We found it nostalgic to watch [ve3iku] fire up an old Loran-A receiver and, as you can see in the video below, he got it working. If you aren’t familiar with LORAN, it was a common radio navigation technique before GPS took over everything.

LORAN — an acronym for Long Range Navigation — was a US byproduct of World War II and was similar in many ways to Britain’s Gee system. However, LORAN operated at lower frequencies to improve its range. It was instrumental in helping convoys cross the Atlantic and also found use in the Pacific theater.

youtube.com/embed/CAYVwltGHSQ?…

How it Worked

The video shows a Loran-A receiver, which, in its day, would have been known as LORAN. The A was added after versions B and C appeared. Back in the 1940s, something like this with a CRT and precision electronics would have been very expensive.

Unlike GPS, keeping a highly synchronized clock over many stations was impractical at the time. So, LORAN stations operated in pairs on different frequencies and with a known distance between the two. The main station sends a blip. When the secondary station hears the blip, it sends its own blip. Sometimes there were multiple secondaries, too.

If you receive both blips, you can measure the time between them and use it to get an idea of where you are. Suppose the stations were 372 miles apart. That means the secondary will hear the blip roughly 2 milliseconds after the primary sends it (the speed of light is about 186 miles per millisecond). You can characterize how much the secondary delays, so let’s just say that’s another millisecond.

Reception

Now both transmitted blips have to make it to your receiver. Let’s take a sill example. Suppose you are on top of station B. You’ll hear station A at the same time station B hears it. Then, when you subtract out the delay for station B, you’ll hear its blip immediately. You could easily guess you were 372 miles from station A.

It is more likely, though, that you will be somewhere else, which complicates things. If you find there is a 372-mile difference in your distance from station A to station B, that could mean you were 186 miles away from each station. Or, you could be 202 miles from station A and 170 miles from station B.

If you plot all the possibilities, you’ll get a hyperbolic curve. You are somewhere on the curve. How do you know where? You take a reading on a different pair of transmitters, and the curves should touch on two points. You are on one of those points.

This is similar to stellar navigation, and you usually have enough of an idea where you are to get rid of one of the points as ridiculous. You do, however, have to take into account the motion of your vehicle between readings. If there are multiple secondary stations, that can help since you can get multiple readings without switching to an entirely new pair. The Coast Guard video below explains it graphically, if that helps.

youtube.com/embed/PDtHulWGMGg?…

Receiver Tech

The receiver was able to inject a rectangular pulse on both channels to use as a reference, which is what the video talks about being the “pedestal” (although the British typically called it a cursor).

LORAN could operate up to 700 nautical miles in the day, but nighttime propagation would allow measurements up to 1,400 nautical miles away. Of course, the further away you are, the less accurate the system is.

During the day, things were simple because you typically just got one pulse from each station. But at night, you could get multiple bounces, and it was much more difficult to interpret.

If you want to dive really deep into how you’d take a practical fix, [The Radar Room] has a very detailed video. It shows multiple pulses and uses a period-appropriate APN-4 receiver.

In Care Of…

The U.S. Army Air Force originated LORAN. The Navy was working on Loran-B, but later gave up on it and took over an Air Force project with similar goals. In 1957, the Coast Guard took over both systems and named them Loran-A and Loran-C and decided they weren’t acronyms anymore. Loran-A started going away in the mid-1970s, although some overseas systems were active well into the 1990s. Loran-C survived even longer than that.

Oddly, the development of LORAN took place in a radiation laboratory. GPS isn’t that different other than having super synchronized clocks, many transmitters, and some very fancy math.

Featured Image: Detail of USAF special Loran chart. (LS-103) from the David Rumsey Map Collection, David Rumsey Map Center, Stanford Libraries.

hackaday.com/2025/01/06/before…

Recensione : No Strange Chiedilo a Te Stesso
No Strange e il loro nuovo album Chiedilo a Te Stesso: un inno alla creatività dell'epoca d'oro del garage e della psychedelia italiana. Scopri la magia! @Musica Agorà

iyezine.com/no-strange-chiedil…

No Strange Chiedilo a Te Stesso

No Strange Chiedilo a Te Stesso - No Strange e il loro nuovo album Chiedilo a Te Stesso: un inno alla creatività dell'epoca d'oro del garage e della psychedelia italiana. Scopri la magia! - No Strange Chiedilo a Te Stesso

^{Il Santo (In Your Eyes ezine)}

Cassette tapes were a major way of listening to (and recording) music througout the 1980s and 1990s and were in every hi-fi stereo, boom box, and passenger vehicle of the era. Their decline was largely as a result of improvements in CD technology and the rise of the MP3 player, and as a result we live in a world largely absent of this once-ubiquitous technology. There are still a few places where these devices crop up, and thanks to some modern technology their capabilities as a music playback device can be greatly enhanced.

