Running A PC Off AA Cells With Buck Converters Really Boosts Performance

March 13, 2026 by Maya Posch 17 Comments

After the previous attempt of running a PC off AA cells got a lot of comments, [ScuffedBits] decided to do the scientifically responsible thing and re-ran the experiment with all the peer-reviewed commentary in mind. Although we noted with the previous experiment that only alkaline cells were used, [ScuffedBits] rectified this by stating that both carbon and alkaline AA cells were used the first time around.

For this second experiment a number of changes were made, though still both carbon and alkaline cells were put into the mix. To these a third string was added, consisting of NiMH cells, for a total of 64 cells with each of the three strings outputting around 25 VDC when fully charged. These fed a cheap buck regulator module to generate the 12 VDC for the DC-DC converter on the mainboard’s ATX connector.

Although it appears that the same thin Cat-5e-sourced wiring was used, with the higher voltage this meant a lower current, making it significantly less sketchy. Unlike with the first experiment, this time around the Core i3 530 based PC could run much longer and even boot off the DIY battery pack. After a quick game and pushing through a Cinebench run for 64 Watts maximum power usage, it turned out that there was still plenty of time for more fun activities, such as troubleshooting Minecraft and even playing it.

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How Would A Field Sequential Home Computer Have Worked?

March 12, 2026 by Jenny List 19 Comments

The early history of colour TV had several false starts, of which perhaps one of the most interesting might-have-beens was the CBS field-sequential system. This was a rival to the nascent system which would become NTSC, which instead of encoding red, green, and blue all at once for each pixel, made sequential frames carry them.

The Korean war stopped colour TV development for its duration in the early 1950s, and by the end of hostilities NTSC had matured into what we know today, so field-sequential colour became a historical footnote. But what if it had survived? [Nicole Express] takes into this alternative history, with a look at how a field-sequential 8-bit home computer might have worked.

The CBS system had a much higher line frequency in order to squeeze in those extra frames without lowering the overall frame rate, so given the clock speeds of the 8-bit era it rapidly becomes obvious that a field-sequential computer would be restricted to a lower pixel resolution than its NTSC cousin. The fantasy computer discussed leans heavily on the Apple II, and we explore in depth the clock scheme of that machine.

While it would have been possible with the faster memory chips of the day to achieve a higher resolution, the conclusion is that the processor itself wasn’t up to matching the required speed. So the field-sequential computer would end up with wide pixels. After a look at a Breakout clone and how a field-sequential Atari 2600 might have worked, there’s a conclusion that field-sequential 8-bit machines would not be as practical as their NTSC cousins. From where we’re sitting we’d expect them to have used dedicated field-sequential CRT controller chips to take away some of the heartache, but such fantasy silicon really is pushing the boundaries.

Meanwhile, while field-sequential broadcast TV never made it, we do have field-sequential TV here in 2026, in the form of DLP projectors. We’ve seen their spinning filter disks in a project or two.

1950 CBS color logo: Archive.org, CC0.

A black circuit board with many colored banana connector plugs in placed on a table. Behind it, two analogue voltage dials stand on either side of an oscilloscope stand. The oscilloscope is a cheap model, with a small LCD display and an exposed red circuit board.

Building An Analogue Computer To Simulate Neurons

March 8, 2026 by Aaron Beckendorf 2 Comments

The rapidly-improving speed and versatility of digital computers has mostly driven analogue computers out of use in modern systems, as has the relative difficulty of programming an analogue computer. There is a kind of art, though, in weaving together a series of op-amps to perform mathematical calculations; between this, a historical interest in the machines, and their rarity value, it’s no wonder that new analogue computers are being designed even now, such as [Markus Bindhammer]’s system.

The computer is built around a combined circuit board and patch panel, based on the designs included in three papers in a online library of analogue computer references. The housing around the patch panel took design cues from the Polish AKAT-1 analogue computer, including the two dial voltage indicators and an oscilloscope display, in this case an inexpensive DSO-138. The patch panel uses banana connectors and the jumper wires use stackable connectors, so several wires can be connected to the same socket.

The computer itself has a summing amplifier circuit, a multiplier circuit, an integrator, and square, triangle, and sine wave generators. This simple set of tools is enough to simulate both simple and complex math; for example, [Markus] squared five volts with the multiplier, resulting in 2.5 volts (the multiplier divides the result by ten). A more advanced example is a leaky-integrator model of a neuron, which simulates a differential equation.

We’ve covered a few analogue computers before, as well as a neuron-simulating circuit similar to [Markus]’s demonstration.

The LEGO-lookalike displaying [Paul]'s dashboard

LEGO Space Computer Made Full Size, 47 Years On

March 5, 2026 by Tyler August 10 Comments

There’s just something delightful about scaled items. Big things shrunk down, like LEGO’s teeny tiny terminal brick? Delightful. Taking that terminal brick and scaling it back to a full-sized computer? Even better. That’s what designer [Paul Staal] has done with his M2x2 project.

In spite of the name, it actually has a Mac Mini M4 as its powerful beating heart. An M2 might have been more on-brand, but it’s probably a case of wanting the most horsepower possible in what [Paul] apparently uses as his main workstation these days. The build itself is simple, but has some great design details. As you probably expected, the case is 3D printed. You may not have expected that he can use the left stud as a volume control, thanks to an IKEA Symfonisk remote hidden beneath. The right stud comes off to allow access to a wireless charger.

