Acoustic Accordion Becomes MIDI; Oh the Complexity!

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.

Remarkably, he accomplished this without any major hurdles (just a lot of time). The photo-interrupters were installed, and all of the electronics were tucked in nicely inside the body of the accordion. To start, [Brendan] had this wired to his computer with a USB cable from the Arduino in order to prove the concept. After that worked, he upgraded the setup with Bluetooth to transmit the signals, and even added a barometric pressure sensor that allows him to use the bellows for expression and volume changes. Although we’ve seen elaborate MIDI builds before, this might just take the cake for complexity in a small package. Oh, and just sheer coolness.

[via r/somethingimade]

17 thoughts on “Acoustic Accordion Becomes MIDI; Oh the Complexity!

  1. Wireless sure is better than a 50 pin plug and a cable as thick as a finger to feed a tube organ stuffed into a guitar amp sized case. Whew! Taking the 120 chord-bass apart, I would not try. For those who don’t know, it’s a 120 input ROM with 3 or 4 out of 12. Like an IC in wire model in 3D. Moving parts! As complicated as it sounds it has just one octave of notes to play, plus an octave of bass notes. Optical is the most reliable “contact” method to use, not overkill. I need to find out more about the otherwise useless Blurtooth interface. Is there any lag?

    1. That’s probably the most unique way I’ve ever heard someone describe the Stradella bass system. Yeah, it was definitely intimidating the first time I took it apart, but once I dove in, cleaned it, and put it all back together I had a much better appreciation for the mechanics of my favorite instrument.

      As far as lag goes, I don’t have the tools measure exactly from key input to sound output, but adding up the lag in the Arduino reading the ports (up to 3.5ms plus an optional 2ms w/BMP180), the Hairless MIDISerial converter, and the audio driver latency (using ASIO4All), you’re probably looking at about a 15-20ms delay total, which is noticeable on the accordion, but not unplayable. Using a sound card with native ASIO-support would probably cut that in half.

    1. It absolutely is – I won’t deny that. I can’t say I’m super proud of that particular part of the job, but I feel I did well enough considering the only tool I had was a power drill and it was the first time I’d ever done something like that. I may go in and straighten it up later, especially if I decide to add more ports and/or MIDI controllers.

  2. Interestingly, around 25 years ago, I worked with someone in Scotland who had hacked up his accordion for MIDI. Used to charm the tourists playing the Edinburgh military tattoo on his squeezebox ( drums triggered from the buttons, bagpipes triggered from the keys). Sadly, pre-internet, so no YouTube link to prove my story, but Dave, if you’re reading, I salute ya.

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