Building The Simplest Atomic Force Microscope

March 23, 2025 by 22 Comments

Doing it yourself may not get you the most precise lab equipment in the world, but it gets you a hands-on appreciation of the techniques that just can’t be beat. Today’s example of this adage: [Stoppi] built an atomic force microscope out of mostly junk parts and got pretty good results, considering. (Original is in German; read it translated here.)

The traditional AFM setup uses a piezo micromotor to raise and lower the sample into a very, very fine point. When this point deflects, it reads the height from the piezo setup and a motor stage moves on to the next point. Resolution is essentially limited by how fine a point you can make and how precisely you can read from the motion stages. Here, [stoppi]’s motion stage follows the traditional hacker avenue of twin DVD sleds, but instead of a piezo motor, he bounces a laser off of a mirror on top of the point and reads the deflection with a line sensor. It’s a clever and much simpler solution.

A lot of the learnings here are in the machine build. Custom nichrome and tungsten tips are abandoned in favor of a presumably steel compass tip. The first-draft spring ended up wobbling in the X and Y directions, rather than just moving in the desired Z, so that mechanism got reinforced with aluminum blocks. And finally, the line sensors were easily swamped by the laser’s brightness, so neutral density filters were added to the project.

The result? A nice side effect of the laser-bouncing-off-of-mirror setup is that the minimum resolvable height can be increased simply by moving the line sensors further and further away from the sample, multiplying the deflection by the baseline. Across his kitchen, [stoppi] is easily able to resolve the 35-um height of a PCB’s copper pour. Not bad for junk bin parts, a point from a crafts store, and a line sensor.

If you want to know how far you can push a home AFM microscope project, check out [Dan Berard]’s absolutely classic hack. And once you have microscope images of every individual atom in the house, you’ll, of course, want to print them out.

The Mysterious Mindscape Music Board

March 23, 2025 by 13 Comments

Sound cards on PC-compatible computer systems have a rather involved and convoluted history, with not only a wide diversity of proprietary standards, but also a collection of sound cards that were never advertised as such. Case in point the 1985 Mindscape Music Board, which was an add-on ISA card that came bundled with [Glen Clancy]’s Bank Street Music Writer software for IBM PC. This contrasted with the Commodore 64 version which used the Commodore SID sound chip. Recently both [Tales of Weird Stuff] and [The Oldskool PC] on YouTube both decided to cover this very rare soundcard.

Based around two General Instruments AY-3-8913 programmable sound generators, it enabled the output of six voices, mapped to six instruments in the Bank Street Music Writer software. Outside of this use this card saw no use, however, and it would fade into obscurity along with the software that it was originally bundled with. Only four cards are said to still exist, with [Tales of Weird Stuff] getting their grubby mitts on one.

As a rare slice of history, it is good to see this particular card getting some more love and attention, as it was, and still is, quite capable. [The Oldskool PC] notes that because the GI chip used is well-known and used everywhere, adding support for it in software and emulators is trivial, and efforts to reproduce the board are already underway.

Top image: Mindscape Music Board (Credit: Ian Romanick)

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Booting A Desktop PDP-11

March 23, 2025 by 22 Comments

Ever heard of VENIX? There were lots of variants of Unix back in the day, and VENIX was one for the DEC Professional 380, which was — sort of — a PDP 11. The 1982 machine normally ran the unfortunately (but perhaps aptly) named P/OS, but you could get VENIX, too. [OldVCR] wanted to put one of these back online and decided the ST-506 hard drive was too risky. A solid-state drive upgrade and doubling the RAM to a whole megabyte was the plan.

It might seem funny to think of a desktop workstation that was essentially a PDP-11 minicomputer, but in the rush to corner the personal computer market, many vendors did the same thing: shrinking their legacy CPUs. DEC had a spotty history with small computers. [Ken Olsen] didn’t think anyone would ever want a personal computer, and the salespeople feared that cheap computers would eat into traditional sales. The Professional 350 was born out of DEC’s efforts to catch up, as [OldVCR] explains. He grabbed this one from a storage unit about to be emptied for scrap.

The post is very long, but you get a lot of history and a great look inside this vintage machine. Of course, the PDP-11 couldn’t actually handle more than 64K without tricks and you’ll learn more about that towards the end of the post, too.

Just as a preview, the story has a happy ending, including a surprising expression of gratitude from the aging computer. DEC didn’t enjoy much success in the small computer arena, eventually being bought by Compaq, which, in turn, was bought by Dell HP. During their heyday, this would have been unthinkable.

The PDP/11 did have some success because it was put on a chip that ended up in several lower-end machines, like the Heathkit H11. Ever wonder how people programmed the PDP computers with switches and lights?

