The Raspberry Pi has been around for over a decade now in various forms, and we’ve become plenty familiar with the Pi Pico in the last three years as well. Still, these devices have a great deal of potential if you know where to look. If you wade beyond the official datasheets, you might even find more than you expected.

Kumar is presently a software engineer with Google, having previously worked for Analog Devices earlier in his career. But more than that, Kumar has been doing a deep dive into maxing out the capabilities of the Raspberry Pi and the Pi Pico, and shared some great findings in an excellent talk at the 2023 Hackaday Supercon.

Under The Hood

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Kumar begins by noting that a great many resources went into the creation of this talk. Worthy of note are Jeremy Bentham’s blog, which provided plenty of details on the Raspberry Pi and the workings of the Secondary Memory Interface (SMI). Beyond that, the Pi Pico documentation proved fruitful, as did several logic analyzer projects from out in the wild. Kumar collated this knowledge along with plenty of research, and put together a guide to some of the deeper functionality of the hardware with regards to the concept of a Pi Pico-based logic analyzer capable of running at 100 megasamples per second.
Kumar’s concept is for a hat that has an RP2040 connected to the Raspberry Pi via the SMI interface. It in turn is controlled via its debug pins.
Kumar notes the RP2040 chip at its heart has the useful Programmable I/O (PIO) subsystem, which allows for doing various I/O and data tasks quickly and efficiently. However, the chip is still limited to just 256 KB of RAM and a 1.5 MB/sec max data speed over USB. However, by combining the Pico with a Raspberry Pi 4, Kumar reckons its possible to create a 16 bit, 100 megasample/sec logic analyzer by using the right techniques. For looking at 3.3 V logic, the minimum hardware required would just be a Raspberry Pi and a single RP2040 microcontroller.

However, a little extra functionality never goes astray. Kumar talks about building a prototype HAT add-on that adds a separate LDO regulator for the RP2040, 5 V tolerant logic buffers, and an I2C input expander to create a pretty useful little logic analyzer. Kumar’s original idea was to use the Pi Pico itself, but there was a problem. With only 26 usable GPIOs, it’s not possible to get 16-bits in and out of the device very easily. Hence, the idea to use the raw RP2040 for direct access to all the necessary pins. However, there was still a problem. The PIO subsystem can only control 30 pins.
Kumar was hacking on the prototype up to the last minute.
To get around this, Kumar noted that the less-flexible SIO subsystem can control all 36 GPIO pins. Kumar found a way to use the dual cores of the Pi Pico to sample the GPIOs via the SIO hardware every clock cycle while remaining in sync. Basically, the SIO hardware samples the inputs, puts the results in RAM, and then the DMA subsystem trucks this over to the PIO. The PIO then handles clocking the data out to the attached Raspberry Pi as required. Combining this technique with overclocking the Pi Pico would help Kumar nail the 100 megasamples/sec target; at the stock clockrate, it wouldn’t be fast enough.

Things only get more complicated from there. Kumar explains issues around bus contention within the Pico, as well as how to clock data into the Pi via the SMI interface. It’s poorly documented, but Jeremy Bentham’s blog was a big help. The talk gets into the nitty gritty here, diving into the precise conditions needed to pipe lots of data out of the RP2040 and into the Pi itself. Meanwhile, the Pi itself gets control over the RP2040 via the SWD pins and GDB debugging with OpenOCD. Everything was then laced together with some code crafted with the aid of ChatGPT.
There were some kinks left to work out, with some aberrations that aren’t quite right in the data marked in red in Kumar’s testing.
By the time Supercon rolled around, Kumar was still tangling with some details. The system was passing data from RP2040 to the Raspberry Pi at 41.666 MHz, though there were some aberrations. There was work left to be done on flow control and some other details to get the thing more functional. Kumar also speculated that the Pi 5 might open up new avenues to further improve the project.

It’s always interesting to see a project that pushes the limits of existing hardware. Kumar might not have finished his project just yet, but this talk gives us a great look at the challenges you face when you start trying to truck masses of data into and out of an RP2040, and in to a Raspberry Pi to boot!

hackaday.com/2024/09/30/superc…

[Andre Me] has long-standing interest in automating 3D print jobs, and his latest project is automating build plate changes on the Bambu A1 Mini.

