Hacker Tactic: Single-PCB Panels

Ordering a PCB? Two of them? Three? Five? For about eight years now, I’ve been regularly ordering large numbers of different PCBs, and, naturally, have developed a toolkit to make things smoother. One trick is PCB panelization, and you should really know about it.

You might’ve encountered PCB panels already. Perhaps, if you order PCBA at a fab, you will get your board returned in a whole new form-factor, with rails on the sides that you have to snap off before your PCB is usable. Those rails are used so that your PCBs are easier to handle during assembly, but that’s far from the only reason why you would make a panel.

If you need multiple pieces of a PCB, your fab may say that building 50 pcs is classified as “large batch” and that takes longer than 30 days, which delays your entire PCB order. I’ve been there, five years ago, running out of time right before Chinese New Year. The fix was simple – I made a 2×2 panel and ordered that in quantity of 10-15. Panelization might be a little more expensive, or maybe even cheaper, but, most importantly, it will be faster.

In a few hours’ time, I sat down, figured out that KiCad has built-in features for panelization, and ordered panels instead of separate PCBs. Thanks to that, I made the Chinese New Year deadline that year and could successfully restock my store, letting me earn a fair bit of money instead of keeping a popular product out-of-stock – ultimately, helping my family stay up on rent that month.

Panelization lets you hack around many PCB ordering and assembly limitations, and I’ve only gotten started – there’s way way more! For now, let’s sort out panelizing multiples of the same PCB. As long as your boards are using KiCad (or KiCad-converted from Eagle/EasyEDA/Altium/gerbers), there’s no better software than KiKit.

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An example of the case generated for a simple PCB, being shown in the OpenSCAD viewer

Turbocase Generates A PCB Shell For You

Our PCBs greatly benefit from cases – what’s with all the pins that can be accidentally shorted, connectors that stick out of the outline, and cables pulling the board into different directions. Designing a case for your PCB might feel like a fair bit of effort – but it likely isn’t, thanks to projects like turbocase from [Martijn Braam].

This script generates simple and elegant OpenSCAD cases for your KiCad PCBs – you only need to draw a few extra lines in the PCB Editor, that’s it. It makes connector openings, too – add a “Height” property to your connector footprints to have them be handled automatically. Oh, and there’s a few quality-of-life features – if your project has mounting holes, the script will add threaded-insert-friendly standoffs to the case; yet another argument for adding mounting holes to your boards, in case you needed more.

Installing the script is a single line, running it is merely another, and that will cover an overwhelming majority of boards out there; the code is all open too, of course. Want some more customization? Here’s some general project enclosure tutorials for OpenSCAD, and a KiCad-friendly StepUp tutorial. Oh, and of course, there’s many more ways to enclose PCBs – our own [Bob Baddeley] has written a guide to project enclosures that you are bound to learn new things from.

We thank [adistuder] for sharing this with us!

Screenshot of the GitHub Marketplace action listing, describing the extension

Giving Your KiCad PCB Repository Pretty Pictures

Publishing your boards on GitHub or GitLab is a must, and leads to wonderful outcomes in the hacker world. On their own, however, your board files might have the repo look a bit barren; having a picture or two in the README is the best. Making them yourself takes time – what if you could have it happen automatically? Enter kicad-render, a GitHub and GitLab integration for rendering your KiCad projects by [linalinn].

This integration makes your board pictures, top and bottom view, generated on every push into the repo – just embed two image links into your README.md. This integration is made possible thanks to the new option in KiCad 8’s kicad-cli – board image generation, and [linalinn]’s code makes KiCad run on GitHub/GitLab servers.

For even more bling, you can enable an option to generate a GIF that rotates your board, in the style of that one [arturo182] demo – in fact, this integration’s GIF code was borrowed from that script! Got a repository with many boards in one? There’s an option you could make work for yourself, too.

All you need to do is to follow a couple of simple steps; [linalinn] has documented both the GitHub and GitLab integration. We’ve recently talked about KiCad integrations in more detail, if you’re wondering what else your repository could be doing!

Reverse Engineering The Quansheng Hardware

In the world of cheap amateur radio transceivers, the Quansheng UV-K5 can’t be beaten for hackability. But pretty much every hack we’ve seen so far focuses on the firmware. What about the hardware?

To answer that question, [mentalDetector] enlisted the help of a few compatriots and vivisected a UV-K5 to find out what makes it tick. The result is a complete hardware description of the radio, including schematics, PCB design files, and 3D renders. The radio was a malfunctioning unit that was donated by collaborator [Manuel], who desoldered all the components and measured which ones he could to determine specific values. The parts that resisted his investigations got bundled up along with the stripped PCB to [mentalDetector], who used a NanoVNA to characterize them as well as possible. Documentation was up to collaborator [Ludwich], who also made tweaks to the schematic as it developed.

