Behind The Lens: Tearing Down A Rare Soviet Zenit 19

February 23, 2025 by Heidi Ulrich 3 Comments

If you’re into Soviet-era gear with a techy twist, you’ll love this teardown of a rare Zenit 19 camera courtesy of [msylvain59]. Found broken on eBay (for a steal!), this 1982 made-in-USSR single-lens reflex camera isn’t the average Zenit. It features, for example, electronically controlled shutter timing – quite the upgrade from its manual siblings.

The not-so-minor issue that made this Zenit 19 come for cheap was a missing shutter blade. You’d say – one blade gone rogue! Is it lost in the camera’s guts, or snapped clean off? Add to that some oxidized battery contacts and a cracked viewfinder, and you’ve got proper fixer-upper material. But that’s where it gets intriguing: the camera houses a rare hybrid electronic module (PAPO 074), complete with epoxy-covered resistors. The shutter speed dial directly adjusts a set of resistors, sending precise signals to the shutter assembly: a neat blend of old-school mechanics and early electronics.

Now will it shutter, or stutter? With its vertical metal shutter – uncommon in Zenits – and separate light metering circuitry, this teardown offers a rare glimpse into Soviet engineering flair. Hungry for more? We’ve covered a Soviet-era computer and a radio in the past. If you’re more into analog camera teardowns, you might like this analog Pi upgrade attempt, or this bare minimum analog camera project.

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How Rutherford Proved That Atoms Are Mostly Empty Space

February 23, 2025 by Maya Posch 26 Comments

By the beginning of the 20th century scientists were only just beginning to probe the mysteries of the atomic world, with the exact nature of these atoms subject to a lot of speculation and theory. Recently [The Action Lab] on YouTube replicated one of the most famous experiments performed at the time, commonly known as Rutherford’s gold-foil experiment.

A part of Rutherford’s scattering experiments, this particular experiment involved shooting alpha particles at a piece of gold foil with the source, foil, and detector placed in a vacuum vessel. Rutherford’s theoretical model of the atom that he developed over the course of these experiments differed from the contemporary Thomson model in that Rutherford’s model postulated that atoms consisted of a single large charged nucleus at the core of the atom, with the electrons spread around it.

As can be seen in the video, the relatively large alpha particles from the Americium-241 source, available from many smoke detectors, will most of the time zip right through the foil, while suffering a pretty major deflection in other times when a nucleus is hit. This is consistent with Rutherford’s model of a small nucleus surrounded by what is effectively mostly just empty space.

While Rutherford used a screen that would light up when hit with alpha particles, this experiment with a Geiger counter is an easy way to replicate the experiment, assuming that you have access to a large enough vacuum chamber.

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LCD Stackup Repair: Not For The Faint Of Heart

February 23, 2025 by Elliot Williams 11 Comments

Coming straight to the point: [Ron Hinton] is significantly braver than we are. Or maybe he was just in a worse situation. His historic Acer K385s laptop suffered what we learned is called vinegar syndrome, which is a breakdown in the polarizers that make the LCD work. So he bit the bullet and decided to open up the LCD stack and replace what he could.

Nothing says “no user serviceable parts inside” quite like those foil-and-glue sealed packages, but that didn’t stop [Ron]. Razor blades, patience, and an eye ever watchful for the connectors that are seemingly everywhere, and absolutely critical, got the screen disassembled. Installation of the new polarizers was similarly fiddly.

In the end, it looks like the showstopper to getting a perfect result is that technology has moved on, and these older screens apparently used a phase correction layer between the polarizers, which might be difficult to source these days. (Anyone have more detail on that? We looked around and came up empty.)

This laptop may not be in the pantheon of holy-grail retrocomputers, but that’s exactly what makes it a good candidate for practicing such tricky repair work, and the result is a readable LCD screen on an otherwise broken old laptop, so that counts as a win in our book.

If you want to see an even more adventurous repair effort that ended in glorious failure, check out [Jan Mrázek]’s hack where he tries to convert a color LCD screen to monochrome, inclusive of scraping off the liquid crystals! You learn a lot by taking things apart, of course, but you learn even more by building it up from first principles. If you haven’t seen [Ben Krasnow]’s series on a completely DIY LCD screen, ITO-sputtering and all, then you’ve got some quality video time ahead of you.

Handheld Compass CNC Lets Teensy Do The Driving

February 23, 2025 by Tom Nardi 20 Comments

If somebody asked you to visualize a CNC router, you’d probably think of some type of overhead gantry that moves a cutting tool over a stationary workpiece. It’s a straightforward enough design, but it’s not without some shortcomings. For one thing, the scale of such a machine can quickly become an issue if you want to work on large pieces.

But what if you deleted the traditional motion system, and instead let the cutting tool roam freely? That’s the idea behind the open source Compass Handheld CNC. Looking a bit more like a combat robot than a traditional woodworking tool, the Compass tracks its movement over the workpiece using a Teensy 4.1 microcontroller and four PMW3360 optical flow sensors. With a pair of handles that look like a flight yoke and a display that shows the router’s current position versus where it should be, the user can “drive” the tool to cut or carve the desired design.

Admittedly, the Compass doesn’t pack quite the same punch as a more traditional setup. Rather than a beefy spindle motor or a full-sized consumer router clamped up in the gantry, the Compass uses a Dremel 3000. It’s fine for routing out an engraving and other fine work, but you wouldn’t want to use it for cutting thick stock. To help keep the work area clear and prevent dust and chips from jamming up the works, the 3D printed body for the tool includes a connection for a dust collection system.

