Author: Dan Maloney

3366 Articles

Look! It’s A Knob! It’s A Jack! It’s Euroknob!

April 28, 2025 by 25 Comments

Are your Eurorack modules too crowded? Sick of your patch cables making it hard to twiddle your knobs? Then you might be very interested in the new Euroknob, the knob that sports a hidden patch cable jack.

Honestly, when we first saw the Euroknob demo board, we thought [Mitxela] had gone a little off the rails. It looks like nothing more than a PCB-mount potentiometer or perhaps an encoder with a knob attached. Twist the knob and a row of LEDs on the board light up in sequence. Nice, but not exactly what we’re used to seeing from him. But then he popped the knob off the board, revealing that what we thought was the pot body is actually a 3.5-mm audio jack, and that the knob was attached to a mating plug that acts as an axle.

The kicker is that underneath the audio jack is an AS5600 magnetic encoder, and hidden in a slot milled in the tip of the audio jack is a tiny magnet. Pop the knob into the jack, give it a twist, and you’ve got manual control of your module. Take the knob out, plug in a patch cable, and you can let a control voltage from another module do the job. Genius!

To make it all work mechanically, [Mitxela] had to sandwich a spacer board on top of the main PCB. The spacer has a large cutout to make room for the sensor chip so the magnet can rotate without hitting anything. He also added a CH32V003 to run the encoder and drive the LEDs to provide feedback for the knob-jack. The video below has a brief demo.

This is just a proof of concept, to be sure, but it’s still pretty slick. Almost as slick as [Mitxela]’s recent fluid-motion simulation pendant, or his dual-wielding soldering irons.

Continue reading “Look! It’s A Knob! It’s A Jack! It’s Euroknob!” →

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Hackaday Links: April 27, 2025

April 27, 2025 by 14 Comments

Looks like the Simpsons had it right again, now that an Australian radio station has been caught using an AI-generated DJ for their midday slot. Station CADA, a Sydney-based broadcaster that’s part of the Australian Radio Network, revealed that “Workdays with Thy” isn’t actually hosted by a person; rather, “Thy” is a generative AI text-to-speech system that has been on the air since November. An actual employee of the ARN finance department was used for Thy’s voice model and her headshot, which adds a bit to the creepy factor.

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Quick And Easy Digital Stethoscope Keeps Tabs On Cat

April 27, 2025 by 8 Comments

For all their education, medical practitioners sometimes forget that what’s old hat to them is new territory for their patients. [David Revoy] learned that when a recent visit to the veterinarian resulted in the need to monitor his cat’s pulse rate at home, a task that he found difficult enough that he hacked together this digital cat stethoscope.

Never fear; [David] makes it clear that his fur-baby [Geuloush] is fine, although the gel needed for an echocardiogram likely left the cat permanently miffed. With a normal feline heart rate in the 140s, [David] found it hard to get an accurate pulse by palpation, so he bought a cheap stethoscope and a basic lavalier USB microphone. Getting them together was as easy as cutting the silicone tubing from the stethoscope head and sticking the microphone into it.

The tricky part, of course, would be getting [Geuloush] to cooperate. That took some doing, but soon enough [David] had a clean recording to visualize in an audio editor. From there it’s just a simple matter of counting up the peaks and figuring out the beats per second. It probably wouldn’t be too hard to build a small counter using a microcontroller so he doesn’t have to count on the cat napping near his PC, but in our experience, keyboards are pretty good cat attractants.

This is one of those nice, quick hacks whose simplicity belies their impact. It’s certainly not as fancy as some of the smart stethoscopes we’ve seen, but it doesn’t need to be.

Thanks to [Spooner] for the tip.

Clickspring’s Experimental Archaeology: Concentric Thin-Walled Tubing

April 25, 2025 by 33 Comments

It’s human nature to look at the technological achievements of the ancients — you know, anything before the 1990s — and marvel at how they were able to achieve precision results in such benighted times. How could anyone create a complicated mechanism without the aid of CNC machining and computer-aided design tools? Clearly, it was aliens.

