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Thread: Teensy 4.0 modular platform

  1. #1
    Member ghostintranslation's Avatar
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    Teensy 4.0 modular platform

    Hi,

    About a year ago I posted here to show the very first version of my work.

    Now I have a pretty stable platform, but I'd like to hear any ideas how to improve quality of the electronics, or even the concept itself.

    The platform I made is in the Eurorack physical format, but it uses midi which is connected on the back of the modules to avoid the classic Eurorack spaghetti.

    I have made 3 versions of what I call Motherboards, the bases of any modules: Motherboard6 has 6 controls, Motherboard9 has 9 controls, and Motherboard12 has 12 controls.

    But it's not that simple, the PCBs allow to solder either a potentiometer, or a rotary encoder, or a push button for each control. The PCB is modular itself basically.
    That means it's meant to handle all these types of inputs and it gives the ability to reuse the same PCB to build different modules, then it's just a matter of making a front panel.

    To be able to use the Audio Board, that means a very limited number of inputs are available on Teensy. And I had to deal with a lot of inputs, up to 12 controls but because I allow for rotary encoders that means 12 * 3 = 36 inputs, and also some analog some not, and also a dipswitch to select a MIDI channel, and up to 12 LEDs. So in order to deal with all of these I use multiplexers all connected to 1 main multiplexer. That means on Teensy there is only 1 pin receiving inputs and outputing for the LEDs, and luckily it switches fast enough. I also use a matrix to reduce the number of multiplexers required.

    On the code side, because the 3 are very similar, I made a class that is almost identical for each of them which handles the inputs and outputs and abstracts all the low level work. Then when I want to make a new module I don't have to think again about how to get the value of the rotary encoder number 3 basically, I can just get its value and handle the logic of the module instead. That makes making modules very easy.

    With that flexibility I have made a few modules already.

    They communicate via midi, which is directly connected to the Teensy serial in and out. Which I know means in case I want to connect something else than Teensy I have to be careful of the power applied to the pin.

    See the schematics and code of the 3 Motherboards here:
    https://github.com/ghostintranslation/motherboard6
    https://github.com/ghostintranslation/motherboard9
    https://github.com/ghostintranslation/motherboard12

    And the modules I made based on these 3 Motherboards:
    https://github.com/ghostintranslation/synth
    https://github.com/ghostintranslation/drone
    https://github.com/ghostintranslation/ds909
    https://github.com/ghostintranslation/psyc03
    https://github.com/ghostintranslation/cycle
    https://github.com/ghostintranslation/byte

    You can see photos in those GitHub links too to have an idea of what it looks like, if you want to see videos I would suggest you to look at my Instagram:
    https://www.instagram.com/ghostintranslation

    So far I used only through hole components to keep it simple so people with not too much soldering practice can try it, and they did I got some good feedback so far.

    But in the next big version increment I think I'll embrace fully SMD to be able to use chips like the Cirrus Logic CS42448 to add 8 audio outputs, and the PCA9685 to handle the LEDs, and 16:1 multiplexers to keep it small.
    In the future version I also plan on adding an optocoupler for the MIDI In.

    So if you have any ideas, or comments... if you see something bad in the schematics, tell me

  2. #2
    Senior Member+ Frank B's Avatar
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    Nice boards!
    Are the gerber files available?

  3. #3
    Member ghostintranslation's Avatar
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    Quote Originally Posted by Frank B View Post
    Nice boards!
    Are the gerber files available?
    Thanks,

    I sell the boards to help me with the cost of engineering all this, so I haven't shared the Gerber files yet, but I intend to open source everything so I give all the schematics and code. With time I will also share the Gerber for sure.

  4. #4
    Senior Member+ Frank B's Avatar
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    No problem!
    I'm going to ask my son wether he has time and wants to build something. Personally, I've never done anything with midi, and I can't play any instrument, but my son may be interested in a project for the holidays.
    Shipping from canada will take some time, though..

    DO you know a good beginner project ("Beginner" in terms of midi-music-equipment) - As far as I know he has a midi-capable keyboard, not more.

  5. #5
    Member ghostintranslation's Avatar
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    Quote Originally Posted by Frank B View Post
    No problem!
    I'm going to ask my son wether he has time and wants to build something. Personally, I've never done anything with midi, and I can't play any instrument, but my son may be interested in a project for the holidays.
    Shipping from canada will take some time, though..

    DO you know a good beginner project ("Beginner" in terms of midi-music-equipment) - As far as I know he has a midi-capable keyboard, not more.
    Shipping takes a good 2 weeks to Europe, maybe 3 this time of the year.

    I'd say it's pretty easy, there are only through hole components and not a big list of them. Just make sure to read the documentation I provide on GitHub for a complete components list and for other useful informations.

  6. #6
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    Hi ghostintranslation,

    I checked out your projects and they are very noteworthy. I appreciate the modular approach. This is a great way to do something like this where you want to make things simple and expandable. If I have a need for a controller in this format I'll definitely keep your project in mind.

    As someone who also has and is continuing to develop some music related modules for the Teensy, I can say I know how much time you've spent on this. I hope you find some people to buy your products so you can continue on your journey. Great work, keep it up.

    Jay

    PS - do you have a tindie setup yet? I don't, not yet.

  7. #7
    Member ghostintranslation's Avatar
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    Quote Originally Posted by JayShoe View Post
    Hi ghostintranslation,

    I checked out your projects and they are very noteworthy. I appreciate the modular approach. This is a great way to do something like this where you want to make things simple and expandable. If I have a need for a controller in this format I'll definitely keep your project in mind.

    As someone who also has and is continuing to develop some music related modules for the Teensy, I can say I know how much time you've spent on this. I hope you find some people to buy your products so you can continue on your journey. Great work, keep it up.

    Jay

    PS - do you have a tindie setup yet? I don't, not yet.
    Thank you I appreciate that,
    I didn't know about Tindie actually I just googled it and it looks interesting, thanks for the tip

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