A vanadium based flow battery made with 3D printed parts

A Vanadium Redox Flow Battery You Can Build

March 9, 2024 by 36 Comments

Vanadium flow batteries are an interesting project, with the materials easily obtainable by the DIY hacker. To that effect [Cayrex2] over on YouTube presents their take on a small, self-contained flow battery created with off the shelf parts and a few 3D prints. The video (embedded below) is part 5 of the series, detailing the final construction, charging and discharging processes. The first four parts of the series are part 1, part 2, part 3, and part 4.

The concept of a flow battery is this: rather than storing energy as a chemical change on the electrodes of a cell or in some localised chemical change in an electrolyte layer, flow batteries store energy due to the chemical changediagram of a vanadium flow battery of a pair of electrolytes. These are held externally to the cell and connected with a pair of pumps. The capacity of a flow battery depends not upon the electrodes but instead the volume and concentration of the electrolyte, which means, for stationary installations, to increase storage, you need a bigger pair of tanks. There are even 4 MWh containerised flow batteries installed in various locations where the storage of renewable-derived energy needs a buffer to smooth out the power flow. The neat thing about vanadium flow batteries is centred around the versatility of vanadium itself. It can exist in four stable oxidation states so that a flow battery can utilise it for both sides of the reaction cell.

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a CH32V003 Linux-bearing PCB, single-sided, hand-etched, lovely

Bring Linux To CH32V003 Through, Yes, RISC-V Emulation

March 3, 2024 by 14 Comments

Like playing around with Linux on low-power devices? You’d be hard pressed to find a better example than the [tvlad1234]’s linux-ch32v003 project. It’s not just a one-off — it’s something you could build right now, since it requires hardly any extra parts.

With help of a 8 MB PSRAM chip for RAM supplementation purposes and an SD card, plus some careful tailoring of the Linux .config parameters, you get Linux on a chip never meant to even come close to handling this much power. The five minutes it takes to boot up to a prompt is part of the experience.

As usual with [tvlad1234]’s projects, there’s a fun twist to it! Running Linux on this chip is only possible thanks to [chlohr]’s mini-rv32ima project, which, as you might remember, is a RISC-V emulator. Yes, this runs Linux by running a RISC-V emulator on a RISC-V chip. The main reason for that is because the MCU can’t map the PSRAM chip into RAM, but if you use an emulator, memory mapping is only a matter of software. Having applied a fair amount of elbow grease, [tvlad1234] brings us buildroot and mainline Linux kernel configs you can compile to play with this — as well as a single-layer-ready KiCad board project on GitHub. Yep, you could literally etch a PCB for this project from single-sided copper-clad FR4 with a bit of FeCl3.

While the CH32V003 is undoubtedly a more impressive target for Linux, the RP2040 Linux project might be more approachable in terms of having most of the parts in your parts box. At least, up until we start valuing the CH32V003 for all the cool stuff it can do!

This Week In Security: Forksquatting, RustDesk, And M&Ms

March 1, 2024 by 14 Comments

Github is struggling to keep up with a malware campaign that’s a new twist on typosquatting. The play is straightforward: Clone popular repositories, add malware, and advertise the forks as the original. Some developers mistake the forks for the real projects, and unintentionally run the malware. The obvious naming choice is forksquatting, but the researchers at apiiro went with the safer name of “Repo Confusion”.

The campaign is automated, and GitHub is aware of it, with the vast majority of these malicious repositories getting removed right away. For whatever reason, the GitHub algorithm isn’t catching all of the new repos. The current campaign appears to publishing millions of forks, using code from over 100,000 legitimate projects. It’s beginning to seem that the squatting family of attacks are here to stay.

RustDesk and Odd Certificates

The RustDesk remote access software is interesting, as it’s open source, allows self-hosting, and written in Rust. I’ve had exploring RustDesk as a todo item for a long time, but a bit of concerning drama has just finished playing out. A user pointed out back in November that a test root certificate was installed as part of the RustDesk installation. That root cert is self-signed with SHA1. There is also concern that the RustDesk binaries are signed with a different certificate.

There have been new events since then. First, there was a Hacker News thread about the issue earlier this month. The next day, CVE-2024-25140 was registered with NIST, ranking an insane CVE 9.8 CVSS. Let’s cut through some FUD and talk about what’s really going on.