The build starts, as one might expect, by disassembling the cassette and removing the magnetic tape from the plastic casing. With the interior of the cassette empty it’s capable of holding a small battery, USB-C battery charger, and a Bluetooth module. The head of an old tape deck can be wired to the audio output of the Bluetooth module and then put back in place in the housing in place of the old tape. With the cassette casing reassembled, there’s nothing left to do but pair it to a smartphone or other music-playing device and push play on the nearest tape deck.

As smartphones continue to lose their 3.5 mm headphone jacks, builds like this can keep lots of older stereos relevant and usable again, including for those of us still driving older vehicles that have functioning tape decks. Of course, if you’re driving a classic antique auto with a tape technology even older than the compact cassette, there are still a few Bluetooth-enabled options for you as well.

youtube.com/embed/yFBVTpooZD0?…

hackaday.com/2025/01/06/casset…

I ricercatori di sicurezza informatica hanno scoperto un nuovo malware chiamato PLAYFULGHOST che ha ampie capacità di raccolta di informazioni. Le sue funzionalità includono keylogging, acquisizione di schermate e audio, accesso remoto alla riga di comando e trasferimento ed esecuzione di file.

Come sottolinea il team di Google Cloud Security, questo malware presenta somiglianze con Gh0st RAT, un noto strumento di amministrazione remota il cui codice sorgente è stato divulgato nel 2008. Le principali vie di infezione di PLAYFULGHOST sono le e-mail di phishing e lo spoofing SEO.

In uno dei casi di phishing gli aggressori hanno utilizzato un archivio RAR mascherato da immagine con estensione “.jpg”. Una volta estratto ed eseguito, l’archivio scarica un file eseguibile dannoso sul dispositivo, che alla fine scarica e attiva PLAYFULGHOST da un server remoto.

Un altro metodo di infezione tramite spoofing SEO prevede il download del programma di installazione LetsVPN, che contiene codice dannoso intermedio responsabile dell’installazione di componenti malware.

Per effettuare l’attacco, gli aggressori utilizzano tecniche come DLL Hijacking e DLL Sideloading per lanciare una libreria dannosa che carica e decrittografa PLAYFULGHOST nella memoria del dispositivo. In scenari complessi, più file vengono combinati per formare una DLL dannosa utilizzando una versione modificata dell’utilità Curl.

PLAYFULGHOST viene fissato nel sistema tramite chiavi di registro, pianificazione delle attività, cartella di avvio e servizi Windows. Il malware è in grado di raccogliere dati digitati, screenshot, audio, informazioni sull’account, contenuti degli appunti, metadati di sistema e prodotti antivirus installati. Può anche bloccare l’input da tastiera e mouse, cancellare i registri eventi di Windows, eliminare le cache del browser, i profili di messaggistica ed eseguire altre operazioni pericolose.

Inoltre, PLAYFULGHOST può distribuire strumenti aggiuntivi, inclusi Mimikatz e rootkit che nascondono file e processi. Uno di questi strumenti è Terminator, che sfrutta le vulnerabilità dei driver per distruggere i processi di sicurezza. Ad un certo punto dell’analisi, gli esperti hanno registrato che PLAYFULGHOST viene distribuito utilizzando il caricatore BOOSTWAVE, che utilizza il codice shell per iniettare file eseguibili dannosi.

App mirate come Sogou, QQ e 360 ​​Safety, nonché esche sotto forma di LetsVPN, indicano una possibile attenzione agli utenti Windows di lingua cinese. In precedenza, nel luglio 2024, la società canadese eSentire aveva segnalato operazioni dannose simili in cui venivano utilizzati falsi programmi di installazione di Google Chrome per distribuire Gh0st RAT.

L'articolo VPN Con Sorpresa! Oltre all’Anonimato, Offerta anche una Backdoor Gratuitamente proviene da il blog della sicurezza informatica.

