A man playing an accordion-like instrument made from two Commodore 64s

The Commodordion Turns Two C64s Into A Single Instrument

October 22, 2022 by Robin Kearey 16 Comments

One of the main reasons the Commodore 64 became an icon of the 1980s was its MOS 6581 “SID” sound chip that gave it audio capabilities well beyond those of other microcomputers of the 8-bit era. The SID became something of a legend by itself among chiptune enthusiasts, and several electronic instruments have been designed that generate their sound through a SID chip. Not many of those look anything like traditional musical instruments however, so we’re delighted to see [Linus Åkesson]’s new project: two Commodore 64s joined back-to-back using a bellows to form a wonderful new instrument called the Commodordion. It can be played in a similar way one plays a traditional accordion: melodies are played with the right hand, chords with the left, and volume is adjusted by varying the pressure in the bellows.

The two computers are basically unmodified, and boot Commodore BASIC like they normally would. A custom circuit board emulates a cassette player and provides the software to be loaded into memory. Both computers run the same program and can be switched between the right-hand and left-hand role by pressing a specific key combination. The software in question is called Qwertuoso, and basically maps notes and various features of the SID chip to keys on the Commodore’s keyboard.

Of course, it’s the bellows that makes this instrument a true member of the accordion family. Made from 5.25″ floppy disks and sticky tape, it forms a more-or-less air-tight system linking the two computers. The airflow in the bellows is measured through a microphone placed next to the air intake: the amount of noise generated is roughly proportional to the amount of air being expelled or inhaled. This information is then used to modulate the volume generated by the two SID chips.

By [Linus]’s own admission it’s not the most ergonomic of instruments, so we’re doubly impressed by the amount of skill he demonstrates while playing it in the video embedded below. It’s not the first time either that he has turned a Commodore 64 into a musical instrument: he previously built a church organ and a theremin. While the Commodordion may look complicated, it’s actually much simpler in construction than a mechanical accordion.

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Acordeonador, an 555 accordion powered by a CD player based genrator

CD Player Powered 555 Piano Goes Accordion To Plan

December 30, 2021 by Ryan Flowers 8 Comments

Ah yes, the 555 piano project. Be it the Atari Punk Console, or some other 555 based synthesizer, Hackers just love to hear what the 555 can do when attached to a few passives and a speaker. It’s a sound to behold. But for [Berna], that wasn’t quite enough! Below the break, you can see his creation, called the Acordeonador.

A portmanteau of the Spanish words for “Accordion” and Generator”, the Acordeonador does what no project we’ve seen so far can do: It turns a CD drive into a generator for a 555 based synthesizer.

To give the Acordeonador a more analog feeling, a large 4700uf electrolytic capacitor stores just enough energy to make the music generation more than an on/off affair. It’s a great effect, and it works well! Not being one to leave any details out, [Berna] prototyped the build on perf board and then covered the board in what appears to be an wood grained contact paper, giving it that 1970’s dual keyboard electric organ feel.

It really just goes to prove that a 555 project can be the source of a great time! Hackaday is rife with 555 projects, but if you enjoy this, be sure to check out The Most Important Device In the Universe, which is of course powered by a 555. Continue reading “CD Player Powered 555 Piano Goes Accordion To Plan” →

Quieting Down A Bandoneon Accordion With MIDI

April 13, 2020 by Danie Conradie 9 Comments

The bandoneon, known as the tango accordion, is quite a loud instrument to practice within the confines of an apartment, and could possibly lead to some neighborly disputes. [HLB] enjoyed playing his but wanted a way to turn down the volume a bit without, in consideration to his neighbors. Instead of building a whole soundproof room, he decided to throw Arduino’s and MIDI at the problem.

Bandoneons, like all accordions, are operated by pushing air from manually pumped bellows through a series of reeds, which are each opened and closed by a valve mechanism. [HLT] turned each valve lever into a simple on/off switch by attaching a magnet, with hall-effect sensors on long custom PCBs next to each row of valves. The hall effect sensors are connected to I2C I/O expander ICs which connect to an Arduino Nano, one for each side of the instrument, which sends out MIDI messages via serial. Everything is mounted inside what looks like quite an old instrument with Blu Tack to avoid having to make a lot of permanent modifications.

The bandoneon still functions normally with no permanent modifications, so to play with MIDI-only the bellow is simply not pumped. This means [HLB] can’t modulate the MIDI velocity (loudness) while playing, which he admits is a limitation but better than not playing at all. He does, however, note that he could add a pressure sensor inside the bellow if we wanted to add velocity to the midi output when neighbourliness isn’t a consideration. On the audio output side [HLB] built a small stand-alone synthesizer with an Odroid SBC running FluidSynth and a HiFi shield.

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Acoustic Accordion Becomes MIDI; Oh The Complexity!

February 1, 2017 by Cameron Coward 20 Comments

Everyone knows accordions are cool — they look fly, make neat noises, and get your romantic interests all hot and bothered. What isn’t cool is being relegated to acoustics only. How are you going to play a packed stadium or lay down a crystal clear track like that? You could go out and buy an electric accordion, but even low-end models carry a hefty price tag. But, this is Hackaday, and you know we’re going to be telling you about someone who found a better way.

That better way, shown in a build by [Brendan Vavra], was to take an acoustic accordion and convert it to MIDI. The base for his build was a decent full-size acoustic accordion purchased on eBay for just $150. Overall, it was in good mechanical condition, but some of the reeds were out of tune or not working at all. Luckily, that didn’t matter, since he wouldn’t be using them anyway. Don’t be fooled in the demo video below; it sounds like he’s playing the acoustic according but notice he’s not pumping those bellows! However, the bellows isn’t useless either since it can feed data back as a MIDI input.

[Brendan’s] build plan called for an Arduino Mega to be tied to a series of photo-interrupters that would detect button pushes and fire MIDI signals. But, first he had to take the thing apart — no small task, given the complexity of the instrument. The accordion has 120 buttons, and they’re not interchangeable, which means he had to carefully keep track of them as they were disassembled.

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Self Playing Bayan Built Nearly 22 Years Ago

September 5, 2010 by Jakob Griffith 57 Comments

The year is 1988, where a Russian engineer [Vladimir Demin] has combined a Bayan, or button accordion, with several (we lost count at about 96) solenoids. If that alone doesn’t blow your mind the computer, also hand built by [Vladimir], controls the whole process leaving the operator to only work the bellows. Putting truth to the fact in Soviet Russia, accordion plays you. We wish we could find some more information about the instrument, but curse our inability to read Russian. Alas check after the break for a shorter version of the video in the link above.

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Moolodeon Electric Accordion

December 28, 2009 by Mike Szczys 23 Comments

[youtube=http://www.youtube.com/watch?v=Dc1a5ig_M94]

[Lee] wanted an electric Melodeon to use with his band. A Melodeon is a chromatic accordion and there are people who already make electric versions but they are a little too expensive for him. Instead, he bought a toy accordion and added electronics to it.

After being thwarted by forgotten PIC skills of yore, he went with an Arduino as the controller. Two pressure sensors are used to detect the squeezing and pulling of the instrument’s bellows. His did some solid work. The video above uses 8-bit sounds like we’re used to from video games and the one after the break sources more traditional accordion sounds.

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