Adding MIDI To An Old Casio Keyboard

Not content to rule the world of digital watches, Casio also dominated the home musical keyboard market in decades past. If you wanted an instrument to make noises that sounded approximately nothing like what they were supposed to be, you couldn’t go past a Casio. [Marwan] had just such a keyboard, and wanted to use it with their PC, but the low-end instrumented lacked MIDI. Of course, such functionality is but a simple hack away.

The hack involved opening up the instrument and wiring the original keyboard matrix to the digital inputs of an Arduino Uno. The keys are read as a simple multiplexed array, and with a little work, [Marwan] had the scheme figured out. With the Arduino now capable of detecting keypresses, [Marwan] whipped up some code to turn this into relevant MIDI data. Then, it was simply a case of reprogramming the Arduino Uno’s ATMega 16U2 USB interface chip to act as a USB-MIDI device, and the hack was complete.

Now, featuring a USB-MIDI interface, it’s easy to use the keyboard to play virtual instruments on any modern PC DAW. As it’s a popular standard, it should work with most tablets and smartphones too, if you’re that way inclined. Of course, if you’re more into modular synthesizers, you might want to think about working with CV instead!

22 thoughts on “Adding MIDI To An Old Casio Keyboard

  1. “I am writing on behalf of CASIO, which is a member of REACT (also known as the Anti-Counterfeiting Network ). REACT actively fights the trade-in counterfeiting products on behalf of its members,” the complaint reads. You are using the name CASIO which is a copyrighted word that belongs to one of our members and we insist that you cease and desist forthwith, or sooner.

    1. Time there was severe criminal and civil penalties for misuse of DMCA, 10 year mandatory minimum custodial sentence for all personnel involved in filing such drivel, $1 million compensation to falsely accused and $1 million fine donated to the EFF.

    2. The article actual use the right words. ““It came to our attention that the below-mentioned repository is using copyrighted source code in order to modify Casio’s copyrighted program.”

      Casio is a trademark. Their source code and their programs are copyrighted. Casio the word itself isn’t copyrighted as that would mean that their name will be public domain one of these days.

    3. Right, this must be more fallout from that massive leak of Casio IP in which all their C and Verilog for 30 years of stuff ended up on Pirate Bay. Oh wait, did that happen? I don’t think that happened. Mandela Effect Confirmed!

    1. Mostly because it’s much harder — note the long, long process it’s been to have a workable electric guitar-to-midi converter, where having a special pickup catch each string worked in the ’80s. And a guitar has the same(ish) waveform to recognize pitches in! Recognizing notes in a polyphonic pileup like a chord is even harder.

      My single-note experiments in this vein have mostly fallen down on latency — the waveform has to be present for a while before the micro I was using decided what pitch it was, and we’re apparently really good at recognizing the delay between hitting a key/string and hearing a note from the software synth you’re trying to control.

  2. But… but… that one mini toy KB had 4-position voice switch and one of them was called “FANTASY” and seemed to belong to a Zelda game. Sorry, I can’t remember anything else except it was a rather light color, almost white or maybe pink.

  3. The cool trick would be to make the keyboard MIDI controlled to play its built in sounds. All this does is make it a generic MIDI input keyboard, which could be done with any old keyboard.

    1. The PT-87 uses hot-swappable ROM for playing a few pre-recorded multitrack songs and the Hitachi ‘SoC’ has a multitimbral, possibly polyphonic synth, even though playing the keys is always mono. At least for that one, there’s a way to push something in– you “only” have to learn the format and (probably) translate from MIDI and make your MCU also hit the play button after it starts up. That’s the strategy, anyway.

    2. On the other side of the coin: this hack could be reused on any non-velocity keyboard, which makes it kinda useful.

      Maybe even more useful than the comedy effect of playing old video game MIDIs on this horrendous thing. Which, granted, would be hella cool.

  4. Thats so cool! Is there any chance of making a tutorial for this? I have a Casio PT – 82 that I want “MIDI-fied”. I don’t really have tech experience but I really want my Casio as a MIDI controller! Any hope for me?

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