The regenerative radio is long-ago superseded in commercial receivers, but it remains a common project for electronics or radio enthusiasts seeking to make a simple receiver. It’s most often seen for AM band receivers or perhaps shortwave ham band ones, but it’s a circuit which also works at much higher frequencies. [Perian Marcel] has done just this, with a regenerative receiver for the FM broadcast band.

The principle of a regenerative receiver is that it takes a tuned radio frequency receiver with a wide bandwidth and poor performance, and applies feedback to the point at which the circuit is almost but not quite oscillating. This has the effect of hugely increasing the “Q”, or quality factor of the receiver, giving it much more sensitivity and a narrow bandwidth. They’re tricky to tune but they can give reasonable performance, and they will happily slope-demodulate an FM transmission.

This one uses two tubes from consumer grade TV receivers, the “P” at the start of the part number being the giveaway for a 300mA series heater chain. The RF triode-pentode isn’t a radio part at all, instead it’s a mundane TV field oscillator part pushed into service at higher frequencies, while the other triode-pentode serves as an audio amplifier. The original circuit from which this one is adapted is available online, All in all it’s a neat project, and a reminder that exotic parts aren’t always necessary at higher frequencies. The video is below the break.

youtube.com/embed/oJzA40-luss?…

hackaday.com/2024/11/04/humble…

If you’re planning on working satellites or doing any sort of RF work where the signal lives down in the dirt, you’re going to need a low-noise amplifier. That’s typically not a problem, as the market is littered with dozens of cheap options that can be delivered in a day or two — you just pay your money and get to work. But is there a case to be made for rolling your own LNA?

[Salil, aka Nuclearrambo] thinks so, and he did a nice job showing us how it’s done. The first step, as always, is to define your specs, which for [Salil] were pretty modest: a low noise figure, moderate gain, and good linearity. He also wanted a bandpass filter for the 2-meter amateur radio band and for weather satellite downlinks, and a bias-tee to power the LNA over the coax feedline. The blog post has a detailed discussion of the electrical design, plus some good tips on PCB design for RF applications. We also found the discussion on bias-tee design helpful, especially for anyone who has ever struggled with the idea that RF and DC can get along together on a single piece of coax. Part 2 concentrates on testing the LNA, mostly using hobbyist-grade test gear like the NanoVNA and tiny SA spectrum analyzer. [Salil]’s tests showed the LNA lived up to the design specs and more, making it more than ready to put to work with an RTL-SDR.

Was this more work than buying an LNA? Absolutely, and probably with the same results. But then again, what’s to learn by just getting a pre-built module in the mail?

hackaday.com/2024/11/04/a-less…

The ever-shrinking size of electronics and sensors has allowed wearables to help us quantify more and more about ourselves in smaller and smaller packages, but one major constraint is the size of the battery you can fit inside. What if you could remotely power a wearable device instead?

Researchers at Carnegie Mellon University were able to develop a power transmitter that lets power flow over human skin to remote devices over distances as far a head-to-toe. The human body can efficiently transmit 40 MHz RF energy along the skin and keeps this energy confined around the body and through clothing, as the effect is capacitive.

The researchers were able to develop several proof-of-concept devices including “a Bluetooth
ring with a joystick, a stick-and-forget medical patch which logs data, and a sun-exposure patch with a screen — demonstrating user input, displays, sensing, and wireless communication.” As the researchers state in the paper, this could open up some really interesting new wearable applications that weren’t possible previously because of power constraints.

If you’re ready to dive into the world of wearables, how about this hackable smart ring or a wearable that rides rails?

youtube.com/embed/5PEN04-jyCU?…

hackaday.com/2024/11/04/power-…

Negli ultimi giorni gli operatori dei nodi Tor hanno iniziato a ricevere in massa notifiche di abusi. Le notifiche si riferiscono a tentativi di accesso SSH falliti causati da presunti attacchi da parte dei loro host, indicando attacchi di forza bruta.

