Simplest Speaker Oscillator, Now Even Simpler

It never fails. Lay down some kind of superlative — fastest, cheapest, smallest — around this place and someone out there says, “Hold my beer” and gets to work. In this case, it’s another, even simpler audio oscillator, this time with just a loudspeaker and a battery.

Attentive readers will recall the previous title holder was indeed pretty simple, consisting only of the mic and speaker from an old landline telephone handset wired in series with a battery. Seeing this reminded [Hydrogen Time] of a lucky childhood accident while experimenting with a loudspeaker, which he recreates in the video below. The BOM for this one is even smaller than the previous one — just a small speaker and a battery, plus a small scrap of solid hookup wire. The wire is the key; rather than connecting directly to the speaker terminal, it connects to the speaker frame on one end while the other is carefully adjusted to just barely touch the flexible wire penetrating the speaker cone on its way to the voice coil.

When power is applied with the correct polarity, current flows through the wire into the voice coil, which moves the cone and breaks the circuit. The speaker’s diaphragm resets the cone, completing the circuit and repeating the whole process. The loudspeaker makes a little click with each cycle, leading to a very rough-sounding oscillator. [Hydrogen Time] doesn’t put a scope on it, but we suspect the waveform would be a ragged square wave whose frequency depends on the voltage, the spring constant of the diaphragm, and the spacing between the fixed wire and the voice coil lead.

Yes, we realize this is stretching the definition of an audio oscillator somewhat, but you’ve got to admit it’s simple. Can you get it even simpler?

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Making Beer Like It’s 1574, For Science And Heritage

Are you interested in the history of beer, food science, or just a fan of gathering “um, actually” details about things? Well you’re in for a treat because FoodCult (exploring Food, Culture, and Identity in early modern Ireland) has a fantastic exhibition showcasing their recreation of beer last brewed in the sixteenth century by putting serious scientific work into it, and learning plenty in the process.

A typical historical beer of middling strength was around 5% alcohol by volume, similar to a modern-day lager.

The recipes, equipment and techniques are straight from what was used at Dublin Castle in the late 1500s. This process yielded very interesting insights about what beer back then was really like, how strong it was, and what was involved in the whole process.

Documentation from the era also provides cultural insight. Beer was often used to as payment and provided a significant amount of dietary energy. Dublin Castle, by the way, consumed some 26,000 gallons per year.

In many ways, beer from back then would be pretty familiar today, but there are differences as well. Chief among them are the ingredients.

While the ingredients themselves are unsurprising in nature, it is in fact impossible to 100% recreate the beer from 1574 for a simple reason: these ingredients no longer exist as they did back then. Nevertheless, the team did an inspired job of getting as close as possible to the historical versions of barley, oats, hops, yeast, and even the water. Continue reading “Making Beer Like It’s 1574, For Science And Heritage”

Most of a three-key macro pad featuring a 3D-printed, LEGO-compatible plate.

3D-Printed Macro Pad Plate Is LEGO-Compatible

We love LEGO, we love keyboards, and when the two join forces, we’re usually looking at a versatile peripheral that’s practically indestructible. Such seems to be the case with [joshmarinacci]’s LEGO-compatible 3D-printed plate for a three-key macro pad. For a first foray into scratch-built keyboard construction, we think this is pretty great.

The idea here is threefold: the plate holds the switches in place, negates the need for a PCB, and makes it possible to build the case completely out of LEGO. In fact, [joshmarinacci]’s plan for the keycaps even includes LEGO — they are going to 3D print little adapters that fit the key switch’s stem on one side, and the underside of a 2×2 plate on the other.

Although [joshmarinacci]’s plan is to design a PCB for the next version, there is plenty to be said for combining the plate and the PCB by printing guides for the wires, which we’ve seen before. We’ve also seen LEGO used to create a keyboard stand that fits just right. 