Here’s how it works: each build plate gets a sort of “shoe” affixed to it, with which attachments on the printer itself physically interact when loading new plates and removing filled ones.

When a print job is finished, custom G-code causes an attachment on the printer to wedge itself under the build plate and peel it off until it is freed from the magnetic bed, after which the finished plate can be pushed towards the front. A stack of fresh build plates is behind the printer, and the printer slips a new one from the bottom when needed. Again, since the printer’s bed is magnetic, all one has to do is get the new plate to reliably line up and the magnetic attraction does the rest.

Some methods of automating print jobs rely on ejecting the finished parts and others swap the print beds. [Andre]’s is the latter type and we do really like how few moving parts are involved, although the resulting system has the drawback of requiring considerably more table space than just the printer itself. Still, it’s not at all a bad trade-off.

Watch it in action in the two videos embedded below. The first shows a time-lapse of loading and ejecting over 100 build plates in a row, and the second shows the whole system in action printing bowls in different colors.

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hackaday.com/2024/09/30/3d-pri…

A range of academics, from Turing award-winner Yoshua Bengio to PhD candidates have been named chairs and vice-chairs of working groups that will draft a Code of Practice on general-purpose artificial intelligence (GPAI), according to a Monday (30 September) Commission press release.

euractiv.com/section/tech/news…

La Commissione irlandese per la protezione dei dati (DPC) ha multato Meta Platforms Ireland Limited (MPIL) di 91 milioni di euro per aver archiviato le password di centinaia di milioni di utenti in chiaro. Il DPC sta indagando su questo incidente dal 2019.

Ricordiamo che nel 2019 i ricercatori hanno scoperto che le password di 200-600 milioni di utenti di Facebook Lite, Facebook e Instagram venivano erroneamente archiviate sui server dell’azienda in formato testo ed erano accessibili a migliaia di dipendenti dell’azienda.

I registri hanno rivelato che circa 2.000 ingegneri e sviluppatori dell’azienda hanno effettuato circa 9.000.000 di richieste interne per elementi di dati contenenti password degli utenti in chiaro.

È interessante notare che Meta ha poi ammesso di aver effettivamente memorizzato le password, ma non ha fornito numeri specifici, dicendo solo che l’incidente ha colpito centinaia di milioni di utenti di Facebook Lite, decine di milioni di utenti di Facebook e milioni di utenti di Instagram.

Ora la Commissione irlandese per la protezione dei dati, che è l’organismo principale dell’UE in materia di privacy e questioni relative a Meta (poiché la sede europea della società è in Irlanda), ha completato un’indagine di cinque anni sull’incidente.

“Nel marzo 2019, MPIL ha notificato al DPC di aver inavvertitamente archiviato le password di alcuni utenti di social media in “testo semplice” sui suoi sistemi interni (ovvero, senza protezione crittografica o crittografia)”, si legge nella dichiarazione del DPC.

Anche se è noto che terze parti hanno avuto accesso alle password, le revisioni condotte non hanno rilevato alcuna prova di abuso o accesso non autorizzato.

Poiché la memorizzazione delle password senza adeguate misure di sicurezza, come la crittografia e il controllo degli accessi, costituisce una violazione di diversi articoli del Regolamento generale sulla protezione dei dati dell’UE (GDPR), l’autorità di controllo ha deciso di infliggere a Meta una multa di 91 milioni di euro (101,6 milioni di dollari USA).

Ad oggi, Meta è stata multata per oltre 2,23 miliardi di dollari nell’UE per varie violazioni del GDPR, entrato in vigore nel 2018. Questo importo include anche una multa record di 1,3 miliardi di dollari che è stata inflitta alla società lo scorso anno, contro la quale Meta sta ora cercando di presentare ricorso.

L'articolo Meta multata per 91 milioni di euro! Password in chiaro per uno scandalo globale proviene da il blog della sicurezza informatica.

