TechyMagThings

If you’re working with surface mount components, you’re likely going to want a reflow plate at some point. [Vitaly] was in need of just such a tool, and thus whipped up a compact reflow plate that is conveniently powered via USB-C. 

This reflow rig is designed for smaller work, with a working area of 80 mm x 70 mm. There are two options for the heating element—either a metal core PCB-based heater, or a metal ceramic heater. The former is good for working with Sn42Bi58 solder paste at 138 C, according to [Vitaly], while the latter will happily handle Sn63Pb37 at 183 C if the dirty stuff is more your jam.

Running the show is an ESP32-C3-WROOM, which serves up a web-based control panel over Bluetooth for setting the heating profiles. Using Bluetooth over WiFi might seem like an odd choice at first, but it means you don’t have to add the hot plate to the local wireless network to access it, handy if you’re on the move. It’s also worth noting that you can’t run this off any old USB charger—you’ll need one compatible with USB Power Delivery (PD) that can deliver at least 100 watts.

If you’re needing to whip up small boards with regularity, a hotplate like this one can really come in handy. Files are on GitHub for those eager to build their own.

This isn’t the first time we’ve seen USB-C powering a small reflow plate. Of course, if you make your PCBs self heating, you can sidestep all that entirely.

Devices that were limited to only run a web browser were relatively common around 2000, as many people wanted to surf the Information Super Highway, but didn’t quite want to get a regular PC — being in many ways the retro equivalent of a Chromebook. The Compaq iPAQ IA-2 from 2000 that [Dave Luna] got is no exception, with a Microsoft CE-based OS that is meant to be used with Microsoft Network (MSN) dial-up, which amusingly is still available today.

In order to get a more useful OS on it, like Windows 98, you have to jump through quite a few hoops, as [Dave] found out. Although there is an IDE connection on the mainboard, this cannot be booted from, likely due to BIOS limitations. This means that he had to chain boot via the 16 MB NAND Flash drive that the original OS booted from, which was done by writing MS-DOS to the Flash drive using another workaround as it’s not a standard IDE device either.

From this you can then boot Windows 98 from an IDE drive by pretending that it’s an ATAPI IDE device to dodge a limitation on IDE devices. The system’s hardware isn’t really going to make it into a blazing fast retro computer. It only has a 266 MHz Geode GX1 CPU and supports up to 256 MB of SDRAM. The IA-2 is also limited to 800×600, which required the use of an external monitor (as seen above) hooked up to the internal VGA port to set the proper resolution in the OS.

But at least it can run DOOM, so that bare minimum requirement can be ticked off.

The BC250 is what AMD calls an APU, or Accelerated Processing Unit. It combines a GPU and CPU into a single unit, and was originally built to serve as the heart of certain Samsung rack mount servers. If you know where to find cheap surplus units of the BC250, you can put them to good use for AI work, as [akandr] demonstrates.

The first thing you’ll have to figure out is how to take an individual BC250 APU and get it up and running. It’s effectively a full system-on-chip, combining a Zen 2 CPU with a Cyan Skillfish RDNA 1.5 GPU. However, it was originally intended to run inside a rackmount server unit rather than a standalone machine. To get it going, you’ll need to hook it up with power and some kind of cooling solution.

From there, it’s a matter of software. [akandr] explains how to get AI workflows running on the BC250 using Ollama and Vulkan, while noting useful hacks to improve performance like disabling the GUI and tweaking the CPU governor. The hardware can be used with a wide range of different models depending on what you’re trying to achieve, it just takes some careful management of the APU’s resources to get the most out of it. Thankfully, that’s all in the guide on GitHub.

We’ve already seen these AMD APUs repurposed before for gaming use. Unfortunately the word is out already  about their capabilities, so prices have risen significantly in response to demand. Still, if you manage to score a BC250 and do something cool with it yourself, be sure to let us know on the tipsline!

This week Jonathan chats with Valentyn Danylchuk about BreezyBox — an interactive shell and toolkit that provides various tools and a compiler on an ESP32 microcontroller. What was the inspiration for this impressive project, and what direction is it heading? Watch to find out!

• https://github.com/valdanylchuk/breezydemo
• https://github.com/valdanylchuk/xcc700
• https://www.linkedin.com/in/valdanylchuk
• https://hackaday.com/2026/02/06/breezybox-a-busybox-like-shell-and-virtual-terminal-for-esp32/

Did you know you can watch the live recording of the show right on our YouTube Channel? Have someone you’d like us to interview? Let us know, or have the guest contact us! Take a look at the schedule here.

Direct Download in DRM-free MP3.

If you’d rather read along, here’s the transcript for this week’s episode.

