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Thread: Teensy Audio without audioshield

  1. #1
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    Teensy Audio without audioshield

    Good day everyone,

    MY first post here.

    So i've been looking to use teensy as an audio filter but what I've seen so far from my search shows an audioshield involved in the process. I'm still trying to understand everything and I guess If i did i'd know whether or not I could forego the audioshield to do what I want to accomplish.

    Mic->Op amp -> Teensy Filter -> Interpret information.
    Last edited by donperryjm; 01-10-2019 at 09:42 PM.

  2. #2
    Senior Member+ Theremingenieur's Avatar
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    Reading the exhaustive documentation of the audio library (pdf, tutorial video, and GUI design tool) on the PJRC website will tell you that you can use the audio library without the audio shield. The audio libray works with the internal ADCs and DAC(s) of the Teensy 3.x MCUs, too, as long as your use case is fine with 12bit resolution.

  3. #3
    Senior Member+ Frank B's Avatar
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    The shield is not that expensive.. and gives you great quality sound.

  4. #4
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    Hey frank, thanks for replying.

    Expense is not as much of an issue as real estate.

    I tried following the video and it seems to have a set path outside of which I'd like to go - the audio shield. It's kinda hard to imagine how to get things going without the audio shield. I'm drawn to teensy and purchased one because of the arduino env that i'm familiar with

  5. #5
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    I found this link. Will explore and come back if something isn't clear. I'm not looking for spoonfeeding, just directions thanks again

    https://forum.pjrc.com/threads/42981...n-audio-shield

  6. #6
    Senior Member
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    Quote Originally Posted by donperryjm View Post
    Mic->Op amp -> Teensy Filter -> Interpret information.
    I'd go with an I2S microphone like: https://www.tindie.com/products/oneh...al-microphone/
    This will give you digital input direct from the MEMS mic to the Teensy. No Op Amp or other analog signal chain required.

    How will you "Interpret information"?

  7. #7
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    OK. a digital mic is not an option as i'm applying it to an existing hardware.

    I want to see the amplitude of the sound after the frequency is filtered.


    Code:
    #include <Audio.h>
    #include <Wire.h>
    #include <SPI.h>
    #include <SD.h>
    #include <SerialFlash.h>
    
    // GUItool: begin automatically generated code
    AudioInputAnalog         adc1;           //xy=283,132
    AudioFilterBiquad        biquad1;        //xy=451.00000762939453,142.00000095367432
    AudioAmplifier           amp1;           //xy=680.0000076293945,164.00000190734863
    AudioConnection          patchCord1(adc1, biquad1);
    AudioConnection          patchCord2(biquad1, amp1);
    // GUItool: end automatically generated code
    
    void setup() {
      // put your setup code here, to run once:
    AudioNoInterrupts();
    AudioMemory(16);
    audioShield.enable();
    
    
    
    
    
    AudioInterrupts();
    }
    
    void loop() {
      // put your main code here, to run repeatedly:
    
    }

  8. #8
    Junior Member
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    OK So i'm looking in the designer and I see they point to some example in the arduino that I cannot find. I see other teensy examples but not the audio examples. Is there somwhere to download them?

    Edit, i found the github https://github.com/PaulStoffregen/Au...kMeterMono.ino

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