Static electricity often just seems like an everyday annoyance when a wool sweater crackles as you pull it off, or when a doorknob delivers an unexpected zap. Regardless, the phenomenon is much more fascinating and complex than these simple examples suggest. In fact, static electricity is direct observable evidence of the actions of subatomic particles and the charges they carry.

While zaps from a fuzzy carpet or playground slide are funny, humanity has learned how to harness this naturally occurring force in far more deliberate and intriguing ways. In this article, we’ll dive into some of the most iconic machines that generate static electricity and explore how they work.

What Is It?

Before we look at the fancy science gear, we should actually define what we’re talking about here. In simple terms, static electricity is the result of an imbalance of electric charges within or on the surface of a material. While positively-charged protons tend to stay put, electrons, with their negative charges, can move between materials when they come into contact or rub against one another. When one material gains electrons and becomes negatively charged, and another loses electrons and becomes positively charged, a static electric field is created. The most visible result of this is when those charges are released—often in the form of a sudden spark.

Since it forms so easily on common materials, humans have been aware of static electricity for quite some time. One of the earliest recorded studies of the phenomenon came from the ancient Greeks. Around 1000 BC, they noticed that rubbing amber with fur would then allow it to attract small objects like feathers. Little came of this discovery, which was ascribed as a curious property of amber itself. Fast forward to the 17th century, though, and scientists were creating the first machines designed to intentionally store or generate static electricity. These devices helped shape our understanding of electricity and paved the way for the advanced electrical technologies we use today. Let’s explore a few key examples of these machines, each of which demonstrates a different approach to building and manipulating static charge.

The Leyden Jar

An 1886 drawing of Andreas Cunaeus experimenting with his apparatus. In this case, his hand is helping to store the charge. Credit: public domain
Though not exactly a machine for generating static electricity, the Leyden jar is a critical part of early electrostatic experiments. Effectively a static electricity storage device, it was independently discovered twice, first by a German named Ewald Georg von Kleist in 1745. However, it gained its common name when it was discovered by Pieter van Musschenbroek, a Dutch physicist, sometime between 1745 and 1746. The earliest versions were very simple, consisting of water in a glass jar that was charged with static electricity conducted to it via a metal rod. The experimenter’s hand holding the jar served as one plate of what was a rudimentary capacitor, the water being the other. The Leyden jar thus stored static electricity in the water and the experimenter’s hand.

Eventually the common design became a glass jar with layers of metal foil both inside and outside, separated by the glass. Early experimenters would charge the jar using electrostatic generators, and then discharge it with a dramatic spark.

The Leyden jar is one of the first devices that allowed humans to store and release static electricity on command. It demonstrated that static charge could be accumulated and held for later use, which was a critical step in understanding the principles that would lead to modern capacitors. The Leyden jar can still be used in demonstrations of electrostatic phenomena and continues to serve as a fascinating link to the history of electrical science.

The Van de Graaff Generator

A Van de Graaff generator can be configured to run in either polarity, depending on the materials chosen and how it is set up. Here, we see the generator being used to feed negative charges into an attached spherical conductor. Credit: Omphalosskeptic, CC BY-SA 3.0
Perhaps the most iconic machine associated with generating static electricity is the Van de Graaff generator. Developed in the 1920s by American physicist Robert J. Van de Graaff, this machine became a staple of science classrooms and physics demonstrations worldwide. The device is instantly recognizable thanks to its large, polished metal sphere that often causes hair to stand on end when a person touches it.

The Van de Graaff generator works by transferring electrons through mechanical movement. It uses a motor-driven belt made of insulating material, like rubber or nylon, which runs between two rollers. At the bottom roller, plastic in this example, a comb or brush (called the lower electrode) is placed very close to the belt. As the belt moves, electrons are transferred from the lower roller onto the belt due to friction in what is known as the triboelectric effect. This leaves the lower roller positively charged and the belt carrying excess electrons, giving it a negative charge. The electric field surrounding the positively charged roller tends to ionize the surrounding air and attracts more negative charges from the lower electrode.

