A photo of the front-panel with a bunch of lamps and knobs.

The Making Of A Minimalist Analog Drum Machine

Our hacker [Moritz Klein] shows us how to make a minimalist analog drum machine. If you want the gory details check out the video embedded below and there is a first class write-up available as a 78 page PDF manual too. Indeed it has been a while since we have seen a project which was this well documented.

A typical drum machine will have many buttons and LEDs and is usually implemented with a microcontroller. In this project [Moritz] eschews that complexity and comes up with an analog solution using a few integrated circuits, LEDs, and buttons.

The heart of the build are the integrated circuits which include two TL074 quad op amps, a TL072 dual op amp, a CD4520 binary counter, and eight CD4015 shift registers. Fifteen switches and buttons are used along with seven LEDs. And speaking of LEDs, our hacker [Moritz] seems to have an LED schematic symbol tattooed to his hand, and we don’t know about you, but this screams credibility to us! :)

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NTRON Plays Games, Music

What do you get if you meld a Raspberry Pi, a chiptune synthesizer, and a case that looks like an imaginary Kenback-2000? Well, if you are [Artifextron], you get the NTRON. Part Nintendo console, part chip tune synthesizer, and part objet d’art. You can see the device do its things in the video below.

This is less of a bare metal design and more of a synthesis of parts, but it is a very clever system design using audio mixers and an assortment of modules to do its tasks. It does have an IC handling the gamepad ports. Of course, it also features a ton of 3D printed parts.

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Bringing Bluetooth To The Zune

The Zune might have joined the portable media player game too late to ever really be competition for the iPod, but that doesn’t mean it didn’t pick up some devoted fans along the way. Some of them are still breathing new life into the device, such as [The Director of Legal Evil Emeritus] at the Louisville Hackerspace, with this project that gives it Bluetooth capability.

As far as media players go, there’s still some solid reasons to rock a Zune. Compared to other devices of the era, it offers a better DAC, an FM tuner, and no iTunes reliance. The goal of this project was to bring a bit of modern functionality without having to do any modification of the Zune itself. As the player supported docks with IR remotes, this build involves using an ESP32 to listen to the Bluetooth signal coming from the speakers, interpret any button presses, and forward them along to the Zune’s dock.

There is a dedicated scene for these old music players, but this build is unique for not needing to crack open the case and splice in a Bluetooth module. Even then, those typically don’t have the ability to interact with things like this speaker with its integrated control buttons.

We don’t often seen Zune hacks come our way — the last time Microsoft’s player graced these pages was in 2010, when the Open Zune Development Kit was released.

Thanks to [JAC_101] for the tip!

March To The Beat Of Your Own Piezoelectric Drum

Drums! You hit them, and they vibrate. It’s kind of fun. Piezoelectric elements can create electric current when they vibrate. [Will Dana] put two and two together to try and charge his phone on his YouTube channel WillsBuilds embedded below.

It worked… about as well as you might expect. Which is to say: not very well. The random piezo elements [Will] glues to his drum almost certainly aren’t optimized for this use case. Adding weight helps, but it doesn’t look like a tuned system. Even if it was, piezoelectric generators aren’t terribly efficient by nature, and the (small) losses from the required bridge rectifiers aren’t helping. An energy-harvesting chip might have worked better, but it probably wouldn’t have worked well.

Since he cannot produce enough voltage in real time, [Will] opts to charge a capacitor bank that he can dump into the phone once it gets enough charge in it to register with the phone’s circuitry. It takes about 30 minutes drumming to charge the capacitors in parallel, before switching to series to get the voltage up to discharge. The capacitors drain in about a quarter second, probably to no measurable result– but the phone does read as “charging”, which was the goal.

Did it work? Technically, yes. The phone was “charging”. Is it practical? Certainly not. Is it a hack? Undeniably so.

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Give Your Band The Music Of The Bands

The way to get into radio, and thence electronics, in the middle years of the last century, was to fire up a shortwave receiver and tune across the bands. In the days when every country worth its salt had a shortwave station, Cold War adversaries boomed propaganda across the airwaves, and even radio amateurs used AM that could be listened to on a consumer radio, a session in front of the dial was sure to turn up a few surprises. It’s a lost world in the 21st century, as the Internet has provided an easier worldwide medium and switch-mode power supplies have created a blanket of noise. The sounds of shortwave are thus no longer well known to anyone but a few enthusiasts, but that hasn’t stopped [gnd buzz] investigating their potential in electronic music.

There’s very little on the air which couldn’t be used in some form by the musician, but the samples are best used as the base for further processing. One example takes a “buzzer” signal and turns it into a bass instrument. The page introduces the different types of things which can be found on the bands, for which with the prevalence of WebSDRs there has never been a lower barrier to entry.

If you’re too young to have scanned the bands, a capable receiver can now be had for surprisingly little.

Radio dial header: Maximilian Schönherr, CC BY-SA 3.0.

Musical Motors, BLDC Edition

This should count as a hack: making music from a thing that should not sing. In this case, [SIROJU] is tickling the ivories with a Brushless DC motor, or BLDC. 

To listen to a performance, jump to 6:27 in the embedded video. This BLDC has a distinctly chip-tune like sound, not entirely unlike other projects that make music with stepper motors. Unlike most stepper-based instruments we’ve seen [SIROJU]’s BLDC isn’t turning as it sings. He’s just got it vibrating by manipulating the space vector modulation that drives the motor — he gets a response of about 10 kHz that way. Not CD-quality, no, but plenty for electronic music. He can even play chords of up to 7 notes at a time.

There’s no obvious reason he couldn’t embed the music into a proper motor-drive signal, and thus allow a drone to hum it’s own theme song as it hovers along. He’s certainly got the chops for it; if you haven’t seen [SIROJU]’s videos on BLDC drivers on YouTube, you should check out his channel. He’s got a lot of deep content about running these ubiquitous motors. Sure, we could have just linked to him showing you how to do FOC on an STM32, but “making it sing” is an expression for mastery in English, and a lot more fun besides.

There are other ways to make music with motors. If you know of any others, don’t hesitate to send us a tip.

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Round And Round With A Tape Delay Synth

Over the years we’ve been entertained by an array of musical projects from [Look Mum No Computer], and his latest is no exception. It’s a tape delay, loop generator, and synth all in one. Confused? That’s what you get if you position a load of tape heads around a rotating disk with magnetic tape on its perimeter.

Taking a circular piece of inch-thick Perspex, he wraps a length of one inch tape round its perimeter. This is placed as though it were a turntable on a stepper motor with variable speed, and the tape heads are positioned around its edge. Each read head feeds its own preamp which in turn drives a mixer array, and there’s also a record head and an erase head. If you’ve ever played with tape loops you’ll immediately understand the potential for feedback and sequence generation to make interesting sounds. There’s a lot of nuance to the build, in designing the mount for the motor to stop the enclosure flexing, in using a gearbox for increased torque, and in balancing the disk.

The result is as much an effect as it is an instrument in its own right, particularly in its prototype phase when the read head was movable. We’re treated to a demo/performance, and we look forward to perhaps seeing this in person at some point. There’s a future video promised in which a fix should come for a click caused by the erase circuitry, and he’ll make a more compact enclosure for it. Continue reading “Round And Round With A Tape Delay Synth”