You probably do not need us to tell you that Arsenic is not healthy stuff. This wasn’t always such common knowledge, as for a time in the 19th century a chemical variously known as Paris or Emerald Green, but known to chemists as copper(II) acetoarsenite was a very popular green pigment. While this pigment is obviously not deadly on-contact, given that it’s taken 200 years to raise the alarm about these books (and it used to be used in candy (!)), arsenic is really not something you want in your system. Libraries around the world have been quarantining vintage green books ̶f̶o̶r̶ ̶f̶e̶a̶r̶ ̶b̶i̶b̶l̶i̶o̶p̶h̶i̶l̶i̶es ̶m̶i̶g̶h̶t̶ ̶b̶e̶ ̶t̶e̶m̶p̶t̶e̶d̶ ̶t̶o̶ ̶l̶i̶c̶k̶ ̶t̶h̶e̶m̶ out of an abundance of caution, but researchers at The University of St. Andrews have found a cheaper method to detect the poison pigment than XRF or Raman Spectroscopy previously employed.

The hack is simple, and in retrospect, rather obvious: using a a hand-held vis-IR spectrometer normally used by geologists for mineral ID, they analyzed the spectrum of the compound on book covers. (As an aside, Emerald Green is similar in both arsenic content and color to the mineral conichalcite, which you also should not lick.) The striking green colour obviously has a strong response in the green range of the spectrum, but other green pigments can as well. A second band in the near-infrared clinches the identification.

A custom solution was then developed, which sadly does not seem to have been documented as of yet. From the press release it sounds like they are using LEDs and photodetectors for color detection in the green and IR at least, but there might be more to it, like a hacked version of common colour sensors that put filters on the photodetectors.

While toxic books will still remain under lock and key, the hope is that with quick and easy identification tens of thousands of currently-quarantined texts that use safer green pigments can be returned to circulation.

Tip of the hat to [Jamie] for the tip off, via the BBC.

hackaday.com/2025/06/09/saving…

The Functionalist design philosophy that Dieter Rams brought to Braun from the 50s to the 90s still inspires the look of a few devices, including Apple’s iPod, Teenage Engineer’s synthesizers and recorders – and [2dom]’s IR7 streaming radio.

The streaming radio was inspired by Braun’s portable radios, particularly the SK2, TP1, and the T3 pocket radio. [2dom] started with the T3’s circular pattern of holes and experimented with several variations, finally settling on a cylindrical shape with a central display; a prototype with a low-power monochrome rectangular display was eventually rejected in favor of a circular LCD. The housing consists of four 3D-printed components: an upper and lower shell, a resonator for the speaker, and a knob for a rotary encoder.

Electronics-wise, an ESP32 handles the computing requirements, while the LCD and rotary encoder provide a user interface. For audio, it uses a VS1053 MP3 decoder, PAM8403 amplifier, and a wideband speaker, with an audio isolation transformer to clean up the audio. To reduce power consumption, a MOSFET cuts power to the peripheral components whenever the device is in sleep mode. The full design is available on GitHub.

The end result of this effort is a quite authentic-looking 21st-century adaptation of Rams’s original designs. If you’re interested in more Braun designs, check out this replica of one of their desk fans. We’ve also seen a restoration of one of Braun’s larger radios, the TS2.

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hackaday.com/2025/06/09/a-mode…

If you’re into automotive hacks and don’t watch [Robot Cantina], you are missing out. This hack has [Jimbo] taking a break from automotive hacking to butcher a poor, innocent Tecumseh lawnmower to run diesel fuel (or anything else) by converting the motor into a hot bulb engine. (Video embedded below.)

The secret is a long stack of anti-fouling adapters, which are essentially extension tubes that move the spark plug out of the combustion chamber to keep it from getting crudded up in an engine that’s burning too much oil. In this case, burning is what’s happening inside the anti-fouling adapters: by stacking seven of them, [Robot Cantina] is able to create a hot-bulb– volume that stays hot enough between strokes to induce spontaneous combustion of the fuel-air mix.

Hot-bulb engines were popular for certain tractors (the Lanz Bulldog being the most famous) and stationary engines from the late 19th century until Rudolf Diesel’s eponymous invention drove them out of their niche completely sometime after WWII.

Traditionally, a torch would have been used to heat the hot bulb, but here [Jimbo] starts the engine on gasoline with a spark plug at the end of the stack, and disconnect the spark once the hot bulb has warmed sufficiently. Given how rough the engine runs before the ersatz hot bulb heats up enough for spontaneous combustion, tradition seems like the way to go. Even once heated up, the “chaos in the combustion chamber” (probably knocking) is enough to pop the (now disconnected) spark plug from the end of the stack of adapters at one point.

