2026-04-07 23:30:51
It is a running gag around here that whenever a project posts, someone will inevitably point out that it could have been done with a 555 timer IC. [Stephen Woodward] went the opposite way and built a simple thermostat using the ubiquitous chip.
To be fair, this isn’t some sophisticated PID controller — it’s basically a bang-bang controller. Since the device has a comparator and the circuits use a thermistor, it seems like a clever but simple idea on the surface. However, there are some neat tricks. For example, if you tie the 555 threshold pin to Vdd, then the trigger pin acts as an inverting analog comparator. Another nice feature: the setpoint depends on a resistance ratio, so there is no need for a precise input voltage reference.
A simple circuit change can switch the circuit to power a heater or a cooler. The chip can handle a surprising amount of power, but for some applications, you may need some output drive circuitry. The simple circuit even has hysteresis, which you can set with a different resistor. Pretty impressive for a cheap chip, two resistors, a thermistor, and a battery.
We’ve seen a lot of strange 555 circuits in our contests. We even had a 555 Timer Contest.
2026-04-07 22:00:04
If you’ve ever bought a suspiciously cheap Ethernet cable from an online listing, there’s a decent chance you’ve encountered Copper Clad Aluminum. Better known as CCA, it’s exactly what it sounds like—an aluminium conductor with a thin skin of copper deposited on the outside. Externally, cables made with this material look largely like any other, with perhaps the only obvious tell being that they feel somewhat lighter in the hand.
CCA is cheaper than proper copper cabling, and it conducts signals well enough to function in an Ethernet cable. And yet, it’s a prime example of corner-cutting that keeps standards bodies and professional installers up at night. But just how dangerous is this silent scourge, found lurking in so many network cabinets around the world?
Everything you need to know about CCA is in the name—it refers to an aluminium wire with a thin copper cladding, typically applied through a die extrusion process. The reasoning behind this exploits a real physical phenomenon called the skin effect, wherein higher-frequency AC signals tend to travel along the outer surface of a conductor. The idea goes that since most of the current moves through the outer copper skin layer anyway, the less-conductive aluminium core doesn’t unduly impact the wire’s performance. Using copper-clad aluminium wiring is, in theory, desirable because aluminium is much cheaper than copper, which can really add up over long cable runs. Imagine you’re wiring a building with with hundreds of miles of Ethernet cabling, all with eight conductors each—the savings add up pretty quickly.
There’s a problem with CCA cabling in these contexts, though. Due to prevailing cabling standards, any cable made with CCA is technically not even a real Ethernet cable at all. The relevant documents are unambiguous.
ANSI/TIA-568.2-D requires conductors in Category-rated cable to be solid or stranded copper. No other materials are acceptable, and thus CCA is explicitly excluded from use in Category cable applications. A cable with CCA conductors cannot legitimately carry a Cat5e, Cat6, or any related designation under any circumstances. Similarly, ISO/IEC 11801 has the same requirement. The U.S. National Electrical Code also states that conductors in communications cables, other than coaxial cable, shall be copper. This isn’t a suggestion or a best practice; it’s the letter of the code. Anything lesser is simply not allowed.
CCA cabling can be hard to detect, particularly where a manufacturer has intentionally hidden the fact that the inferior wiring is used. One way to be sure is to strip a wire and scrape away at the copper to see if there’s aluminium lurking inside.
The simple fact is that regulators demand a certain level of quality for communications cable, and CCA just isn’t it. In the specific case of Ethernet cabling, it is worth noting that the skin effect that makes CCA construction useful in other applications doesn’t really apply. That’s because the skin effect is frequency-dependent, and so it doesn’t apply to DC power as used in Power over Ethernet. In fact, the DC resistance of a CCA conductor of the same gauge is roughly 55% higher than copper of the same gauge. CCA cables also tend to be less flexible and more brittle than the proper all-copper equivalent. These are fundamental physical ways in which CCA doesn’t measure up to scratch. These differences aren’t enough to stop the cables working for their intended purpose in many cases, but it’s part of the reason that standards organizations mandate pure copper and nothing less.