In genere, i nodi Tor inoltrano solo il traffico tra i nodi di origine e di destinazione della rete Tor e non dovrebbero avviare connessioni SSH per aprire host su Internet, soprattutto con attacchi di forza bruta.

Tuttavia, l’analisi di un ricercatore sotto lo pseudonimo “delroth” ha dimostrato che la maggior parte dei nodi Tor non genera traffico SSH.

Si scopre che gli aggressori stanno falsificando gli indirizzi IP dei nodi Tor, conducendo attacchi di forza bruta su larga scala su honeypot e reti con sistemi di rilevamento delle intrusioni che segnalano automaticamente attività sospette, con conseguenti false notifiche di abuso ai nodi Tor.

Di conseguenza, gli host che ricevono più tentativi di accesso falliti finiscono nelle liste nere, in quanto gli IP avranno una “cattiva reputazione”. Ciò porta molti provider a disabilitare tali host, a volte senza possibilità di riattivazione.

Gli attacchi hanno lo scopo di indebolire l’infrastruttura dei nodi Tor, creando un’ondata di denunce di abusi. Al momento, l’attività dannosa è moderata e gli aggressori rimangono sconosciuti.

Mentre gli operatori dei nodi Tor vengono incoraggiati a presentare ricorsi e a implementare nodi aggiuntivi per sostituire quelli persi, ai fornitori stessi viene chiesto di esaminare attentamente i reclami per evitare falsi divieti.

L'articolo Indebolire la Rete TOR. I Relay Bombardati da Richieste Malevole per metterli in Blacklist proviene da il blog della sicurezza informatica.

This year we challenged the Hackaday community to develop Shitty Simple Supercon Add-Ons (SAO) that did more than just blink a few LEDs. The SAO standard includes I2C data and a pair of GPIO pins, but historically, they’ve very rarely been used. We knew the talented folks in this community would be able to raise the bar, but as they have a tendency to do, they’ve exceeded all of our expectations.

As we announced live during the closing ceremony at the 2024 Hackaday Supercon, the following four SAOs will be put into production and distributed to all the attendees at Hackaday Europe in Spring of 2025.

Best Overall: SAO Multimeter

For the “Best Overall” category, we only intended to compare it with the other entries in the contest. But in the end, we think there’s a strong case to be made that [Thomas Flummer] has created the greatest SAO of all time. So far, anyway.

This add-on is a fully functional digital multimeter, with functions for measuring voltage, resistance, and continuity. The design is a pure work of art, with its structure combining stacked PCBs and 3D printed parts. There’s even tiny banana plugs to connect up properly scaled probes. Incredible.

In the documentation [Thomas] mentions there are additional functions he didn’t have time to include in the firmware, such as modes to analyze the I2C and GPIO signals being received. Now that it’s been selected for production, we’re hoping he’ll have the time to get the code finished up before its European debut.

Fun: Etch sAo Sketch

This SAO recreates the iconic art toy in a (hopefully) non-trademarked way, with a 1.5″ inch 128 x 128 grayscale OLED display and a pair of trimpots capped with 3D printed knobs. Drawing is fun enough, but the nostalgia really kicks in when you give it a good shake — the onboard LIS3DH 3-axis accelerometer picks up the motion and wipes the display just like the real thing.

Created by [Andy Geppert], this SAO isn’t just a pretty face. Flipping it over shows an exceptionally clever technique for connecting the display board to the main PCB. Tiny metal balls (or “alignment spheres” if you want to get fancy) mate up with the mounting holes on the OLED board and center it, and a touch of solder locks it all in place.

Fine Art: Bendy SAO

While this wacky, waving, inflatable, arm-flailing SAO might look like the sort of thing that would be outside of a used car dealership, but creator [debraansell] managed to shrink it down so the point that it’s reasonable to plug into your badge. More or less.

