A bird-shaped yellow PCB with legs wound out of wire, perched on its creator's arm. The bird has a lot of through-hole components on it, as well as an assortment of different-colored LEDs.

Printed Circuit Bird Family Calls For Us To Consider Analog

On our favourite low-attention-span content site, [Kelly Heaton] has recently started sharing a series of “Printed Circuit Birds”. These are PCBs shaped like birds, looking like birds and chirping like birds – and they are fully analog! The sound is produced by a network of oscillators feeding into each other, and, once tuned, is hardly distinguishable from the bird songs you might hear outside your window. Care and love was put into making this bird life-like – it perches on Kelly’s arm with legs woven out of single-strand wire and talons made out of THT resistors, in the exact same way you would expect a regular bird to sit on your arm – that is, if you ever get lucky enough. It’s not just one bird – there’s a family of circuit animals, including a goose, a crow and even a cricket.

Why did these animals came to life – metaphorically, but also, literally? There must be more to a non-ordinary project like this, and we asked Kelly about it. These birds are part of her project to explore models of consciousness in ways that we typically don’t employ. Our habit is to approach complex problems in digital domains, but we tend to miss out on elegance and simplicity that analog circuits are capable of. After all, even our conventional understanding of a neural network is a matrix of analog coefficients that we then tune, a primitive imitation of how we assume human brains to work – and it’s this “analog” approach that has lately moved us ever so closer to reproducing “intelligence” in a computer.

Kelly’s work takes a concept that would have many of us get the digital toolkit, and makes it wonderfully life-like using a small bouquet of simple parts. It’s a challenge to our beliefs and approaches, compelling in its grace, urging us to consider and respect analog circuits more when it comes to modelling consciousness and behaviours. If it’s this simple to model sounds and behaviour of a biological organism, a task that’d have us writing DSP and math code to replicate on a microcontroller – what else are we missing from our models?

Kelly has more PCBs to arrive soon in preparation for her NYC exhibit in February, and will surely be posting updates on her Twitter page! We’ve covered her work before, and if you haven’t seen it yet, her Supercon 2019 talk on Electronic Naturalism would be a great place to start! Such projects tend to inspire fellow hackers to build other non-conventional projects, and this chirping pendant follows closely in Kelly’s footsteps! The direction of this venture reminds us a lot of BEAM robotics, which we’ve recently reminisced upon as something that’s impacted generations of hackers to look at electronics we create through an entirely different lens.

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Dirty faders.

Giving Vintage Synths New Life In A Potentiometer Cleaning Showdown

As anyone who has ever owned a piece of older equipment that has a potentiometer in it can attest to, these mechanical components do need their regular cleaning ritual. Whether it’s volume knobs on a receiver or faders on a mixer, over time they get crackly, scratchy and generally imprecise due to the oxidation and gunk that tends to gather inside them.

This is your potentiometer caked with gunk.
This is your potentiometer caked with gunk.

In this blast from the past, [Keith Murray] shows a few ways in which fader-style potentiometers can be cleaned, and how well each cleaning method works by testing the smoothness of the transition over time with an oscilloscope. It’s enlightening to see just how terrible the performance of a grimed-up fader is, and how little a blast of compressed air helped. Contact cleaner works much better, but it’s essential to get all of the loosened bits of gunk out of the fader regardless.

In the end, a soak in isopropyl alcohol (IPA), as well as a full disassembly followed by manual cleaning were the only ones to get the fader performance back to that of a new one. Using contact cleaner followed by blasting the fader out with compressed air seems to be an acceptable trade-off to avoid disassembly, however.

What is your preferred way to clean potentiometers to keep that vintage (audio) gear in peak condition? Let us know in the comments below.

Thanks, [Grant Freese], for the tip!

The Eerie Sounds Of Ioalieia: An ESP32/Valve/Analog Hybrid Circuit Sculpture

We’ve not had a circuit sculpture piece for a while, so here’s “ioalieia” a lovely hybrid digital-analog sound sculpture by [Eirik Brandal] to dig into.

Tidy straight lines. Nice job!

The host of the show is the ESP32 module, which generates audio frequency square waves, which are fed into a MCP4251 digital potentiometer. From there, it is fed into a AS3320 Voltage controlled filter (VCF), from Latvia-based ALFA (which is new to us, despite them being manufacturing electronics for sixty years!) This is an interesting device that has a four independently configurable filter elements with voltage controlled inputs for frequency control and resonance. The output from the VCF is then fed into a 6n2p (Soviet equivalent to the 12ax7) twin-triode vacuum tube, which is specifically aimed at audio applications.

The suitably distorted filtered square waves then pass into a Princeton Tech Corp PT2399 echo processor chip, which being digitally constructed, uses the expected ADC/RAM/DAC signal chain to implement an audio echo effect. As with the VCF, the echo depth can be modulated via the digipot, under the ESP32’s command. For a bit of added bling, the vacuum tube output feeds back into the ESP32, to be consumed by the internal ADC and turned into a light show via some PWM controlled LEDs. Lovely.

