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Thread: N00b project- Using teensy to translate CV into MIDI DIN out

  1. #1
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    N00b project- Using teensy to translate CV into MIDI DIN out

    Hello-
    New to the forum, hi, how are you?

    I'm a relative n00b to working with Teensy, but I've dabbled in Arduino projects so I have some, very basic, working knowledge. I'm a musician and I've worked on some controllers, sensor arrays, etc all for the purpose of sending MIDI CC's over USB to be used by a DAW. That's been fun and relatively easy to bumble through so far. But I'd like to construct a new device that is slightly more complicated and I'm not sure how to really get going on it.
    I'd like to build a control pedal to directly control my Strymon TimeLine delay pedal. What I'd like to do is set up some pots and footswitches to give me extended control over some of the "hidden" functions (basically things that are controllable via MIDI CC's but require a bit of menu-diving to access on the pedal itself). To further complicate matters, I would also like to be able to take CV signals from my modular synth and be able to use those to control certain parameters as well. Finally, the signals need to be output via MIDI DIN, since I want to interface with the Strymon directly, no laptop required, and that's the part that I have no experience working with.

    Just looking for a little assistance in how to start approaching this- to begin with, how to take CC's generated by pots and output them as MIDI through a DIN socket. The CV control, I think, sort of follows from that- I believe I can input CV into the analog ins of the Teensy (provided I have a voltage clamp on the circuit so the voltage doesn't exceed 5V) and that should essentially work just like a pot would. But please correct me if I'm wrong!

    I currently have a Teensy 2.0, would a newer model be more suited for my project or will this board work for me? I was planning on using switched jacks for the CV inputs so they would piggyback on the inputs used by the pots (since they would, in most cases) be targeting the same CC's.

    Thanks in advance for any words of wisdom/caution/general advice


    EDIT- after I posted this I saw a post further down the page with tons of info re: how to interface the Teensy with a modular so that seems covered. The OP in that thread is using a 3.1 but I assume my 2.0 will be ok, correct?
    Last edited by atari5200; 10-13-2014 at 06:12 PM.

  2. #2
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    Hi, and welcome to the forum. Yes, this sort of CV-to-MIDI device is all doable. Some suggested reading:
    - interfacing with a modular synth
    - MIDI over DIN, with the MIDI library

    You have two options for dealing with pots and CV: either normal the pot voltage to the switching input on the CV input jack, so the pot is only used if there is no cable patched; or else use an op-amp mixer to combine the pot and CV signals.

    A Teensy 2.0 should be able to do this, depending on how complicated you need it to be. Unlike the Arduino boards, the hardware Serial on Teensy is avaailable to drive the MIDI output, it is totally separate from the USB connection. (Most Arduino boards need to use a software serial emulation, which is an extra complication). On the other hand the available RAM for variables and the stack is quite limited. If you find yourself running out of RAM, a Teensy 3.1 has much more RAM (and Flash memory for your program) and is significantly faster. Teensy 3.1 is 5V tolerant, which makes interfacing easier, but the maximum voltage that can be read by the ADC is still 3.3 volts. And yes, voltage protection on the inputs will certainly be needed.

  3. #3
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    Hi did you end up making the midi controller for your timeline? Iím looking doing the same but not as elaborate as yours. I just want 6 switches to control the looper functions over midi din.

  4. #4
    Senior Member oddson's Avatar
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    Btw... This is an ancient thread and you don't seem to be asking about CV for modular synths which I take to be the original topic.

    But six buttons should be fairly simple.

    A DIN output is trivial and an input is still simple enough if you follow instructions carefully.

    USB MIDI directly is Teensy's easiest method... but if you want DIN start here https://www.pjrc.com/teensy/td_libs_MIDI.html

    For USB
    https://www.pjrc.com/teensy/td_midi.html

    There is a midi button example with the Teensyduino download and both DIN and usbMIDI use essentially the same calls.

    I'd recommend starting with usbMIDI before trying to build a DIN interface.
    Last edited by oddson; 01-16-2020 at 04:43 AM.

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