A computer program written in basic next to a modular synthesizer with many switches and lights

Modular Synth Pairs Perfectly With The Apple II

February 4, 2022 by Chris Wilkinson 4 Comments

We have a soft spot for synthesizers – seriously, who doesn’t? So when [Joshua Coleman] combined his retro-looking DIY modular synth with the equally retro Apple II computer, we just had to share it with you.

The two machines are paired using a vintage digital-to-analog logic controller pack. This DAC was originally used to control model trains using your Apple II – something that we now desperately need to see in action. The pack can output voltages between 0 and 2.55 V at 8-bit resolution (or 256 steps), which is plenty for a retro synth.

With the card installed in Slot 7 of the Apple II and the DAC wired through to the synth’s CV/gate, it’s then a trivial matter of writing POKE statements in Applesoft BASIC to control the synth. The video after the break demonstrates playing a simple melody, as well as how one might use the Apple II keyboard to ‘play’ the synth in real time.

If you’re interested in building your own, the video below has all the information needed, as well as helpful advice on where to find a DAC for your preferred model of vintage computer. If all that doesn’t tickle your musical fancy, make sure to check out our coverage on the Game Boy MIDI synth, or perhaps this peculiar synth and visualizer combo.

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Conveyor Belt Printer Mod Is Nearly All Printed

February 3, 2022 by Al Williams 19 Comments

[Call Me Swal] wanted to experiment with large 3D prints. So he took a Hornet 3D printer and designed a lot of 3D parts to convert it into an “infinite” conveyor belt printer. It looks like — as you can see in the video below — that all the parts are 3D printed but you will still need to buy material for the actual belt.

Of course, you may not have a Hornet, but the idea would be applicable to just about any similar printer. You’d have to, of course, adapt or redesign the parts.

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Retrotechtacular: Understanding The Strength Of Structural Shapes

February 3, 2022 by Ryan Flowers 13 Comments

Strength. Rigidity. Dependability. The ability to bear weight without buckling. These are all things that we look for when we build a mechanical structure. And in today’s Retrotechtacular we take a closer look at the answer to a question: “What’s in A Shape?”

As it turns out, quite a lot. In a wonderful film by the prolific Jam Handy Organization in the 1940’s, we take a scientific look at how shape affects the load bearing capacity of a beam. A single sided piece of metal, angle iron, C-channel, and boxed tubing all made of the same thickness metal are compared to see not just just how much load they can take, but also how they fail.

The concepts are then given practical application in things that we still deal with on a daily basis: Bridges, cars, aircraft, and buildings. Aircraft spars, bridge beams, car frames, and building girders all benefit from the engineering discussed in this time capsule of film.

None of the concepts in this video are suddenly out of date, because while our understanding of engineering has certainly progressed since this film was made, these basic concepts remain the same. As such, they will apply to any structural or mechanical devices that we make, be it 3d printed, CNC routed, welded, glued, vacuum formed, zip tied, duct taped, bailing wired, or hot glued.

Keep your eyes open for a wonderful sights and sounds of a rare Boeing 314 Clipper landing on water and a 1920’s Buffalo Springfield Steam Roller demonstrating how wonderful the film’s sponsor, Chevrolet, makes their automobile frames.

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3D Printing Goes Near Infrared

February 3, 2022 by Al Williams 17 Comments

Researchers at the University of Texas have been experimenting with optical 3D printing using near infrared (NIR) light instead of the more traditional ultraviolet. They claim to have a proof of concept and, apparently, using NIR has many advantages. The actual paper is paywalled, but there are several good summaries, including one from [3D Printing Industry].

UV light degrades certain materials and easily scatters in some media. However, decreasing the wavelength of light used in 3D printing has its own problems, notably less resolution and slower curing speed. To combat this, the researchers used an NIR-absorbant cyanine dye that exhibits rapid photocuring. The team reports times of 60 seconds per layer and resolution as high as 300 micrometers. Nanoparticles in the resin allow tuning of the part’s appearance and properties.

