Technology Mag Things

A lot of hams like to carry a VHF radio. Of course, nearly everyone wants to carry a phone. Now, thanks to the kv4p HT, you don’t have to carry both. The open-source device connects to your Android smartphone and turns it into a radio transceiver. You can build it yourself for about $35. Check out the video below.

The device uses an ESP32 and only transmits one watt, but it has lots of features like APRS and scanning.

The brain is an ESP-WROOM-32. There’s also a ham radio “module” that is easily imported.  The rest is fit, finish, and software. The PCB is fairly simple and inexpensive. A 3D-printed case completes things.

There is a new version of the PCB that hasn’t been tested as of this post, but the older version (1.5) seems to work ok, too, if you don’t want to risk trying the 1.6 version and you don’t want to wait.

We always marvel at how many building blocks you can get now. Grab a computer and a radio, and use your phone for power and a user interface. This would have been an enormous project to complete not long ago and now it is an hour’s time and $35. You’ll probably spend as much time ordering parts as building.

If your phone mostly trades cat memes, it fits right in with old ham tech. Just watch the antenna.

We really like PCB-level hacks, especially ones that show ingenuity in solving a real problem while being super cheap to implement. Hackaday.IO user [Steph] wanted a cheap way to switch a wearable on and off without having to keep popping out the battery, so they came up with a tweaked battery footprint, which is also a simple slide switch.

Most people making badges and wearables will follow the same well-trodden path of just yanking out the cell or placing some cheap switch down and swallowing the additional cost. For [Steph], the solution was obvious. By taking a standard surface-mount CR2032 button cell holder footprint, extending its courtyard vertically, and moving the negative pad up a smidge, the battery can be simply slid up to engage the pad and slid down to disengage and shut off the juice. The spring section of the positive terminal keeps enough pressure on the battery to prevent it from sliding out, but if you are worried, you can always add a dummy pad at the bottom, as well as a little solder bump to add a bit more security.

Now, why didn’t we think of this before? The KiCad footprint file can be downloaded from the project GitHub page, imported into your project and used straight away.

Many of our gadgets are powered by CR2032 cells—so many so that eliminating the need for them leads to interesting projects, like this sweet USB-powered CR2032 eliminator. But how far can you push the humble cell? Well, we held a contest a few years ago to find out!

Ah, Lisp, the archaic language that just keeps on giving. You either love or hate it, but you’ll never stop it. [David Johnson-Davies] is clearly in the love it camp and, to that end, has produced a fair number of tools wedging this language into all kinds of nooks and crannies. The particular nook in question is the RISC-V ISA, with their Lisp-to-RISC-V compiler. This project leads on from their RISC-V assembler by allowing a Lisp function to be compiled directly to assembly and then deployed as callable, provided you stick to the supported language subset, that is!

The fun thing is—you guessed it—it’s written in Lisp. In fact, both projects are pure Lisp and can be run on the uLisp core and deployed onto your microcontroller of choice. Because who wouldn’t want to compile Lisp on a Lisp machine? To add to the fun, [David] created a previous project targeting ARM, so you’ve got even fewer excuses for not being able to access this. If you’ve managed to get your paws on the new Raspberry Pi Pico-2, then you can take your pick and run Lisp on either core type and still compile to native.

The Lisp-Risc-V project can be found in this GitHub repo, with the other tools easy enough to locate.

We see a fair few Lisp projects on these pages. Here’s another bare metal Lisp implementation using AVR. And how many lines of code does it take to implement Lisp anyway? The answer is 42 200 lines of C, to be exact.

We’ve all heard stories of the dangers of 3D printing, with fires from runaway hot ends or dodgy heated build plates being the main hazards. But what about the particulates? Can they actually cause health problems in the long run? Maybe, if new research into the carcinogenicity of common 3D printing plastics pans out.

According to authors [CheolHong Lim] and [DongSeok Seo], the research covered in this paper was undertaken because of reports of rare cancers among Korean STEM teachers, particularly those who used 3D printers in their curricula. It was thought that only long-term, continued exposure to the particulates generated by 3D printers could potentially be hazardous and that PLA was less likely to be hazardous than ABS. The study was designed to assess the potential carcinogenicity of both ABS and PLA particulates under conditions similar to what could be expected in an educational setting.

To do this, they generated particulates by heating ABS and PLA to extruder temperatures, collected and characterized them electrostatically, and dissolved them in the solvent DMSO. They used a cell line known as Balb/c, derived from fibroblasts of an albino laboratory mouse, to assess the cytotoxic concentration of each plastic, then conducted a comet assay, which uses cell shape as a proxy for DNA damage; damaged cells often take on a characteristically tailed shape that resembles a comet. This showed no significant DNA damage for either plastic.

But just because a substance doesn’t cause DNA damage doesn’t mean it can’t mess with the cell’s working in other ways. To assess this, they performed a series of cell transformation assays, which look for morphological changes as a result of treatment with a potential carcinogen. Neither ABS nor PLA were found to be carcinogenic in this assay. They also looked at the RNA of the treated cells, to assess the expression of genes related to carcinogenic pathways. They found that of 147 cancer-related genes, 113 were either turned up or turned down relative to controls. Finally, they looked at glucose metabolism as a proxy for the metabolic changes a malignant cell generally experiences, finding that both plastics increased metabolism in vitro.

Does this mean that 3D printing causes cancer? No, not by a long shot. But, it’s clear that under lab conditions, exposure to either PLA or ABS particulates seems to be related to some of the cell changes associated with carcinogenesis. What exactly this means in the real world remains to be seen, but the work described here at least sets the stage for further examination.

What does this all mean to the home gamer? For now, maybe you should at least crack a window while you’re printing.

