Embedded audio playback controller

Firmware flow

Trigger SD playback from two microphone inputs

Selected playback branches from a Teensy audio firmware variant; the microphone levels and current time are read earlier in the loop.

The two input checks run in order and can both trigger during one loop iteration. Each eligible input stops its player if necessary, requests the corresponding WAV file and stores a new cooldown timestamp.

The checks use signal level, not rising-edge detection. A sustained input above threshold can retrigger after each cooldown. The return value from play() is not checked, so the calls establish playback requests rather than confirmed sound output.

  // Mic A triggers B.wav on Left output
  if (lvlA > THRESHOLD && now - lastA >= COOLDOWN) {
    Serial.println(">> Trigger: Mic A detected vibration → playing B.WAV on Left");
    if (playA.isPlaying()) playA.stop();
    playA.play("B.WAV");
    lastA = now;
  }

  // Mic B triggers A.wav on Right output
  if (lvlB > THRESHOLD && now - lastB >= COOLDOWN) {
    Serial.println(">> Trigger: Mic B detected vibration → playing A.WAV on Right");
    if (playB.isPlaying()) playB.stop();
    playB.play("A.WAV");
    lastB = now;
  }