Possibly-Smallest ESP32 Board Uses Smallest-Footprint Parts

November 19, 2025 by Tyler August 20 Comments

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!

Charge NiMH Batteries With Style, Panache And An RP2040

November 19, 2025 by Tyler August 22 Comments

The increasing dominance of lithium cells in the market place leave our trusty NiMH cells in a rough spot. Sure, you can still get a chargers for the AAs in your life, but it’s old tech and not particularly stylish. That’s where [Maximilian Kern] comes in, whose SPINC project was recently featured in IEEE Spectrum— so you know it has to be good.

With the high-resolution LCD, the styling of this device reminds us a little bit of the Pi-Mac-Nano— and anything that makes you think of a classic Macintosh gets automatic style points. There’s something reminiscent of an ammunition clip in the way batteries are fed into the top and let out the bottom of the machine.

[Maximilian] thought of the, ah, less-detail-oriented amongst us with this one, as the dedicated charging IC he chose (why reinvent the wheel?) is connected to an H-bridge to allow the charger to be agnostic as to orientation. That’s a nice touch. An internal servo grabs each battery in turn to stick into the charging circuit, and deposits it into the bottom of the device once it is charged. The LCD screen lets you monitor the status of the battery as it charges, while doubling as a handy desk clock (that’s where the RP2040 comes in). It is, of course powered by a USB-C port as all things are these days, but [Maximilian] is just drawing from the 5V line instead of making proper use of USB-C Power Delivery. (An earlier draft of this article asserted incorrectly that the device used USB-C-PD.) Fast-charging upto 1A is enabled, but you might want to go slower to keep your cells lasting as long as possible. Firmware, gerbers and STLs are available on GitHub under a GPL-3.0 license– so if you’re still using NiCads or want to bring this design into the glorious lithium future, you can consider yourself welcome to.

We recently featured a AA rundown, and for now, it looks like NiMH is still the best bang for your buck, which means this project will remain relevant for a few years yet. Of course, we didn’t expect the IEEE to steer us wrong.

Thanks to [George Graves] for the tip.

In Praise Of Plasma TVs

November 18, 2025 by Tyler August 42 Comments

I’m sitting in front of an old Sayno Plasma TV as I write this on my media PC. It’s not a productivity machine, by any means, but the screen has the resolution to do it so I started this document to prove a point. That point? Plasma TVs are awesome.

Always the Bridesmaid, Never the Bride

An Egyptian god might see pixels on an 8K panel, but we puny mortals won’t. Image “Horus Eye 2” by [Jeff Dahl]

The full-colour plasma screens that were used as TVs in the 2000s are an awkward technological cul-de-sac. Everyone knows and loves CRTs for the obvious benefits they offer– bright colours, low latency, and scanlines to properly blur pixel art. Modern OLEDs have more resolution than the Eye of Horus, never mind your puny human orbs, and barely sip power compared to their forbearers. Plasma, though? Not old enough to be retro-cool, not new enough to be high-tech, plasma displays are sadly forgotten.

It’s funny, because I firmly believe that without plasma displays, CRTs would have never gone away. Perhaps for that I should hate them, but it’s for the very reasons that Plasma won out over HD-CRTs in the market place that I love them.

What You Get When You Get a Plasma TV

I didn’t used to love Plasma TVs. Until a few years ago, I thought of them like you probably do: clunky, heavy, power-hungry, first-gen flatscreens that were properly consigned to the dustbin of history. Then I bought a house.

The house came with a free TV– a big plasma display in the basement. It was left there for two reasons: it was worthless on the open market and it weighed a tonne. I could take it off the wall by myself, but I could feel the ghost of OSHA past frowning at me when I did. Hauling it up the stairs? Yeah, I’d need a buddy for that… and it was 2020. By the time I was organizing the basement, we’d just gone into lockdown, and buddies were hard to come by. So I put it back on the wall, plugged in my laptop, and turned it on.

I was gobsmacked. It looked exactly like a CRT– a giant, totally flat CRT in glorious 1080p. When I stepped to the side, it struck me again: like a CRT, the viewing angle is “yes”. Continue reading “In Praise Of Plasma TVs” →

Supersized Calculator Brings The Whole Intel 4004 Gang Together

November 16, 2025 by Tyler August 23 Comments

Though mobile devices and Apple Silicon have seen ARM-64 explode across the world, there’s still decent odds you’re reading this on a device with an x86 processor — the direct descendant of the world’s first civilian microprocessor, the Intel 4004. The 4004 wasn’t much good on its own, however, which is why [Klaus Scheffler] and [Lajos Kintli] have produced super-sized discrete chips of the 4001 ROM, 4002 RAM, and 4003 shift register to replicate a 1970s calculator at 10x the size and double the speed, all in time for the 4004’s 50th anniversary.