The primary feature of stepper motors is listed right within their name: their ability to ‘step’ forwards and backwards, something which they (ideally) can do perfectly in sync with the input provided to their distinct coils. It’s a feature that allows the connected controller to know the exact position of the stepper motor, without the need for any sensor to provide feedback after a movement, saving a lot of hardware and effort in the process.

Naturally, this is the optimal case, and there are a wide number of different stepper motor configurations in terms of coil count, types of rotors and internal wiring of the coils, as well as complications such as skipped steps due to mechanical or driver issues. Despite this, in general stepper motors are quite reliable, and extremely versatile. As a result they can be found just about anywhere where accurate, step-based movement is desirable, such as (3D) printers and robotics.

For each application the right type of stepper motor and driving circuit has to be determined, of course, as they also have many reasons why you’d not want to use them, or just a particular type. When diving into a new stepper motor-based project, exactly what are the considerations to pay attention to?

Stepper Motor Types

Exploded view of a 28BYJ-48 stepper motor. (Credit: Cookie Robotics)
Every stepper motor has a stator and rotor, effectively like any other electric motor. Their unique feature is the segmented nature of the stator, forming what are commonly referred to as ‘teeth’. These stator teeth are used for the coils, which align with either a permanent magnet ring, a soft iron core or both on the rotor. Much like with other electric motors the stator coils rotate the rotor, but due to this segmented design activating one coil can make the rotor progress one step in a very deterministic fashion. By successively activating these coils, the rotor will follow the magnetic field being generated and ‘stepping’ forward by a set amount on the output shaft.

As an example of a basic form you got a unipolar coil design with a permanent magnetic (PM) core, such as the very common 28BYJ-48. This stepper motor features 8 ‘teeth’ on the stator, driven by two coils wound as two levels (top and bottom) with a common center tap, giving a total of five control lines. This makes it a four-phase design, with four lines, two of which are energized in turn to move the rotor and one common line.

Although many schematic diagrams show pronounced teeth on the stator and/or rotor, this doesn’t have to be the case, as evidenced by e.g. this teardown of a 28BYJ-48 stepper motor by Cookie Robotics. The stator and its teeth are here formed by two coils, each encased in a metal plate with ‘claws’, as is typical for a tin-can stepper motor design. The metal claws are magnetized when the corresponding coil is energized, creating the north and south poles affecting the smooth permanent magnet rotor. This latter rotor’s magnet has a total of 8 alternating north-south pairs.
Single coil and claws section of a 28BYJ-48 stepper motor illustrated with current direction and resulting claw magnetization. (Credit: Cookie Robotics)
The choice for a PM rotor in this particular stepper motor is likely due to simplicity, while also providing decent torque when moving as well as when unpowered. Also known as cogging torque, detent torque is a property of PM rotor electric motors where the interaction between the stator and PM rotor resists movement of the latter. While useful in stepper motors with resisting a position change, it also means a lower speed and resolution compared to the alternatives, being:

• Variable reluctance core (VRC) in which the soft iron rotor has temporary magnetism due to the powered stator coils. This provides a faster speed and higher precision, but lower torque and no detent torque.
• Hybrid form, where the rotor has both PM and VRC elements, combining their advantages. The main disadvantage is the much more complex rotor construction and thus higher stepper motor cost.

What is also of note here is the gear train on the 28BYJ-48. While a stepper motor can have a gear train, it’s an optional trade-off between speed and torque. Confusingly, the 28BYJ-48 appears to come with a wide range of gear ratios, ranging from 1/64 to 1/16 and so on. This is likely due to how there is not a single manufacturer for this stepper motor, and thus a single model name covers both the 5V and 12V version, and a wide spectrum of gear ratios. Ergo, caveat emptor.

Uni- And Bipolar

Bipolar Stepper Motor Driving Circuit (Credit: Monolithic Power)
The difference between unipolar and bipolar design is covered in this stepper motor overview by Monolithic Power. A unipolar stepper motor like the 28BYJ-48 has four phases, each of which is controlled by turning the coil on or off, requiring quite basic circuitry. This means that the current in each coil will always only travel in a single direction, ergo unipolar.

This contrasts with bipolar stepper motors, which do not have the common line and only half the coils, but which can power each coil with the current travelling either direction, ergo bipolar. Naturally, this precludes using a simple unipolar driver like an ULN2003 Darlington array, as these cannot invert the current.