The minifigs aren’t required to charge those airpods, but they’re never out of place.

The 7″ screen can display anything, but [Paul] mostly uses it either for a custom home assistant dashboard, or to display an equalizer, both loosely styled after ‘screen’ on the original brick. We have to admit, as cool as it looked with the minifigs back in the day, that sharp angle to the screen isn’t exactly ergonomic for humans.

Perhaps the best detail was putting LEGO-compatible studs on top of the 10:1 scaled up studs, so the brick that inspired the project can sit securely atop its scion. [Paul] has provided a detailed build guide and the STLs necessary to print off a brick, should anyone want to put one of these nostalgic machines on their own desk.

We’ve covered the LEGO computer brick before, but going the other way–putting a microcontroller and display in the brick it to run DOOM. We’ve also seen it scaled up before, but that project was a bit more modest in size and computing power.

Turning A Cast-Iron Radiator Into A Water-Cooled PC

March 1, 2026 by Maya Posch 19 Comments

Bottom of the cast-iron radiator gaming PC during plumbing. (Credit: Billet Labs, YouTube)

Water-cooled PCs generally have in common that there’s a radiator somewhere in the loop, yet nobody said that you can’t build the PCB into the radiator. Something like a genuine Victorian-era cast-iron radiator, for example. For the folk over at [Billet Labs], this is just your typical project, of course, even if it took a solid three months to make it all work.

Their previous project was also a water-cooled PC, but in the form of a steampunk-esque wall-mounted installation. What differentiates this new build is that it’s trying to be more of a sleeper PC, as long as you ignore some copper tubing and the like running around the outside of this vintage radiator.

Of course, by using a vintage cast-iron radiator like this, you’re also dealing with all the disadvantages of cast-iron, such as the countless impurities in the metal and the immense weight. With water in the loop, the entire build comes in at about 99 kilograms, and cleaning the radiator of particulates released inside it — including rust — was a challenge.

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Running A Desktop PC Off AA Alkaline Cells

February 28, 2026 by Maya Posch 17 Comments

Everyone is probably familiar with the concept of battery-powered devices, but generally, this involves a laptop with a beefy battery pack and hardware optimized for low power draw. You could also do the complete opposite and try to run a desktop PC off alkaline AA cells, as [ScuffedBits] recently did out of morbid curiosity. Exactly how many alkaline cells does it take to run a desktop PC for any reasonable amount of time?

One nice thing about using batteries with a desktop PC is that you can ditch the entire AC-DC power conversion step and instead use a DC-DC adapter like the well-known PicoATX and its many clones. These just take in 12 VDC and tend to have a fairly wide input voltage range, which is useful when your batteries begin to run out of juice. In this case, just above 10 VDC seemed to be the cut-off point for the used DC-DC adapter.

In the end, [ScuffedBits] used what looks like 56 alkaline AA cells connected in both parallel and series, along with two series-connected 6,800 µF, 40V electrolytic capacitors to buffer the spikes in power demand, after early experiments showed that the cells just cannot provide power that quickly. Although admittedly, the initial thin wiring didn’t help either. With alkaline rather than carbon AA cells, improved wiring, and some buffer capacitors, it turns out that you can indeed run a desktop PC off AA cells, if only just about long enough for a small game of Minesweeper.

Amusingly, the small LCD monitor used in the experiment drew so little power that it happily ran on eight NiMH cells for much longer, highlighting just how important power conservation is for battery-powered devices. We wonder if you could marry this project to a battery project we saw and end up with something practically portable?

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Bionode Is Hand Truck Transformed Into Mobile Computing Lab

February 26, 2026 by Donald Papp 13 Comments

[Steven K. Roberts] is the original digital nomad, having designed and built mobile computing for his own use since the 80s. His latest project is Bionode, a portable computing lab built into a hand truck that can accommodate a wide spectrum of needs for a person on the go.

Far more than just a portable computer with wheels and a handle, Bionode is an integrated collection of systems with power management, a sensor suite, multiple computers, NAS for storage, networking, video production tools, and even the ability to be solar charged. [Steven] also uses a laptop, and Bionode complements it by being everything else.

If one truly wishes to be mobile and modular as well as effective, then size and weight begins to be just as important as usability. Everything in Bionode has a purpose, and it currently contains a PC with GPU for local AI and machine learning work, a NAS with 14 TB of storage, an Ubuntu machine, a Raspberry Pi 5 running Home Assistant, another Raspberry Pi 5 for development work, a Raspberry Pi 3 for running his 3D printer, and a Raspberry Pi 4 for SDR (software-defined radio) work. A smart KVM means a single keyboard, mouse, and display can be shared among machines as needed and additional hardware in a thoughtful layout makes audio and video projects workable. Everything is integrated with sensors and Home Assistant with local AI monitoring, which [Steven] likes to think of as the unit’s nervous system.

Bionode is therefore more than just a collection of computers crammed into a hand truck; it’s a carefully-selected array of hardware that provides whatever [Steven] needs.

Give it a look if you want to see what such a system looks like when it’s been designed and assembled by someone who’s “been there, done that” when it comes to mobile computing. Bionode would complement something like a mobile workshop quite nicely; something [Steven] has also done before.

Thanks [Paul] for the tip!