As the belt moves upward, it carries these electrons to the top of the generator, where another comb or brush (the upper electrode) is positioned near the large metal sphere. The upper roller is usually metal in these cases, which stays neutral rather than becoming intensely charged like the bottom roller. The upper electrode pulls the electrons off the belt, and they are transferred to the surface of the metal sphere. Because the metal sphere is insulated and not connected to anything that can allow the electrons to escape, the negative charge on the sphere keeps building up to very high voltages, often in the range of hundreds of thousands of volts. Alternatively, the whole thing can be reversed in polarity by changing the belt or roller materials, or by using a high voltage power supply to charge the belt instead of the triboelectric effect.

The result is a machine capable of producing massive static charges and dramatic sparks. In addition to its use as a demonstration tool, Van de Graaff generators have applications in particle physics. Since they can generate incredibly high voltages, they were once used to accelerate particles to high speeds for physics experiments. These days, though, our particle accelerators are altogether more complex.

The Whimsical Wimshurst Machine

Two disks with metal sectors spin in opposite directions upon turning the hand crank. A small initial charge is able to induce charge in other sectors as the machine is turned. Credit: public domain
Another fascinating machine for generating static electricity is the Wimshurst machine, invented in the late 19th century by British engineer James Wimshurst. While less famous than the Van de Graaff generator, the Wimshurst machine is equally impressive in its operation and design.

The key functional parts of the machine are the two large, circular disks made of insulating material—originally glass, but plastic works too. These disks are mounted on a shared axle, but they rotate in opposite directions when the hand crank is turned. The surfaces of the disks have small metal sectors—typically aluminum or brass—which play a key role in generating static charge. As the disks rotate, brushes made of fine metal wire or other conductive material lightly touch their surfaces near the outer edges. These brushes don’t generate the initial charge but help to collect and amplify it once it is present.

The key to the Wimshurst machine’s operation lies in a process called electrostatic induction, which is essentially the influence that a charged object can exert on nearby objects, even without touching them. At any given moment, one small area of the rotating disk may randomly pick up a small amount of charge from the surrounding air or by friction. This tiny initial charge is enough to start the process. As this charged area on the disk moves past the metal brushes, it induces an opposite charge in the metal sectors on the other disk, which is rotating in the opposite direction.

For example, if a positively charged area on one disk passes by a brush, it will induce a negative charge on the metal sectors of the opposite disk at the same position. These newly induced charges are then collected by a pair of metal combs located above and below the disks. The combs are typically connected to Leyden jars to store the charge, until the voltage builds up high enough to jump a spark over a gap between two terminals.
It is common to pair a Wimshurst machine with Leyden jars to store the generated charge. Credit: public domain
The Wimshurst machine doesn’t create static electricity out of nothing; rather, it amplifies small random charges through the process of electrostatic induction as the disks rotate. As the charge is collected by brushes and combs, it builds up on the machine’s terminals, resulting in a high-voltage output that can produce dramatic sparks. This self-amplifying loop is what makes the Wimshurst machine so effective at generating static electricity.

The Wimshurst machine is seen largely as a curio today, but it did have genuine scientific applications back in the day. Beyond simply using it to investigate static electricity, its output could be discharged into Crookes tubes to create X-rays in a very rudimentary way.

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The Electrophorus: Simple Yet Ingenious

One of the simplest machines for working with static electricity is the electrophorus, a device that dates back to 1762. Invented by Swedish scientist Johan Carl Wilcke, the electrophorus consists of two key parts: a flat dielectric plate and a metal disk with an insulating handle. The dielectric plate was originally made of resinous material, but plastic works too. Meanwhile, the metal disk is naturally conductive.
An electrophorus device, showing the top metal disk, and the bottom dielectric material, at times referred to as the “cake.” The lower dielectric was classically charged by rubbing with fur. Credit: public domain
To generate static electricity with the electrophorus, the dielectric plate is first rubbed with a cloth to create a static charge through friction. This is another example of the triboelectric effect, as also used in the Van de Graaff generator. Once the plate is charged, the metal disk is placed on top of it. The disc then becomes charged by induction. It’s much the same principle as the Wimshurst machine, with the electrostatic field of the dielectric plate pushing around the charges in the metal plate until it too has a distinct charge.