Theme music: “Newer Wave” Kevin MacLeod (incompetech.com)

Licensed under Creative Commons: By Attribution 4.0 License

Many substances display crystallization, allowing them to keep adding to a basic shape to reach pretty humongous proportions. Although we usually tend to think of pretty stones that get fashioned into jewelry or put up for display, sugar also crystallizes and thus you can create pretty large sugar crystals. How to do this is demonstrated by [Chase] of Crystalverse fame in a recent video.

This is effectively a follow-up to a 2022 blog article in which [Chase] showed a few ways to create pretty table sugar (sucrose) based crystals. In that article the growth of single sucrose crystals was attempted, but a few additional crystals got stuck to the main crystal so that it technically wasn’t a single crystal any more.

With this new method coarse sugar is used both for seed crystals as well as for creating the syrupy liquid from mixing 100 mL of water with 225 grams of sugar. Starting a single crystal is attempted by using thin fishing wire in a small vessel with the syrup and some seed crystals, hoping that a crystal will lodge to said fishing wire.

After a few attempts this works and from there the crystals can be suspended in the large jar with syrup to let them continue growing. It’s important to cover the jar during this period, as more crystals will form in the syrup over time, requiring occasional removal of these stray ones.

Naturally this process takes a while, with a solid week required to get a sizeable crystal as in the video. After this the crystal is effectively just a very large version of the sugar crystals in that 1 kg bag from the supermarket, ergo it will dissolve again just as easily. If you want a more durable crystal that’s equally easy to grow, you can toss some vinegar and scrap copper together to create very pretty, albeit toxic, copper(II) acetate crystals.

Iomega’s Zip drives filled an interesting niche back in the 1990s. A magnetic disk that was physically floppy-sized, but much larger in capacity– starting at 100 MB, and reaching 750 MB by the end–they never quite had universal appeal, but never really went away until flash memory chased them out of the marketplace in the early 2000s. While not everyone is going to miss them, some of us still think it’s a better form factor than having a USB stick awkwardly protruding from a computer, or microSD cards that are barely large enough to see with the naked eye. [Minh Danh] is one of those who still has affection for Zip drives, and when his parallel port Zip 100 drive started to give up the ghost last year, he decided to do something bold: reverse engineer it, and produce an emulator. First software, and then in hardware.

The first was to create a virtual zip drive that could run on a virtual machine and be accessed with DOS or Windows up to XP. The next task was to move that functionality onto a microcontroller to create something like a GoTek floppy emulator for LPT Zip drives that he’s calling the LPT100. Yes, Zip drives were built for APATI, SCSI, FireWire and USB, too, but [Minh]’s was on the parallel port and that’s what he wanted to replace, so the LPT interface is what set out to recreate.

It works, too, though took more guts than was expected– the 8-bit PIC18F4680 he started with just wasn’t up to the task. He moved up to a 32-bit PIC, the PIC32MZ2048EFH144 to be specific, which proved adaquate when testing with his Book 8088, a new DOS PC from 2023. Iomega’s official driver won’t run on an 8088, but the PALMZIP utility does and was able to transfer files, though only at the slow nibble rate due to limitations with the Book8088’s LPT hardware. Watch it in action below.

Alas, moving up to the Pocket386, it seemed the PIC just could not keep up. [Minh] says he’s thinking of moving to the faster Teensy 4.1, which sounds like a good idea. Considering the Teensy can be configured to serve as a drop-in replacement for a 68000, bit-banging the bus at 7.8 MHz, we’d think it should handle anything a parallel port can throw at it.

Thanks to [Minh Danh] for the tip!

Although the term ‘Iron Curtain’ from the Cold War brings to mind something like the Berlin Wall and its forbidding No Man’s Land, there was still active trade between the Soviet Union and the West. This included devices like the M4100/4 insulation tester that the [Three-phase] YouTube channel recently looked at, after previously poking at a 1967 USSR resistance bridge.

This particular unit dates to 1985, and comes in a rather nice-looking case that somewhat looks like bakelite. It’s rated for up to 1 gigaohm, putting out 1,000 V by using the crank handle. Because of the pristine condition of the entire unit, including seals, it was decided to not look at the internals but only test its functionality.

After running through the basic usage of the insulation tester it’s hooked up to a range of testing devices, which shows that it seems to be mostly still in working condition. The first issue noticed was that the crank handle-based generator was a bit tired, so that it never quite hit the maximum voltage.

With no parallax correction and no known last calibration date, it still measured to about 10% of the actual value in some tests initially, but in later tests it was significantly off from the expected value. At this point the device was suspected of being faulty, but it defied being easily opened, so any repair will have to be put off for now. That said, it being in such good condition raises the prospect of it being an easy repair, hopefully in an upcoming video.