What if circuit boards could glow in the dark? It’s a fun question, and one [Botmatrix] sought to answer when approached by manufacturer PCBWay to run a project together. It turns out that it’s quite possible to make glowing PCBs, with attractive results. (Video after the break.)

Specifically, PCBWay has developed a workable glow-in-the-dark silkscreen material that can be applied to printed circuit boards. As a commercial board house, PCBWay hasn’t rushed to explain how precisely they pulled off this feat, but we don’t imagine that it involved anything more than adding some glow-in-the-dark powder to their usual silkscreen ink, but we can only speculate.

On [Botmatrix]’s end, his video steps through some neat testing of the performance of the boards. They’re tested using sensors to determine how well they glow over time.

It might seem like a visual gimmick, and to an extent, it’s just a bit of fun. But still, [Botmatrix] notes that it could have some practical applications too. For example, glow-in-the-dark silkscreen could be used to highlight specific test points on a board or similar, which could be instantly revealed with the use of a UV flashlight. It’s an edge case, but a compelling one. It’s also likely to be very fun for creating visually reactive conference badges or in other applications where the PCB plays a major cosmetic role.

[Botmatrix] says these are potentially the first commercially-available glow-in-the-dark printed PCBs. We love glow in the dark stuff; we’ve even explored how to make your own glowing material before, too. .

[Mikey Sklar] had a problem—namely, running low on the brass material typically used for making PCB stencils. Thankfully, a replacement material was not hard to find. It turns out you can use aluminum business card blanks to make viable PCB stencils.

Why business card blanks? They’re cheap, for a start—maybe 15 cents each in quantity. They’re also the right thickness, at just 0.8 mm, and they’re flat, unlike rolled materials that can tend to flip up when you’re trying to spread paste. They’re only good for small PCBs, of course, but for many applications, they’ll do just fine.

To cut these, you’ll probably want a laser cutter. [Mikey] was duly equipped in that regard already, which helped. Using a 20 watt fiber laser at a power of 80%, he was able to get nice accurate cuts for the stencils. Thanks to the small size of the PCBs in question, the stencils for three PCBs could be crammed on to a single card.

If you’re not happy with your existing PCB stencil material, you might like to try these aluminium blanks on for size. We’ve covered other stenciling topics before, too.

One of those useful things to have around on your bench is a decade resistance box, essentially a dial-a-resistance instrument. They used to be quite expensive in line with the cost of close-tolerance resistors, but the prices have come down and it’s within reach to build your own. Electronic design consultancy Dekimo have a nice design for one made from a series of PCBs which they normally give out at trade fairs, but now they’ve released the files for download.

It’s released as Gerbers and BOM with a pick-and-place file only, and there’s no licence so it’s free-as-in-beer, but that should be enough if you fancy a go. Our Gerber viewer is playing up so we’re not entirely sure how reliable using PCBs as wafer switches will be long-term, but since the pictures are all ENIG boards we’d guess the gold plating will be much better than the HASL on all those cheap multimeters.

We like this as a conference giveaway, being used to badges it’s refreshing to see a passive take on a PCB artwork. Meanwhile this isn’t the first resistance box we’ve seen with unconventional switches.

If you’ve ever fancied building a ZX Spectrum clone without hunting down ancient ULAs or soldering your way through 60+ chips, [Alex J. Lowry] has just dropped an exciting build. He has recreated the Leningrad-1, a Soviet-built Spectrum clone from 1988, with a refreshingly low component count: 44 off-the-shelf ICs, as he wrote us. That’s less than many modern clones like the Superfo Harlequin, yet without resorting to programmable logic. All schematics, Gerbers, and KiCad files are open-source, listed at the bottom of [Alex]’ build log.

The original Leningrad-1 was designed by Sergey Zonov during the late Soviet era, when cloning Western tech was less about piracy and more about survival. Zonov’s design nailed a sweet spot between affordability and usability, with enough compatibility to run 90-95% of Spectrum software. [Alex]’ replica preserves that spirit, with a few 21st-century tweaks for builders: silkscreened component values, clever PCB stacking with nylon standoffs, and a DIY-friendly mechanical keyboard hack using transparent keycaps.

While Revision 0 still has some quirks – no SCART color output yet, occasional flickering borders with AY sound – [Alex] is planning for further improvements. Inspired to build your own? Read [Alex]’ full project log here.

Many of us use touch pads daily on our laptops, but rarely do we give much thought about what they really do. In fact they are a PCB matrix of conductive pads, with a controller chip addressing it and sensing the area of contact. Such a complex and repetitive pattern can be annoying to create by hand in an EDA package, so [Timonsku] has written a script to take away the work.

It starts with an OpenSCAD script (originally written by Texas Instruments, and released as open source) that creates a diamond grid, which can be edited to the required dimensions and resolution. This is then exported as a DXF file, and the magic begins in a Python script. After adjustment of variables to suit, it finishes with an Eagle-compatible board file which should be importable into other EDA packages.

