An Unexpected Appearance Of An Iconic Motorola Chip

August 31, 2023 by Maya Posch 24 Comments

Big Clive's reverse-engineered schematic of the USB charger containing the MC34063 IC. — Big Clive’s reverse-engineered schematic of the USB charger containing the MC34063 IC.

Generally when you crack open a cheap car-to-USB charger unit that came with some widget, you do not expect to find anything amazing inside. That’s why it was such a surprise to [Big Clive] when said car USB charger revealed a blast from the past in the form of an MC34063. This is a switching regulator that supports buck, boost and inverting topologies, but perhaps it most notable feature is that it was first produced by Motorola in the early 1980s.

This particular IC is marked as having been produced by ON Semiconductor which means that it’s technically still manufactured by Motorola – with ON Semiconductor being the Phoenix division that was spun off in 1999 – but it’s somewhat remarkable that this particular chip isn’t only produced by ON Semi today, but also by Texas Instruments. Much like the venerable NE555 timer IC and Intel’s 8051 MCU architecture, it would seem that certain chips and designs are simply made to become commodities in the future.

This appears to be the case for the MC34063 as well, which may lack some niceties of more modern ICs, such as built-in thermal protection, and it switches at only up to 100 kHz, but it can be bought for peanuts, has a wide input voltage range of 3 to 40 V, can switch up to 1.5 A and supports multiple common topologies. Often a 100 kHz switching regulator is all you need, in which case it’s handy to have a stack of such commodity chips lying around, plus the MC34063 comes in PDIP packaging as well, which is a boon for prototyping.

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Diving Into Starlink’s User Terminal Firmware

August 31, 2023 by Maya Posch 7 Comments

The average Starlink user probably doesn’t spend a lot of time thinking about their hardware after getting the dish aligned and wiring run. To security researchers, however, it’s another fascinating device to tinker with as they reverse-engineer the firmware and try to both find out what makes it tick, as well as how to break it. This is essentially the subject of [Carlo Ramponi]’s article over at Quarkslab as he digs into the firmware architecture and potential weaknesses in its internal communication.

The user terminal hardware itself is a quite standard AArch64 ARM-based SoC, along with the proprietary communication interface, all of which is controlled by the Linux-based firmware. Dumping the firmware itself was made easy thanks to existing work by researchers at the KU Leuven, involving dumping the contents of the onboard eMMC storage. After this the firmware architecture could be analyzed, which turned out to consist out of mostly C++-based binaries, but with a single big binary for the user front-end written in Go.

Communication between these processes is handled through a custom inter-process protocol called ‘Slate Sharing’, all of which is coordinated via the core User Terminal Control process. It are these Slate IPC messages which form the most likely attack surface for a fuzzing attack, with the SoftwareUpdateRequest command being an interesting target as it would seem to not require authentication since it doesn’t address a specific user. This work is part of [Carlo]’s master’s thesis, and should form the basis of further research on the Starlink User Terminal firmware.

The McDonald’s Ice Cream Machine Saga And Calls For Right To Repair

August 30, 2023 by Maya Posch 45 Comments

The inside of a Taylor C709 ice cream machine, as seen from the back with the cover on the electronics removed. (Credit: iFixit) — The inside of a Taylor C709 ice cream machine, as seen from the back with the cover over the electronics removed. (Credit: iFixit)

Raising a likely somewhat contentious topic, iFixit and Public Knowledge have challenged the manufacturer behind McDonald’s ice cream machines to make them easy to diagnose and repair. This is a subject that’s probably familiar to anyone who is vaguely familiar with US news and the importance of ice cream at McDonald’s locations to the point that a live tracker was set up so that furtive customers can catch a glimpse at said tracker before finding themselves staring in dismay at an ‘Out of Order’ sign on one of these Taylor ice cream machines.

The story is more complex than just a machine being “broken”, however. The maintenance contracts are lucrative, the instruction manual is long, and the error codes are cryptic. When you add to that the complexity of cleaning and maintaining the machines, it’s tempting to just claim the machine is out of order. These Taylor machines (the C602 and the C709 from the iFixit video) are a bit more complex than your usual ice cream maker in that they also have a pasteurization element that’s supposed to keep already poured mix safe to use the next day.

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The 2003 Northeast Blackout And The Harsh Lessons Of Grid Failures

August 29, 2023 by Maya Posch 87 Comments

The grid failure in 2003 which reverted much of the eastern US and Canada back to a pre-electrification era may be rather memorable, yet it was not the first time that a national, or even international power grid failed. Nor is it likely that it will be the last. In August of 2023 we mark the 20th anniversary of this blackout which left many people without electricity for up to three days, while costing dozens of people their lives. This raises the question of what lessons we learned from this event since then.