The final audio output from the echo chip is then fed into a speaker via a pair of LM380 amplifiers giving a power of about 5 W. It sounds pretty good if you ask us, and software configurable via Wi-Fi, giving this sculpture plenty of tweakabilty.

Of course circuit sculpture come in all shapes and sizes, and it wouldn’t do to not mention at least one sculpture clock project, and while we’re on it, here’s last year’s Remoticon circuit sculpture workshop.

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Travel Guitar Hacked With Digital FX Setup

[Courcirc8] was a big fan of the ALP AD-80, with the travel guitar being a surprisingly competent instrument despite its folding form-factor. However, the onboard headphone amp left something to be desired, so it was time to get hacking.

To achieve better audio output, [courcirc8] decided to purchase an iRig HD 2 guitar interface, and installed it inside the body of the compact guitar. The original volume pot on the guitar was instead spliced into the iRig circuit, and a switch hooked up to allow the guitar to output clean tones to an amp or the digital audio output of the iRig instead. It’s a tight fit inside, but it all nestles in there rather neatly when finished.

The result is a compact guitar that has a capable digital FX platform built in to the body; all one has to do is hook up a smartphone to gain access to a broad selection of software effects.  It makes the guitar much more of a Swiss Army knife when playing on the road.

We’ve seen others before installing guitar effects into the instrument itself; it remains perhaps one of the best ways a hacker can express themselves with a completely individual instrument!

Artist operating artistic visualizer with MIDI keyboard

Synth And Visualizer Combo Has Retrocomputing Vibe

[Love Hultén]’s latest piece of interactive art is the SYNTH#BOI, a super-clean build with something of the semi-cyberdeck, semi-vintage computing vibe to it. The device is a combination synthesizer and visualizer, with a 15-inch display, MIDI keyboard, and based on an Intel NUC i5 small form factor PC.

There are not many details about the internal workings of the device, but the high quality of the build is very evident. Photos show a fantastic-looking enclosure with clean lines and sharp finish; it’s a reminder that careful measuring and attention to detail can be the difference between something that looks like a hack job, and something that looks like a finished product.

Watch the SYNTH#BOI in action in the video, embedded below. And if the name [Love Hultén] seems familiar, it’s probably because we featured his VOC-25 “Pink Denture Synth”, a concept instrument with a decidedly memorable design of its own.

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Electronic Drum Toy Built From Scratch

Drum kits used to be key to any serious band, however, these days, much of our music is created on computer or using a drum machine instead. [spanceac] has built a simple example of the latter, using a microcontroller to build a basic sample-based drum toy.

The brains of the operation is the STM32F100VET6B, which comes complete with a 12-bit DAC for outputting sound. It’s also got a healthy 512 KB of flash, enabling it to store the drum samples onboard without the need for extra parts. Samples are stored at a sample rate of 22,050 Hz in 16-bit resolution – decent quality for a tiny little build, even if the DAC chops that back down to 12-bits later.

[spanceac] was sure to code proper mixing into the drum machine, so that triggering a second sample doesn’t stop the first one playing. With a kick, snare, two toms, and crash and ride samples onboard, there’s plenty to get a solid beat going on the kit.  It’s all built up on a small PCB with tactile buttons to activate each sound.

The demo video shows the kit performing ably; it’s not clear if there’s an issue with latency on the samples or that’s just from the difficulty of [spanceac] playing one-handed. If the former, likely some code tweaks or simply trimming silence at the start of samples would be all that was needed. Overall, it’s a neat little groovebox, and the kind of thing that’s great fun to use when jamming with other musicians. Video after the break.

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Vacuum tube Atari Punk Console

The Atari Punk Console, Now With More Vacuum Tubes

Most of us have beheld the sonic glory of an Atari Punk Console, that lo-fi synth whose classic incarnation is a pair of 555 timers set up to warble and bleep in interesting ways. Very few of us, however, have likely seen an APC built from 555s that are made from vacuum tubes.

It’s little surprise to regular readers that this one comes to us by way of [David] at Usagi Electric, who hasn’t met a circuit that couldn’t be improved by realizing it in vacuum tubes. His “hollow-state” Atari Punk Console began with the 18-tube version of the 555 that he built just for fun a while back, which proved popular enough that he’s working on a kit version, the prototype of which served as the second timer for the synth. With 32 tubes aglow amid a rats-nest of jumpers, the console managed to make the requisites sounds, but lacked a certain elegance. [David] then vastly simplified the design, reducing the BOM to just four dual-triode tubes. Housed on a CNC milled PCB in a custom wood box, the synth does a respectable job and looks good doing it. The video below shows both versions in action, as well as detailing their construction.

As cool as a vacuum tube synth may be, we realize that not everyone goes for the hot glass approach. No worries — plenty of silicon Atari Punk Consoles to choose from here. There’s one built into a joystick, a circuit sculpture version complete with mini-CRT, or even eight APCs teamed up with MIDI control.

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