The trade-off between uni- and bipolar stepper motors is thus basically one between driver and stepper motor complexity. Yet as bipolar stepper motor drivers become more affordable and prevalent, the disadvantage of a unipolar stepper motor’s requirement to have twice as much copper in coils and thus weight and bulk is unlikely to ever improve significantly.

Driver Circuits

At this point we have established that driving stepper motors requires activation of their coils in a sequence and manner that produces the desired effect on the output shaft. Here we have effectively four techniques to pick from:

• Wave mode: activate just one phase in sequence.
• Full-step mode: activate two phases adjoining the rotor’s orientation. Increases torque due to activation of two phases at the same time.
• Half-step mode: combines wave and full-step to half the size of steps. Has irregular torque as sometimes two, and sometimes one phase is active.
• Microstepping: evolution of half-step whereby the current and thus the intensity of the magnetic field from one phase is varied.

Unsurprisingly, each change to a simple wave mode requires a more complex controller, and also increases the chance of skipping a step. When picking a ready-made stepper motor driver, these can be controlled in a wide range of ways, from instructing it to step forwards/backwards, to controlling stator’s phases, or even using pulse-width modulation to control the gate signals of the FETs in a bipolar stepper motor driver.

Picking the correct driver is of course completely project-dependent, and reliant on how much control you need over the stepper motor, as well as your budget for said driver. It might even be that what you actually want is a servo motor, as also pointed out in Douglas W. Jones’ excellent tutorial on controlling stepper motors.

General Disadvantages

As useful as stepper motors are, they have a number of clear disadvantages, not the least of which is their constant current draw. As there is no mechanical mechanism to hold the stator in place, their ability to hold position and generate torque is purely determined by the powered coils and whatever magnetism the rotor may have.

This means that they are not a great choice for low-power applications, or where high load torque is a requirement. In the case of the 28BYJ-48 which we looked at in this article, that current is 240 mA typical at 5VDC, per the datasheet.

All of this has to be weighed up against the ease of driving them, their (often) low cost and lack of need for a closed feedback system. While having a decelerating gear train as in the 28BYJ-48 helps to increase the torque, ultimately stepper motors are primarily about what’s in their name: stepping in a (usually) deterministic fashion.

Featured image: Still from [Lauri Rantala]’s first steps into stepper driving.

hackaday.com/2025/01/06/one-sm…

EROE DI CARTA

Vorrei avere il dono di viaggiare nel tempo
Un tappeto volante per il passato
E artigli,
più lunghi e decisi
Per riprendermi qualcosa cui dar nome non so
Qualcosa, che solamente il cuore
Isole genuine e pure che anima ignota
sicuro mi rubò

Nel tempo, così pensavo
osservando il fantasma di greto
d'un rivo antico disseccato
Combatterei a capo di mille guerrieri
se fosse servito a farti voltare
Donna mia
dallo sguardo che avvolge
Fuoco che consuma
e addolcisce il mio giorno
Saper di avere più cose in comune
Un senso di strano e un brandello di pelle
Tutti i guai in attesa di volo
Qualcuno - meno male
col passaporto già scaduto

E mi risvegliai sereno
dopo averti in qualche modo vissuto
Eri un bianconero di fumetto
E nel ricordo di acqua pura e fresca
la voce d’eremita
di un ruscello stretto in quota
S'accende la Grigna d'arancione
saluta la luce d'occaso
C'è chi ne resta ipnotizzato
Io non ci casco, e sarà pure bello e che
Però Io
Io Rivoglio solo te

Un altro anno nasce; e sarà già duro e vecchio
Oltre il passo delle luci e dei bicchieri
Oltre la montagna lo stesso sole
Con la testa sopra il mio cuscino di gambe
curiosa mi domandavi ripetendo: E poi
E poi, e poi ma cosa mai vuoi
che Io ti dica di più
Donna mia
Fotogramma di sorrisi e un pizzico di follia
Amore già sublimato via

Rotolando nei meandri del giorno
Strattonato dalla luce
Frettolosa
Dei pomeriggi d'inverno
Un ruscello di pietra guarda giù
Non vede e tacito insiste e illuso reclama
Ma l'acqua pura di ieri, di qui
più non passerà. Ed Io

Vorrei avere il dono di viaggiare nel tempo
Tappeto volante per dove ho già dato…

Mi sono spesso chiesto cosa differenzi il rock del XX secolo da quello del XXI secolo. La differenza di forma è lampante e in qualche modo fisiologica, perché legata necessariamente alle risorse tecnologiche a disposizione al momento della produzione, all' evoluzione tecnico stilistica dei musicisti stessi, ecc. Ma c'è qualcosa di più profondo.

