These days, if you want a reverb effect, you just dial up whatever software plugin most appeals to you and turn the dials to taste. However, [Something Physical] specialises in… physical things… and thus built a reverb the old fashioned way. Using a trashcan, of course.

The concept is simple enough—the method of operation is exactly the same as any old plate reverb. Audio is played through a speaker connected to the plate (or trashcan), causing it to vibrate. The sound is then picked up at another point on the plate (or trashcan) with some kind of microphonic pickups, amplified, and there you have your reverb signal.

Given it’s built around a piece of street furniture, [Something Physical] has dubbed this the Street-Verb. It uses a class D amp to drive a speaker with a bolt stuck to it. The bolt is then put in contact with the trashcan itself to transfer the vibration. A pair of piezo elements are used as the pickups, run through a preamps built with a humble BC109C transistor. Since there are two pickups, the Street-Verb is effectively a stereo reverb unit, though the input is only mono. [Something Physical] set up the speaker driver and pickups to be easily movable, and was able to test the device with all kinds of street furniture, like gates and street signs, but the trashcan ‘verb setup is by far the most compelling.

We’ve featured other plate reverb builds before, too, albeit less garbage-themed. Video after the break.

youtube.com/embed/J2e8JIxW1g4?…

hackaday.com/2025/08/11/buildi…

When you think of neon, you might think of neon signs or the tenth element, a noble gas. But there was a time when neon bulbs like the venerable NE-2 were the 555 of their day, with a seemingly endless number of clever circuits. What made this little device so versatile? And why do we see so few of them today?

Neon’s brilliant glow was noted when William Ramsay and Morris Travers discovered it in 1898. It would be 1910 before a practical lighting device using neon appeared. It was 1915 when the developer, Georges Claude, of Air Liquide fame, received a patent on the unique electrodes suitable for lighting and, thus, had a monopoly on the technology he sold through his company Claude Neon Lights.

However, Daniel Moore in 1917 developed a different kind of neon bulb while working for General Electric. These bulbs used coronal discharge to produce a red glow or, with argon, a blue glow. This was different enough to earn another patent, and neon bulbs found use primarily as indicator lamps before the advent of the LED. However, it would also find many other uses.

How It Worked

An NE-2 with AC power applied (public domain by [junkyardsparkle]).Despite the name, a neon bulb typically has only 99.5% neon, and the rest is usually argon, which tunes the voltage where the gas breaks down. This breakdown voltage is the key to the bulb’s properties. The gas is at a very low pressure. Other gases and impurities can also change the color of the bulb, but the most common ones were neon and argon.

There are two electrodes within, an anode and a cathode. When a DC voltage excites the bulb sufficiently, a glow forms around one electrode. AC makes both electrodes glow alternately. The striking voltage changes based on ambient light or radioactive exposure, as well as the bulb’s gas mix and pressure.

Until the strike voltage occurs, the bulb is effectively an open circuit. When it does strike, however, the resistance goes down and will sustain even at a lower voltage. Like an LED, current limiting is essential, or the bulb will burn out. The NE-2, arguably the most common neon bulb, triggers at 90 V, nominally, and will conduct until the voltage drops to about 60 V.

So It Lights Up?

The lighting up is good, but you do need a lot of voltage to get it going. The bulb will easily light up from 120 V line voltage, for example. But the really interesting property is that the bulbs, when glowing, exhibit negative resistance. That is, as current increases, voltage decreases.

You can also make the bulbs operate in a bistable mode, where they can work in logic circuits. They weren’t common, but some bulbs had special features for logic use. These bulbs were not made to glow necessarily, and sometimes had a third wire used as a control electrode.

Since the gas inside the tube can ionize, neon bulbs can also detect things like light, microwaves, or heavy electrostatic fields. They can even pick up audio.

What Could You Do?

Of course, the normal application was to use the devices as a lamp, like you’d use an LED today. Power pilot lights were common. Special neon lights looking like digits form the basis of nixie tubes.

