Building A Multi-Purpose Electrochemistry Device

September 13, 2024 by 11 Comments

We don’t get enough electrochemistry hacks on these pages, so here’s [Markus Bindhammer] of YouTube/Marb’s lab fame to give us a fix with their hand-built general-purpose electrochemistry device.

The basic structure is made from plyboard cut to size on a table saw and glued’n’screwed together. The top and front are constructed from an aluminium sheet bent to shape with a hand-bender. A laser-printed front panel finishes the aesthetic nicely, contrasting with the shiny aluminium. The electrode holders are part of off-the-shelf chemistry components, with the electrical contacts hand-made from components usually used for constructing stair handrails. Inside, a 500 RPM 12 V DC geared motor is mounted, driving a couple of small magnets. A PWM motor speed controller provides power. This allows a magnetic stirrer to be added for relevant applications. Power for the electrochemical cell is courtesy of a Zk-5KX buck-boost power supply with a range of 0 – 36 V at up to 5 A  with both CV and CC modes. A third electrode holder is also provided as a reference electrode for voltammetry applications. A simple and effective build, we reckon!

Over the years, we’ve seen a few electrochemical hacks, like this DIY electroplating pen, a DIY electrochemical machining rig, and finally, a little something about 3D printing metal electrochemically.

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2024 Tiny Games Contest: Neat PCB Business Card Was Inspired By The Arduboy

September 13, 2024 by No comments

The humble business card is usually a small slip of cardboard with some basic contact details on it — but as hackers know, it can be so much more. [Marian] has provided us a great example in the form of his own digital business card, which doubles as a handheld game!

Wanting to make his business card more interesting for better engagement, [Marian] was inspired by the Arduboy to give it some interactivity. He chose the STM32G030F6 microcontroller as a cheap and reliable option to run his business card. He then created a 10×9 LED matrix display using Charlieplexing to minimize the amount of I/O pins required. For controls, he went with the usual directional cross plus two action buttons. He implemented a variety of games on the card—including a Flappy Bird clone and a game similar to the classic Simon toy.

Files are on GitHub for the curious. We’ve featured some other great business cards this year, too. Indeed, we ran a whole challenge! If you’re cooking up your own exemplary little PCB to hand out at conferences, don’t hesitate to let us know!

2024 Tiny Games Challenge

Where Do You Connect The Shield?

September 13, 2024 by 21 Comments

When it comes to polarizing and confusing questions in electronics, wiring up shields is on the top-10 list when sorted by popularity. It’s a question most of us need to figure out at some point – when you place a USB socket symbol on your schematic, where do you wire up the SHIELD and MP pins?

Once you look it up, you will find Eevblog forum threads with dozens of conflicting replies, Stackexchange posts with seven different responses plus a few downvoted ones, none of them accepted, and if you try to consult the literature, the answer will invariably be “it depends”.

I’m not a connector-ground expert, I just do a fair bit of both reading and hacking. Still, I’ve been trying to figure out this debate, for a couple years now, re-reading the forum posts each time I started a new schematic with a yet-unfamiliar connector. Now, of course, coming to this question with my own bias, here’s a summary you can fall back on.

Consumer Ports

Putting HDMI on your board? First of all, good luck. Then, consider – do you have a reason to avoid connecting the shield? If not, certainly connect the shield to ground, use jumpers if that’s what makes you comfortable, though there’s a good argument that you should just connect directly, too. The reason is simple: a fair few HDMI cables omit GND pin connections, fully relying on the shield for return currents. When your HDMI connection misfires, you don’t want to be debugging your HDMI transmitter settings when the actual No Signal problem, as unintuitive as it sounds, will be simply your shield not being grounded – like BeagleBone and Odroid didn’t in the early days. By the way, is a DVI-D to HDMI adapter not working for you? Well, it might just be that it’s built in a cheap way and doesn’t connect the shields of the two sockets together – which is fixable.

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Hackaday Podcast Episode 288: Cyanotypes, Antique 21-Segment Displays, And The Voynich Manuscript In A New Light

September 13, 2024 by No comments

It’s Friday the 13th, and despite having to dodge black cats and poorly located ladders, Elliot and Dan were able to get together and run down the best hacks of the first week of September. Our luck was pretty good, too, seeing how we stumbled upon a coffee table that walks your drink over to you on Strandbeest legs, a potato that takes passable photographs, and a cool LED display three times better than a boring old seven-segment.