If this all seems familiar, you may be remembering a tool we first covered nearly a decade ago — the Shaper Origin. That router, which is still on the market incidentally, utilizes optical tracking and fiducial markers to keep track of its position. We’d be interested in seeing how well the Compass compares over large distances without similar reference points.

NEMA Releases Standard For Vehicle-to-Grid Applications

February 22, 2025 by Navarre Bartz 70 Comments

Vehicle-to-grid (V2G) has been hailed as one of the greatest advantages of electrifying transportation, but has so far remained mostly in the lab. Hoping to move things forward, the National Electrical Manufacturers Association (NEMA) has released the Electric Vehicle Supply Equipment (EVSE) Power Export Permitting Standard.

The new standards will allow vehicle manufacturers and charger (EVSE) suppliers to have a unified blueprint for sending power back and forth to the grid or the home, which has been a bit of a stumbling block so far toward adoption of a seemingly simple, but not easy, technology. As renewables make up a larger percentage of the grid, using the increasing number of EVs on the road as battery backup is a convenient solution.

While the standard will simplify the technology side of bidirectional charging, getting vehicle owners to opt into backing up the grid will depend on utilities and regulators developing attractive remuneration plans. Unfortunately, the standard itself is paywalled, but NEMA says the standard “could put money back in electric vehicle owners’ pockets by making it easier for cars to store energy at night or when turned off and then sell power back to grids at a profit during peak hours.”

We’ve covered some of the challenges and opportunities of V2G systems in the past and if you want something a little smaller scale, how about using a battery that was once in a vehicle to backup your own home?

Cyanotype Prints On A Resin 3D Printer

February 22, 2025 by Tom Nardi 18 Comments

Not that it’s the kind of thing that pops into your head often, but if you ever do think of a cyanotype print, it probably doesn’t conjure up thoughts of modern technology. For good reason — the monochromatic technique was introduced in the 1840s, and was always something of a niche technology compared to more traditional photographic methods.

The original method is simple enough: put an object or negative between the sun and a UV-sensitive medium, and the exposed areas will turn blue and produce a print. This modernized concept created by [Gabe] works the same way, except both the sun and the negative have been replaced by a lightly modified resin 3D printer.

A good chunk of the effort here is in the software, as [Gabe] had to write some code that would take an image and turn it into something the printer would understand. His proof of concept was a clever bit of Python code that produced an OpenSCAD script, which ultimately converted each grayscale picture to a rectangular “pixel” of variable height. The resulting STL files could be run through the slicer to produce the necessary files to load into the printer. This was eventually replaced with a new Python script capable of converting images to native printer files through UVtools.

On the hardware side, all [Gabe] had to do was remove the vat that would usually hold the resin, and replace that with a wooden lid to both hold the UV-sensitized paper in place and protect the user’s eyes. [Gabe] says there’s still some room for improvement, but you wouldn’t know it by looking at some of the gorgeous prints he’s produced already.

No word yet on whether or not future versions of the project will support direct-to-potato imaging.

DataSaab: Sweden’s Lesser-Known History In Computing

February 22, 2025 by Heidi Ulrich 6 Comments

Did you know that the land of flat-pack furniture and Saab automobiles played a serious role in the development of minicomputers, the forerunners of our home computers? If not, read on for a bit of history. You can also go ahead and watch the video below, which tells it all with a ton of dug up visuals.

Sweden’s early computer development was marked by significant milestones, beginning with the relay-based Binär Aritmetisk Relä-Kalkylator (BARK) in 1950, followed by the vacuum tube-based Binär Elektronisk SekvensKalkylator (BESK) in 1953. These projects were spearheaded by the Swedish Board for Computing Machinery (Matematikmaskinnämnden), established in 1948 to advance the nation’s computing capabilities.

In 1954, Saab ventured into computing by obtaining a license to replicate BESK, resulting in the creation of Saab’s räkneautomat (SARA). This initiative aimed to support complex calculations for the Saab 37 Viggen jet fighter. Building on this foundation, Saab’s computer division, later known as Datasaab, developed the D2 in 1960 – a transistorized prototype intended for aircraft navigation. The D2’s success led to the CK37 navigational computer, which was integrated into the Viggen aircraft in 1971.

Datasaab also expanded into the commercial sector with the D21 in 1962, producing approximately 30 units for various international clients. Subsequent models, including the D22, D220, D23, D5, D15, and D16, were developed to meet diverse computing needs. In 1971, Datasaab’s technologies merged with Standard Radio & Telefon AB (SRT) to form Stansaab AS, focusing on real-time data systems for commercial and aviation applications. This entity eventually evolved into Datasaab AB in 1978, which was later acquired by Ericsson in 1981, becoming part of Ericsson Information Systems.

Parallel to these developments, Åtvidabergs Industrier AB (later Facit) produced the FACIT EDB in 1957, based on BESK’s design. This marked Sweden’s first fully domestically produced computer, with improvements such as expanded magnetic-core memory and advanced magnetic tape storage. The FACIT EDB was utilized for various applications, including meteorological calculations and other scientific computations. For a short time, Saab even partnered with the American Unisys called Saab-Univac – a well-known name in computer history.

These pioneering efforts by Swedish organizations laid the groundwork for the country’s advancements in computing technology, influencing both military and commercial sectors. The video below has lots and lots more to unpack and goes into greater detail on collaborations and (missed) deals with great names in history.

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