments

What if I told you that you might never need to draw a new footprint again? Such is my friend’s impression of the tool that she’s shown me and I’m about to show you in turn, having used this tool for a few projects, I can’t really disagree!

We all know of the JLCPCB/LCSC/EasyEDA trio, and their integration makes a lot of sense. You’re expected to design your boards in EasyEDA, order the components on LCSC, and get the boards made by JLCPCB. It’s meant to be a one-stop shop, and as you might expect, there’s tight integration between all three. If there wasn’t, you’d be tempted to step outside of the ecosystem, after all.

But like many in this community, I use KiCad, and I don’t expect to move to a different PCB design suite — especially not a cloud one. Still, I enjoy using the JLCPCB and LCSC combination in the hobby PCB market as it stands now, and despite my KiCad affinity, it appears that EasyEDA can help me after all!

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Different Etching Strokes For Different PCBs, Folks

August 8, 2023 by Dan Maloney 44 Comments

[Sebastian] probably didn’t think he was wading into controversial waters when he posted on his experimental method for etching PCBs (in German). It’s not like etching with hydrochloric acid and peroxide is anything new, really; it was just something new to him. But is it even possible these days to post something and not find out just how wrong you are about it?

Sadly, no, or at least so it appears from a scan of [Sebastian]’s tweet on the subject (Nitter). There are a bunch of ways to etch copper off boards, including the messy old standby etchant ferric chloride, or even [Sebastian]’s preferred sodium persulfate method. Being out of that etchant, he decided to give the acid-peroxide method a go and was much pleased by the results. The traces were nice and sharp, the total etching time was low, and the etchant seemed pretty gentle when it accidentally got on his skin. Sounds like a win all around.

But Twitter wouldn’t stand for this chemical heresy, with comments suggesting that the etching process would release chlorine gas, or that ferric chloride is far safer and cleaner. It seems to us that most of the naysayers are somewhat overwrought in their criticism, especially since [Sebastian]’s method used very dilute solutions: a 30% hydrochloric acid solution added to water — like you oughta — to bring it down to 8%, and a 12% peroxide solution. Yes, that’s four times more concentrated than the drug store stuff, but it’s not likely to get you put on a terrorism watch list, as some wag suggested — a hair stylist watchlist, perhaps. And 8% HCl is about the same concentration as vinegar; true, HCl dissociates almost completely, which makes it a strong acid compared to acetic acid, but at that dilution it seems unlikely that World War I-levels of chlorine gas will be sweeping across your bench.

As with all things, one must employ caution and common sense. PPE is essential, good chemical hygiene is a must, and safe disposal of spent solutions is critical. But taking someone to task for using what he had on hand to etch a quick PCB seems foolish — we all have our ways, but that doesn’t mean everyone else is wrong if they don’t do the same.

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Nail, Meet KiCad

July 24, 2023 by Matthew Carlson 25 Comments

You know the old saying. When all you have open is KiCad, everything looks like a PCB. That was certainly true for [Evan], who needed to replace a small part recently and turned to PCBs to get the job done.

The part in question was a sheered apart detent cam from a retractable cord reel. Glue and epoxy might have worked, and [Evan] was worried about how a 3D printed PLA part would have held up. The part is an extruded 2D shape, making PCBs a non-traditional but viable choice. Using the old scanner trick, he traced the outline in KiCad 7 (which adds image references). Then with the five boards stacked up, solid core wire, solder, and a propane torch worth of heat fused it. Ultimately, this machine’s tolerances are generous, so it worked wonderfully.

Was it the “right” tool for the job? Right or wrong, it is hard to argue that in terms of durability and ease per dollar, this doesn’t come out on top. PCB files are on GitHub if you have a 5020TF-4c retractable cord reel that needs a new cam. PCBs have a fun way of adopting different use cases like enclosures, but perhaps the idea of PCBs as a mechanical part could be applied elsewhere.