If you’re getting PCBs professionally made, silkscreen usually comes free as part of the package. However, if you’re making your own, the job is on you. [Tony Goacher] makes his own PCBs on a CNC router, so he’s not getting any silkscreening as part of that bargain. But he wondered—could he do something analogous with a laser cutter?
The answer is yes. The silkscreen layer was first exported from DesignSpark, with the file then sent to LightBurn to prep it for laser cutting. The board outline layer was first engraved on to a piece of scrap as an alignment aid. Then, the board was placed in the laser cutter, with the silkscreen scorched directly on to the fiberglass.
The results are encouraging, if imperfect. [Tony] says he ran at “quite fast speed at quite high power.” The markings are all there, but they’re a little melty and difficult to read. He noted at lower speeds and lower power, the results were a bit more readable.
Building your own handheld gaming console has been a popular project for many years, but recently it has become significantly easier to get a lot of power into a small package. Like many others, [TommyB] made his own Raspberry Pi SBC-based handheld in the past, which results in a rather bulky and underpowered package. A more performant solution would be to stuff laptop guts into a handheld case, but until Framework came onto the scene this wasn’t easy and would get you a sloppy one-off solution. With [TommyB]’s current handheld project he uses a standard Framework laptop mainboard, along with the official battery to get a very capable gaming system.
Getting the ergonomics and fit for the components just right took many tries, but eventually a prototype shell was designed that fits the Framework mainboard, the battery, twin Framework speakers, an 8″ LCD panel from Waveshare (connected via USB-C to HDMI) and mechanical switches for the buttons. These switches connect to an RP2040-based board that runs the GP2040-CE firmware, allowing the operating system to detect it as an XBox controller. Although still far from finished, it shows just how beneficial standard laptop parts are, with a massive gap in the market where Framework could make its own handheld shell available. We’re looking forward to [TommyB] demonstrating the finished version of his Framework handheld, and the inevitable upgrade from the 11th-gen Intel mainboard to one of the sparkling new mainboards with even better specs.
Here’s a question for you: when your PCB has a ground plane layer, where do return signals flow? It seems like a trick question, but as [Kristof Mulier] explains, there’s more to return path routing than just doing a copper pour and calling it a day.
Like so many other things in life, the answer to the above question is “it depends,” and as [Kristof] ably demonstrates in this concise article, the return path for a signal largely depends on its frequency. He begins by explaining current loop areas and how they factor into the tendency for a circuit to both emit and be susceptible to electromagnetic noise. The bigger the loop area, the worse things can get from a noise perspective. At low frequencies, return signals will tend to take the shortest possible path, which can result in large current loop areas if you’re not careful. At higher frequencies, though, signals will tend to follow the path of minimal energy instead, which generally ends up being similar to the signal trace, even if it has a huge ground plane to flow through.
Since high-frequency signals naturally follow a path through the ground plane that minimizes the current loop, that means the problem takes care of itself, right? It would, except that we have a habit of putting all kinds of gaps in the way, from ground plane vias to isolation slots. [Kristof] argues that this can result in return paths that wiggle around these features, increasing the current loop area to the point where problems creep in. His solution? Route all your signal return paths. Even if you know that the return traces are going to get incorporated into a pour, the act of intentionally routing them will help minimize the current loop area. It’s brilliantly counterintuitive.
This is the first time we’ve seen the topic of high-frequency return paths tackled. This succinct demonstration shows exactly how return path obstructions can cause unexpected results.
The Raspberry Pi has provided experimenters with many channels of enquiry, and for me perhaps the furthest into uncharted waters it has led me has come through its camera interface. At a superficial level I can plug in one of the ready-made modules with a built-in tiny lens, but as I experiment with the naked sensors of the HD module and a deconstructed Chinese miniature sensor it’s taken me further into camera design than I’d expected.
I’m using them with extra lenses to make full-frame captures of vintage film cameras, in the first instance 8 mm movie cameras but as I experiment more, even 35 mm still cameras. As I’m now channeling the light-gathering ability of a relatively huge area of 1970s glass into a tiny sensor designed for a miniature lens, I’m discovering that maybe too much light is not a good thing. At this point instead of winging it I found it was maybe a good idea to learn a bit about lenses, and that’s how I started to understand what those F-numbers mean.
More Than The Ring You Twiddle To Get The Exposure Right
I’m not a photographer, instead I’m an engineer who likes tinkering with cameras and who takes photographs as part of her work but using the camera as a tool. Thus the f-stop ring has always been for me simply the thing you twiddle when you want to bring the exposure into range, and which has an effect on depth of field.