We featured this project a couple of years back, when it was just a lonely microprocessor. Adding the other MSC-4 series chips enabled the pair to faithfully reproduce the logic of a Busicom 141-PF calculator, the very first to market with Intel’s now-legendary microprocessor. Indeed, this calculator is the raison d’etre for the 4004: Busicom commissioned the whole Micro-Computer System 4-bit (MCS-4) set of chips specifically for this calculator. Only later, once they realized what they had made, did Intel buy the rights back from the Japanese calculator company, and the rest, as they say, is history.

Continue reading “Supersized Calculator Brings The Whole Intel 4004 Gang Together” →

The Simplest Ultrasound Sensor Module, Minus The Module

November 16, 2025 by Tyler August 5 Comments

Just about every “getting started with microcontrollers” kit, Arduino or otherwise, includes an ultrasonic distance sensor module. Given the power of microcontrollers these days, it was only a matter of time before someone asked: “Could I do better without the module?” Well, [Martin Pittermann] asked, and his answer, at least with the Pi Pico, is a resounding “Yes”. A micro and a couple of transducers can offer a better view of the world.

The project isn’t really about removing the extra circuitry on the SR-HC0, since there really isn’t that much to start. [Martin] wanted to know just how far he could push ultrasound scanning technology using RADAR signal processing techniques. Instead of bat-like chirps, [Martin] is using something called Frequency-Modulated Continuous Wave, which comes from RADAR and is exactly what it sounds like. The transmitter emits a continuous carrier wave with a varying frequency modulation, and the received wave is compared to see when it must have been sent. That gives you the time of flight, and the usual math gives you a distance.

Continue reading “The Simplest Ultrasound Sensor Module, Minus The Module” →

The Fastest (68k) Macintosh Might Not Be An Amiga Anymore

November 15, 2025 by Tyler August 19 Comments

Amiga and Atari fans used to lord over their Apple-eating brethren the fact that Cupertino never moved to the most advanced 68k processors — so for a while, thanks to 68060 accelerator cards, the fastest thing running Macintosh software was an Amiga (or Atari). After all these years, the Macintosh community is finally getting the last laugh, as [zigzagjoe] demonstrates an actual Macintosh booting with a 68060 CPU for the first time in a thread on 68KMLA. Video or it didn’t happen? Check it out below.

The Mac in question is a Quadra 650, which is a good choice since it was about the last thing Apple sold before switching to PowerPC, and ran the 68040 processor. [Reinauer] had already produced a 68040-to-68060 socket adapter (the two chips not being pinout compatible), so the hardware part of the battle was already set. Software, however? That was a different story, and where [zigzagjoe] put in the effort.

Continue reading “The Fastest (68k) Macintosh Might Not Be An Amiga Anymore” →

A closeup of a transparent-bodied example of the new Steam Frame VR headset

The Engineering Behind Valve’s New VR Headset

November 15, 2025 by Tyler August 16 Comments

Valve’s new Steam Frame is what all the well-connected YouTubers are talking about, but most of them are talking about what it’s like to game on it. That’s great content if you’re into it, but not exactly fodder for Hackaday — with one exception. [Gamers Nexus] gives us a half hour of relatively-unedited footage of them just chatting with the engineers behind the hardware.

It’s great stuff right from the get-go: they start with how thermal management drove the PCB design, and put the SoC on the “back” of the chip, sandwiched betwixt heat pipes. We don’t usually think of taking heat through the PCB when building a board, so it’s a neat detail to learn about before these things get into the hands of the usual suspects who will doubtless give us teardown videos in a few months.

From there wanders to power delivery — getting the voltage regulators packaged properly was a challenge, since impedance requirements meant a very tight layout. Anyone who has worked on this kind of SBC might be familiar with that issue, but for those looking in from the outside, it’s a fascinating glimpse at electrical sausage being made. That’s just the first half.

The heat-regulation conversation is partially repeated the next conversation (which seems to have happened first) where they get into the cooling requirements of the LCD screens. This requires less than you might think, as they like to run warm for fast refresh. It’s really more about keeping your face cool. They also they discuss acoustic vibration — you don’t want your integrated audio shaking your IMUs apart — and why the prototype was being blasted with freakin’ laser beams to monitor it.

If you haven’t seen or read any other coverage on the Steam Frame, you’re going to miss some context here, but if you’ve not hid under a rock for that announcement, this is amazing detail to have. We’re hugely impressed that Valve let their engineers out of their cubicle-cave to talk to media.

Sure, it’s not an open-source VR headset, but compared to the deafening silence coming from the likes of Meta, this level of information is still awesome to have.

Continue reading “The Engineering Behind Valve’s New VR Headset” →