Making A Nichrome Wirewound Power Resistor

Although not really a cost-effective or a required skill unless you have some very specific needs not met by off-the-shelf power resistor options, making your own own wirewound power resistor is definitely educational, as well as a fascinating look at a common part that few people spare a thought on. Cue [TheElectronBench]’s video tutorial on how to make one of these components from scratch.

The resistance value is determined by the length of nichrome wire, which is an alloy of nickel and chromium (NiCr) with a resistivity of around 1.12 µΩ/m. It’s also extremely durable when heated, as it forms a protective outer layer of chromium oxide. This makes it suitable for very high power levels, but also requires the rest of the power resistor assembly to be able to take a similar punishment.

For the inner tube of this DIY power resistor a tube of alumina ceramic was used, around which the nichrome wire is wound. This resistor targets 15 Ohm at a maximum load of 50 Watt, this means a current of about 1.83 A is expected at 27.4 V. The used nichrome wire has a measured resistance of 10.4 Ohm, ergo 1.44 meter has to be cut and wound.

This entire assembly is then embedded in refractory cement (fireproof cement), as this will keep the wire in place, while also able to take the intense temperature cycling during operation. As a bonus this will prevent toasting the surrounding environment too much, never mind lighting things on fire as the nichrome wire heats up.

As explained in the video, this is hardly the only way to create such a power resistor, with multiple types of alternative alloys available, different cores to wind around and various options to embed the assembly. The demonstrated method is however one that should give solid results and be well within the capabilities and budget of a hobbyist.

An important point with nichrome is that you cannot really solder to it, so you’ll need something along the lines of a mechanical (crimping) connection. There are also different winding methods that can affect the inductance of the resistor, since this type of resistor is by its design also a coil. This is however not covered in the video as for most applications it’s not an issue.

Overall, this video tutorial would seem to be a solid introduction to nichrome power resistors, including coverage of many issues you may encounter along the way. Feel free to sound off in the comment section with your own experiences with power resistors, especially if you made them as well.

Using FireWire On A Raspberry Pi Before Linux Drops Support

Once the premium option for data transfers and remote control for high-end audiovisual and other devices, FireWire (IEEE 1394) has been dying a slow death ever since Apple and Sony switched over to USB. Recently Apple correspondingly dropped support for it in MacOS 26, and Linux will follow in 2029. The bright side of this when you’re someone like [Jeff Geerling] is that this means three more years of Linux support for one’s FireWire gear, including on the Raspberry Pi with prosumer gear from 1999.

If you’re not concerned about running the latest and greatest – and supported – software, then using an old or modern Mac or PC is of course an option, but with Linux support still available [Jeff] really wanted to get it working on Linux. Particularly on a Raspberry Pi in order to stay on brand.

Adding a FireWire port to a Raspberry Pi SBC is easy enough with an RPi 5 board as you can put a Mini PCIe HAT on it into which you slot a mini PCIe to Firewire adapter. At this point lspci shows the new device, but to use it you need to recompile the Linux kernel with Firewire support. On the Raspberry Pi you then also need to enable it in the device tree overlay, as shown in the article.

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Water Cooling The MacBook Neo Laptop To Double Gaming Performance

Recently [ETA Prime] felt a bit underwhelmed by the raw performance of his MacBook Neo when it came to running for extended periods under full load, such as when gaming. Thus the obvious solution is to mildly over-engineer a cooling solution that takes care of issues like thermal throttling.

The Apple MacBook Neo with its repurposed iPhone 16 SoC seems to have leaned hard into answering the question whether a smartphone can be a good general purpose personal computer. Ignoring the lack of I/O, it’s overall not a bad SoC for a laptop, but like when you try to push the CPU and GPU on a smartphone, they do get pretty toasty. Due to the minimalistic cooling solution in the MacBook Neo it’ll easily hit the 105°C thermal throttle limit.

Technically the ‘heatsink’ for this laptop is the aluminium case, as the SoC is coupled via a thermal pad to the case. This doesn’t leave a lot of space and the case will heat soak pretty fast, while also making retrofitting a cooling solution a challenge.

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Improving Soda By Turning It Into Mead

Test tasting soda mead. (Credit: Golden Hive Mead, YouTube)
Test tasting soda mead. (Credit: Golden Hive Mead, YouTube)

You can certainly just chug down that bottle of soda you purchased, but if you accept the premise that the preparation of food and drink is just a subset of chemistry, and that chemistry is fun, then it naturally follows that using soda as the basis for brewing up some mead makes perfect sense. Thus the [Golden Hive Mead] blokes over on YouTube decided to create some Coca Cola flavored mead.

Mead is essentially just water mixed with honey that is left to ferment after adding yeast, resulting in what is also called ‘honey wine’, with an ethanol content of usually between 3.5% and 20%. Since soda is mostly water and comes with its own supply of sugar for yeast to feast on, this isn’t such a crazy choice in that respect. Just make sure to remove the carbonation, as the CO2 makes the soda too acidic for the yeast to be happy.

Instead of straight honey, caramelized honey was used for extra flavor after which the brew was left to ferment for a while. For extra flavor notes aged oak, vanilla and cinnamon were added as well, to ensure that the fermentation didn’t erase those core notes of the coke. The result was apparently rather flavorful, with about a 10.5% ethanol content, receiving the full approval of both tame test tasters.

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Comparing The Power Usage Of 12 VDC And 240 VAC Kettles

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.

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Reconstructed SC62015 Opcode Reference For Sharp Pocket Computers

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.

Testing Severely Neglected VHS Tapes And CDs

Check your tape for spider nests before rewinding. (Credit: Brady Brandwood, YouTube)
Check your tape for spider nests before rewinding. (Credit: Brady Brandwood, YouTube)

Physical media has a certain amount of durability associated with it, a quality which is naturally determined by the way that they’re stored. Generally this does not involve being abandoned on the porch of a dilapidated, abandoned house where the elements and any passing critter can have their way with it.

Exactly how playable would these VHS tapes and CDs still be? Whether it was out of a sense of burning curiosity, or for a similar reason that [Brady Brandwood] has a habit of adopting former seafood critters like lobsters as adorable pets, these items got recently collected and put to the test.

Normally VHS tapes are kept safely in a little sleeve or box in a dry, cool place, similar to CDs and DVDs. These particular items had however been left for at least a decade out in the open amidst the ransacked remains of abandoned homes. This meant that the VHS tapes were full of dirt and debris, and at least in one case with a spider nest that jammed up the thrift-store VHS/DVD combo player.

The CDs were cleaned and tried in a G5 iMac, with the obvious results there being that as long as the shiny layer with the data was intact, they worked fine. While a damaged disc tried to play somewhat, even the amazing audio CD error-correcting algorithms can not compensate for see-through gashes.

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