While shockingly an inspection revealed no obvious damage to the engine after the first day’s experiments, this is probably not a hack you would want to use on a motor you intended to keep — or run for very long, for that matter. Practical or not, it is fascinating to know you can go back in time to the hot-bulb era with such a simple modification. Watching this motor pop and snarl while drinking down diesel fuel, acetone, or 190 proof alcohol is a bit like watching the proverbial dancing bear: the point is not how well it dances, but that it can dance at all. If you can’t get enough of it, they made a second video that features further fuel-testing fun, and even a mowing montage.

We’ve featured other [Robot Cantina] hacks that were arguably more practical, like hacking an old Saturn’s ECU to allow for Honda Insight-style lean burning or this DIY dynomometer for similarly small engines.

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hackaday.com/2025/06/09/run-a-…

One of the difficult things about raising chickens is that you aren’t the only thing that finds them tasty. Foxes, raccoons, hawks — if it can eat meat, it probably wants a bite of your flock. [donutsorelse] wanted to protect his flock and to be able to know when predators were about without staying up all night next to the hen-house. What to do but outsource the role of Chicken Guardian to a Raspberry pi?

Object detection is done using a YOLOv8 model trained on images of the various predators local to [donutorelse]. The model is running on a Raspberry Pi and getting images from a standard webcam. Since the webcam has no low-light capability, the system also has a motion-activated light that’s arguably goes a long way towards spooking predators away itself. To help with the spooking, a speaker module plays specific sound files for each detected predator — presumably different sounds might work better at scaring off different predators.

If that doesn’t work, the system phones home to activate a siren inside [donutorelse]’s house, using a Blues Wireless Notecarrier F as a cellular USB modem. The siren is just a dumb unit; activation is handled via a TP-Link smart plug that’s hooked into [donutorelse]’s custom smart home setup. Presumably the siren cues [donutorelse] to take action against the predator assault on the chickens.

Weirdly enough, this isn’t the first time we’ve seen an AI-enabled chicken coop, but it is the first one to make into our ongoing challenge, which incidentally wraps up today.

hackaday.com/2025/06/09/2025-p…

Today, we think nothing of sticking thousands of pages of documents on a tiny SD card, or just pushing it out to some cloud service. But for decades, this wasn’t possible. Yet companies still generated huge piles of paper. What could be done? The short answer is: microfilm.

However, the long answer is quite a bit more complicated. Microfilm is, technically, a common case of the more generic microform. A microform is a photographically reduced document on film. A bunch of pages on a reel of film is microfilm. If it is on a flat card — usually the size of an index card — that’s microfiche. On top of that, there were a few other incidental formats. Aperture cards were computer punch cards with a bit of microfilm included. Microcards were like microfiche, but printed on cardboard instead of film.

In its heyday, people used specialized cameras, some made to read fanfold computer printer paper, to create microfilm. There were also computer output devices that could create microfilm directly.

How Did That Happen?

Although microfilm really caught on in the mid-20th century, it is much older than that. John Benjamin Dancer appears to have been the first to reduce documents by about 160:1 using daguerreotypes in 1839. He also used wet collodion plates later, but didn’t see any real point to the work.

However, two astronomers, James Glaisher and John Herschel, did see the value of the technology in the early 1850s. By 1870, carrier pigeons were carrying newspaper pages by microfilm into blockaded Paris during the Franco-Prussian War’s Siege of Paris, thanks to René Dagron. During the relatively short conflict, about 115,000 messages had flown by pigeon.

The technology languished for a while, although Reginald A. Fessenden did suggest in 1896 that engineering documents would be a good thing to microfilm, proposing 150 million words in a square inch of film. In fact, nearly a century later, many electronic vendors made their databooks and application notes available on microfiche.

However, it would be 1920 before we see “modern” microfilm usage. The Checkograph, a device patented in 1925 by George McCarthy (with a US Patent in 1930), let banks store cancelled checks on film. Kodak acquired the device in 1928 and rebranded it Recordak.

As you might expect, big libraries jumped right in. Starting in the late 1920s, libraries including the British Library and the Library of Congress adopted microforms. Kodak started filming The New York Times for distribution, while Harvard University Library started filming foreign newspapers in 1938.

While most uses of microfilm are made to save storage space, it can also help save space for carrying mail, as the military did during World War II.

Alternatives

The Fiske-o-scope. From Scientific American, 1922
There were many less-than-successful attempts to bring microfilm into the hands of readers. Retired Navy Admiral Bradley Allen Fiske created the Fiske-O-Scope. The earliest designs had two eyepieces, but they eventually evolved into a single-eye viewing scope. A roller shifted the eyepiece along the reading material, which, initially, were long sheets of paper. Eventually, the Fiske-O-Scope changed to film.