Or, as [Chris] from Click Spring demonstrates by creating precision nesting thin-wall tubing, it was human beings running the same wetware as what’s running between our ears but with a lot more patience and ingenuity. It’s part of his series of experiments into how the craftsmen of antiquity made complicated devices like the Antikythera mechanism with simple tools. He starts by cleaning up roughly wrought brass rods on his hand-powered lathe, followed by drilling and reaming to create three tubes with incremental precision bores. He then creates matching pistons for each tube, with an almost gas-tight enough fit right off the lathe.

Getting the piston fit to true gas-tight precision came next, by lapping with a jeweler’s rouge made from iron swarf recovered from the bench. Allowed to rust and ground to a paste using a mortar and pestle, the red iron oxide mixed with olive oil made a dandy fine abrasive, perfect for polishing the metal to a high gloss finish. Making the set of tubes concentric required truing up the bores on the lathe, starting with the inner-most tube and adding the next-largest tube once the outer diameter was lapped to spec.

Easy? Not by a long shot! It looks like a tedious job that we suspect was given to the apprentice while the master worked on more interesting chores. But clearly, it was possible to achieve precision challenging today’s most exacting needs with nothing but the simplest tools and plenty of skill. Continue reading “Clickspring’s Experimental Archaeology: Concentric Thin-Walled Tubing” →

To See Within: Detecting X-Rays

April 23, 2025 by 19 Comments

It’s amazing how quickly medical science made radiography one of its main diagnostic tools. Medicine had barely emerged from its Dark Age of bloodletting and the four humours when X-rays were discovered, and the realization that the internal structure of our bodies could cast shadows of this mysterious “X-Light” opened up diagnostic possibilities that went far beyond the educated guesswork and exploratory surgery doctors had relied on for centuries.

The problem is, X-rays are one of those things that you can’t see, feel, or smell, at least mostly; X-rays cause visible artifacts in some people’s eyes, and the pencil-thin beam of a CT scanner can create a distinct smell of ozone when it passes through the nasal cavity — ask me how I know. But to be diagnostically useful, the varying intensities created by X-rays passing through living tissue need to be translated into an image. We’ve already looked at how X-rays are produced, so now it’s time to take a look at how X-rays are detected and turned into medical miracles.

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A Scratch-Built Commodore 64, Turing Style

April 23, 2025 by 18 Comments

Building a Commodore 64 is among the easier projects for retrocomputing fans to tackle. That’s because the C64’s core chipset does most of the heavy lifting; source those and you’re probably 80% of the way there. But what if you can’t find those chips, or if you want more of a challenge than plugging and chugging? Are you out of luck?

Hardly. The video below from [DrMattRegan] is the first in a series on his scratch-built C64 that doesn’t use the core chipset, and it looks pretty promising. This video concentrates on building a replacement for the 6502 microprocessor — actually the 6510, but close enough — using just a couple of EPROMs, some SRAM chips, and a few standard logic chips to glue everything together. He uses the EPROMs as a “rulebook” that contains the code to emulate the 6502 — derived from his earlier Turing 6502 project — and the SRAM chips as a “notebook” for scratch memory and registers to make a Turing-complete random access machine.

[DrMatt] has made good progress so far, with the core 6502 CPU built on a PCB and able to run the Apple II version of Pac-Man as a benchmark. We’re looking forward to the rest of this series, but in the meantime, a look back at his VIC-less VIC-20 project might be informative.

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Hackaday Links: April 20, 2025

April 20, 2025 by 8 Comments

We appear to be edging ever closer to a solid statement of “We are not alone” in the universe with this week’s announcement of the detection of biosignatures in the atmosphere of exoplanet K2-18b. The planet, which is 124 light-years away, has been the focus of much attention since it was discovered in 2015 using the Kepler space telescope because it lies in the habitable zone around its red-dwarf star. Initial observations with Hubble indicated the presence of water vapor, and follow-up investigations using the James Webb Space Telescope detected all sorts of goodies in the atmosphere, including carbon dioxide and methane. But more recently, JWST saw signs of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), organic molecules which, on Earth, are strongly associated with biological processes in marine bacteria and phytoplankton.

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