The problem that stems from this is that installing CCA communications cable in a building can make the installation non-compliant and potentially even illegal in jurisdictions that adopt these relevant standards. Much of the concern comes down to fire ratings and insurance concerns. For example, the UL 444 standard lays out the requirements for cables to meet the CM, CMR, CMG, and CMP fire ratings you see printed on legitimate cable jackets. These rules require copper conductors. Thus, CCA cable cannot carry a valid UL listing and any install using it will not be compliant with fire safety regulations. A building with such cable installed would be potentially liable to have any insurance invalidated for not meeting basic code requirements. Any contractor installing such cable could be liable in turn.
Grabbing a cigarette lighter can also help determine if given cabling is pure copper or copper clad aluminium.
The question is, though—are CCA cables actually a real-world fire risk? That is harder to answer. The common concern is that a tightly-wrapped bundle of CCA Ethernet cables running Power over Ethernet could get hotter than intended due to increased resistance, eventually overheating, melting, or catching alight. With that said, we are yet to see any grand examples of buildings catching fire and burning to the ground because of CCA cabling. Such cables might not be to spec, and they might not do as well when used for Power over Ethernet due to their higher resistance, particularly over longer runs. However, issues are likely to be more related to insufficient power delivery rather than severe overheating. Where there’s no smoke, there usually isn’t fire. There would be plenty of photos online of melted CCA cables being pulled out of smoking rubble if this was occurring on the regular.
Ultimately, if you’ve got a CCA cable or two running around your house, you probably don’t have a lot to worry about. They might not survive as well as a proper copper cable, and they might be a little dodgy on long runs with PoE equipment, but they aren’t just going to burst into flames at the drop of a hat. With that said, they are technically uncompliant with all relevant standards, and if you’re trying to meet code, you should absolutely steer clear of CCA in all cases. This warning, and so many that have come before, won’t do much to stem the flow of CCA cables into the market, but it might at least stop you making a mistake the next time you’re speccing a new cable project. Stay safe out there.
2026-04-07 19:00:38
There’s been a lot of virtual ink spilled in environmental circles about the cooling water requirements of data centers, but less consideration of what happens with all the heat coming out of these buildings. Naturally, it’s going to warm the surrounding environment, but how much? Around 2 C (3.6 F) on average, and potentially much more than that, according to a recent study on the data heat island effect.
It’s common sense, of course: heat removed from the data center doesn’t go away. That heat might go into a body of water if one is available, but otherwise it’s out into the atmosphere to warm up everybody else’s day. In some places — like a Canadian winter — that might not be so bad. In others, where climate change and urban heat islands are cranking up the summertime temperatures, it very much could be. Especially if you’re in the worst-case scenario micro-climate described by the paper, which saw a predicted increase of 9.1 C (16 F).
Now, these results are theoretical and need to be ground-truthed, but anyone who has huddled next to the air-exchange unit of a large building for warmth knows there’s something to them. Unfortunately there don’t seem to be before-and-after measurements available for existing data-centers — AI or otherwise — to show exactly what their heat output is doing in the real world, but the urban heat island effect from all the dark asphalt in our cities is well known. Cooling paint and green roofs can help with that, but they won’t do much for the megawatts being pumped out to keep your cousin’s AI girlfriend online.
Some would argue that all this heat wouldn’t be a problem if we could launch the data centers outside the environment — just have a care the front doesn’t fall off.
2026-04-07 16:00:36
In the mid 1970s there were a spate of movies depicting the romance and lifestyle of truck drivers in the southern half of the United States. Over on the other side of the Atlantic these were naturally received not as works of drama but as documentaries, and thus began a craze for British drivers to do up their Ford Capri so in the right light and with your eyes nearly closed, it almost looked like Burt Reynolds’ Pontiac Trans Am from Smokey and the Bandit.
Such a fine automobile was of course incomplete without a CB radio, highly illegal at the time, which led to an underground CB craze and its eventual legalization in 1981. [Ringway Manchester] is here with a tale from that era, of 934 MHz CB, an odd and underused allocation that was eventually phased out for commercial services.