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ESP32 Weather Station Looks Great With Color E-Paper Display

February 28, 2024 by 20 Comments

[educ8s.tv] has built weather stations before, but his latest is his best yet. It’s all thanks to its low-power design, enabled by its e-paper display.

The build is based around an ESP32 microcontroller, combined with a BMP180 sensor for measuring barometric pressure, and a DHT22 sensor for measuring temperature and humidity. By taking these values and feeding them into the Zambretti algorithm, it’s possible to generate a rudimentary weather forecast.

The weather station looks particularly impressive thanks to its six-color e-paper display. It’s brightly colored and easy to read, and displays graphs of temperature, pressure, and humidity over time. Plus, by virtue of the fact that it only draws power when updating, it allows the project to last a long time running solely on battery power.

As far as DIY weather stations go, this is an attractive and clean design that offers plenty of useful data to the user. We’ve seen some other neat builds in this vein before, too.

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Your Scope, Armed And Ready

February 24, 2024 by 13 Comments

[VoltLog] never has enough space on his bench. We know the feeling and liked his idea of mounting his oscilloscope on an articulated arm. This is easy now because many new scopes have VESA mounts like monitors or TVs. However, watching the video below, we discovered there was a bit more to it than you might imagine.

First, there are many choices of arms. [VoltLog] went for a cheap one with springs that didn’t have a lot of motion range. You may want something different. But we didn’t realize that many of these arms have a minimum weight requirement, and modern scopes may be too light for some of these arms. Most arms require at least 2 kg of weight to balance the tensions in their springs or hydraulics. Of course, you could add a little weight to the mounting plate of the arm if you needed it. The only downside we see is that it makes it hard to remove the scope if you want to use it somewhere else.

Assuming you have a mount you like, the rest is easy. Of course, your scope might not have VESA mounting holes. No problem. You can probably find a 3D printed design for an adapter or make (or adapt) your own. You might want to print a cable holder at the same time.

Honestly, we’ve thought of mounting a scope to the wall, but this seems nicer. We might still think about 3D printing some kind of adapter that would let you easily remove the scope without tools.

Of course, there is another obvious place to mount your scope. Monitor arms can also mount microscopes.

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Mirror, Mirror, Electron Mirror…

February 23, 2024 by 2 Comments

If you look into an electron mirror, you don’t expect to see your reflection. As [Anthony Francis-Jones] points out, what you do see is hard to explain. The key to an electron mirror is that the electric and magnetic fields are 90 degrees apart, and the electrons are 90 degrees from both.

You need a few strange items to make it all work, including an electron gun with a scintillating screen in a low-pressure tube. Once he sets an electric field going, the blue line representing the electrons goes from straight to curved.

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Reggaeton-Be-Gone Disconnects Obnoxious Bluetooth Speakers

February 23, 2024 by 29 Comments

If you’re currently living outside of a Spanish-speaking country, it’s possible you’ve only heard of the music genre Reggaeton in passing, if at all. In places with large Spanish populations, though, it would be more surprising if you hadn’t heard it. It’s so popular especially in the Carribean and Latin America that it’s gotten on the nerves of some, most notably [Roni] whose neighbor might not do anything else but listen to this style of music, which can be heard through the walls. To solve the problem [Roni] is now introducing the Reggaeton-Be-Gone. (Google Translate from Spanish)

Inspired by the TV-B-Gone devices which purported to be able to turn off annoying TVs in bars, restaurants, and other places, this device can listen to music being played in the surrounding area and identify whether or not it is hearing Reggaeton. It does this using machine learning, taking samples of the audio it hears and making decisions based on a trained model. When the software, running on a Raspberry Pi, makes a positive identification of one of these songs, it looks for Bluetooth devices in the area and attempts to communicate with them in a number of ways, hopefully rapidly enough to disrupt their intended connections.

In testing with [Roni]’s neighbor, the device seems to show promise although it doesn’t completely disconnect the speaker from its host, instead only interfering with it enough for the neighbor to change locations. Clearly it merits further testing, and possibly other models trained for people who use Bluetooth speakers when skiing, hiking, or working out. Eventually the code will be posted to this GitHub page, but until then it’s not the only way to interfere with your neighbor’s annoying stereo.

Thanks to [BaldPower] and [Alfredo] for the tips!