You can see the Admiral using his device, along with some reading material in the accompanying figure. Although the experience of reading with the Fiske-O-Scope may have left something to be desired, the concept itself was clearly well ahead of its time. Ultimately, it promised to let the user carry their personal library around with them — an idea that arguably wouldn’t truly be realized until the birth of the modern e-reader.

Like many great ideas, there wasn’t a single point where the perfect machine appeared. It was more of a slow ooze. There was clearly a need to compress stored documents. It just needed the right equipment.

Equipment and Film

Early microforms were projected with conventional equipment like a magic lantern or eyeballed with a magnifier. However, modern readers generally project onto the rear of a glass screen. More expensive ones could even print what was on the screen using a photocopier-like mechanism.

The University of Arizona has a video showing how to use a classic reader, which you can watch below. Their fancy reader can handle both microfilm and microfiche.

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The Hoover Institution Library has a moderately recent video about using their super-modern microfilm reader if you would like to have a peek at how to use one. Note this one uses a computer, so the experience isn’t as authentic as using an old 1960s reader.

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Film reels tend to be either 16 mm or 35 mm, and some machines could do either. Typically, 35 mm microfilm was the order of the day for large-format scans. Letter-sized material commonly went on 16 mm film. Sometimes the film was on an open reel. Other times, it would be in a cartridge. There were M-type cartridges and ANSI cartridges (and probably others).

Either way, the film could have a single image per frame (simplex) or two images, such as the front and back of a document, per frame. That’s a duplex microfilm.

Some systems used “blips” at the edge of the film to mark when an image starts so that all the pages don’t have to be the same size. Nice machines could count the blips so if someone told you look on “roll 295, frame 952,” you could load the right roll, set the counter to 952, and let the machine fast forward, counting blips, until the counter went to zero and the machine stopped.

Super fancy machines used a double blip to mark the start of a document. This allows you to refer to “roll 295, document 3, frame 80” or — more commonly — to tell the machine to skip to the next document.

Microfiche cards varied somewhat, but were normally very close to 4×6 inches. Jacket versions held strips of film, but specially-made microfiche cards might be just a single sheet of film.

Computer Output Microfilm

The easiest way to create microforms, though, was to have the computer do it directly. Early models displayed data on a CRT, so a camera could snap a picture. By 1977, though, you could get machines that used a laser to directly write on the output medium. COM — Computer Output Microfilm (or Microform) — was widely used, although some mainframe computers sent tapes to service companies to actually make the microfilm.

Kodak Komstar microfiche “printer” (image CC-BY-4.0 by [CERN PhotoLab]Oddly enough, although most mainframes of the era were IBM, they didn’t produce a COM machine. They did make two attempts. In the late 1950s, they developed a tube-based device based on several specialized CRTs. They didn’t market it, but a single unit made it to the Social Security Administration.

IBM’s second attempt at COM was the IBM 1360, but it ultimately didn’t take off, either. It wasn’t exactly a COM output device but a way to store a whopping 128 GB on photographic film cards. There were only six made.

The biggest producer of COM output devices was probably Stromberg Carlson. Kodak was another big name. The Komstar series was made to connect to IBM computers as if they were actual printers. There was also a model made to connect to a magnetic tape drive. These were made well into the 1990s.

Microfilm Today

Most things today are in digital form and a great deal of old microform records are now in digital form, too. However, there was such a flood of microforms that there are still records that you need to find a reader to see them. The Internet Archive, as you might expect, digitizes a lot of microform documents and, if you are watching at the right time, you can look over their shoulder while they do it.

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Of course, in addition to military mail, extreme microfilm works for spies, too. If you find a cache of microfiche cards, you can always build your own reader.

hackaday.com/2025/06/09/inform…

Amici miei, devo confessarvi che, sebbene io abbia sempre dieci anni, la mia età è fatta non di primavere, ma di sussurri antichi e di sogni mai svaniti.

E fu proprio un sussurro, flebile come un ricordo quasi dimenticato, a chiamarmi in una mattina che sembrava come tante altre.

Avevo il solito vortice di energie e un desiderio d'avventura che mi pulsava nelle vene. Mi trovavo in una regione poco battuta delle Alpi Marittime, non lontano dal mio amato Viù, ma in un bosco così antico che gli alberi sembravano aver visto il tempo nascere e morire mille volte. Era la “Foresta delle Memorie Perdute”, la chiamavano i pochi valligiani che osavano avventurarsi tra i suoi sentieri intricati.

