A Low-Cost ROM Programmer With An AI Twist

March 23, 2024 by Dan Maloney 11 Comments

There are 0x10 ways to look at ROM programmers: they’re either relatively low-cost tools that let you quickly get about the business of programming vintage ROMs and get back to your retrocomputing activities, or they’re egregiously overpriced on a per-use basis. [Anders Nielsen] seems to land in the latter camp, firmly enough that he not only designed a dedicated ROM programmer for his 65uino ecosystem, but also suffered the indignities of enlisting ChatGPT to “help” him program the thing.

We’ll explain. [Anders]’ 65uino project has been going on for a while, with low-cost ROM programming only the latest effort. To his way of thinking, a $60 or $70 programmer might just be a significant barrier to those trying to break into retrocomputing, and besides, he seems to be more about the journey than the destination. He recently tackled the problem of generating the right programming voltages; here he turns his attention to putting that to work programming vintage ROMs like the W27C512.

Doing so with a 6502-based Arduino-compatible microcontroller requires some silicon calisthenics, including a trio of shift registers to do the addressing using a minimum of GPIO. As for the ChatGPT part, [Anders] thought asking the chatbot to help write some of the code would be a great way to increase his productivity. We thought so too, at least once, and like us, [Anders] concluded that while perhaps helpful in a broad sense, the amount of work you put into checking a chatbot’s work probably exceeds the work saved. But no matter, because in the end the code and the hardware came together to create a prototype ROM programmer for only about $10 worth of parts.

True, the resulting circuit is a bit complex, at least on a breadboard. It should clean up nicely for an eventual PCB version, though, one that plugs right into the 65uino board or even other microcontrollers. Either way, it could make creating custom ROMs for the 65uino a little more accessible.

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Open HT Surgery Gives Cheap Transceiver All-Band Capabilities

March 22, 2024 by Dan Maloney 35 Comments

Watch out, Baofeng; there’s a new kid on the cheap handy talkie market, and judging by this hardware and firmware upgrade to the Quansheng UV-K5, the radio’s hackability is going to keep amateur radio operators busy for quite a while.

Like the ubiquitous Baofeng line of cheap transceivers, the Quansheng UV-K5 is designed to be a dual-band portable for hams to use on the 2-meter VHF and 70-centimeter UHF bands. While certainly a useful capability, these bands are usually quite range-limited, and generally require fixed repeaters to cover a decent geographic area. For long-range comms you want to be on the high-frequency (HF) bands, and you want modulations other than the FM-only offered by most of the cheap HT radios.

Luckily, there’s a fix for both problems, as [Paul (OM0ET)] outlines in the video below. It’s a two-step process that starts with installing a hardware kit to replace the radio’s stock receiver chip with the much more capable Si4732. The kit includes the chip mounted on a small PCB, a new RF choke, and a bunch of nearly invisible capacitors. The mods are straightforward but would certainly benefit from the help of a microscope, and perhaps a little hot air rework. Once the hardware is installed and the new firmware flashed, you have an HT that can receive signals down to the 20-meter band, with AM and SSB modulations, and a completely redesigned display with all kinds of goodies.

It’s important to note that this is a receive-only modification — you won’t be transmitting on the HF bands with this thing. However, it appears that the firmware allows you to switch back and forth between HF receive and VHF/UHF transceive, so the radio’s stock functionality is still there if you need it. But at $30 for the radio and $12 for the kit, who cares? Having a portable HF receiver could be pretty handy in some situations. This looks like yet another fun hack for this radio; we’ve seen a few recently, including a firmware-only band expansion and even a Trojan that adds a waterfall display and a game of Pong. Continue reading “Open HT Surgery Gives Cheap Transceiver All-Band Capabilities” →

Arduino Gear Shift Indicator Finds ‘Em So You Won’t Grind ‘Em

March 20, 2024 by Dan Maloney 75 Comments

Now, it’s been a shamefully long time since we’ve driven a car with a manual transmission, but as we recall it was pretty straightforward. It certainly didn’t require a lot of help with the shifting pattern, at least not enough to require a technical solution to know what gear you’re in. But then again, we suspect that’s not really the point of [upir]’s latest build.

Oh sure, it’s pretty cool to display your current gear selection on a little LCD screen using an Arduino. And [upir] promises a follow-up project where the display goes inside the shifter knob, which will be really cool. But if you take a look at the video below, you’ll see that the real value of this project is the stepwise approach he takes to create this project. [upir] spends most of the time in the video below simulating the hardware and the code of the project in Wokwi, which lets him make changes and tune the design up before committing anything to actual hardware.

That turned out to be particularly useful with this build since he chose to use analog Hall sensors to detect the shift lever position and didn’t know exactly how that would work. Wokwi let him quickly build a virtual prototype for one sensor (using a potentiometer as a stand-in, since the simulator lacked a Hall sensor model), then quickly expand to the four sensors needed to detect all six gear positions.

By the time his simulation was complete, the code was almost entirely written. [upir] also walks us through his toolchains for both designing the graphics and laying out the PCB, a non-trivial task given the odd layout. We particularly enjoyed the tip on making smooth curved traces around the oval cutout for the shift lever in the board.

The video below is on the longish side, but it’s chock full of great little tips. Check out some more of [upir]’s work, like his pimped-out potentiometer or his custom animations on 16×2 LCDs.

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Proper Routing Makes For Many Happy Return Paths

March 18, 2024 by Dan Maloney 18 Comments

Here’s a question for you: when your PCB has a ground plane layer, where do return signals flow? It seems like a trick question, but as [Kristof Mulier] explains, there’s more to return path routing (alternate link in case you run into a paywall) than just doing a copper pour and calling it a day.

