2026-03-27 07:00:09
If you have a 12 VDC power system, like the battery of a PV solar system or car, would it be more efficient to boil water for that cup of tea with that 12V straight from the battery, or use a 240 VAC mains kettle via a ~90% efficient inverter instead? That’s the question that [Cahn] decided to answer experimentally, using a bulky 3 kW inverter and a collection of electric kettles.
Although the used amount of 500 mL of water is boiled much faster in the 2,200 Watt mains kettle than in the 150 and 350 Watt low-voltage kettles, this obvious difference is somewhat irrelevant if you’re only concerned with efficiency. To measure the power used a Victron smart shunt was used with each run, keeping in mind that a perfect efficiency for heating 500 mL from room temperature to boiling is around 43-44 Wh.
With two runs per kettle, the 240 VAC kettle used 65-70 Wh. The first ‘150 Watt’ kettle pulled nearly 200 Watt to boil the water after about 20 minutes, using 62-64 Wh. The second ‘150 Watt’ kettle pulled around 180 Watt, took 23-25 minutes and used 68-74 Wh. Finally, the ‘350 Watt’ kettle drew over 420 Watt and used 50-56 Wh in just over 8 minutes.
When you look at the final results, it’s interesting to note that the low-voltage kettles got both first and last place in this contest, even when factoring in the inverter losses for the 2.2 kW kettle. This makes it quite obvious that the issue at hand is less about DC vs AC or mains vs low-voltage.
The 350 Watt kettle is clearly better designed, featuring a level of insulation that the cheap 12V kettles lack, while pumping more energy into the water at a much faster pace due to the higher current.
Of course, this also shows the whole headache of using 12 VDC appliances like this, as you can only pull so much current from a cigarette lighter socket, while connecting directly to the battery and its juicy 100 A or more poses its own logistical problems. Taking the inverter losses as the price to pay for convenience is thus another totally valid option whenever you’re out camping or at that off-grid cabin.
2026-03-27 04:00:56
So-called bug out cars are a rather silly venture that serve little purpose more than snagging your jumper. The odds of a car working well through a nuclear winter are rather minimal. But what about a bicycle? On paper it’s a better choice, with extreme efficiency, reliability, and runs off whatever sustenance you can find in the barren landscape of a collapsed society. But [Seth] over at Berm Peak proved an apocalypse bike is at least as silly as a bug out car.
While a utilitarian bike fit for a cross-country trek across a nuclear wasteland can certainly be a reasonable venture, this particular bicycle is not that. This three wheeled monstrosity of a bicycle (is it still a bicycle if it has three wheels?) was built by [TOMO] for the Bespoked bike show’s apocalypse buildoff. It placed second among a number of strange bikes with features ranging from pedal driven circular saws to beer keg grills. But this particular example of apocalypse bike is easily the strangest example of the lot.
The features on this custom build are rather extensive, but the star of the show is the trailing link two wheel drive rear end. The third wheel was thrown on last minute with a random shock providing some measure of compliance to the rather unwieldy system. But while adding unnecessary complexity, the third wheel does offer the benefit of bringing along a number of spare parts on the last bikepacking trip of a lifetime. Moreover, it can be easily removed to get something resembling bicycle.
The aforementioned front of the bike while being an actual bike, is likewise a rather strange build. It’s best described as a fat-tired long nosed tall cargo bike. The removable cargo rack is quite effective in storing heavy loads by keeping the center of gravity near or below the axles, it can remain rideable with quite heavy loads. But, if ground clearance is needed, then simply remove the cargo rack, and the bike becomes a bike capable of navigating the nuclear wasteland it was made for.
While this is a silly and questionable bike, it’s certainly not the first strange bike we have seen.
2026-03-27 02:30:30
Pocket computers like Sharp’s 8-bit computing marvels were a big part of the 1980s, providing super-portable processing power to anyone who wanted a bit more than what something like a scientific calculator could provide at the time. These days they are mostly just a collector’s item for retrocomputing enthusiasts, which also means that a lot of the knowledge about how to program the CPUs in them is at risk of being lost.
This is why [gikonekos] decided to combine as much knowledge they can glean from official documentation into a reference project on GitHub for the SC62015 equipped Sharp pocket computers like the PC-E550.
Generally you’d program in Sharp’s dialect of BASIC on these computers, such as the ‘PLAY3’ program that [gikonekos] recently unearthed from a November 1993 copy of ‘Pocket Computer Journal’ using which you can create polyphonic tunes. This only unlocks a small part of what the hardware can do, of course, so having a full opcode reference like this is important.