Although damage to transmission lines and related infrastructure is a big cause of power outages – especially in countries where overhead wiring is the norm – the most serious blackouts involve the large-scale desynchronization of the grid, to the point where generators shutdown to protect themselves. Bringing the grid back from such a complete blackout can take hours to days, as sections of the grid are reconnected after a cascade scenario as seen with the 2003 blackout, or the rather similar 1965 blackout which affected nearly the same region.

With how much more modern society relies today on constant access to electrical power than it did twenty, let alone fifty-eight years ago, exactly how afraid should we be of another, possibly worse blackout?

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Microelectrode (Utay) array and the decoding of the corresponding actions. (Francis R. Willet et al., 2023)

Restoring A Person’s Voice Using A Brain-Computer Interface

August 28, 2023 by Maya Posch 5 Comments

Being able to vocalize is one of the most essential elements of the human experience, with infants expected to start babbling their first words before they’re one year old, and much of their further life revolving around interacting with others using vocalizations involving varying degrees of vocabulary and fluency. This makes the impairment or loss of this ability difficult to devastating, as is the case with locked-in syndrome (LIS), amyotrophic lateral sclerosis (ALS) and similar conditions, where talking and vocalizing has or will become impossible.

In a number of concurrent studies, the use of a brain-computer interface (BCI) is investigated to help patients suffering from LIS (Sean L. Metzger et al., 2023) and ALS (Francis R. Willett et al., 2023) to regain their speaking voice. Using the surgically implanted microelectrode arrays (Utah arrays) electrical impulses pertaining to the patient’s muscles involved in speaking are recorded and mapped to phonemes, which are the elements that make up speech. Each of these phonemes requires a specific configuration of the muscles of the vocal tract (e.g. lips, tongue, jaw and larynx), which can be measured with a fair degree of accuracy. Continue reading “Restoring A Person’s Voice Using A Brain-Computer Interface” →

Close-up of a magnetic tentacle robot next to a phantom bronchiole (Credit: University of Leeds)

The Healing Touch Of Magnetic Tentacles In Photothermal Lung Cancer Therapy

August 28, 2023 by Maya Posch 11 Comments

Of the body’s organs, the lungs are among the trickiest to take a biopsy and treat cancer in, both due to how important they are, as well as due to their inaccessibility. The total respiratory surface within the average human lungs is about 50 to 75 square meters. Maneuvering any kind of instrument down the endless passages to reach a suspicious area, or a cancerous region to treat is nearly impossible. This has so far left much of the lungs inaccessible.

The standard of care for lung cancer is generally surgical: remove parts of the lung tissue. However, a proposed new method using magnetic tentacles may soon provide a more gentle approach, as described in Nature Engineering Communications by Giovanni Pittiglio and colleagues (press release).

The tentacles are made out of a silicone substrate with embedded magnets that allow for it to be steered using external magnetic sources. With an embedded laser fiber, the head of the tentacle can be guided to the target area, and the cancerous tissue sublimated using an external laser source. In experiments on cadavers with this system, the researchers found that they could enter 37% deeper into the lungs than with standard equipment. The procedure was also completed with less tissue displacement.

Considering the high fatality rate of lung cancers, the researchers hope that this approach could soon be turned into a viable therapy, as well as for other medical conditions where a gentle tentacle slithering into the patient’s body could effect treatments previously considered to be impossible.

Heading image: Close-up of a magnetic tentacle robot next to a phantom bronchiole (Credit: University of Leeds)

Input impedance plottet as a function of trace impedance for trace lengths of 1/10, 1/16 and 1/20 of a wavelength. (Credit: Baltic Labs)

When Does Impedance Matching A PCB Trace Become Unavoidable?

August 27, 2023 by Maya Posch 21 Comments

A common joke in electronics is that every piece of wire and PCB trace is an antenna, with the only difference being whether this was intentional or not. In practical terms, low-frequency wiring is generally considered to be ‘safe’, while higher frequency circuits require special considerations, including impedance (Z) matching. Where the cut-off is between these two types of circuits is not entirely clear, however, with various rules-of-thumb in existence, as [Sebastian] over at Baltic Lab explains.

A popular rule is that no impedance matching between the trace and load is necessary if the critical length of a PCB trace (l_crit) is 1/10th of the wavelength (λ). Yet is this rule of thumb correct? Running through a number of calculations it’s obvious that the only case where the length of the PCB trace doesn’t matter is when trace and load impedance are matched.

According to these calculations, the 1/10 rule is not a great pick if your target is a mismatch loss of less than 0.1 dB, with 1/16 being a better rule. Making traces wider on the PCB can be advisable here, but ultimately you have to know what is best for your design, as each project has its own requirements. Even when the calculations look good, that’s no excuse to skip the measurement on the physical board, especially with how variable the dielectric constant of FR4 PCB material can be between different manufacturers and batches.

Heading image: Input impedance plotted as a function of trace impedance for trace lengths of 1/10, 1/16, and 1/20 of a wavelength. (Credit: Baltic Labs)

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