Another neat display trick was the “blown fuse” indicator. Fuse holders often had neon bulbs in them that connected across the fuse terminals. In normal operation, the voltage across the fuse was practically zero, so the bulb stayed dark. But if the fuse blew, you’d have 120 V across the bulb, which would then light up. A high-value resistor prevented any significant current from flowing.

By far the most common non-lighting use was as a part of a relaxation oscillator. Consider a circuit with a resistor and a capacitor, but the capacitor has a neon bulb across it. The capacitor will charge until it hits the neon bulb’s trigger voltage. The bulb will light and discharge the capacitor until it drops below the holding voltage for the bulb. Then the process starts over. You could use neons to make a clock.

Long History

The NE-2 could create high-voltage regulator circuits (from Elementary Electronics, 1965)
[E. Norbert Smith] wrote about the “1001” uses for the NE-2 — probably not an exaggeration, but [Smith] didn’t get that many in the article — in a 1965 Elementary Electronics magazine article.

The circuits he shows include a 50 V regulated power supply. (Regulators weren’t held to the same standard in those days as we would expect now.) Need 150 V? Use three of them. Or put them in parallel to improve regulation performance.

Some of the circuits are probably not useful if you aren’t building with tubes. And, of course, if you aren’t building with tubes, you are less likely to have the high voltages you need, so there is that.

He also covers the classic self-indicating fuse and the relaxation oscillator. Of course, if you can make one neon bulb blink, you can also make two blink alternately. Blink it fast enough and you can make a code practice oscillator with just a few parts and a 90 V battery.
A 100 kHz oscillator gets the divide by 10 treatment with a simple neon bulb circuit (from Elementary Electronics, 1965)
If you wondered how neon bulbs could handle logic, that same article will answer that question, too. Just be aware that a logic 1 is 10 V — not a problem — but a logic 0 is -10 V. The nice thing about demonstrating logic circuits with neon bulbs is that you don’t need a logic probe or scope to see the state of the machine.

There were many other ways to use these bulbs. Since the trigger voltage was stable, you could use it as a voltage indicator if you coupled it with a voltage divider. In fact, many cheap AC socket testers still work this way. A typical circuit for a capacitor checker could be found in “36 Time Tested Circuits,” a book from Popular Electronics.
This capacitor tester required a keen eye and sense of timing. From a collection of circuits from Popular Electronics, 1992.
The capacitor is hooked up to the AC line via some 470 kΩ resistors. If you connect a capacitor to it, the neon bulb should light up. If not, it is open. When you push the button, you switch to DC, and you should be able to see one side of the neon bulb dim. If it doesn’t dim or doesn’t go all the way off, the capacitor is shorted or leaky. Supposedly, you could get a feel for the value of the capacitor by how long it took half of the bulb to go out. Makes you appreciate your digital capacitance meter, right?

Why Gone?

Why do you so rarely see neon bulbs today? They are still around, but the number of circuits you have where you have the requisite 100 V or so to drive them is not what it used to be. On top of that, as an indicator, an LED is usually a far better choice.

If you want negative resistance, your choices are less obvious. Some special diodes present a negative resistance in certain operating regimes, and you can coax the behavior from some transistors. However, as a matter of practicality, today, you’d probably just use an active switch and be done with it, especially for an oscillator circuit. Then again, if you really want an oscillator, as we are always reminded, you can do it with a 555, among other methods.

We have no doubt that [Smith] was right. There are probably at least 1,001 different uses, but you get the idea. Did you use an NE-2 for something interesting? Let us know about it in the comments. Still want more neon bulb circuits? We’ve seen plenty.

hackaday.com/2025/08/11/neon-b…

If you used the internet at home a couple of decades or more ago, you’ll know the characteristic sound of a modem connecting to its dial-up server. That noise is a thing of the past, as we long ago moved to fibre, DSL, or wireless providers that are always on. It’s a surprise then to read that AOL are discontinuing their dial-up service at the end of September this year, in part for the reminder that AOL are still a thing, and for the surprise that in 2025 they still operate a dial-up service.