We’ve never made a touchpad ourselves, but having dome other such repetitive PCB tasks we feel the pain of anyone who has. Looking at this project we’re struck by the thought that its approach could be adapted for other uses, so it’s one to file away for later.

This isn’t the first home-made touchpad project we’ve brought you.

FR4 is FR4, right? For a lot of PCB designs, the answer is yes — the particular characteristics of the substrate material don’t impact your design in any major way. But things get a little weird up in the microwave range, and having one of these easy methods to measure the dielectric properties of your PCB substrate can be pretty handy.

The RF reverse-engineering methods [Gregory F. Gusberti] are deceptively simple, even if they require some fancy test equipment. But if you’re designing circuits with features like microstrip filters where the permittivity of the substrate would matter, chances are pretty good you already have access to such gear. The first method uses a ring resonator, which is just a PCB with a circular microstrip of known circumference. Microstrip feedlines approach but don’t quite attach to the ring, leaving a tiny coupling gap. SMA connectors on the feedline connect the resonator to a microwave vector network analyzer in S21 mode. The resonant frequencies show up as peaks on the VNA, and can be used to calculate the effective permittivity of the substrate.

Method two is similar in that it measures in the frequency domain, but uses a pair of microstrip stubs of different lengths. The delta between the lengths is used to cancel out the effect of the SMA connectors, and the phase delay difference is used to calculate the effective permittivity. The last method is a time domain measurement using a single microstrip with a couple of wider areas. A fast pulse sent into this circuit will partially reflect off these impedance discontinuities; the time delay between the reflections is directly related to the propagation speed of the wave in the substrate, which allows you to calculate its effective permittivity.

One key takeaway for us is the concept of effective permittivity, which considers the whole environment of the stripline, including the air above the traces. We’d imagine that if there had been any resist or silkscreen near the traces it would change the permittivity, too, making measurements like these all the more important.

Do you do PCB design for a living? Has KiCad been just a tiny bit insufficient for your lightning-fast board routing demands? We’ve just been graced with the KiCad 9 release (blog post, there’s a FOSDEM talk too), and it brings features of the rank you expect from a professional-level monthly-subscription PCB design suite.

Of course, KiCad 9 has delivered a ton of polish and features for all sorts of PCB design, so everyone will have some fun new additions to work with – but if you live and breathe PCB track routing, this release is especially for you.

One of the most flashy features is multichannel design – essentially, if you have multiple identical blocks on your PCB, say, audio amplifiers, you can now route it once and then replicate the routing in all other blocks; a stepping stone for design blocks, no doubt.

Other than that, there’s a heap of additions – assigning net rules in the schematic, dragging multiple tracks at once, selectively removing soldermask from tracks and tenting from vias, a zone fill manager, in/decrementing numbers in schematic signal names with mousewheel scroll, alternate function display toggle on symbol pins, improved layer selection for layer switches during routing, creepage and acute angle DRC, DRC marker visual improvements, editing pad and via stacks, improved third-party imports (specifically, Eagle and Altium schematics), and a heap of other similar pro-level features big and small.

Regular hackers get a load of improvements to enjoy, too. Ever wanted to add a table into your schematic? Now that’s doable out of the box. How about storing your fonts, 3D models, or datasheets directly inside your KiCad files? This, too, is now possible in KiCad. The promised Python API for the board editor is here, output job templates are here (think company-wide standardized export settings), there’s significantly more options for tweaking your 3D exports, dogbone editor for inner contour milling, big improvements to footprint positioning and moving, improvements to the command line interface (picture rendering in mainline!), and support for even more 3D export standards, including STL. Oh, add to that, export of silkscreen and soldermask into 3D models – finally!

Apart from that, there’s, of course, a ton of bugfixes and small features, ~1500 new symbols, ~750 footprints, and, documentation has been upgraded to match and beyond. KiCad 10 already has big plans, too – mostly engine and infrastructure improvements, making KiCad faster, smarter, and future-proof, becoming even more of impressive software suite and a mainstay on an average hacker’s machine.

For example, KiCad 10 will bring delay matching, Git schematic and PCB integrations, PNG plot exports, improved diffpair routers, autorouter previews, design import wizard, DRC and length calculation code refactoring, part height support, and a few dozen other things!

We love that KiCad updates yearly now. Every FOSDEM, we get an influx of cool new features into the stable KiCad tree. We’re also pretty glad about the ongoing consistent funding they get – may they get even more, in fact. We’ve been consistently seeing hackers stop paying for proprietary PCB software suites and switching to KiCad, and hopefully some of them have redirected that money into a donation towards their new favorite PCB design tool.

Join the pro club, switch to the new now-stable KiCad 9! If you really enjoy it and benefit from it, donate, or even get some KiCad merch. Want to learn more about the new features? Check out the release blog post (many cool animations and videos there!), or the running thread on KiCad forums describing the new features&fixes in length, maybe if you’re up for video format, check out the KiCad 9 release talk recording (29m48s) from this year’s FOSDEM, it’s worth a watch.