Possibly-Smallest ESP32 Board Uses Smallest-Footprint Parts

Whenever there’s a superlative involved, you know that degree of optimization has to leave something else on the table. In the case of [PegorK]’s f32, the smallest ESP32 dev board we’ve seen, the cost of miniaturization is GPIO.

There’s only one GPIO pin broken out, and it’s pre-wired to an LED. That’s the bad news, and depending on what you want an ESP32 for, it might not phase you at all. What is impressive here, if not the number of I/O pins, is the size of the board: at 9.85 mm x 8.45 mm barely overhangs the USB-C socket that takes up one side of the board.
Pegor provides this helpful image in the readme so you know what you’re getting into with the 01005 resistors.
In order to get the ESP32-C3FH4 onto such a tiny board, all of the other support hardware had to be the smallest possible sizes– including resistors in 01005. If you don’t speak SMD, one could read that number code as “oh god too small” — at 0.4 mm x 0.2 mm it’s as minuscule as you’ll find– and [Pegor] hand soldered them.

OK, he did use a hot plate for the final step, but he did tin the pads manually with a soldering iron, which is still impressive. Most of us probably would have taken PCBWay up on their offer of assembly services, but not [Pegor]. Apparently part of the reason for this project was that he was looking for an excuse to use the really small footprint components.

Aside from leaving out GPIO and needing too-small SMD components, [Pegor] admits that pesky little details like antenna matching circuits and decoupling capacitors had to get cut to make the tiny footprint, so this board might be more of a stunt than anything practical. So what can you do with the smallest ESP32 board? Well, [Pegor] put up a basic web interface up to get you started blinking the built-in LED; after that, it’s up to you. Perhaps you might fancy a teeny-tiny minecraft server? If you can stand to increase the volume a little bit, we’ve seen how to hack a C3 for much better wifi performance.

Thanks to [Pegor] for the tip, and remember– submit your projects, big or small, we read ’em all!

hackaday.com/2025/11/19/possib…

Around 15 years ago the web engineers first proposed mechanism that would allow user browser to transparently communicate to website their cookie and tracking preferences (DNT and then Tk headers).

In response to the subsequent EU cookie regulations, Google, Mozilla & friends had implemented an “Italian-strike” - instead of resorting to DNT/Tk, they simply implemented absolutely terrible “cookie consent” pop-ups in a way that offered the worst possible user experience. And then blamed them on… EU regulation.

Right now EU seems to have drawn lessons from that past sabotage and proposes a regulation that will force websites to respect user cookie preferences sent transparently by the user browser.

theverge.com/news/823788/europ…

That would immediately put end to the “cookie consent” pop-ups and I’m very much wondering what kind of QWAC-like “grassroots campaign” Google, Mozilla & friends will now come up to convince users it’s not in their best interest to decide if they want or not to be tracked by 700 “advertising partners” per website…

ЗМІ: Україна та Греція спільно вироблятимуть морські дрони

Грецькі суднобудівники разом з українськими фахівцями розроблятимуть вдосконалену модель морського дрону, яка вже проявила себе в бойових умовах.

Первая европейская страна заявила о прекращении выдачи мультивиз россиянам

В МИД Болгарии рассказали изданию «Вот Так», что страна будет выполнять решение Еврокомиссии о прекращении выдачи россиянам многократных виз. В ведомстве добавили, что там готовы рассмотреть аналогичные ограничения в отношении граждан Беларуси.

Президент Польши готовит почву для выхода страны из ЕС, — глава МИД Польши Сикорский

"Намекая на то, что европейская интеграция — это заговор против Польши, вы не помогаете ни ЕС, ни Польше. Вы готовите психологическую и политическую почву для выхода из Евросоюза", — заявил он, обращаясь к президенту Навроцкому.

Build a Stranger Things Wall You Can Freak Out At In Your Own Home

When Stranger Things premiered in 2016, it was a cultural force. Foreign DJs gushed over the lush 80s soundtrack, fashionistas loved the clothing, and the world became obsessed with the idea of using Christmas lights to communicate across material planes. [kyjohnso] has recreated that experience with the technology of today.

If you haven’t watched the show — Joyce Byers is trying to communicate with her son Will, who just so happens to be stuck in another plane of existence called the Upside Down. She screams questions at her living room wall, upon which hangs a series of Christmas lights, marked with the letters A to Z. Will is able to communicate back by causing the lights to flash, one letter at a time.

This build works a little differently. You basically type a message into a terminal on a Raspberry Pi, and it gets sent to a large language model—namely, the Claude API. The response from Claude (or Will Byers, if you’re imagining) is then flashed out on a WS2812B set of LED Christmas lights on the wall. [kyjohnso] added dramatic pauses whenever there’s a space in the output, somewhat replicating the dramatic elements of the show itself. Files are on GitHub for the spooky and curious.

It’s a neat build that would be a hit at any Halloween party. We can’t imagine how much more immersive it would be if paired with a speech-to-text engine so you could actually scream at the thing like a distraught Midwestern parent who has just lost her youngest child. It’s all about committing to the bit; if you build such a thing, don’t hesitate to notify the tipsline!

hackaday.com/2025/11/19/build-…

FLOSS Weekly Episode 855: Get in the Minecart, Loser!

