Self-Driving Cars And The Fight Over The Necessity Of Lidar

October 30, 2025 by Maya Posch 73 Comments

If you haven’t lived underneath a rock for the past decade or so, you will have seen a lot of arguing in the media by prominent figures and their respective fanbases about what the right sensor package is for autonomous vehicles, or ‘self-driving cars’ in popular parlance. As the task here is to effectively replicate what is achieved by the human Mark 1 eyeball and associated processing hardware in the evolutionary layers of patched-together wetware (‘human brain’), it might seem tempting to think that a bunch of modern RGB cameras and a zippy computer system could do the same vision task quite easily.

This is where reality throws a couple of curveballs. Although RGB cameras lack the evolutionary glitches like an inverted image sensor and a big dead spot where the optical nerve punches through said sensor layer, it turns out that the preprocessing performed in the retina, the processing in the visual cortex and analysis in the rest of the brain is really quite good at detecting objects, no doubt helped by millions of years of only those who managed to not get eaten by predators procreating in significant numbers.

Hence the solution of sticking something like a Lidar scanner on a car makes a lot of sense. Not only does this provide advanced details on one’s surroundings, but also isn’t bothered by rain and fog the way an RGB camera is. Having more and better quality information makes subsequent processing easier and more effective, or so it would seem.

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Why Sodium-Ion Batteries Are Terrible For Solar Storage

October 30, 2025 by Maya Posch 82 Comments

These days just about any battery storage solution connected to PV solar or similar uses LiFePO4 (LFP) batteries. The reason for this is obvious: they have a very practical charge and discharge curve that chargers and inverters love, along with a great round trip efficiency. Meanwhile some are claiming that sodium-ion (Na+) batteries would be even better, but this is not borne out by the evidence, with [Will Prowse] testing and tearing down an Na+ battery to prove the point.

The Hysincere brand battery that [Will] has on the test bench claims a nominal voltage of 12 V and a 100 Ah capacity, which all appears to be in place based on the cells found inside. The lower nominal voltage compared to LFP’s 12.8 V is only part of the picture, as can be seen in the OCV curve. Virtually all of LFP’s useful capacity is found in a very narrow voltage band, with only significant excursions when reaching around >98% or <10% of state of charge.

What this means is that with existing chargers and inverters, there is a whole chunk of the Na+ discharge curve that’s impossible to use, and chargers will refuse to charge Na+ batteries that are technically still healthy due to the low cell voltage. In numbers, this means that [Will] got a capacity of 82 Ah out of this particular 100 Ah battery, despite the battery costing twice that of a comparable LFP one.

Yet even after correcting for that, the internal resistance of these Na+ batteries appears to be significantly higher, giving a round trip efficiency of 60 – 92%, which is a far cry from the 95% to 99% of LFP. Until things change here, [Will] doesn’t see much of a future for Na+ beyond perhaps grid-level storage and as a starter battery for very cold climates.

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Hello World In C Without Linking In Libraries

October 29, 2025 by Maya Posch 27 Comments

If there’s one constant with software developers, it is that sometimes they get bored. At these times, they tend to think dangerous thoughts, usually starting with ‘What if…’. Next you know, they have gone down a dark and winding rabbit hole and found themselves staring at something so amazing that the only natural conclusion that comes to mind is that while educational, it serves no immediate purpose.

The idea of applying this to snipping out the <stdio.h> header in C and the printf() function that it provides definitely is a good example here. Starting from the typical Hello World example in C, [Old Man Yells at Code] over at YouTube first takes us from the standard dynamically linked binary at a bloated 16 kB, to the statically linked version at an eyepopping 767 kB.

To remove any such dynamic linkages, and to keep file sizes somewhat sane, he then proceeds to first use the write()function from the <unistd.h> header, which does indeed cut out the <stdio.h> include, before doing the reasonable thing and removing all includes by rewriting the code in x86 assembly.

While this gets the final binary size down to 9 kB and needs no libraries to link with, it still performs a syscall, after setting appropriate register values, to hand control back to the kernel for doing the actual printing. If you try doing something similar with syscall(), you have to link in libc, so it might very well be that this is the real way to do Hello World without includes or linking in libraries. Plus the asm keyword is part of C, although one could argue that at this point you could just as well write everything in x86 ASM.

Of course, one cannot argue that this experience isn’t incredibly educational, and decidedly answers the original ‘What if…’ question.

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Testing Cheap DC Breakers And How To Not Start Fires

October 28, 2025 by Maya Posch 11 Comments

One characteristic of adding PV solar to homes is a massive increase in high-voltage and high-current DC installations. With this comes a need for suitable breakers, but without the requisite knowledge it can be easy to set up a fire hazard. There is also the issue of online shopping platforms making it easy to get fuses and breakers that may not be quite as capable as they claim, never mind being rated for DC use.

Recently [Will Prowse] had a poke at a range of common purportedly DC-rated breakers from everyone’s favorite US-based seller of tat, to see whether they should be bought or avoided at all cost. Perhaps unsurprisingly the cheap breakers are about as dodgy as you’d imagine. With a hundred plus amps flowing through them they get surprisingly crispy, even if they generally did their job. Minus the few that arrived in a broken condition, of course.