If you’ve never heard of the Voynich manuscript, you’re in luck too, because we got a chance to look inside this medieval comic book literally, with multispectral analysis. Is your cruise ship too short? No worries, just lop it in two and add a section. Speaking of cutting things up, that’s what you need to do to see how your plus-size DIY rocket engine performed after test firing.

And finally, it was a sweep for Jenny this week with our “Can’t Miss” articles, where she both pines for a simpler, smaller web experience and wonders what the future holds for biomass fuels.

 

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Recreating A Popular Faux-Nixie Clock

September 13, 2024 by 14 Comments

There’s a good chance you’ve seen “Nixie clocks” on the Internet that replace the classic cold cathode tubes with similarly sized LCD panels. The hook is that the LCDs can show pictures and animations of Nixie tubes — or pretty much anything else for that matter — to recreate the look of the real thing, while being far cheaper and easier to produce. It’s a hack for sure, and that’s the way we like it.

[Trung Tran] liked the idea, but didn’t just want to buy a turn-key clock. So he’s decided to build his own version based on the ESP32-S3. The WiFi-enabled microcontroller syncs up to the latest time via NTP, then uses a PCF8563 real-time clock (RTC) module to keep from drifting too far off the mark. The six displays, which plug into the custom PCB backplane, can then show the appropriate digits for the time. Since they’re showing image files, you can use any sort of font or style you wish. Or you could show something else entirely — the demo video below shows off each panel running the Matrix “digital rain” effect.

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This Week In Security: Malicious Rollback, WHOIS, And More

September 13, 2024 by 4 Comments

It’s time to talk about Microsoft’s patch Tuesday, and the odd vulnerability rollback that happened. CVE-2024-43491 has caught some attention, as it’s a 9.8 on the CVSS scale, is under active exploitation, and results in Remote Code Execution (RCE). Yikes, it sounds terrible!

First off, what actually happened? The official statement is that “build version numbers crossed into a range that triggered a code defect”. We don’t know the exact details, but it’s something like an unsigned integer that was interpreted as a signed integer. A build number could have rolled over 32767, and what was intended to be 32768 or higher suddenly became −32767. Lots of “if greater than or equal” logic breaks down in that situation. Because of a logic flaw like this, certain versions of Windows 10 were unintentionally opting out of some historical security fixes.

And that’s where the high CVSS score and active exploitation descriptor comes from. This is simply the highest score of the resurgent flaws, and an acknowledgement that they have been exploited in the past. The good news is that this only applies to Windows 10 build 1507, so either the original install without any of the major updates installed, or one of the Windows 10 Enterprise Long-Term Servicing Branch (LTSB) versions. It seems that the March 2024 monthly security update introduced the problem, and it wasn’t fixed until this month’s updates. Continue reading “This Week In Security: Malicious Rollback, WHOIS, And More” →

Doing MIDI With Discrete Logic Is Neat, If Not Particularly Useful

September 13, 2024 by 4 Comments

MIDI is normally baked into the chipset of a synthesizer, or something you use a microcontroller to handle. But that’s not the only way to speak the language! [Kevin] decided to have some fun doing MIDI with discrete logic instead, with some pretty neat results.

[Kevin] had previously built a control voltage step sequencer called the Baby8, which relied on 4017 counter ICs. He later realized he could repurpose three of his old Baby8 PCBs to create something that could generate MIDI using nothing more than discrete logic. The stack of three boards generate a simple MIDI message—in this case, a two-byte Program Change command. At 8 bits per byte, plus a start and stop bit, that comes out to 20 bits in total. The bits to be sent are configured via the switches on the PCBs, and clocked out through the counter ICs via a clock running at the MIDI baud rate of 31,250 Hz.

Obviously, it’s not very practical to code your MIDI commands manually via DIP switches and then clock them out in this fashion. But—it does work, and you can do it! If you wanted to build an old-school logic circuit that just spits out simple short MIDI commands, this is one way to go about it.

We’ve seen [Kevin]’s work before, too, like this neat musical rotary phone build.

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