Musings On A Good Parallel Computer

March 23, 2025 by 28 Comments

Until the late 1990s, the concept of a 3D accelerator card was something generally associated with high-end workstations. Video games and kin would run happily on the CPU in one’s desktop system, with later extensions like MMX, 3DNow!, and SSE providing a significant performance boost for games that supported them. As 3D accelerator cards (colloquially called graphics processing units, or GPUs) became prevalent, they took over almost all SIMD vector tasks, but one thing that they’re not good at is being a general-purpose parallel computer. This really ticked [Raph Levien] off and it inspired him to cover his grievances.

Although the interaction between CPUs and GPUs has become tighter over the decades, with PCIe in particular being a big improvement over AGP and PCI, GPUs are still terrible at running arbitrary computing tasks, and even PCIe links are still glacial compared to communication within the GPU and CPU dies. With the introduction of asynchronous graphic APIs this divide became even more intense. [Raph]’s proposal is to invert this relationship.

There’s precedent for this already, with Intel’s Larrabee and IBM’s Cell processor merging CPU and GPU characteristics on a single die, though both struggled with developing for such a new kind of architecture. Sony’s PlayStation 3 was forced to add a GPU due to these issues. There is also the DirectStorage API in DirectX, which bypasses the CPU when loading assets from storage, effectively adding CPU features to GPUs.

As [Raph] notes, so-called AI accelerators also have these characteristics, with often multiple SIMD-capable, CPU-like cores. Maybe the future is Cell after all.

Piezo Sensor Reviewed

March 22, 2025 by 16 Comments

If you do FDM 3D printing, you know one of the biggest problems is sensing the bed. Nearly all printers have some kind of bed probing now, and it makes printing much easier, but there are many different schemes for figuring out where the bed is relative to the head. [ModBot] had a Voron with a clicky probe but wanted to reclaim the space it used for other purposes. In the video, also linked below, he reviews the E3D PZ probe which is a piezoelectric washer, and the associated electronics to sense your nozzle crashing into your print bed.

There are many options, and it seems like each has its pros and cons. We do like solutions that actually figure out where the tip is so you don’t have to mess with offsets as you do with probes that measure from a probe tip instead of the print head.

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Microscopic view of chiral magnetic material

Twisting Magnetism To Control Electron Flow

March 22, 2025 by 11 Comments

If you ever wished electrons would just behave, this one’s for you. A team from Tohoku, Osaka, and Manchester Universities has cracked open an interesting phenomenon in the chiral helimagnet α-EuP3: they’ve induced one-way electron flow without bringing diodes into play. Their findings are published in the Proceedings of the National Academy of Sciences.

The twist in this is quite literal. By coaxing europium atoms into a chiral magnetic spiral, the researchers found they could generate rectification: current that prefers one direction over another. Think of it as adding a one-way street in your circuit, but based on magnetic chirality rather than semiconductors. When the material flips to an achiral (ferromagnetic) state, the one-way effect vanishes. No asymmetry, no preferential flow. They’ve essentially toggled the electron highway signs with an external magnetic field. This elegant control over band asymmetry might lead to low-power, high-speed data storage based on magnetic chirality.

If you are curious how all this ties back to quantum theory, you can trace the roots of chiral electron flow back to the early days of quantum electrodynamics – when physicists first started untangling how particles and fields really interact.

There’s a whole world of weird physics waiting for us. In the field of chemistry, chirality has been covered by Hackaday, foreshadowing the lesser favorable ways of use. Read up on the article and share with us what you think.

Generative Art Machine Does It One Euro At A Time

March 22, 2025 by 14 Comments

[Niklas Roy] obviously had a great time building this generative art cabinet that puts you in the role of the curator – ever-changing images show on the screen, but it’s only when you put your money in that it prints yours out, stamps it for authenticity, and cuts it off the paper roll with a mechanical box cutter.

If you like fun machines, you should absolutely go check out the video, embedded below. The LCD screen has been stripped of its backlight, allowing you to verify that the plot exactly matches the screen by staring through it. The screen flashes red for a sec, and your art is then dispensed. It’s lovely mechatronic theater. We also dig the “progress bar” that is represented by how much of your one Euro’s worth of art it has plotted so far. And it seems to track perfectly; Bill Gates could learn something from watching this. Be sure to check out the build log to see how it all came together.

You’d be forgiven if you expected some AI to be behind the scenes these days, but the algorithm is custom designed by [Niklas] himself, ironically adding to the sense of humanity behind it all. It takes the Unix epoch timestamp as the seed to generate a whole bunch of points, then it connects them together. Each piece is unique, but of course it’s also reproducible, given the timestamp. We’re not sure where this all lies in the current debates about authenticity and ownership of art, but that’s for the comment section.

If you want to see more of [Niklas]’s work, well this isn’t the first time his contraptions have graced our pages. But just last weekend at Hackaday Europe was the first time that he’s ever given us a talk, and it’s entertaining and beautiful. Go check that out next. Continue reading “Generative Art Machine Does It One Euro At A Time” →