Add a second button to inject a MIDI marker

[Pomax]

that way you can go "oh that bit was particularly sweet, click" and then move on again.

[Pomax]

This involved injecting a <delta> FF 06 <byte length> <ASCII bytes>, and because folks won't be able to type anything, let's make that a simple number that starts at 1?

[Pomax]

Time to update the post.

circuit:

identical to beep button

code

#define PLACE_MARKER_PIN 4
int lastMarkState = 0;
int nextMarker = 1;

...

void loop() {
  checkForMarker();
}

void checkForMarker() {
  int markState = digitalRead(PLACE_MARKER_PIN);
  if (markState  != lastMarkState) {
    lastMarkState = markState;
    if (markState == 1) {
      writeMidiMarker();
    }
  }
}

void writeMidiMarker() {
  if (!file) return;

  // delta + op code
  writeVarLen(file, getDelta());
  file.write(0xFF);
  file.write(0x06);

  // how many bytes are we writing?
  byte len = 1;
  if (nextMarker > 9) len++;
  if (nextMarker > 99) len++;
  if (nextMarker > 999) len++;
  file.write(len);

  // our label:
  byte marker[len];
  String(nextMarker++).getBytes(marker, len);
  file.write(marker, len);
}

screenshot

[Pomax]

landed