Quel giorno, però, il richiamo non era visibile né tangibile; era un suono che non era un suono, ma una melodia che vibrava nell'aria. Era un invito, una domanda silenziosa che la mia sete di conoscenza non poteva ignorare. Feci quello che faccio sempre: andai avanti. Il bosco, denso e ombroso, sembrava farsi sempre più silenzioso, quasi stesse trattenendo il respiro. Ogni foglia caduta, ogni rametto spezzato sotto i miei stivali, risuonava con una chiarezza innaturale. Mi sentii più… pesante. Era un po' come la nebbia che mi portò al mio primo passaggio tra i mondi.

Dopo ore di cammino, attraverso rovi e tronchi secolari, la fitta vegetazione si diradò improvvisamente, rivelando uno spettacolo che mi lasciò senza fiato. Non c'era un castello maestoso, né un villaggio incantato. C'erano rovine. Non rovine di una fortezza da cui partire, ma di una città antica, completamente inghiottita dal muschio e dal tempo. Era fatta di pietre grigie, scolpite con simboli che non avevo mai visto, ma che parlavano di storie infinite. E il silenzio... era assoluto. Non un canto d'uccello, non il fruscio di un animale. Sembrava che la città avesse dimenticato come fare rumore.

“Dove sono?” pensai. Era un luogo così estraneo, eppure così familiare, come un sogno che non avevo ancora fatto. Mentre esploravo le vie coperte di vegetazione, notai una strana struttura al centro di ciò che doveva essere stata una piazza. Era una sorta di grande arpa, fatta di cristallo opaco e metallo brunito, con corde sottili che sembravano tessute con ragnatele di luna. Non emanava alcun suono.

Mi avvicinai, la mia curiosità più forte di ogni timore. Le mie avventure mi avevano insegnato che anche le leggende hanno un'anima e che la magia può essere palpabile nell'aria. Con la mano, toccai una delle corde. Era fredda. Niente. Provai con un'altra. Ancora niente. Poi, mi venne un'idea. Io non sono fatto di carne e sangue, ma di pensieri e desideri. Forse, per far risuonare questa “Arpa delle Echi”, dovevo credere abbastanza.

Chiusi gli occhi e mi concentrai. Pensai a tutte le storie che avevo ascoltato, a tutte le avventure che avevo vissuto. Pensai al nonno che leggeva alla luce della lucerna, alla nonna che raccontava storie nel buio. Pensai al Golem che custodiva segreti millenari, alle fate che danzavano tra le luci scintillanti. Pensai a quell'uomo che, incontrandomi, aveva creduto in me.

Fu allora che le corde dell'arpa iniziarono a vibrare. Non con un suono udibile, ma con un'onda che sentii nel cuore. E poi, il silenzio della città si ruppe. Non con un rumore forte, ma con un coro di sussurri. Erano voci lontane, risate di bambini, il tintinnio di attrezzi, un lamento di tristezza, il fruscio di abiti, frammenti di canzoni e discorsi. Era la memoria stessa della città, liberata. Era come se le pareti di pietra fossero imbevute di quelle vite passate.

Capii. Questa non era una città abbandonata perché morta. Era silente perché aspettava un ascoltatore. Aspettava qualcuno che credesse abbastanza da liberare i suoi ricordi. Ogni sussurro era una storia, un pezzo di vita che la città aveva custodito per secoli. Sentii il peso di quella storia. La città era fatta di storie, proprio come me.

Mi sedetti, ascoltando. Ascoltai le vite degli abitanti, i loro amori e le loro paure, le loro gioie e i loro dolori. Mi sentii un custode di quei misteri antichi. Quando le prime luci del pomeriggio iniziarono a filtrare attraverso le rovine, i sussurri si affievolirono, l'arpa di cristallo tornò silenziosa. La città era tornata al suo riposo, ma non era più muta per me.

Mi alzai, il cuore colmo di nuove esperienze. La Foresta delle Memorie Perdute non era più solo un bosco. Era la custode di una città che viveva attraverso i suoi echi, e io ero diventato il suo testimone.
Quando tornai sui miei passi, il sentiero mi sembrò diverso, come se la magia lo avesse trasformato. Sapevo che, pur non avendo portato con me oro o gioielli, avevo trovato un tesoro ben più prezioso: le voci di un mondo dimenticato. E ora, quella storia, quei sussurri, erano dentro di me, pronti per essere raccontati e condivisi con chiunque avesse il coraggio di credere.

Tenete gli occhi aperti, amici miei. A volte, le storie più belle sono quelle che non fanno rumore, ma che sussurrano nel cuore di chi sa ascoltare. E quando la nebbia arriva, o un sussurro chiama, Bigoulin potrebbe essere vicino.