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Thread: Starting a simple midi controller advice

  1. #1
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    Starting a simple midi controller advice

    Hi
    this is my first post here

    I'm planing to build my own controller !!
    Just have few questions :
    Between 3.3v and 5v which one should I choose for midi controller ? (I think 5v is the best for this application)
    or which Teensy is the best choice for this application ? (LC, 2, 4.0)

    I was thinking to buy one or two CD74HC4067 to add more control

    https://www.sparkfun.com/products/9056
    or is Any Analog/Digital MUX Breakout with this chipset is ok ?

    Best
    Zoltan

  2. #2
    Senior Member oddson's Avatar
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    1) Voltage - there is no pressing need for 5 volt for MIDI. The old Teensy 2.0 are more than adequate for MIDI controllers and they work at 5 volt but the LC is cheaper and is the obvious choice because of that.
    When using a 3.3 teensy you just need to power any voltage dividers with a 3.3 volt source so that the range is correct.

    Even if you are sending and receiving serial MIDI there are 3.3 volt circuits that work fine for this.

    2) MUX - I bought that very board to help someone on the forum and it worked well for me (although I don't build massive controllers so I can't say I've tested under use but I'm pretty sure this board is a fine choice IF and WHEN you are ready for bigger projects). Paul's documentation (usbMidi page near bottom) is for an 8 channel mux but an extra selector signal is really the only difference in making them work.

    Adding MUX is a major complication if you are not already adept at coding and troubleshooting.

    Borrowing code might work but you might find it difficult to get things working if you don't understand the code.

    Standard advice here.... many start large MIDI projects but few see them through.

    The physical build seems simple until you have wires everywhere with dodgy solder joints and borrowed code you don't understand and can't troubleshoot.

    If you've not already do some tutorials or at least figure out how to read a value from a voltage divider.

    Some specifics on what you hope to achieve would be beneficial to giving advice.
    Last edited by oddson; 12-13-2019 at 08:56 PM.

  3. #3
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    Hi Oddson
    thank your for your answer !
    in fact I already made some few test with Arduino Uno and it's works fine, but I look at the teensy for the direct detecter USB driver instead of Arduino who is more 5 pin cable

    I found this tutoriel http://community.axoloti.com/t/make-...for-cheap/3866
    and think is a good start ?
    I'm taking my time and ask fews questions when needed

  4. #4
    Senior Member oddson's Avatar
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    Teensy is not just another Arduino especially if you are making a USB MIDI compliant device but it's good to know you're not a noob to coding.

    I'm always a bit skeptical when there is talk about MUX in a user's first post... the history isn't good there.

    Here's a post where I tried to guide a previous poster to the existing MUX code examples.
    https://forum.pjrc.com/threads/52856...l=1#post181888

    If you could indicate the numbers and types of signals you want to support I could give you an indication of what would be required and how much can be done with existing example code.

    btw- the link in your post don't work for me here at work but that appears to be a corporate block on axoloti from my end so I'll have a look at that later.

  5. #5
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    thank you !
    I will read the forum.
    I know that MUX can be a bit complicated so I was looking for a teensy with more input

  6. #6
    Senior Member oddson's Avatar
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    Well the T3.5 is 5 volt tolerant (if you do have to use 5v sensors etc. this can be a big advantage).

    It has a lot of inputs (something like) 40 readily available from a breadboard through single headers and a few extra if you need them from less accessible pins.

    It's already faster than any MIDI controller needs to be so don't bother with the T3.6 for a controller.

    The real advantage to Teensy for MIDI is Paul's USB support for class-compliant devices with no need for serial workarounds or other unnecessary complexity.

    I gather there's more options out there than when I found Teensy years ago but I suspect Paul's solution is still the best/smoothest out there. (Anyone know better what the options are like now?)

  7. #7
    Senior Member PaulStoffregen's Avatar
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    You can certainly get a lot of direct inputs (no mux chips) with Teensy 3.5 or 3.6, but the cost is higher for those boards. Still, might be worthwhile for the much simpler coding. Often non-electronic hardware & materials for a MIDI controller with so many buttons or knobs can add up to much more than the electronics... just something to keep in mind when considering if $15 more is worthwhile to make the coding side much easier.

    Another thing to consider is using multiple Teensy LC boards with a USB hub. One huge advantage of that approach is everything is much more modular and easier to troubleshoot if you make a mistake in wiring or something breaks with heavy use.

  8. #8
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    Ok so I think to buy the 3.5, I think it's a good way to start for me
    code is not so much a problem (even when it's works ahah)

    My live set up is already using some usb controller (Doepfer dark time, Ableton push, minilabs, and MF3D) so I have to minimize my usb input ^^

    Thank you for your answer
    Like this kind of forum where even none advanced users get answer !!

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