Reverse Engineering The Quansheng Hardware

April 23, 2024 by Dan Maloney 11 Comments

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

March 15, 2024 by Dave Rowntree 27 Comments

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

March 11, 2024 by Arya Voronova 23 Comments

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.

Continue reading “Share Your Projects: KiCad Automations And Pretty Renders” →

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

February 26, 2024 by Arya Voronova 60 Comments

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.

Continue reading “KiCad 8 Makes Your Life Better Without Caveats” →

render of a sample board produced with help of this plugin. it's pretty, has nice lighting and all!

From KiCad To Blender For A Stunning Render

January 3, 2024 by Arya Voronova 34 Comments

We love Blender. It brings you 3D modeling, but not in a CAD way — instead, people commonly use it to create animations, movies, games, and even things like VR models. In short, Blender is about all things art and visual expression. Now, what if you want a breathtaking render of your KiCad board? Look no further than the pcb2blender tool from [Bobbe 30350n].

This isn’t the first time we’ve seen KiCad meet Blender. However, compared to the KiCad to Blender paths that people used previously, pcb2blender makes the import process as straightforward and as quick as humanly possible. Install a plugin for both tools, and simply transfer a .pcb3d file out of the KiCad plugin into the Blender plugin. Want to make the surfaces of your design look like they’re meant to look in real life? Use the free2ki plugin to apply materials to your 3D models. In fact, you should check out [30350n]’s Blender plugin collection and overall portfolio, it’s impressive.

There’s no shortage of Blender hacks – just this year we’ve covered a hacker straight up simulating an entire camera inside Blender for the purpose of making renders, and someone else showing how to use Stable Diffusion to texture 3D scenes at lightning speed. We even recently published a comprehensive tutorial on how to animate your robot in Blender ourselves! Want to give it a shot? Check out this quick and simple Red Bull can model design tutorial.

Thanks to [Aki] for sharing this with us!

Revive A Sony Vaio P-Series With KiCad’s Background Bitmaps

November 20, 2023 by Arya Voronova 28 Comments

You might remember that KiCad 7 came out this February, with a multitude of wonderful features. One of them was particularly exciting to see, and the KiCad newsletter even had an animated GIF to properly demo it – a feature called “Background Bitmaps”, which is the ability to add existing board images into your board editor, both front and back, and switch between them as you design the board. With it, you can draw traces, recreate the outline and place connectors over these images, giving you a way to quickly to reproduce everything on an existing PCB! I’ve seen some friends of mine use this feature, and recently, I’ve had a project come up that’s a perfect excuse for me to try it.

Back in 2020, I managed to get a Sony Vaio P from a flea market, for about 20€. It’s a beloved tiny laptop from 2009, now a collectors item, and we’ve covered a few hacks with it! The price was this wonderful only because it was not fit for regular flea market customers – it was in bad condition, with the original DC jack lost and replaced by some Molex-like power connector, no hard drive, and no battery in sight.

In short, something worth selling to a known tinkerer like me, but not particularly interesting otherwise. Nevertheless, about half a year later, when I fed it the desired 10.5 V from a lab PSU and gave the power button a few chances, it eventually booted up and shown me the BIOS menu on the screen! I’ve disassembled and reassembled it a few times, replaced the DC jack with an original one from a different Vaio ultrabook I happened to have parts from, and decided to try to bring it back to original condition.

Continue reading “Revive A Sony Vaio P-Series With KiCad’s Background Bitmaps” →

Vectorscope KiCad Redrawing Project

November 13, 2023 by Chris Lott 23 Comments

When I saw this year’s Supercon Vectorscope badge, I decided that I had to build one for myself. Since I couldn’t attend in-person, I immediately got the PCBs and parts on order. Noting that the GitHub repository only had the KiCad PCB file and not the associated schematics and project file, I assumed this was because everyone was in a rush during the days leading up to Supercon weekend. I later learned, however, that there really wasn’t a KiCad project — the original design was done in Circuit Maker and the PCB was converted into KiCad. I thought, “how hard can this be?” and decided to try my hand at completing the KiCad project.

Fortunately I didn’t have to start from scratch. The PCB schematics were provided, although only as image files. They are nicely laid out and fortunately don’t suffer the scourge of many schematics these days — “visual net lists” that are neither good schematics nor useful net lists. To the contrary, these schematics, while having a slightly unorthodox top to bottom flow, are an example of good schematic design. Continue reading “Vectorscope KiCad Redrawing Project” →