There was a brief period in which instead of going online via the internet itself, the masses were offered online services through walled gardens of corporate content. Companies such as AOL and Compuserve bombarded consumers with floppies and CD-ROMs containing their software, and even Microsoft dipped a toe in the market with the original MSN service before famously pivoting the whole organisation in favour of the internet in mid 1995. Compuserve was absorbed by AOL, which morphed into the most popular consumer dial-up ISP over the rest of that decade. The dotcom boom saw them snapped up for an exorbitant price by Time Warner, only for the expected bonanza to never arrive, and by 2023 the AOL name was dropped from the parent company’s letterhead. Over the next decade it dwindled into something of an irrelevance, and is now owned by Yahoo! as a content and email portal. This dial-up service seems to have been the last gasp of its role as an ISP.

So the eternal September, so-called because the arrival of AOL users on Usenet felt like an everlasting version of the moment a fresh cadre of undergrads arrived in September, may at least in an AOL sense, finally be over. If you’re one of the estimated 0.2% of Americans still using a dial-up connection don’t despair, because there are a few other ISPs still (just) serving your needs.

hackaday.com/2025/08/11/end-of…

Gli esperti di Lumia hanno pubblicato un’indagine tecnica chiamata AppleStorm, in cui si sostiene che l’assistente vocale Siri trasmetta ai server Apple più dati utente di quanti ne siano necessari per completare le attività. In particolare, l’attenzione si è concentrata sui messaggi dettati tramite Siri nelle app di messaggistica WhatsApp e iMessage: a quanto pare, vengono inviati ai server dell’azienda anche se l’attività può essere elaborata localmente, senza accedere ai sistemi cloud.

Apple dichiara elevati standard di privacy e utilizza un modello di intelligenza artificiale ibrido che combina l’elaborazione locale con il servizio cloud Private Cloud Compute (PCC). Tuttavia, è emerso che Siri accede anche ad altri server che non fanno parte dell’architettura PCC. Tra questi, i server di dettatura, l’infrastruttura di ricerca (sottodominio smoot.apple.com) e server di estensione Apple Intelligence separati, attraverso i quali, ad esempio, avviene l’interazione con ChatGPT.

Durante gli esperimenti, i ricercatori hanno utilizzato gli strumenti mitmproxy e Frida su macOS Sequoia con Apple Intelligence abilitata. Semplici query come “Ciao” o “Che ore sono?” venivano elaborate localmente. Tuttavia, quando si chiedeva informazioni sul meteo, venivano registrate due connessioni esterne: una al server di riconoscimento vocale, la seconda al servizio di ricerca. L’analisi dei dati trasmessi ha mostrato che Siri raccoglie automaticamente informazioni sulle applicazioni installate sul dispositivo, anche se sono in esecuzione in un ambiente virtuale. Pertanto, quando si chiedeva informazioni sul meteo, le chiamate venivano registrate sia all’applicazione Apple Weather integrata che all’applicazione Windows nell’ambiente Parallels.

Inoltre, i dati inviati contenevano le coordinate esatte della posizione dell’utente. Anche con la trasmissione della geolocalizzazione formalmente abilitata, tali dettagli sarebbero stati ridondanti per una richiesta di informazioni meteo. L’analisi dei pacchetti ha anche rivelato la trasmissione di metadati relativi ad altre applicazioni, fino ai nomi dei file e dei processi aperti al momento della richiesta a Siri.

La trasmissione del contenuto dei messaggi solleva interrogativi particolarmente acuti. Utilizzando Siri per inviare una frase tramite WhatsApp, si è scoperto che il testo, il numero del destinatario e altri attributi del messaggio venivano inviati ai server Apple e non all’infrastruttura PCC. Tuttavia, la funzionalità non dipende dal lato server: anche quando le connessioni sono bloccate, il messaggio viene inviato correttamente. Ciò indica che l’invio al cloud avviene senza necessità tecnica.

Nel tentativo di chiarire se questo sia correlato alle specifiche dell’integrazione di WhatsApp tramite SiriKit, il ricercatore ha creato una propria applicazione basata sulla documentazione Apple, riscontrando un comportamento identico: anche i messaggi inviati tramite Siri dall’applicazione di prova venivano indirizzati ai server Apple. Un quadro simile si osserva con iMessage.