Ultimately [Will] found that the molded case circuit break (MCCB) by one ‘DIHOOL’ performed the best. Compared to the competition, it is much larger and has sizeable terminals that avoid the quaint heat-soaking issues seen with the cheap-and-cheerful rest. At a mere $34 for the 125A-rated version, it’s still a fraction of the cost of a comparable Eaton MCCB, but should upset your insurance company significantly less than the alternatives.

Don’t forget to add in fuses, with [Will] testing a range of cheapo 12V DC fuses, to see which one will prevent fires, and which one cause them. Unsurprisingly, some of them like the Bojack-branded ones ran very hot, making them more of a liability than an asset.

As for what makes DC breakers so different from AC one is that the extinguishing point of a DC arc is much steeper, which means that an AC breaker is likely to fail to extinguish the arc when used for DC applications. This is why a properly rated and ideally certified breaker is essential, and also not really the point where you want to start saving money.

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Making A Virtual Machine Look Like Real Hardware To Malware

October 27, 2025 by Maya Posch 35 Comments

Running suspicious software in a virtual machine seems like a basic precaution to figure out whether said software contains naughty code. Unfortunately it’s generally rather easy to detect whether or not one’s software runs inside a VM, with [bRootForce] going through a list of ways that a VirtualBox VM can be detected from inside the guest OS. While there are a range of obvious naming issues, such as the occurrence of the word ‘VirtualBox’ everywhere, there many more subtle ways too.

Demonstrated is the PoC ‘malware’ application called Al-Khaser, which can be used to verify one’s anti-malware systems, such as when trying to unleash a debugger on a piece of malware, run it inside a VM, along with many more uses. Among its anti-virtualization features are specific registry key names and values, file system artefacts, directory names, MAC addresses, virtual devices, etc.

In order to squeeze by those checks, [bRootForce] created the vbox_stealth shell script for Bash-blessed systems in order to use the VirtualBox Manager for the renaming of hardware identifier, along with the VBoxCloak project’s PowerShell script that’s used inside a Windows VirtualBox guest instance to rename registry keys, kill VirtualBox-specific processes, and delete VirtualBox-specific files.

Theoretically this should make it much harder for any malware to detect that it’s not running inside Windows on real hardware, but as always there are more subtle ways that are even harder to disguise.

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Building A Hydraulic Gear Pump Isn’t So Easy

October 27, 2025 by Maya Posch 8 Comments

The gear pump prototype in action. (Credit: Artisan Makes, YouTube)

Hydraulic gear pumps are deceptively simple: just two gears rotating together, forcing the hydraulic oil from one side to the other where the teeth don’t meet, and thus providing the ability to pressurize said oil to make hydraulic cylinders, final drives, etc. do their thing. As with most machining projects like this, the devil is absolutely in the details, particularly in the tolerances. This is the crash course that the [Artisan Makes] channel on YouTube is currently going through.

In this part one of a series on a DIY gear pump, scrap aluminium is used for the housing, along with 1045 medium carbon steel for the gears and W1A high carbon steel for bearings and other wear surfaces. Since at least one of the gears needs to be driven, a lip seal rated for 10 bar is used to provide a path for the shaft. As noted in the video, this is supposed to be a learning experience, ergo it’s a simplified design that merely targets being functional as a gear pump.

With the basic design figured out, the parts were created on the lathe and mill, followed by assembly. Most of the controversy is about the tolerances within the housing, as any leakage will reduce the efficiency. This means the spacing between the gears and housing, space between the gears and bearings, as well as that provided by the gasket that seals the housing base and top. This is where the comment section somewhat explodes with criticism and advice.

As can be seen in the demonstration with a better gasket, there is absolutely flow when driven at 1200 RPM, but also clearly severe leakage as evidenced by said flow not moving quite as fast as it should. We’re looking forward to the next part, in which addressing these tolerances is tackled, with hopefully a much more performant gear pump resulting.

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Satellite Snooping Reveals Sensitive Unencrypted Data

October 27, 2025 by Maya Posch 25 Comments

In an era where running a website without HTTPS is shunned, and everyone wants you to encrypt your DNS queries, you’d expect that the telecommunications back-ends are secured tightly as well. Especially the wireless bits between terra firma and geosynchronous communication satellites.

But as recently discovered by US researchers, the opposite is actually true. The paper by [Wenyi Morty Zhang] et al. (PDF) goes into great detail on how they discovered these unencrypted IP traffic flows and what they found in these captures.

With an off-the-shelf consumer satellite dish mounted to the roof of a university building in San Diego, they performed a scan of IP traffic on 39 geosynchronous satellites. To their surprise, they found unencrypted data that belonged to companies like T-Mobile for their cellular backhaul, Internet traffic targeting airliners, and VoIP communication — all in the clear.

Even more worrying was what looked like military traffic and corporate VPN data containing unencrypted login details, corporate emails and much more. While T-Mobile immediately enabled encryption after this discovery, it remains to be seen whether anyone else will. It’s probably best to assume that any communication can be intercepted and to use e.g. PGP-encrypted emails for anything sensitive.

The researchers have made the IP encapsulation parser (in Python) for DVB-S2(X) captures available for anyone who wants to give this experiment a whirl themselves.