Senza mettermi a scrivere un trattato a riguardo, in primis perché non ne sarei in grado, citerei giusto qualche episodio.

- 4 gennaio 1969. giusto ieri ricorreva il cinquantaseiesimo anniversario del ban di Jimi Hendrix dalla BBC. Il buon Jimi in quell'occasione decise di non seguire le regole del programma che imponevano di far salire la presentatrice Lulu durante il finale di Hey Joe, ma bloccò la sua hit più famosa a metà, e partì a dedicare "Sunshine of your love" a quelli che da poco erano diventati gli ex-Cream. La cosa fece incazzare non poco i bacchettoni della rete britannica. bbc.co.uk/programmes/p032vp1d
- Gennaio 1970. Concerto improvvisato dai Beatles sul tetto dello studio di registrazione dopo un mese di session, abbandoni e ritorni, Yoko Ono onnipresente che-fa-cose-a-caso e improbabili ospiti a spot, creatività alle stelle e frizioni. Serie documentario di Peter Jackson da vedere assolutamente. youtube.com/watch?v=Auta2lagtw…
- Anno 1982. Fondamentalisti cristiani americani danno dei satanisti agli Iron Maiden per l'album "the Number of the Beast", i quali di tutta risposta li prendono bellamente per il culo. Guarda caso a tutt'oggi la più grande band heavy metal della storia non è ancora stata inserita nella rock and roll hall of fame di Cleveland. A detta della stessa band non gliene può fregare di meno, e a ragione, visto che dopo cinquant'anni continuano ancora a riempire stadi in tutti e cinque i continenti. youtube.com/watch?v=A5W2A0PW0X…
- Anno 1992. Nirvana agli MTV video music awards. Vorrebbero eseguire "Rape me", la rete rifiuta per il testo troppo esplicito che potrebbe urtare delle sensibilità, così si accordano per "Lithium". Al momento dell'esibizione, dopo aver accennato qualche verso di "Rape me", Kurt parte con "Lithium" affiancato da Kris che nel mentre fa il gesto del saluto militare. Alla fine sfasciano tutto e Kris quasi sviene dopo essersi beccato il basso in testa. Punkissimi. youtube.com/watch?v=fOmUEHxZFq…

Voltiamo pagina.

- Il film "school of rock" col simpatico, positivo, sopra le righe ma non troppo Jack Black: posette, corna, linguacce, mitizzazioni che diventano formalizzazioni, conformazioni al sistema dominante. Dissacriamo, ma con la giusta misura, alle nove si va a nanna e ricordiamoci di mangiare le nostre verdure. youtube.com/watch?v=5afGGGsxvE…
- Celebrazione della musica dei Led Zeppelin con tanto di medaglie e autorità. Esecuzione (tecnicamente meravigliosa, tanto di cappello agli organizzatori) di "Stairway to Heaven" con presidente degli Stati Uniti in platea che annuisce orgoglioso. youtube.com/watch?v=2cZ_EFAmj0…

Fade to black.

Ricapitolando, la domanda è : "perché adoro Jimi Hendrix, i Beatles, gli Iron Maiden, i Nirvana, ma non riesco a farmi piacere i Foo Fighters, detesto Jack Black, adoro la musica delle tre messicane (musiciste meravigliose) The Warning ma senza particolare coinvolgimento emotivo? È solo perché sto diventando vecchio o c'è dell'altro?" La risposta è nell'accostamento di due immagini: da una parte Kris Novoselic che mima provocatoriamente un "Signorsì, Signore" ai soloni di MTV, dall'altra Obama che approva orgoglioso l'incasellamento nel sistema dominante di una delle band simbolo del rock degli anni settanta.

È toccato al jazz (da qualche tempo si insegna persino nei conservatori), è toccato al rock, toccherà all'hip-hop. L'assimilazione è il modo preferito dal capitalismo per eliminare tutto ciò che rappresenta in qualche modo un intralcio al proprio dominio.

"We are Borg, resistance is futile".