La complessità delle policy sulla privacy contribuisce ad aumentare la confusione. Siri e Apple Intelligence sono regolati da documenti diversi. Di conseguenza, due comandi quasi identici – ad esempio “Che tempo fa oggi?” e “Chiedi a ChatGPT che tempo fa?” – vengono elaborati da sistemi diversi con diversi livelli di protezione e diverse condizioni di raccolta dati. L’utente non ha modo di sapere quale sottosistema verrà utilizzato.

Apple ha riconosciuto il trasferimento di dati, ma non lo ha considerato un problema di Apple Intelligence . Ha invece attribuito parte della colpa agli sviluppatori terzi che utilizzano SiriKit. Tuttavia, Siri stessa sta chiaramente inviando più dati del necessario, e lo fa all’insaputa dell’utente. La trasparenza è uno degli slogan principali di Apple in materia di intelligenza artificiale, ma nella pratica viene implementata in modo selettivo.

L'articolo Siri invia i dati ad Apple senza preavviso: AppleStorm rivela la verità proviene da il blog della sicurezza informatica.

Linus Torvalds ha duramente criticato il primo lotto di patch RISC-V proposte per l’inclusione in Linux 6.17, affermando che le modifiche sono arrivate troppo tardi e contenevano quella che lui ha definito “spazzatura” non correlata a RISC-V e che interessava gli header comuni del kernel.

Era particolarmente infastidito dalla nuova macro helper make_u32_from_two_u16(), che secondo Torvalds rendeva il codice meno chiaro e peggiorava le cose. Notò che la semplice scrittura del form (a mostrava immediatamente cosa stava succedendo, mentre l’uso dell'”helper” oscurava l’ordine delle parole e introduceva ambiguità.
No, questa è spazzatura ed è arrivata troppo tardi. Ho chiesto un ritiro anticipato.richieste perché sono in viaggio, e se non riesci a seguire questa regola, almeno rendi le richieste di pull *buone*.Ciò aggiunge vari elementi indesiderati che non sono specifici di RISC-V ai file di intestazione generici.E con "spazzatura" intendo davvero. Questa è roba che nessuno dovrebbe inviami, figuriamoci in ritardo in una finestra di unione.Come questo folle e inutile "helper" make_u32_from_two_u16().Quella cosa rende il mondo un posto peggiore in cui vivere. È spazzatura inutile che rende incomprensibile qualsiasi utente, e attivamente *PEGGIO* che non usare quello stupido "aiutante".
Torvalds ha sottolineato che tali modifiche non dovrebbero comparire nelle intestazioni generali, né tantomeno essere apportate alla fine della finestra di merge. Ha avvertito che non accetterà più richieste di pull tardive né consentirà la creazione di “spazzatura” al di fuori dell’albero dell’architettura RISC-V.

Secondo lui, gli autori potranno riprovare queste modifiche solo nella versione 6.18 e solo all’inizio della finestra di unione, senza modifiche controverse e inutili.

La vicenda dimostra che, anche in un ecosistema aperto e collaborativo come quello di Linux, l’inclusività non significa accettare qualsiasi contributo senza filtro. L’open source nasce per essere accessibile, ma richiede disciplina, coerenza e qualità tecnica. Come ha dimostrato Torvalds, le regole di integrazione e revisione servono a preservare la stabilità e la chiarezza del codice, evitando l’introduzione di modifiche inutili o dannose.
Ma l’open source non doveva essere inclusivo? Sì, ma inclusivo non vuol dire indulgente con la “spazzatura”: vuol dire garantire che ogni contributo sia valido, utile e ben integrato nell’interesse di tutta la comunità.

L'articolo Linus Torvalds: “Questa è Spazzatura”! Critico per la patch RISC-V per Linux 6.17 proviene da il blog della sicurezza informatica.

Quel partito ha la caratteristica di riuscire a sparire completamente dalla scena per mesi, per anni, tra un'elezione (persa) e l'altra.

O governa, e sappiamo come, o sparisce completamente dalla circolazione.