This week Jonathan chats with Kevin, Colin, and Curtis about Cataclysm: Dark Days Ahead! It’s a rogue-like post-apocalyptic survival game that you can play in the terminal, over SSH if you really want to! Part of the story is a Kickstarter that resulted in a graphics tile-set. And then there’s the mods!

• cataclysmdda.org/
• github.com/CleverRaven/Catacly…

youtube.com/embed/XzS8cOnVFgg?…

Did you know you can watch the live recording of the show right on our YouTube Channel? Have someone you’d like us to interview? Let us know, or have the guest contact us! Take a look at the schedule here.

play.libsyn.com/embed/episode/…

Direct Download in DRM-free MP3.

If you’d rather read along, here’s the transcript for this week’s episode.

Places to follow the FLOSS Weekly Podcast:

• Spotify
• RSS

Theme music: “Newer Wave” Kevin MacLeod (incompetech.com)

Licensed under Creative Commons: By Attribution 4.0 License

hackaday.com/2025/11/19/floss-…

Hackers Can’t Spend a Penny

We aren’t here to praise the penny, but rather, to bury it. The penny, and its counterparts, have been vanishing all around the world as the cost of minting one far outweighs its value. But hackers had already lost a big asset: real copper pennies, and now even the cheaply made ones are doomed to extinction.

If you check your pockets and find a pre-1982 penny, it’s almost all copper. Well, 95% of its slightly-more-than-3-gram heft is pure copper. Since then, the copper penny’s been a fraud, weighing 2.5 g and containing only a 2.5% copper plate over a zinc core. During WWII, they did make some oddball steel pennies, but that was just a temporary measure.

Penny Science

If you are a certain age, you might remember building a “voltaic pile.” These primitive batteries use pennies, cardboard soaked in vinegar, and aluminum foil. Granted, it wasn’t very practical, so raiding your couch for change to make a battery was never really practical, but it was a fun science experiment. There are dozens of YouTube videos showing this popular experiment, including the [ScienceBuddies] video below.

youtube.com/embed/JcRRTHkAl6A?…

Old pennies were also a cheap and easy source of copper. Vinegar or lemon juice and some voltage made it simple to copperplate another metal object, like a nail. Copper also makes a good heatsink. We’ve seen Raspberry Pis and similar boards with heatsinks that cost an integer number of pennies, because that’s all they were. An oxidized penny shows up in some foxhole radios. They were also handy little weights if you made a balance or for taming a wobbly ceiling fan.

If you were a real kid chemist, you might have done the classic trick of turning a penny into “silver” and then “gold.” You used not-so-lovely-to-handle sodium hydroxide, some zinc, and a flame to actually convert the penny to brass. It wasn’t really a precious metal, but still a good trick if you were a kid with a chemistry set. As the video from [Simon] below shows, that will still work with the copperplate pennies.

youtube.com/embed/wmd2teoPUu0?…

New Pennies

Not that you can’t have fun with zinc pennies. If you scratch the plating a bit and dip it in HCL, the zinc core fizzes away. What’s left is a hollow copper penny. If you don’t like using HCL, we hear you can do it over a stove and simply melt the zinc. We wouldn’t try either one of those without a vent hood and an unhealthy disregard for your personal safety, so, you know, don’t do that. But know that you could. [Craig] shows how to remove the zinc or the copper in the video below.

youtube.com/embed/5Cf0gH2LtiE?…

The legality of all this has always been a little suspect. Since 2006, it has been illegal to melt down coins for their metal value. Technically, using it in a science class probably won’t bring the Treasury agents swooping into your classroom, but you have been warned.

Household Hacker

Of course, it is going to take some time for all the pennies to really vanish. There are plenty of them, and you can still get around a hundred for a buck. But when they are gone, what other household items are easy to hack for science? Aluminum foil, maybe? Tell us your favorite in the comments.

Whether they were copper slugs or thinly plated zinc tokens, pennies were a weirdly perfect hacker material: cheap, conductive, sacrificial, and everywhere. We’ll miss them.

Featured image: “wealth of pennies” by [Reza]

hackaday.com/2025/11/19/hacker…

Damn Fine (Solar Powered) Coffee

The folks at Low Tech Magazine are here again, this time with a solar powered coffee maker. Lest you think of a large parabolic mirror with a pot at its focus, in this case the device is much more friendly. It’s a table-top appliance that relies upon a 100 W 12 V panel for its operation.

They make the point that an electric coffee pot requires at least 300 W to work, so what’s the secret? In this case, insulation, as a standard moka pot is placed within a nichrome heating element set in mortar and surrounded by cork. On the outside are tiles, though they appear largely ornamental and the write-up suggests you could experiment with other materials to serve as an enclosure.

It appears to be an effective coffee maker, with the significant caveat that it’s hardly fast. In full sunlight the first pot takes over an hour to brew, with subsequent ones once it’s up to temperature being somewhat faster. But you can’t argue with the idea of free power, even if your favourite caffeinated beverage may now take a while to appear.

We like this idea, despite its slow brewing. We’ve featured Low Tech Magazine before, not least in their solar powered oven.

hackaday.com/2025/11/19/damn-f…