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Getting Root On Linux Amplifier Adds New Inputs

February 3, 2022 by Tom Nardi 26 Comments

We remember when getting Linux on your average desktop computer was a tricky enough endeavor that only those with the most luxurious of graybeards would even attempt it. A “Linux box” in those heady days was more than likely an outdated machine salvaged from the dumpster, side panel forever removed, cranking away in a basement or garage. Fast forward today, and Linux is literally everywhere: from smartphones and luxury cars, to TVs and refrigerators. Ironically it’s still not on most desktop computers, but that’s a discussion for another time.

So when [Michael Nothhard] sent in the fascinating account of how he hacked his Linux-powered Bluesound Powernode N150 amplifier to unlock more inputs, the least surprising element was that there was a “smart amplifier” out there running the free and open source operating system. What piqued our interest was that he was able to bust his way in with relative ease and enable some impressive new capabilities that the manufacturer would probably have rather been kept under wraps.

Configuring the CM6206’s audio settings.

[Michael] explains that the N150 has a USB port on the back side of it, and that officially, it only works with mass storage devices and a handful of approved peripherals such as a Bluetooth dongle. But as he was hoping to connect some more devices to the input-limited amplifier, he wondered if he could get a USB audio adapter recognized by the OS. After using a known exploit to get root access, he started poking around at the underlying Linux system to see what kind of trickery the developers had done.

Based on a fairly common C-Media CM6206 chipset, the StarTech 7.1 USB audio adapter was picked up by the kernel without an issue. But to actually get it working with the amplifier’s stock software, he then needed to add a new <capture> entry to the system’s sovi_info.xml configuration file and make some changes to its default ALSA settings. With the appropriate files modified, the new USB audio input device popped up under the official Bluesound smartphone application.

At the end of the write-up [Michael] notes that you’ll need to jump through a few additional hoops to make sure that an upstream firmware update doesn’t wipe all your hard work. Luckily it sounds like backing up the configuration and returning it to the newly flashed Powernode is easy enough. We’ve certainly seen more elaborate methods of gaining control of one’s sound system over the years.

Keep Track Of Toilet Paper Usage With This IoT Roll Holder

February 3, 2022 by Dan Maloney 51 Comments

Remember the Great Toilet Paper Crisis of 2020? We sure do, and it looks like our old friend [Vije Miller] does as well, while seemingly harboring a somewhat morbid fascination about how much paper every bathroom visitor is consuming. And to that end, we present his IoT toilet sheet tracker.

His 3D printed roll holder has a Hall effect sensor that counts revolutions of the roll and sends it to a NodeMCU. The number of sheets per roll is entered when the roll is changed, so some simple math yields the number of sheets each yank consumes. Or at least a decent estimate — [Vije] admits that there’s some rounding necessary. The best part of the build is the connection to Thingspeak, where sheet usage is plotted and displayed. Go ahead and check it out if you dare; at the time of writing, there was an alarming spike in sheet usage — a sudden need for 68 sheets where the baseline usage is in single digits. We shudder to think what might have precipitated that. The video below is — well, let’s just say there’s a video.

This isn’t the first time we’ve seen bathroom-based projects from [Vije Miller]. A few years back there was an attempt to freshen the air with plasma, and his IoT shower valve controller probably never scalded anyone accidentally.

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Remoticon 2021 // Colin O’Flynn Zaps Chips (And They Talk)

February 3, 2022 by Jenny List 5 Comments

One of the many fascinating fields that’s covered by Hackaday’s remit lies in the world of hardware security, working with physical electronic hardware to reveal inner secrets concealed in its firmware. Colin O’Flynn is the originator of the ChipWhisperer open-source analysis and fault injection board, and he is a master of the art of glitching chips. We were lucky enough to be able to welcome him to speak at last year’s Remoticon on-line conference, and now you can watch the video of his talk below the break. If you need to learn how to break RSA encryption with something like a disposable camera flash, this is the talk for you.

This talk is an introduction to signal sniffing and fault injection techniques. It’s well-presented and not presented as some unattainable wizardry, and as his power analysis demo shows a clearly different trace on the correct first letter of a password attack the viewer is left with an understanding of what’s going on rather than hoping for inspiration in a stream of the incomprehensible. The learning potential of being in full control of both instrument and target is evident, and continues as the talk moves onto fault injection with an introduction to power supply glitching as a technique to influence code execution.