When UK CB was eventually legalized by the government, it was very obvious that they really didn’t want to. Brits got 27 MHz as FM only with meager power and a weird set of frequencies that nobody else had, and a second band way up in the UHF range, at 934 MHz. We remember they originally tried to make a UHF band the only allocation on purpose because it was nearly useless for mobile operation, and Brits only got 27 MHz by fighting back in the political lobbying space.
The video below tells the story of the band, with relatively scarce and expensive equipment leading to it being an exclusive band more similar to the amateur bands, with little resemblance to its raucous 27 MHz counterpart. How much activity there was depended very much on where in the country you were, which of course wasn’t where your Hackaday scribe was as a teenager even if it had been affordable. Eventually the government saw the little flashing pound signs and grabbed it back for a mobile radio service that never materialized, and now the frequencies are part of the mobile phone spectrum.
Have a watch for an odd bit of UK radio nostalgia and some 2020s illegal CB’ers, and if you want more it’s a subject we’ve touched on before.
2026-04-07 13:00:41
The Pokéwalker is a gadget that was sold alongside the Pokémon HeartGold and SoulSilver games for the Nintendo DS, using which you could take a Pokémon of your choice with you on a walk. Not only would you earn points while walking, but you’d be able to find items, battle wild Pokémon, etc. The Pokémon inside the device is however linked to the game cartridge. This fact turned into tragedy when [Etchy] found his old Pokéwalker with a treasured Pokémon still on it, but was forced to erase the device as he had lost the cartridge over the years.
Although he had been told repeatedly by then that it was impossible to transfer such a digital pet to a new save file, this never felt right. Although it made some sense that a specific critter would be linked to a specific save file as a level of security, there’s also the question of whether all data of the Pokémon in question would be erased from said save file.
Fortunately, [Dmitry] has reverse-engineered the Pokéwalker already, including the infrared protocol that uses the IR transceiver in the cartridge itself. As it turns out, only some basic information is sent over to the device, while the Pokémon is simply hidden in the save file, including the data that isn’t sent to the device. Case closed, right?
It would be a sad ending for those who have lost Pokémon on these devices if it was that simple, fortunately. After some digging, [Etchy] found out that the device only checks for three pieces of information to ensure that it is being accessed from a valid game session: the version (HeartGold or SoulSilver), the region (NA, JP, etc.) and the training and secret IDs.
This thus means that if you try long enough, or use an RNG manipulation hack as demonstrated, you can get a new save file created that has the exact same IDs. As long as you after that make sure that your local critter’s details in terms of species and form are the same as on the device, there’s nothing really stopping the device from happily handing over the critter’s details.
Of course, the real thing that defines a single Pokémon is its ID (PID) that defines its properties, and this is only saved in the save file. The final answer is thus that there’s no way to rescue a trapped Pokémon, as it only really exists on the cartridge that may or may not still exist in some physical form.
2026-04-07 10:00:19
A few years back a company had an ad campaign with a discouraged caveman who was angry because the company claimed their website was “so easy, even a caveman could do it.” Maybe that inspired [JuliusBrussee] to create caveman, a tool for reducing costs when using Claude Code.
The trick is that Claude, like other LLMs, operates on tokens. Tokens aren’t quite words, but they are essentially words or word fragments. Most LLM plans also charge you by the token. So fewer tokens means lower costs. However, LLMs can be quite verbose, unless you make them talk like a caveman.
For example, here is some normal output from Claude:
Sure! I’d be happy to help you with that. The issue you’re experiencing is most likely caused by your authentication middleware not properly validating the token expiry. Let me take a look and suggest a fix.
After Caveman that is reduced to:
Bug in auth middleware. Token expiry check use < not <=. Fix:
Turns out, you can understand the caveman output just fine.
There are a few rules. Caveman removes filler words, but knows to keep technical terms, code blocks, and error messages intact. It also outputs normal messages for things like commits.
As the website says: “Caveman not dumb. Caveman efficient. Caveman say what need saying. Then stop. If caveman save you mass token, mass money — leave mass star.”
If you want to code with an LLM, make sure you understand the terms of service. If you want to learn more about how LLMs work with tokens and other details, but want to skip the math, we can help with that.
