Awesome sauce.
Robin2 - I think that "Planning" post you created is exactly what I'm looking. In fact I'm already implementing the empty functions and a "signalData" 2D array in my next iteration. There's a lot of good info in your post, and that first bit about hacking from old tutorial files rings true. I'm taking my time going thru it.
I want to use the Millis interval check just to get the practice of using it, but for my purpose seems overly complex. As I understand it, the millis interval check is great for doing processes simultaneously, but for this project I execute one process at a time.
@DrDiettrich - Task Macros? First I'd ever heard of those. Are they similar to a library/collection that one imports into the sketch? I like the idea of Easy-to-read. If you could point me to a beginners guide to that I'd appreciate it. I did a quick search, but that quickly started to veer. I definitely need the sound signals to abort during play. My plan is to have one button to cycle thru the playout signals, and since each of those take at least 1 minute to play they need to cut out.
The idea is that our fearless solo sailor will flip this on, set the signal and it auto plays, then get back on the tiller and sail sheets, and keep an eye out for other boats.
As for exactness, @thegoodhen, not even a little bit. Normally this task is carried out by a crew member holding an airhorn, looking all around and hopefully remembering to blow the horn sometime before 2 minutes expires. Though that does give me an idea. Depending on how crowded the port is, one might want to increase the frequency of sounding signals. So I'll add a multiplier POT variable.
Good stuff I'm learning a lot. Mostly still the simple things like syntax at this point, but even learning concepts--if you nest a "for loop" in a "while loop", you need to break out of both to get out immediately. I highly recommend that website circuits.io to build little test circuit/sketches.