PCB reverse engineering was pretty intense. The front and back of the PCB — rev 1.4, for those playing along at home — were carefully photographed before getting the sandpaper treatment to reveal the inner two layers. The result was a series of high-resolution photos that were aligned to show which traces connected to which components or vias, which led to the finished schematics. There are still a few unknown components, The schematic has a few components crossed out, mostly capacitors by the look of it, representing unpopulated pads on the PCB.

Hats off to the team for the work here, which should make hardware hacks on the radio much easier. We’re looking forward to what’ll come from this effort. If you want to check out some of the firmware exploits that have already been accomplished on this radio, check out the Trojan Pong upgrade, or the possibilities of band expansion. We’ve also seen a mixed hardware-firmware upgrade that really shines.

CATS mobile transceiver in a 3d-printed case

CATS: A New Communication And Telemetry System

CATS is a new communication and telemetry standard intended to surpass the current Automatic Packet Reporting System (APRS) standard by leveraging modern, super-cheap Frequency Shift Keying (FSK) transceivers rather than standard FM units. The project is in the early stages, but as of this writing, there is a full open source software stack and reference hardware for both Raspberry Pi-based gateway devices and an STM32-based mobile device.

CATS packets are called ‘whiskers!’

From a radio perspective, CATS uses raw FSK rather than the inefficient AFSK used by APRS. A real killer for channel utilization is the PTT time; this is the dead time around a packet APRS requires for ‘keying up’ and ‘keying down.’ The CATS standard is aggressive with PTT timing, enabling the channel to get going on sending the data sooner.

Additionally, compared to APRS, the packet baud rate increases from 1200 baud to 9600 baud. Other key points are using LDPC encoding for forward error correction and data whitening (a useful PDF guide from Ti) to smooth over any burst errors.

One of the neat concepts of APRS is the APRS-IS (APRS Internet service). This enables amateur radio services to be connected over the Internet, vastly improving range. The CATS equivalent is called FELINET (if you’re not spotting all the ‘cat’ references by now, go and get another coffee). Together with the I-gate hardware, FELINET bridges the CATS radio side with the current APRS network. As FELINET expands to more than the current few dozen nodes, APRS services will no longer be required, and FELINET may well replace it. Interestingly, all software for FELINET, the APRS relay, and the I-Gate firmware are written in Rust. We told you learning Rust was going to be worth the effort!

On the reference hardware side of things, the CATS project has delivered a Raspberry Pi hat, which uses a 1 watt RF4463 transceiver and supporting passives. The design is about as simple as it can be. A mobile transceiver version uses an STM32 micro to drive the same RF4463 but with supporting power supplies intended to run from a typical automotive outlet. Both designs are complete KiCAD projects. Finally, once you’ve got some hardware in place and the software installed, you will want to be able to debug it. CATS has you covered with an RTL-SDR I-Gate module, giving you an independent packet log.

APRS is quite mature, and we’ve seen many hacks on these pages. Here’s an earlier APRS IGate build using a Raspberry Pi. Need to hook up your PC to a cheap Chinese transceiver? You need the all-in-one cable. As with many things amateur-radio-oriented, you can get playing cheaply.

Share Your Projects: KiCad Automations And Pretty Renders

I have a pretty large GitHub repository, with all of my boards open-sourced there. Now, I’m finally facing the major problem it has – it can be uncomfortable for others to work with. I don’t store Gerber files in the repository because that will interfere with how Git functions – you’re supposed to only have source files in the repo. Yet, when someone needs Gerbers for my PCB, or a schematic PDF, or just to see how the board looks before they clone the entire repository, I often don’t have a good option for them.

In my experience as a hacker, being able to find others’ PCBs on GitHub is simply wonderful, but a PCB repository without a README feels barren, and a PCB README without pictures makes me sad. On the other hand, not having these files autogenerate is uncomfortable – updating a picture every time is a major drawback in particular.

Let’s take a look at some KiCad Git integrations, and see what they have to offer.

kicad_cli

We’ve mentioned kicad_cli back when KiCad 7 got released, and in the recently released KiCad 8, it’s only become more powerful. Before, it could do gerbers and schematic PDFs, but now, it can even do DRC checks – which is ideal if you want to add a hook for any pull requests you might encounter.

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An image showing the new KiCad feature that allows you to easily generate schematic labels from IC symbol pin names

KiCad 8 Makes Your Life Better Without Caveats

A few days ago, KiCad 8 was released, and it’s a straight upgrade to any PCB designer’s quality of life. There’s a blog post as usual, and, this year, there’s also a FOSDEM talk from [Wayne Stambaugh] talking about the changes that we now all get to benefit from. Having gone through both of these, our impression is that KiCad 8 developers went over the entire suite, asking: “this is cool, but could we make it better”? The end result is indeed a massive improvement in a thousand different ways, from small to fundamental, and all of them seem to be direct upgrades from the KiCad 7 experience.

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