There are several fascinating tricks at work here, from lighting the PCB from the back using side-firing LEDs to the integrated slip rings. If this one didn’t look so good, it would have been a strong contender for the “Least Manufacturable” Honorable Mention.

Functional: Vectrex SAO

Creating a replica of the Vectrex at SAO scale would have been an impressive enough accomplishment, but [Brett Walach] took this one all the way and made it playable.

The display is a 7 x 10 Charlieplexed LED matrix, while the “joystick” is implemented with a 1-button capacitive touch sensor. A PIC16F886 microcontroller runs the simplified version of Scramble, and there’s even a speaker for era-appropriate audio.

But that’s not all! This SAO was also designed to be hacked — so not only is all the hardware and software open source, but there’re various jumpers to fiddle with various settings and an I2C control protocol that lets you command the action from the badge.

Honorable Mentions

As usual, this contest had several Honorable Mentions categories — while we would have loved to put all of these SAOs into production, there’s only so much we can do before now and Spring.

Best Communication:

Using I2C to get SAOs to talk to the badge (or each other) was a big part of this contest, but we were also on the lookout for entries which helped facilitate badge-to-badge communications.

The Badge Tag NFC SAO from [Thomas Flummer] is a perfect example of both — it uses the NXP NTAG I2C Plus to provide 2K of read-write storage that can be accessed either internally through the I2C bus by the badge, or externally by an NFC device such as a smartphone. Modeled after a traditional conference name tag, this SAO was designed to make it easier for sharing your contact info with others during a busy con.

Infrared Communication SAO by [Alec Probst] brings infrared communications to the party, while looking like a classic TV remote. Though the original idea was to get this working in conjunction with the badge to act as a sort of TV-B-Gone, it ended up being used as part of a laser tag game during Supercon.

The GAT Nametag SC8 from [true] tackles communication on a more human level by providing a digital name tag for your badge. This compact board’s secret trick is the ability to make sure your name is legible no matter what its orientation thanks to a LIS2DW12 accelerometer that can detect the SAO’s orientation relative to the ground. RGB LEDs catch the viewer’s eye, but it’s the incredible firmware with seemingly endless options for text styling and tweaks that really set this build apart.

Light Show:

There’s little question that Featuring You! from [Nanik Adnani] is a perfect entry for this category. Nominally, it’s a little arrow you can write your name on and use a name tag. But power it up and you can dazzle anyone standing too close with its array of marching white LEDs. In a particularly nice touch, the circuit is implemented with only discreet components — no microcontroller.

The reDOT_RGB from [Alex] is a tiny 5×7 RGB LED matrix with a minuscule ATtiny816 MCU around the back to control the show. At just 8 x 11 mm, it’s hard to overstate just how tiny this SAO is.

While on the subject of tiny boards, the
Persistence of Vision POV Display is another entry not much larger than the SAO connector itself. Using a row of five tiny white LEDs and a ADXL345 accelerometer, [Michael Yim] is able to write text in mid-air thanks to the gullibility of the human eye.

Least Manufacturable:

Simple Add-Ons are essentially an art form, so it’s not surprising to find that they don’t often lend themselves to mass production. Several of the entries this yeah would be a real challenge to make in large numbers, but the one that really keeps us up at night is the ultra tiny smart SAO from [Alex].

This board is designed to fit inside the space between four header pins. Thanks, but no thanks.

Raising the Bar

Our hope this year was to elevate the Simple Add-On from a decorative piece of flair to something functional, and potentially, even useful. The results were incredible, and while we can only pick four winners this time around, every entry helped push the state-of-the-art forward in its own way. It’s hard to imagine how the SAO envelope can be pushed any further, but we can’t wait to find out.

hackaday.com/2024/11/04/superc…

noblogo.org/transit/camarillo-…

Transit

2024-11-01 09:02:42

Camarillo Brillo Sessions 10 (160)

Alla fine del mondo.

