I deleted the src folder I was referencing before entirely. The sketch now compiles. That doesn't make any sense to me, since if I'm not referencing anything in that folder, how could it interfere?
But anyway, it seems to work perfectly now. I think the only significant difference here from before is the version library.
I'll run some tests to gather evidence for this hypothesis.
Glad to hear it. So can we treat this as Solved?
But once again we don't have your final sketch. Nor an answer to my questiion.
Let's not count it as solved just yet. Many times I have believed to find the cause of an issue only to be mistaken.
My current sketch I am testing is now precisely copy and pasted from yours.
My final sketch is part of a larger project that implements the DFPlayer. I will next update it with the new code (and newer library). After I do that I can share it and also report on how well it is working.
My included zip libraries are sent to C:\Users\Name\Documents\Arduino\libraries
So are all your sketches here?
C:\Users\Name\Documents\Arduino\
No. Just the libraries. I should probably keep sketches in the directory I'm specifying as well.
I suggest you read up on how to install and manage libraries.
And, looking back at your original post 11 days ago, I think we can regard that solved by post #18. As you said: "But anyway, it seems to work perfectly now."
When you are able to be more specific about your latest question ('hypothesis'), then start a fresh thread.
Sadly, I've had a lot of nightmarish experiences working with Arduino where something will work perfectly one moment and then suddenly stop for no discernible reason. I'm currently experiencing that very phenomenon here with RFID sensors here: Help with RFID Sensors - #18 by dwwelch where I've spent weeks trying chasing the reason behind why it sometimes works and sometimes doesn't.
It starts with organization, which you are not doing. Then when you need help, cooperation. You showed neither. Not one sketch posted. Now you are on to another subject inside a totally different topic. Organization. Cooperation. Start now.