Audio System Design Tool

This wiki introduces how to use the Audio System Design Tool to design a audio system for Audio library using Wio Terminal and ReSpeaker 2-Mit Hat. This makes designing audio system much easier when you can see where the inputs and outputs are going.

This is a Seeed's fork of the Audio System Design Tool for Teensy Audio Library.

Getting Started

• Visit the Audio System Design Tool here. For more information about this, please also visit teensy.

• Once you are on the site, you should see all the available features of the Audio library to the left column.

• You can click on each class and see what are the available functions within each class and how to use them.

Designing an Audio System

Playing Music files from SD Card

Let's use walk through an example to get the basic of the Audio Design System. Let's say you want to simply play a song from the SD card via the speaker via ReSpeaker 2-Mic hat:

• INPUT is the play from SD card.

• OUTPUT is the I2S output.

• wm8960 is the control unit of the ReSpeaker 2-Mics.

So the design should look something like this:

• Click the Export on the top to export the Macros definitions for the system to paste to Arduino IDE.

Example Code

This example code uses the Macros definitions from the previously design system, plays music files from the SD card.

note

Please make sure that there are SDTEST1.wav, SDTEST2.wav, SDTEST3.wav and SDTEST4.wav music files in the MicroSD card in Wio Terminal.

#include <Audio.h>
#include <Wire.h>
#include <Seeed_FS.h>
#include "SD/Seeed_SD.h"

// GUItool: begin automatically generated code
AudioPlaySdWav           playSdWav1;     //xy=376,277
AudioOutputI2S           i2s1;           //xy=611,277
AudioConnection          patchCord1(playSdWav1, 0, i2s1, 0);
AudioConnection          patchCord2(playSdWav1, 1, i2s1, 1);
AudioControlWM8960       wm8960_1;       //xy=496,363
// GUItool: end automatically generated code

void setup() {
  Serial.begin(9600);
  while(!Serial);

  // Audio connections require memory to work.  For more
  // detailed information, see the MemoryAndCpuUsage example
  AudioMemory(8);

  wm8960_1.enable();
  wm8960_1.volume(0.7);

  while (!SD.begin(SDCARD_SS_PIN,SDCARD_SPI,10000000UL)) {
    Serial.println("Card Mount Failed");
    return;
  }
}

void playFile(const char *filename)
{
  Serial.print("Playing file: ");
  Serial.println(filename);
  // Start playing the file.  This sketch continues to
  // run while the file plays.
  playSdWav1.play(filename);
  // A brief delay for the library read WAV info
  delay(5);
  // Simply wait for the file to finish playing.
  while (playSdWav1.isPlaying()) {
  }
}

void loop() {
  playFile("SDTEST1.WAV");  // filenames are always uppercase 8.3 format
  delay(500);
  playFile("SDTEST2.WAV");
  delay(500);
  playFile("SDTEST3.WAV");
  delay(500);
  playFile("SDTEST4.WAV");
  delay(1500);
}

Peak Detection

Let's use the design tool to design a system for peak detection whilst playing the music from the SD card.

• INPUT is the play from SD card.

• OUTPUT is the I2S output and two peaks! One peak for left channel, and one peak for the right channel.

• wm8960 is the control unit of the ReSpeaker 2-Mics.

Example Code

Please check here.

Audio Spectrum Visualizer

This is the example of playing music from SD card whilst performing a FFT to get the frequency data for implementing an Audio Spectrum Visualizer.

• INPUT is the play from SD card.

• OUTPUT is the I2S output and FFT calculations.

• wm8960 is the control unit of the ReSpeaker 2-Mics.

Here we will introduce another useful feature, the Mixer. This allows you to combine max four audio channels into one. This is used as performing FFT to combined channels (left and right) is more accurate instead of single channel.

Example Code

Please check here.

Recording and Playing at Real-Time

This time let's design a system to record and play at real-time!

• INPUT is the recording from the mic: Input I2S -> RecordQueue

• OUTPUT is the I2S output. PlayQueue -> Output I2S

• wm8960 is the control unit of the ReSpeaker 2-Mics.

Example Code

Please check here.