A render of the USB Blaster, showing all the major parts

The Cheapest USB Blaster Ever, Thanks To CH552

Here’s a CH552G-based USB Blaster project from [nickchen] in case you needed more CH552G in your life, which you absolutely do. It gives you the expected IDC-10 header ready for JTAG, AS, and PS modes. What’s cool, it fits into the plastic shell of a typical USB Blaster, too!

The PCB is flexible enough, and has all the features you’d expect – a fully-featured side-mounted IDC-10 header, two LEDs, a button for CH552 programming mode, and even a UART header inside the case. There’s an option to add level shifter buffers, too – but you don’t have to populate them if you don’t want to do that for whatever reason! The page outlines all the features you are getting, though you might have to ask your browser to translate from Chinese.

Sadly, there’s no firmware or PCB sources – just schematics, .hex, BOM, and Gerber .zip, so you can’t fix firmware bugs, or add the missing USB-C pulldowns. Nevertheless, it’s a cool project and having the PCB for it is lovely, because you never know when you might want to poke at a FPGA on a short notice. Which is to say, it’s yet another CH552 PCB you ought to put in your PCB fab’s shopping cart! This is not the only CH552G-based programming dongle that we’ve covered – here’s a recent Arduino programmer that does debugWire, and here’s like a dozen more different CH552G boards, programmers and otherwise.

Possibly The Cheapest Way To Film In Bullet Time

When The Matrix hit the cinemas back in 1999 it started a minor revolution with its use of so-called “Bullet time” — a freeze-frame technique in which the action could move round a momentarily frozen subject. It’s filmed using an array of cameras in an arc, something which was pretty expensive back then but is now within the reach of almost anyone. Just how cheaply bullet time can be filmed is shown by [3DSage], who turned nine toy cameras into a budget bullet time rig.

The cameras themselves are what you might expect for the princely sum of nine dollars, but as he points out, their low-resolution video has a certain charm. Some iteration was required to produce the rig without fouling their flip-out screens, and he found that the video quality was far better than their still image quality. But eventually he was able to extract the required array of frames and stitch them together with a video interpolator for the required effect. His cat is a handsome creature from any angle, we can now reveal.

The video below the break has all the details, and while we couldn’t spot quite the same camera he used on our local version of the online shop he used, there seem to be plenty of similar cheap devices should you wish to try it for yourself. Either way, this cost much less than the previous budget bullet time contender.

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Singleboard: Alpha Is A Very Stylish Computer On A Single PCB

When we think single-board computers, we normally envision things like the Raspberry Pi. But Arduboy creator [Kevin Bates] has recently come up with his own take on the SBC that’s a bit like a modernized take on the early computers of the 1980s. Introducing Singleboard: Alpha.

The build has an incredibly pleasing form factor — it’s a single PCB with a capacitive keyboard etched right into the copper. The brains of the Singleboard is an ESP32, which provides plenty of grunt as well as wireless connectivity. Display is via a small LCD, currently configured with a green-on-black terminal that looks fantastic.

You’re not gonna run a fully-fledged GUI operating system on this thing, but that doesn’t mean it can’t be useful. We could imagine a device like this being a flexible wireless terminal for working with headless systems, for example, and it would be a charming one at that.

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2024 Home Sweet Home Automation: The Winners Are In

Home automation is huge right now in consumer electronics, but despite the wide availability of products on the market, hackers and makers are still spinning up their own solutions. It could be because their situations are unique enough that commercial offerings wouldn’t cut it, or perhaps they know how cheaply many automation tasks can be implemented with today’s microcontrollers. Still others go the DIY route because they’re worried about the privacy implications of pushing such a system into the cloud.

Seeing how many of you were out there brewing bespoke automation setups gave us the idea for this year’s Home Sweet Home Automation contest, which just wrapped up last week. We received more than 80 entries for this one, and the competition was fierce. Judging these contests is always exceptionally difficult, as nearly every entry is a standout accomplishment in its own way.

But the judges forged ahead valiantly, and we now have the top three projects which will be receiving $150 in store credit from the folks at DigiKey.

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