While still a work in progress, it’ll eventually contain the full opcode and register tables, addressing modes, instruction summaries and of course a full accounting of how all of this was reconstructed. As the original Sharp documentation wasn’t released to the public, providing these scans is also not a goal, especially not under any kind of free license.
A cursory search reveals an instruction table for the PC-E500 from 1995 by [Andrew Woods], so documenting this is not a new thing, although at the time these Sharp pocket PCs didn’t count as ‘retro systems’ yet.
2026-03-26 22:00:34
Consumer-grade 3D printing is good for prototyping and making relatively soft plastic stuff. If you wanna make tough things, though, it’s really hard to beat the strength of metal. [Shake the Future] has produced a guide on using 3D printing in a process to produce solid parts out of actual cast iron.
The concept is simple. [Shake the Future] uses silicon carbide crucibles, which can heat up by absorbing microwave energy. Put one in an insulated container, dump some metal in, and throw it in a microwave, and soon enough you have a pot of molten metal you can use to cast stuff.
Let’s say you want to make an adjustable wrench, which is how [Shake the Future] demonstrates this technique. The first step is to print the wrench parts in plastic, such as PLA. These parts are then packed into fine sand to create casting molds. The PLA is burned out of the mold, leaving a negative imprint of the geometry. Molten cast iron can then be poured into the mold to create the part in solid metal.
It’s a messy technique that requires a lot of manual labor, but it does work quite well. There are some tricks to learn, though, particularly when it comes to successfully casting parts with holes or fine geometric features.
And before you think that you’re going to put the hardware store out of business, it should also be noted that it failed on first encounter with a real-world nut. The thinnest part by the screw just wasn’t strong enough.
Still, it’s a great demo, and if you’ve ever wanted to make a bespoke cast iron part of your own, this work may be very relevant to you. Alternatively, consider learning about DIY aluminium casting—just consider the pitfalls involved.
2026-03-26 19:00:00
One of the most common ways of comparing the processing power of some microcontroller or older smartphone in a fantastical way was to say that they had more processing power than the Apollo Guidance Computer. While this sounds impressive on the surface, the AGC was the first integrated circuit computer ever built and is predictably under-powered by almost all modern standards. A more apt comparison would be to compare a smartphone to a supercomputer from some bygone era, and someone has recently done just that.
The linked article looks at a modern iPhone 17 compared to the Cray 2 supercomputer. When the Cray 2 was first built in the mid 80s, it was the fastest computer in the world at 1.9 GFLOPS using four vector processors. A modern iPhone is estimated to have slightly more than that, so in some ways the iPhone comes out on top.
However, the Cray 2 was built with vector processors, a specialized type of processor meant to perform rapid calculations on specific types of data sets. So the Cray 2 may have been faster at these types of tasks than the more general-purpose A19 processor, and the A19 may have the edge in other tasks.
The other major difference the article doesn’t discuss is what software runs on these computers. The Cray 2 supercomputer ran a modified version of UNIX System V, which at the time was owned by AT&T (and which ran on plenty of other computers as well). Although proprietary in some sense, it was much more open than Apple’s iOS operating system, allowing users to run whatever software they wanted to run on the supercomputers that they bought and paid for, and to modify many parts of the operating system itself. In that sense, the Cray will always maintain the edge over Apple and their walled garden.
2026-03-26 16:00:16
One might think that [Da_Rius]’s mostly 3D printed wire stripper would count its insulation-shearing blades among the small number of metal parts required, but that turns out to not be the case. The blades are actually printed in PLA, seem to work just fine for this purpose. (We imagine they need somewhat frequent replacement, but still.)
Proper wire strippers are one of the most useful tools for a budding electronics enthusiast, because stripping hookup wire is a common task and purpose-built strippers make for quick and consistent results.
As far as tools go they are neither particularly expensive nor difficult to source, but making one’s own has a certain appeal to it. The process of assembling the tool is doubtless a rewarding one, and it looks like it results in a pretty good conversation starter if nothing else.
As mentioned, the tool is mostly 3D printed and does require some metal parts: fasteners, heat-set inserts, and a couple springs. Metal nuts and heat-set inserts are easy enough to obtain, but springs of particular size and shape are a bit trickier.
It is perfectly possible to make custom springs, and as it happens [Da_Rius] already has that covered with a separate project for using a hex key and printed jig to make exactly the right shapes and sizes from pre-tempered spring wire.