For example, if the dielectric plate has been given a negative charge by rubbing, it will repel negative charges in the metal plate to the opposite side, giving the near surface a positive charge, and the opposite surface a negative charge. The net charge, though, remains neutral. But, if the metal disk is then grounded—for example, by briefly touching it with a finger—the negative charge on the disk can drained away, leaving it positively charged as a whole. This process does not deplete the charge on the dielectric, so it can be used to charge the metal disk multiple times, though the dielectric’s charge will slowly leak away in time.

Though it’s simple in design, the electrophorus remains a remarkable demonstration of static electricity generation and was widely used in early electrostatic experiments. A particularly well-known example is that of Georg Lichtenberg. He used a version a full two meters in diameter to create large discharges for his famous Lichtenberg figures. Overall, it’s an excellent tool for teaching the basic principles of electrostatics and charge separation—particularly given how simple it is in construction compared to some of the above machines.

Zap

Static electricity, once a mysterious and elusive force, has long since been tamed and turned into a valuable tool for scientific inquiry and education. Humans have developed numerous machines to generate, manipulate, and study static electricity—these are just some of the stars of the field. Each of these devices played an important role in furthering humanity’s understanding of electrostatics, and to a degree, physics in general.

Today, these machines continue to serve as educational tools and historical curiosities, offering a glimpse into the early days of electrical science—and they still spark fascination on the regular, quite literally. Static electricity may be an everyday phenomenon, but the machines that harness its power are still captivating today. Just go to any local science museum for the proof!

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2024-09-25 07:46:31

a cura di Maria Teresa Carbone
cliccare per ingrandire
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#AlexandraPetrova #AntonioFrancescoPerozzi #città #dialoghi #GildaPolicastro #GuidoMazzoni #LauraPugno #MariaTeresaCarbone #PiazzaVittorio #ValerioMattioli

26-27-28 settembre, roma: “piazza vittorio. in una qualunque parte del pianeta _ dialoghi”

a cura di Maria Teresa Carbone cliccare per ingrandire

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slowforward.net/2024/09/24/amb…

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2024-09-24 12:57:49

la parola ambientáli può legittimamente vedersi anticipato l’accento: ambièntali, autoesortazione del registrante affinché centri/colga cronotopicamente i cittadini, o i concittadini. (dove non altrimenti specificato, s’intenda dunque: Roma).

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16 set 2024 (2)

slowforward.net/2024/09/24/amb…

#ambientali #audio #podcast

ambièntáli 20240916(2): school

la parola ambientáli può legittimamente vedersi anticipato l’accento: ambièntali, autoesortazione del registrante affinché centri/colga cronotopicamente i cittadini, o i concittadini. (dove n…

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2024-09-24 06:31:58

(sempre che i fascisti al governo non la proibiscano/ostacolino)

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#antisionismo #Cisgiordania #ffffff #Gaza #genocidio #manifestazione #manifestazioneNazionale #Palestina #PalestinaLibera #WestBank

5 ottobre, roma: manifestazione nazionale per la palestina

(sempre che i fascisti al governo non la proibiscano/ostacolino) _

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2024-09-24 00:04:27

instagram.com/p/DAQ_k4Ev52l/

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#art #arte #JeanMichelBasquiat

Casalta on Instagram: "Jean-Michel Basquiat, To Repel Ghosts (1986). - #jeanmichelbasquiat"

12 likes, 0 comments - casalta.nyc on September 23, 2024: "Jean-Michel Basquiat, To Repel Ghosts (1986). - #jeanmichelbasquiat".

^Instagram

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2024-09-23 17:31:46

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#Balestrini #BeniaminoDellaGala #CeciliaBello #CeciliaBelloMinciacchi #LibreriaLibraccio #NanniBalestrini #presentazione #scritturaDiRicerca #scrittureDiRicerca #StefanoColangelo #VociLontaneVociSorelle

video della presentazione di “come agisce nanni balestrini”, di cecilia bello minciacchi (firenze, 10 sett. 2024)

Visita l'articolo per saperne di più.

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