Like so many other things in life, the answer to the above question is “it depends,” and as [Kristof] ably demonstrates in this concise article, the return path for a signal largely depends on its frequency. He begins by explaining current loop areas and how they factor into the tendency for a circuit to both emit and be susceptible to electromagnetic noise. The bigger the loop area, the worse things can get from a noise perspective. At low frequencies, return signals will tend to take the shortest possible path, which can result in large current loop areas if you’re not careful. At higher frequencies, though, signals will tend to follow the path of minimal energy instead, which generally ends up being similar to the signal trace, even if it has a huge ground plane to flow through.

Since high-frequency signals naturally follow a path through the ground plane that minimizes the current loop, that means the problem takes care of itself, right? It would, except that we have a habit of putting all kinds of gaps in the way, from ground plane vias to isolation slots. [Kristof] argues that this can result in return paths that wiggle around these features, increasing the current loop area to the point where problems creep in. His solution? Route all your signal return paths. Even if you know that the return traces are going to get incorporated into a pour, the act of intentionally routing them will help minimize the current loop area. It’s brilliantly counterintuitive.

This is the first time we’ve seen the topic of high-frequency return paths tackled. This succinct demonstration shows exactly how return path obstructions can cause unexpected results.

Thanks to [Marius Heier] for the tip.

Thrift Store CD Rack Turns Into Small Parts Storage Playground

March 17, 2024 by Dan Maloney 15 Comments

What in the world could an accessory for an obsolete audio medium possibly have to do with keeping all your unruly bits and pieces in order? First of all, we’re not sure the CD is quite dead yet; we’ve got about a thousand of them packed away somewhere, and we’re pretty sure they’ll be back in style again one of these days. Until then, though, the lowly CD rack might be just what you need to get your shop under control.

As [Chris Borge] relates the story, he stumbled over this CD rack at a thrift sale and quickly realized its potential. All it took was some quick design work and a bit of 3D printing. Okay, a lot of 3D printing, including some large, flat expanses for the drawer bottoms, which can be a problem to print reliably. His solution was simple but clever: pause the print and insert a piece of stiff card stock to act as the drawer bottom before continuing to print the sides. This worked well but presented an adhesion problem later when he tried to print some drawer dividers, so those were printed as a separate job and inserted later.

Sadly, [Chris] notes that the CD format is not quite Gridfinity compatible, but that’s not a deal breaker. He also doesn’t provide any build files, but none are really necessary. Once you’ve got the basic footprint, what you do with your drawers is largely dependent on what you’ve got to store. The video below has a lot of ideas for what’s possible, but honestly, we’re looking at all those little parts assortment kits from Bojack and Hilitchi piled up in a drawer and just dreaming about the possibilities here. Add a voice-activated, LED inventory locator, and you’d really have something. Off to the thrift store!

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Hackaday Links: March 17, 2024

March 17, 2024 by Dan Maloney 16 Comments

A friend of ours once described computers as “high-speed idiots.” It was true in the 80s, and it appears that even with the recent explosion in AI, all computers have managed to do is become faster. Proof of that can be found in a story about using ASCII art to trick a chatbot into giving away the store. As anyone who has played with ChatGPT or its moral equivalent for more than five minutes has learned, there are certain boundary conditions that the LLM’s ~~creators~~ lawyers have put in place to prevent discussion surrounding sensitive topics. Ask a chatbot to deliver specific instructions on building a nuclear bomb, for instance, and you’ll be rebuffed. Same with asking for help counterfeiting currency, and wisely so. But, by minimally obfuscating your question by rendering the word “COUNTERFEIT” in ASCII art and asking the chatbot to first decode the word, you can slip the verboten word into a how-to question and get pretty explicit instructions. Yes, you have to give painfully detailed instructions on parsing the ASCII art characters, but that’s a small price to pay for forbidden knowledge that you could easily find out yourself by other means.

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A SPIF-fy Way Of Forming Metal

March 16, 2024 by Dan Maloney 23 Comments

Thanks to 3D printing, most of us are familiar with the concept of additive manufacturing, and by extension, subtractive manufacturing. But what is it when you’re neither adding material nor taking it away to create something? Generally speaking, that’s called forming, and while there are tons of ways to do it, one you might not have heard of is single-point incremental forming (SPIF), and it’s pretty cool.

To explore SPIF as a method for making small parts, [Russell Makes] gave it a go on a small CNC mill. The idea is pretty simple, and the video below makes it pretty clear what’s going on. A forming tool is moved over a sheet metal blank that’s held very securely to the mill’s table. The tool has no cutting edges, just a smooth, hard, spherical tip — [Russell] made his own by brazing a carbide ball to a piece of drill rod. The tool is driven slightly into the blank along the Z-axis, while simultaneously tracing out a tool path in the XY plane. The tool spins, but very slowly; ideally, the spindle speed is controlled to keep a single point of contact with the metal as the tool works around its tool path. The tool steps downward incrementally, drawing the metal down with it as it forms the desired shape.

[Russell]’s experiments were pretty promising. He started with titanium sheet, which behaved pretty well except for some galling thanks to lack of lubrication. Aluminum and stainless worked pretty well too, at least for simple hemispherical and cone shapes. More complex shapes proved trickier, but with time he was able to figure out the correct speeds and feeds to keep the metal intact. The amount of tension built up in the metal is impressive, though, and is especially evident when cutting the finished part free from the blank.

Could this work with a hobbyist-grade machine? Possibly, but we’d be afraid that the forces involved might be a bit much for light-duty machines, especially in the Z-axis. And it’s a slow process, so it’s probably only good for one-offs and low-volume work. Once you’ve got a prototype, die stamping might be a more efficient way to go.

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