The Cure – “Songs of a Lost World”, Universal

Ho sempre il timore che, quando un disco mi piace, sia perché nel momento in cui l’ascolto è ciò che (inconsciamente?) il mio “io musicale” vuole in quel periodo della vita, che sia un giorno solo o un anno. Perciò, forse, il mio giudizio è falsato: la stessa opera, a distanza di tempo potrebbe farmi un effetto molto diverso, peggiore, magari. Naturalmente ci sono dischi che resistono allo scorrere della vita e sono di certo quelli che personalmente non posso smettere di ascoltare: hanno acquisito una valenza che supera tutto ciò che gli accade intorno.

Non so se “Songs of a Lost World” dei “Cure” possa ambire a quell’empireo, pittosto ristretto, in verità. Probabilmente è anche dovuto al fatto che i “Cure” non sono mai stati uno dei miei gruppi preferiti, nemmeno all’apice della loro carriera, quando erano di certo una delle band più importanti della scena dark-wave e Robert Smith godeva di una popolarità immensa. Ed anche per questo mi domando se sia una mia mancanza di approfondimento o semplice affermazione di gusti diversi. O, anche più probabile, distrazione.

Un tempo che potremmo pensare ad appannaggio di Peter Gabriel o dei Pink Floyd per uscire con nuova musica (seppur già proposta, in parte, dal vivo): sedici anni e viene dopo un disco, “4:13 dream” che per i più è claudicante, almeno. E si invecchia, nel mentre. Come se accadesse sempre ad altri, magari perché i musicisti si sentono una categoria a parte, ma non è così. Essere umani è eguale per tutti. Ed allora questo diventa un disco sulla difficoltà del vivere, sul dolore (la perdita del fratello, per Smith), sulle inevitabili somme che si devono tirare, su ciò che ci circonda e che peggiora ogni giorno.

Questo è un disco dove la musica prevale, in una sorta di messaggio che travalica le sensazioni date dalle parole. Ogni canzone, e sono quasi tutte lunghissime, c’è una “intro” che precede i versi ed è una scelta che qualche critico ha bollato come un ritorno, ma senza entusiasmo, agli anni ‘80. Invece funziona, eccome. Dona ai brani un’aura quasi epica, anche per il drumming potente e per la chitarra di Reeves Gabrels (recuperate i “Tin Machine” ogni tanto), nella band dal 2012, tagliente, sferzante.

Il secondo singolo, “A fragile Thing”, è esemplificativa di questo mood, con un basso potente, tocchi di chitarra che ricordano un vento gelido, il cantato chiaro, limpido. Invece “Alone”, più lugubre, più ieratica è la prova che questa è un’opra dolente, che sfocia in “I Can Never Say Goodbye” dove la perdita del fratello è un temporale acustico, una litania dolorosa. Ma forse “Endsong”, la canzone finale del disco (oltre i dieci minuti), è quella che può far risaltare di più il valore di queste canzoni. E’ un brano potente, marziale, tribale, dove Gabrels può lasciare spazio alla sua elegiaca musica, un contrappunto alle parole quasi definitive “...it’s all gone/ no hope/ no dreams/ no more” e quel “...nothing” finale che non solo chiude il disco, ma sembra far calare il sipario su una esistenza intera.

E’ un grande disco, questo: lo si intuisce subito, dal primo ascolto. E come tutti i dischi di spessore cresce nel tempo, per ora brevissimo, dopo la sua uscita. Essendo una riflessione in musica, ognuno ne può far parte, per ciò che desidera, perché i temi sono universali. Gli artisti hanno il dono di farci partecipi tutti in egual maniera, ma non a tutti riesce con convinzione. Stavolta sì, anche per uno come me che non è un “fan”. Quelli che lo sono possono gioire.

#Musica #Music #Opinioni #CamarilloBrillo #Blog

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Il blog di Alessandra Corubolo & Daniele Mattioli. On line -in varie forme- dal 2005.

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