The Greengate DS:3 had been re-created in the form of the Goodgreat. Now [Bea Thurman] had to put it to use. If the Greengate DS:3 card was rare,  the keyboard was nearly impossible to find. After a long search, [Bea] bought one all the way from Iceland.  The card of course came courtesy of [Eric]. 

It was time to connect the two together.  But there was a problem — a big problem. The GreenGate  has a DB-25 connected via a ribbon cable to the board’s 2×10 connector. The keyboard that shipped with those cards would plug right in.  Unfortunately, [Bea’s] keyboard had a DIP-40 IDC connector crimped on its ribbon cable.  What’s more the connectors for the sustain and volume pedals were marked, but never drilled out. The GreenGate silk screen was still there though. 

Maybe it was a prototype or some sort of modified hardware. Either way, the 40-pin DIP connector had to go if the keyboard ever were to work with the card. What followed were a few hours of careful wire tracing 

Tracing out pins is always a pain.  To make it worse, the only DB-25 connector [Bea] had on hand was an Insulation Displacement Connector (IDC). It’s the right part to use for the ribbon cable attached to the keyboard, but not what you’d want to use to test pinouts. These connectors are generally crimped once.

The GreenGate keyboard and foot pedals are matrix scanned – much like a standard alphanumeric keyboard. The keyboard also needed some internal cleanup after 40 years. Like many ‘boards of the day, it used small spring wires that made contact with a common bar. After some painstaking debugging, working directly with [Eric] on video chat, [Bea] had the system working.  Now came the fun part — using the keyboard to make music.  

The Greengate hardware is impressive, but the software is stunning. [Bea] got in touch with [Colin Green], who wrote it. He’s also the “green” in Greengate. With [Colin’s] software, Waveforms can be edited in an oscilloscope view, much like one would find in a modern DAW. The software even includes a pattern editor, which can be used for arpeggios.  

The GreenGate has 4 notes of polyphony, is multitimbral, and can layer multiple samples across the keyboard. Considering this is all handled on an Apple II+ with a green screen monitor for a UI, impressive is an understatement.

[Bea] gives us a great walkthrough using the system. She starts by sampling audio from a cassette. With the audio in memory, she uses this to build a simple song. The entire setup made an appearance at VCF MidWest, so if you saw it in person let us know in the comments!

[Bea Thurman] had a retro music conundrum. She loved the classic Greengate DS:3 sampler, but couldn’t buy one, and couldn’t find enough information to build her own. [Bea’s] plea for help caught the attention of [Eric Schlaepfer], aka  [TubeTime]. The collaboration that followed ultimately solved a decades-old mystery. 

In the 1980s, there were two types of musicians: Those who could afford a Fairlight CMI and everyone else. If you were an Apple II owner, the solution was a Greengate DS:3. The DS:3 was a music keyboard and a sampler card for the Apple II+ (or better). The plug-in card was a bit mysterious, though. The cards were not very well documented, and only a few survive today. To make matters worse, some chips had part numbers sanded off. It was a bit of a mystery until [Bea and Tubetime] got involved. 

While [Bea] didn’t have the card itself, she had a photo of the board and a picture of an album that contained the key to everything. The Greengate came packed with a vinyl album, “Into Trouble with the Noise of Art.” An apt title, since the album art was the Greengate PCB top layer. Now if you know [Eric], you know he wrote the book (literally) on taking things apart and taking photos of them, even producing replicas. 

Thoroughly nerdsniped, [Eric] loaded the photos KiCad and started tracing. With the entire top layer artwork and most of the bottom layer, the 8-bit card wasn’t too hard to figure out. The sticky point was one chip. A big 40-pin part with the numbers scrubbed off. One owner pulled the chip to check for fab information on the back, only to be greeted by a proper British “You Nosey S.O.B.” penciled on top of more sanded part numbers. 

If the chip was an ASIC, the project would be blocked until they could get their hands on an actual board for analysis. An ASIC would have custom part numbers on it from the fab though – no need for sanding. It had to be something off the shelf. [Eric] used some context clues to determine that the Mystery chip had to be a DMA controller. This narrowed the field down. From there, he had to compare pinouts until he had a match with the venerable MC6844. 

With the mystery part out of the way, [Eric] put the finishing touches on the PCB, saved it to his GitHub as the GoodGreat DS:3, and sent it off.  A few days later, the bare boards arrived and were quickly populated with vintage parts. [Eric] ran a few tests and sent the card off to [Bea], where we will pick up with part 2. 

At least the device wasn’t protected with a self-destruct code.

We’ve seen many portable laptops using the Raspberry Pi series of boards in the decade-plus since its launch. The appeal of a cheap board that can run a desktop Linux distro without requiring too much battery is hard not to fall for. Over the years, the bar has been raised from a Pi stuck to the back of one of those Motorola netbook accessories, through chunky laptops, to some very svelte and professional-looking machines. A recent example comes from [Michael Mayer], whose Portable Pi 80 is a palmtop design that we’d be happy to take on the road ourselves.

At its heart is a Pi Zero 2, combining as it does a tiny form factor with the useful power of its Pi 3-derived processor. This is mated to a Waveshare 7-inch display, and in the bottom half of the machine sits a 40% mechanical keyboard. Alongside this are a pair of 18650 cells and their associated power modules. The little Arduino, which normally handles the keyboard, has been relocated due to space constraints, which brings us to the case. A project like this one is, in many ways, a task of assembling a set of modules, and it’s in the case that the work here really shines. It’s a 3D-printable case that you can download from Printables, and it’s very nice indeed. As we said, we’d be happy to use one of these.

Portable computing has come a very long way. Often the keyboard can make it or break it.