The numbers were always just numbers, until suddenly I had to understand them for my projects to work. So the first number I had to learn about was the F-number of the lens itself. It’s usually printed on the front next to the focal length and expressed as a ratio of the diameter of the light entrance to the lens focal length. Looking around my bench I see numbers ranging from 1:1 for a Canon 8mm camera to 1:2.8 for a 1950s Braun Paxette 35 mm camera, but it seems that around 1:1.2 is where most 8 mm cameras sit and 1:2 is around where I’m seeing 35 mm kit lenses. The F-stop ring controls an adjustable aperture, and the numbers correspond to that ratio. So that 1:2 kit lens is only 1:2 at the F2 setting, and becomes 1:16 at the F16 setting.
Fighting Too Much Light
My problem is that I’m trying to match a CMOS sensor with a very high sensitivity per unit area against lens systems designed for film, which at the relatively low ISO numbers of 8 mm movie film, has a much lower sensitivity per unit area. 8 mm film is a fantastic medium which provides an aesthetic like no other, but even its most diehard adherent wouldn’t disagree that light levels are of huge importance when using it.
I had some failed experiments with putting the CMOS sensor at the focal point of the camera, but in the end found a far more effective technique of using an M12 screw-in lens as a macro lens to focus on the original focal point from behind. This is great, but has the result that all of that extra light intended for an ISO 50 frame of 8 mm movie film instead lands on a Raspberry Pi sensor designed for a much smaller lens. I need to make it deliver equivalent light to that F number being much higher, but I want my digital cartridge to just drop into an unmodified camera, so I can’t mess about with camera apertures. The solution is to apply a neutral density filter, in effect an attenuator, to the front lens ring. Not ideal, but it’s the best I’ve got.
So this has been my journey into the numbers on the front of a camera lens, and also my journey into understanding how they help me in merging old and new cameras on the cheap. If you’re a seasoned photographer you’ll be wondering how it took me so long, but I hope some of you will have learned something new. If one day I can film a Hackaday report on a vintage Super 8 camera with a digital cartridge, it will all have been worthwhile.
The Chandra X-ray Observatory started its mission back in 1999 when Space Shuttle Columbia released it from its payload bay. Originally, it was supposed to serve only a five-year mission, but it has managed twenty-four years so far and counting, providing invaluable science along with the other Great Observatory: the Hubble Space Telescope. Unfortunately, NASA’s FY2025 budget now looks to threaten all space telescopes and Chandra in particular. This comes as part of the larger FY2025 US budget, which sees total funding for NASA increase by 2%, but not enough to prevent cuts in NASA’s space telescope operations.
NASA already anticipated this cut in 2023, with funding shifting to the Nancy Grace Roman Space Telescope (infrared spectrum, scheduled for 2027). Since Hubble is a joint operation with ESA, any shortfalls might be caught this way, but Chandra’s budget will go from 68.3M USD in FY2023 to 41.4M USD in FY2025 and from there plummeting to 5.2M USD by FY2029, effectively winding down the project and ending NASA’s flagship X-ray astronomy mission. This doesn’t sit well with everyone, with a website called Save Chandra now launched to petition the US government to save the observatory, noting that it still has a decade of fuel for its thrusters remaining and it also has stable mission costs.
So, how do they feel? There is a slight wobble to them, according to [Leo_keeb] — it’s a bit like pressing the left or right side of Tab. But the actuation is smooth, they say.
As you can see, these resin keycaps weren’t designed with the typical Cherry MX profile in mind, they are made for the Topre capacitive key switches of the HHKB. (No, those aren’t weird rubber domes.)
When I asked about sharing the STLs, [Leo_keeb] advised me that they might be willing to release STLs for Cherry MX switches in the US layout if there is enough interest.
The hurdy-gurdy is a fascinating string instrument dating from sometime around the 10th century. There is an active community of modern enthusiasts, but one can’t simply walk into a music shop and buy one. That’s where [XenonJohn] and the Digi-Gurdy come in, bringing some nice features while maintaining all the important elements of the original.
The hurdy-gurdy works by droning strings with a rotating wheel, and the player applies pressure to those strings via keys to play combinations of notes. Here’s a video demonstrating what it sounds like to play one, and one can see a conceptual resemblance to bagpipes, among other things.
The Digi-Gurdy is a modern electronic version that maintains the mechanical elements while sending MIDI signals over USB. It has options for line-out or headphone output. A thriving online community has shaped its development since its inception years ago.
We hope this leaves you wanting to know more because [XenonJohn] has loads of details to share. The main website at digigurdy.com is jam-packed with information about this instrument and its construction, and the project page on Hackaday.io has more nitty-gritty design details and source files for those who crave hardware specifics.
If [XenonJohn]’s name sounds familiar, it’s because we’ve admired his work on DIY self-balancing vehicles over the years. He also submitted an earlier version as an entry into the Hackaday Prize. His careful attention to detail shines through. Check out the two videos (embedded just below the page break): the first demonstrates the Digi-Gurdy, and the second shows off the construction and insides. You’d think a MIDI hurdy-gurdy would be unique, but, actually, we’ve seen more than one.