DIY midi keyboard retrofit with arduino

  • Hello All..
    For a while I've been thinking about trying to somehow retrofit my 49 note portable pump organ so that it can also be used to send midi to virtual instruments and hardware synth modules..

    I wonder if I might use an arduino and low profile triggers to accomplish this..

    Any of you makers out there have some words of advice or links that could get me on the right track?

    Thanks for any help..

  • This chip can handle five octaves worth of keys (with velocity sensitivity if you want to go there):

    I believe it's the same chip used in c-thru music's axis-64, as a matter of fact.

    I have NO idea what to actually do with that chip, mind you. But the one I bought does look pretty on my shelf.

    The site I found that through ( is down. which is a shame, 'cause they had all kinds of mad info. (such as "how do you make something velocity sensitive?")

    This forum is all that remains of them, it looks like:

    Anyway, this is probably closer to what you need:

  • @gtz, where are you located, I might be willing to take that chip off your hands if you're interested. I have a modded Hammond M-103 that I haven't used in a while but would love to resurrect as a midi controller/tonewheel organ. It'd be pretty cool playing actual hammond and generated midi at the same time.

    However, I could also, I guess, make an arduino device using a few shift registers and tapping into the key contacts on one of the upper registers. hmmm.... I could even write my own custom max patch, or use the teensy platform. Heck I think a small $16 teensy 2.0 and some shift registers could gather the data, including from the drawbars and expression pedal and I could have volume control and another set of sliders. Too much for thought.

  • I'm in Los Angeles. But I don't really want to get rid of the chip so much as learn how to read data sheets and build something around it. Someday.

  • Thanks...
    I never explored the potential of arduino outside of the world of monome, but from what I gather it can be programmed to send midi directly to hardware without a computer as a go between..

    There must be a site with code/tutorials/help programming arduino..

    Time to keep looking. Thanks again for your help..

  • It can using the LUFA stuff made for it, but I haven't really gotten in that yet. I still have to do basic things with it. The teensy is nice in that it can be more easily made to present itself as a native midi device.

  • The newer Arduino units (arduino uno) offers an alternate mode that sends midi directly to your computer or your iPad over USB, without an additional computer as a go between. That's usually what people are discussing when they talk about using the Arduino for MIDI.

    That process is a pain and a half, and there are very few tutorials for it that I've found. On most forums where people ask for help, the response is always "get a teensy. it's arduino-compatible, but you won't have to jump through those hoops to output data in the right format."

    But here's some info (scroll to bottom)

    and/or this:

    There are additionally ways to include a standard five-pin MIDI port or two in your sketch, which can then be plugged into hardware without a computer acting as go between. But your hardware will have to support five-pin MIDI cables in order to make use of that. (your computer, for example, does not natively support MIDI hardware, but MIDI adapters are readily available)


    (Note: MIDI out monopolizes your TX port, and MIDI in monopolizes your RX port. So if you need more than two ports, upgrade to the arduino mega)

    And then just for completion, here's a third path:

    In that video, you're walked through an arduino sketch that receives MIDI input over USB and forwards that to 5 pin MIDI out.

    As for a site w/ help, tutorials, etc. for arduino, have you looked at ?

    In particular, I'd recommend
    and of course

  • Oh my guys, that hinton-instruments kv64 sounds like what I need to restore my Kurzweil Ensemble Grand Piano. This piano has beautiful wooden keys that are an absolute pleasure to play but the 1980s electronics have bitten the dust. I can't believe how many boards and power supplies they stuffed inside.

    All I want is midi out and some simple circuit to wire my 88 keys to but until now nothing supported velocity sensitivity, seems the market is slanted towards the diy pipe organ builders and the midi controllers like your namesake.

    Do you know of any examples of someone using the kv64 chip? The chip does not output midi so some other electronics are necessary.

    GreaterThanZero, can you tell me if it was much of a hassle getting the chip?

    Thanks for the great tip!

  • I just ordered it and waited.

    Again, that's still sitting here. I never did figure out how to integrate it with much of anything. But, Mr. Hinton (I lost his first name) seems a friendly sort. I've seen him around in some other forums, and I'm sure he'd be happy to answer a few questions.

    ...just maybe not at the "please design my whole project" level that I probably need, if we're completely honest with ourselves. If you've got any friends who can read schematics and help plan your rebuild, have them act as interpreter when you email the guy. =)